mmu.c 57.1 KB
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/*
 * Xen mmu operations
 *
 * This file contains the various mmu fetch and update operations.
 * The most important job they must perform is the mapping between the
 * domain's pfn and the overall machine mfns.
 *
 * Xen allows guests to directly update the pagetable, in a controlled
 * fashion.  In other words, the guest modifies the same pagetable
 * that the CPU actually uses, which eliminates the overhead of having
 * a separate shadow pagetable.
 *
 * In order to allow this, it falls on the guest domain to map its
 * notion of a "physical" pfn - which is just a domain-local linear
 * address - into a real "machine address" which the CPU's MMU can
 * use.
 *
 * A pgd_t/pmd_t/pte_t will typically contain an mfn, and so can be
 * inserted directly into the pagetable.  When creating a new
 * pte/pmd/pgd, it converts the passed pfn into an mfn.  Conversely,
 * when reading the content back with __(pgd|pmd|pte)_val, it converts
 * the mfn back into a pfn.
 *
 * The other constraint is that all pages which make up a pagetable
 * must be mapped read-only in the guest.  This prevents uncontrolled
 * guest updates to the pagetable.  Xen strictly enforces this, and
 * will disallow any pagetable update which will end up mapping a
 * pagetable page RW, and will disallow using any writable page as a
 * pagetable.
 *
 * Naively, when loading %cr3 with the base of a new pagetable, Xen
 * would need to validate the whole pagetable before going on.
 * Naturally, this is quite slow.  The solution is to "pin" a
 * pagetable, which enforces all the constraints on the pagetable even
 * when it is not actively in use.  This menas that Xen can be assured
 * that it is still valid when you do load it into %cr3, and doesn't
 * need to revalidate it.
 *
 * Jeremy Fitzhardinge <jeremy@xensource.com>, XenSource Inc, 2007
 */
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#include <linux/sched.h>
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#include <linux/highmem.h>
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#include <linux/debugfs.h>
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#include <linux/bug.h>
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#include <linux/vmalloc.h>
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#include <linux/module.h>
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#include <linux/gfp.h>
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#include <asm/pgtable.h>
#include <asm/tlbflush.h>
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#include <asm/fixmap.h>
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#include <asm/mmu_context.h>
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#include <asm/setup.h>
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#include <asm/paravirt.h>
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#include <asm/e820.h>
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#include <asm/linkage.h>
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#include <asm/page.h>
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#include <asm/xen/hypercall.h>
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#include <asm/xen/hypervisor.h>
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#include <xen/xen.h>
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#include <xen/page.h>
#include <xen/interface/xen.h>
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#include <xen/interface/hvm/hvm_op.h>
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#include <xen/interface/version.h>
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#include <xen/interface/memory.h>
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#include <xen/hvc-console.h>
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#include "multicalls.h"
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#include "mmu.h"
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#include "debugfs.h"

#define MMU_UPDATE_HISTO	30

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/*
 * Protects atomic reservation decrease/increase against concurrent increases.
 * Also protects non-atomic updates of current_pages and driver_pages, and
 * balloon lists.
 */
DEFINE_SPINLOCK(xen_reservation_lock);

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#ifdef CONFIG_XEN_DEBUG_FS

static struct {
	u32 pgd_update;
	u32 pgd_update_pinned;
	u32 pgd_update_batched;

	u32 pud_update;
	u32 pud_update_pinned;
	u32 pud_update_batched;

	u32 pmd_update;
	u32 pmd_update_pinned;
	u32 pmd_update_batched;

	u32 pte_update;
	u32 pte_update_pinned;
	u32 pte_update_batched;

	u32 mmu_update;
	u32 mmu_update_extended;
	u32 mmu_update_histo[MMU_UPDATE_HISTO];

	u32 prot_commit;
	u32 prot_commit_batched;

	u32 set_pte_at;
	u32 set_pte_at_batched;
	u32 set_pte_at_pinned;
	u32 set_pte_at_current;
	u32 set_pte_at_kernel;
} mmu_stats;

static u8 zero_stats;

static inline void check_zero(void)
{
	if (unlikely(zero_stats)) {
		memset(&mmu_stats, 0, sizeof(mmu_stats));
		zero_stats = 0;
	}
}

#define ADD_STATS(elem, val)			\
	do { check_zero(); mmu_stats.elem += (val); } while(0)

#else  /* !CONFIG_XEN_DEBUG_FS */

#define ADD_STATS(elem, val)	do { (void)(val); } while(0)

#endif /* CONFIG_XEN_DEBUG_FS */
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/*
 * Identity map, in addition to plain kernel map.  This needs to be
 * large enough to allocate page table pages to allocate the rest.
 * Each page can map 2MB.
 */
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#define LEVEL1_IDENT_ENTRIES	(PTRS_PER_PTE * 4)
static RESERVE_BRK_ARRAY(pte_t, level1_ident_pgt, LEVEL1_IDENT_ENTRIES);
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#ifdef CONFIG_X86_64
/* l3 pud for userspace vsyscall mapping */
static pud_t level3_user_vsyscall[PTRS_PER_PUD] __page_aligned_bss;
#endif /* CONFIG_X86_64 */

/*
 * Note about cr3 (pagetable base) values:
 *
 * xen_cr3 contains the current logical cr3 value; it contains the
 * last set cr3.  This may not be the current effective cr3, because
 * its update may be being lazily deferred.  However, a vcpu looking
 * at its own cr3 can use this value knowing that it everything will
 * be self-consistent.
 *
 * xen_current_cr3 contains the actual vcpu cr3; it is set once the
 * hypercall to set the vcpu cr3 is complete (so it may be a little
 * out of date, but it will never be set early).  If one vcpu is
 * looking at another vcpu's cr3 value, it should use this variable.
 */
DEFINE_PER_CPU(unsigned long, xen_cr3);	 /* cr3 stored as physaddr */
DEFINE_PER_CPU(unsigned long, xen_current_cr3);	 /* actual vcpu cr3 */


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/*
 * Just beyond the highest usermode address.  STACK_TOP_MAX has a
 * redzone above it, so round it up to a PGD boundary.
 */
#define USER_LIMIT	((STACK_TOP_MAX + PGDIR_SIZE - 1) & PGDIR_MASK)

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static unsigned long max_p2m_pfn __read_mostly = MAX_DOMAIN_PAGES;
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#define P2M_ENTRIES_PER_PAGE		(PAGE_SIZE / sizeof(unsigned long))
#define TOP_ENTRIES(pages)		((pages) / P2M_ENTRIES_PER_PAGE)
#define MAX_TOP_ENTRIES			TOP_ENTRIES(MAX_DOMAIN_PAGES)
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/* Placeholder for holes in the address space */
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static RESERVE_BRK_ARRAY(unsigned long, p2m_missing, P2M_ENTRIES_PER_PAGE);
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 /* Array of pointers to pages containing p2m entries */
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static RESERVE_BRK_ARRAY(unsigned long *, p2m_top, MAX_TOP_ENTRIES);
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/* Arrays of p2m arrays expressed in mfns used for save/restore */
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static RESERVE_BRK_ARRAY(unsigned long, p2m_top_mfn, MAX_TOP_ENTRIES);
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static RESERVE_BRK_ARRAY(unsigned long, p2m_top_mfn_list,
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			 (MAX_TOP_ENTRIES / P2M_ENTRIES_PER_PAGE));
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static inline unsigned p2m_top_index(unsigned long pfn)
{
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	BUG_ON(pfn >= max_p2m_pfn);
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	return pfn / P2M_ENTRIES_PER_PAGE;
}

static inline unsigned p2m_index(unsigned long pfn)
{
	return pfn % P2M_ENTRIES_PER_PAGE;
}

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/* Build the parallel p2m_top_mfn structures */
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void xen_build_mfn_list_list(void)
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{
	unsigned pfn, idx;

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	for (pfn = 0; pfn < max_p2m_pfn; pfn += P2M_ENTRIES_PER_PAGE) {
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		unsigned topidx = p2m_top_index(pfn);

		p2m_top_mfn[topidx] = virt_to_mfn(p2m_top[topidx]);
	}

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	for (idx = 0;
	     idx < TOP_ENTRIES(max_p2m_pfn)/P2M_ENTRIES_PER_PAGE;
	     idx++) {
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		unsigned topidx = idx * P2M_ENTRIES_PER_PAGE;
		p2m_top_mfn_list[idx] = virt_to_mfn(&p2m_top_mfn[topidx]);
	}
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}
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void xen_setup_mfn_list_list(void)
{
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	BUG_ON(HYPERVISOR_shared_info == &xen_dummy_shared_info);

	HYPERVISOR_shared_info->arch.pfn_to_mfn_frame_list_list =
		virt_to_mfn(p2m_top_mfn_list);
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	HYPERVISOR_shared_info->arch.max_pfn = max_p2m_pfn;
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}

/* Set up p2m_top to point to the domain-builder provided p2m pages */
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void __init xen_build_dynamic_phys_to_machine(void)
{
	unsigned long *mfn_list = (unsigned long *)xen_start_info->mfn_list;
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	unsigned long max_pfn = min(MAX_DOMAIN_PAGES, xen_start_info->nr_pages);
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	unsigned pfn;
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	unsigned i;

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	max_p2m_pfn = max_pfn;

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	p2m_missing = extend_brk(sizeof(*p2m_missing) * P2M_ENTRIES_PER_PAGE,
				 PAGE_SIZE);
	for (i = 0; i < P2M_ENTRIES_PER_PAGE; i++)
		p2m_missing[i] = ~0UL;

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	p2m_top = extend_brk(sizeof(*p2m_top) * TOP_ENTRIES(max_pfn),
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			     PAGE_SIZE);
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	for (i = 0; i < TOP_ENTRIES(max_pfn); i++)
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		p2m_top[i] = p2m_missing;

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	p2m_top_mfn = extend_brk(sizeof(*p2m_top_mfn) * TOP_ENTRIES(max_pfn),
				 PAGE_SIZE);
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	p2m_top_mfn_list = extend_brk(sizeof(*p2m_top_mfn_list) *
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				      (TOP_ENTRIES(max_pfn) / P2M_ENTRIES_PER_PAGE),
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				      PAGE_SIZE);
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	for (pfn = 0; pfn < max_pfn; pfn += P2M_ENTRIES_PER_PAGE) {
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		unsigned topidx = p2m_top_index(pfn);

		p2m_top[topidx] = &mfn_list[pfn];
	}
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	xen_build_mfn_list_list();
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}

unsigned long get_phys_to_machine(unsigned long pfn)
{
	unsigned topidx, idx;

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	if (unlikely(pfn >= max_p2m_pfn))
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		return INVALID_P2M_ENTRY;

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	topidx = p2m_top_index(pfn);
	idx = p2m_index(pfn);
	return p2m_top[topidx][idx];
}
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EXPORT_SYMBOL_GPL(get_phys_to_machine);
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/* install a  new p2m_top page */
bool install_p2mtop_page(unsigned long pfn, unsigned long *p)
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{
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	unsigned topidx = p2m_top_index(pfn);
	unsigned long **pfnp, *mfnp;
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	unsigned i;

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	pfnp = &p2m_top[topidx];
	mfnp = &p2m_top_mfn[topidx];
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	for (i = 0; i < P2M_ENTRIES_PER_PAGE; i++)
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		p[i] = INVALID_P2M_ENTRY;

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	if (cmpxchg(pfnp, p2m_missing, p) == p2m_missing) {
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		*mfnp = virt_to_mfn(p);
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		return true;
	}

	return false;
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}

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static void alloc_p2m(unsigned long pfn)
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{
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	unsigned long *p;
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	p = (void *)__get_free_page(GFP_KERNEL | __GFP_NOFAIL);
	BUG_ON(p == NULL);

	if (!install_p2mtop_page(pfn, p))
		free_page((unsigned long)p);
}

/* Try to install p2m mapping; fail if intermediate bits missing */
bool __set_phys_to_machine(unsigned long pfn, unsigned long mfn)
{
	unsigned topidx, idx;
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	if (unlikely(pfn >= max_p2m_pfn)) {
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		BUG_ON(mfn != INVALID_P2M_ENTRY);
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		return true;
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	}

	topidx = p2m_top_index(pfn);
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	if (p2m_top[topidx] == p2m_missing) {
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		if (mfn == INVALID_P2M_ENTRY)
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			return true;
		return false;
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	}

	idx = p2m_index(pfn);
	p2m_top[topidx][idx] = mfn;
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	return true;
}

void set_phys_to_machine(unsigned long pfn, unsigned long mfn)
{
	if (unlikely(xen_feature(XENFEAT_auto_translated_physmap))) {
		BUG_ON(pfn != mfn && mfn != INVALID_P2M_ENTRY);
		return;
	}

	if (unlikely(!__set_phys_to_machine(pfn, mfn)))  {
		alloc_p2m(pfn);

		if (!__set_phys_to_machine(pfn, mfn))
			BUG();
	}
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}

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unsigned long arbitrary_virt_to_mfn(void *vaddr)
{
	xmaddr_t maddr = arbitrary_virt_to_machine(vaddr);

	return PFN_DOWN(maddr.maddr);
}

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xmaddr_t arbitrary_virt_to_machine(void *vaddr)
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{
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	unsigned long address = (unsigned long)vaddr;
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	unsigned int level;
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	pte_t *pte;
	unsigned offset;
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	/*
	 * if the PFN is in the linear mapped vaddr range, we can just use
	 * the (quick) virt_to_machine() p2m lookup
	 */
	if (virt_addr_valid(vaddr))
		return virt_to_machine(vaddr);

	/* otherwise we have to do a (slower) full page-table walk */
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	pte = lookup_address(address, &level);
	BUG_ON(pte == NULL);
	offset = address & ~PAGE_MASK;
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	return XMADDR(((phys_addr_t)pte_mfn(*pte) << PAGE_SHIFT) + offset);
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}

void make_lowmem_page_readonly(void *vaddr)
{
	pte_t *pte, ptev;
	unsigned long address = (unsigned long)vaddr;
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	unsigned int level;
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	pte = lookup_address(address, &level);
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	BUG_ON(pte == NULL);

	ptev = pte_wrprotect(*pte);

	if (HYPERVISOR_update_va_mapping(address, ptev, 0))
		BUG();
}

void make_lowmem_page_readwrite(void *vaddr)
{
	pte_t *pte, ptev;
	unsigned long address = (unsigned long)vaddr;
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	unsigned int level;
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	pte = lookup_address(address, &level);
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	BUG_ON(pte == NULL);

	ptev = pte_mkwrite(*pte);

	if (HYPERVISOR_update_va_mapping(address, ptev, 0))
		BUG();
}


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static bool xen_page_pinned(void *ptr)
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{
	struct page *page = virt_to_page(ptr);

	return PagePinned(page);
}

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static bool xen_iomap_pte(pte_t pte)
{
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	return pte_flags(pte) & _PAGE_IOMAP;
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}

static void xen_set_iomap_pte(pte_t *ptep, pte_t pteval)
{
	struct multicall_space mcs;
	struct mmu_update *u;

	mcs = xen_mc_entry(sizeof(*u));
	u = mcs.args;

	/* ptep might be kmapped when using 32-bit HIGHPTE */
	u->ptr = arbitrary_virt_to_machine(ptep).maddr;
	u->val = pte_val_ma(pteval);

	MULTI_mmu_update(mcs.mc, mcs.args, 1, NULL, DOMID_IO);

	xen_mc_issue(PARAVIRT_LAZY_MMU);
}

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static void xen_extend_mmu_update(const struct mmu_update *update)
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{
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	struct multicall_space mcs;
	struct mmu_update *u;
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	mcs = xen_mc_extend_args(__HYPERVISOR_mmu_update, sizeof(*u));

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	if (mcs.mc != NULL) {
		ADD_STATS(mmu_update_extended, 1);
		ADD_STATS(mmu_update_histo[mcs.mc->args[1]], -1);

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		mcs.mc->args[1]++;
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		if (mcs.mc->args[1] < MMU_UPDATE_HISTO)
			ADD_STATS(mmu_update_histo[mcs.mc->args[1]], 1);
		else
			ADD_STATS(mmu_update_histo[0], 1);
	} else {
		ADD_STATS(mmu_update, 1);
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		mcs = __xen_mc_entry(sizeof(*u));
		MULTI_mmu_update(mcs.mc, mcs.args, 1, NULL, DOMID_SELF);
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		ADD_STATS(mmu_update_histo[1], 1);
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	}
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	u = mcs.args;
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	*u = *update;
}

void xen_set_pmd_hyper(pmd_t *ptr, pmd_t val)
{
	struct mmu_update u;

	preempt_disable();

	xen_mc_batch();

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	/* ptr may be ioremapped for 64-bit pagetable setup */
	u.ptr = arbitrary_virt_to_machine(ptr).maddr;
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	u.val = pmd_val_ma(val);
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	xen_extend_mmu_update(&u);
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	ADD_STATS(pmd_update_batched, paravirt_get_lazy_mode() == PARAVIRT_LAZY_MMU);

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	xen_mc_issue(PARAVIRT_LAZY_MMU);

	preempt_enable();
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}

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void xen_set_pmd(pmd_t *ptr, pmd_t val)
{
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	ADD_STATS(pmd_update, 1);

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	/* If page is not pinned, we can just update the entry
	   directly */
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	if (!xen_page_pinned(ptr)) {
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		*ptr = val;
		return;
	}

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	ADD_STATS(pmd_update_pinned, 1);

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	xen_set_pmd_hyper(ptr, val);
}

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/*
 * Associate a virtual page frame with a given physical page frame
 * and protection flags for that frame.
 */
void set_pte_mfn(unsigned long vaddr, unsigned long mfn, pgprot_t flags)
{
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	set_pte_vaddr(vaddr, mfn_pte(mfn, flags));
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}

void xen_set_pte_at(struct mm_struct *mm, unsigned long addr,
		    pte_t *ptep, pte_t pteval)
{
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	if (xen_iomap_pte(pteval)) {
		xen_set_iomap_pte(ptep, pteval);
		goto out;
	}

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	ADD_STATS(set_pte_at, 1);
//	ADD_STATS(set_pte_at_pinned, xen_page_pinned(ptep));
	ADD_STATS(set_pte_at_current, mm == current->mm);
	ADD_STATS(set_pte_at_kernel, mm == &init_mm);

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	if (mm == current->mm || mm == &init_mm) {
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		if (paravirt_get_lazy_mode() == PARAVIRT_LAZY_MMU) {
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			struct multicall_space mcs;
			mcs = xen_mc_entry(0);

			MULTI_update_va_mapping(mcs.mc, addr, pteval, 0);
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			ADD_STATS(set_pte_at_batched, 1);
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			xen_mc_issue(PARAVIRT_LAZY_MMU);
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			goto out;
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		} else
			if (HYPERVISOR_update_va_mapping(addr, pteval, 0) == 0)
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				goto out;
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	}
	xen_set_pte(ptep, pteval);
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out:	return;
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}

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pte_t xen_ptep_modify_prot_start(struct mm_struct *mm,
				 unsigned long addr, pte_t *ptep)
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{
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	/* Just return the pte as-is.  We preserve the bits on commit */
	return *ptep;
}

void xen_ptep_modify_prot_commit(struct mm_struct *mm, unsigned long addr,
				 pte_t *ptep, pte_t pte)
{
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	struct mmu_update u;
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	xen_mc_batch();
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	u.ptr = arbitrary_virt_to_machine(ptep).maddr | MMU_PT_UPDATE_PRESERVE_AD;
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	u.val = pte_val_ma(pte);
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	xen_extend_mmu_update(&u);
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559 560 561
	ADD_STATS(prot_commit, 1);
	ADD_STATS(prot_commit_batched, paravirt_get_lazy_mode() == PARAVIRT_LAZY_MMU);

562
	xen_mc_issue(PARAVIRT_LAZY_MMU);
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563 564
}

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565 566
/* Assume pteval_t is equivalent to all the other *val_t types. */
static pteval_t pte_mfn_to_pfn(pteval_t val)
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567
{
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568
	if (val & _PAGE_PRESENT) {
569
		unsigned long mfn = (val & PTE_PFN_MASK) >> PAGE_SHIFT;
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570
		pteval_t flags = val & PTE_FLAGS_MASK;
571
		val = ((pteval_t)mfn_to_pfn(mfn) << PAGE_SHIFT) | flags;
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572
	}
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573

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574
	return val;
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575 576
}

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577
static pteval_t pte_pfn_to_mfn(pteval_t val)
J
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578
{
J
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579
	if (val & _PAGE_PRESENT) {
580
		unsigned long pfn = (val & PTE_PFN_MASK) >> PAGE_SHIFT;
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581
		pteval_t flags = val & PTE_FLAGS_MASK;
582
		val = ((pteval_t)pfn_to_mfn(pfn) << PAGE_SHIFT) | flags;
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583 584
	}

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585
	return val;
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}

588 589 590 591 592 593 594 595 596 597 598 599 600 601
static pteval_t iomap_pte(pteval_t val)
{
	if (val & _PAGE_PRESENT) {
		unsigned long pfn = (val & PTE_PFN_MASK) >> PAGE_SHIFT;
		pteval_t flags = val & PTE_FLAGS_MASK;

		/* We assume the pte frame number is a MFN, so
		   just use it as-is. */
		val = ((pteval_t)pfn << PAGE_SHIFT) | flags;
	}

	return val;
}

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602
pteval_t xen_pte_val(pte_t pte)
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603
{
604 605 606
	if (xen_initial_domain() && (pte.pte & _PAGE_IOMAP))
		return pte.pte;

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607
	return pte_mfn_to_pfn(pte.pte);
J
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608
}
609
PV_CALLEE_SAVE_REGS_THUNK(xen_pte_val);
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610 611 612

pgdval_t xen_pgd_val(pgd_t pgd)
{
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613
	return pte_mfn_to_pfn(pgd.pgd);
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614
}
615
PV_CALLEE_SAVE_REGS_THUNK(xen_pgd_val);
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616 617 618

pte_t xen_make_pte(pteval_t pte)
{
619 620 621 622 623 624 625 626 627 628
	phys_addr_t addr = (pte & PTE_PFN_MASK);

	/*
	 * Unprivileged domains are allowed to do IOMAPpings for
	 * PCI passthrough, but not map ISA space.  The ISA
	 * mappings are just dummy local mappings to keep other
	 * parts of the kernel happy.
	 */
	if (unlikely(pte & _PAGE_IOMAP) &&
	    (xen_initial_domain() || addr >= ISA_END_ADDRESS)) {
629
		pte = iomap_pte(pte);
630 631
	} else {
		pte &= ~_PAGE_IOMAP;
632
		pte = pte_pfn_to_mfn(pte);
633
	}
634

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635
	return native_make_pte(pte);
J
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636
}
637
PV_CALLEE_SAVE_REGS_THUNK(xen_make_pte);
J
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638 639 640

pgd_t xen_make_pgd(pgdval_t pgd)
{
J
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641 642
	pgd = pte_pfn_to_mfn(pgd);
	return native_make_pgd(pgd);
J
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643
}
644
PV_CALLEE_SAVE_REGS_THUNK(xen_make_pgd);
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645 646 647

pmdval_t xen_pmd_val(pmd_t pmd)
{
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648
	return pte_mfn_to_pfn(pmd.pmd);
J
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649
}
650
PV_CALLEE_SAVE_REGS_THUNK(xen_pmd_val);
651

652
void xen_set_pud_hyper(pud_t *ptr, pud_t val)
653
{
654
	struct mmu_update u;
655

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656 657
	preempt_disable();

658 659
	xen_mc_batch();

660 661
	/* ptr may be ioremapped for 64-bit pagetable setup */
	u.ptr = arbitrary_virt_to_machine(ptr).maddr;
662
	u.val = pud_val_ma(val);
663
	xen_extend_mmu_update(&u);
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664

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665 666
	ADD_STATS(pud_update_batched, paravirt_get_lazy_mode() == PARAVIRT_LAZY_MMU);

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667 668 669
	xen_mc_issue(PARAVIRT_LAZY_MMU);

	preempt_enable();
670 671
}

672 673
void xen_set_pud(pud_t *ptr, pud_t val)
{
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674 675
	ADD_STATS(pud_update, 1);

676 677
	/* If page is not pinned, we can just update the entry
	   directly */
678
	if (!xen_page_pinned(ptr)) {
679 680 681 682
		*ptr = val;
		return;
	}

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683 684
	ADD_STATS(pud_update_pinned, 1);

685 686 687
	xen_set_pud_hyper(ptr, val);
}

688 689
void xen_set_pte(pte_t *ptep, pte_t pte)
{
690 691 692 693 694
	if (xen_iomap_pte(pte)) {
		xen_set_iomap_pte(ptep, pte);
		return;
	}

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695 696 697 698
	ADD_STATS(pte_update, 1);
//	ADD_STATS(pte_update_pinned, xen_page_pinned(ptep));
	ADD_STATS(pte_update_batched, paravirt_get_lazy_mode() == PARAVIRT_LAZY_MMU);

699
#ifdef CONFIG_X86_PAE
700 701 702
	ptep->pte_high = pte.pte_high;
	smp_wmb();
	ptep->pte_low = pte.pte_low;
703 704 705
#else
	*ptep = pte;
#endif
706 707
}

708
#ifdef CONFIG_X86_PAE
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void xen_set_pte_atomic(pte_t *ptep, pte_t pte)
{
711 712 713 714 715
	if (xen_iomap_pte(pte)) {
		xen_set_iomap_pte(ptep, pte);
		return;
	}

716
	set_64bit((u64 *)ptep, native_pte_val(pte));
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717 718 719 720 721 722 723 724 725 726 727
}

void xen_pte_clear(struct mm_struct *mm, unsigned long addr, pte_t *ptep)
{
	ptep->pte_low = 0;
	smp_wmb();		/* make sure low gets written first */
	ptep->pte_high = 0;
}

void xen_pmd_clear(pmd_t *pmdp)
{
728
	set_pmd(pmdp, __pmd(0));
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729
}
730
#endif	/* CONFIG_X86_PAE */
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731

732
pmd_t xen_make_pmd(pmdval_t pmd)
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733
{
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734
	pmd = pte_pfn_to_mfn(pmd);
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735
	return native_make_pmd(pmd);
J
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736
}
737
PV_CALLEE_SAVE_REGS_THUNK(xen_make_pmd);
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738

739 740 741 742 743
#if PAGETABLE_LEVELS == 4
pudval_t xen_pud_val(pud_t pud)
{
	return pte_mfn_to_pfn(pud.pud);
}
744
PV_CALLEE_SAVE_REGS_THUNK(xen_pud_val);
745 746 747 748 749 750 751

pud_t xen_make_pud(pudval_t pud)
{
	pud = pte_pfn_to_mfn(pud);

	return native_make_pud(pud);
}
752
PV_CALLEE_SAVE_REGS_THUNK(xen_make_pud);
753

754
pgd_t *xen_get_user_pgd(pgd_t *pgd)
755
{
756 757 758
	pgd_t *pgd_page = (pgd_t *)(((unsigned long)pgd) & PAGE_MASK);
	unsigned offset = pgd - pgd_page;
	pgd_t *user_ptr = NULL;
759

760 761 762 763 764 765
	if (offset < pgd_index(USER_LIMIT)) {
		struct page *page = virt_to_page(pgd_page);
		user_ptr = (pgd_t *)page->private;
		if (user_ptr)
			user_ptr += offset;
	}
766

767 768 769 770 771 772
	return user_ptr;
}

static void __xen_set_pgd_hyper(pgd_t *ptr, pgd_t val)
{
	struct mmu_update u;
773 774 775

	u.ptr = virt_to_machine(ptr).maddr;
	u.val = pgd_val_ma(val);
776
	xen_extend_mmu_update(&u);
777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792
}

/*
 * Raw hypercall-based set_pgd, intended for in early boot before
 * there's a page structure.  This implies:
 *  1. The only existing pagetable is the kernel's
 *  2. It is always pinned
 *  3. It has no user pagetable attached to it
 */
void __init xen_set_pgd_hyper(pgd_t *ptr, pgd_t val)
{
	preempt_disable();

	xen_mc_batch();

	__xen_set_pgd_hyper(ptr, val);
793 794 795 796 797 798 799 800

	xen_mc_issue(PARAVIRT_LAZY_MMU);

	preempt_enable();
}

void xen_set_pgd(pgd_t *ptr, pgd_t val)
{
801 802
	pgd_t *user_ptr = xen_get_user_pgd(ptr);

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803 804
	ADD_STATS(pgd_update, 1);

805 806
	/* If page is not pinned, we can just update the entry
	   directly */
807
	if (!xen_page_pinned(ptr)) {
808
		*ptr = val;
809
		if (user_ptr) {
810
			WARN_ON(xen_page_pinned(user_ptr));
811 812
			*user_ptr = val;
		}
813 814 815
		return;
	}

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816 817 818
	ADD_STATS(pgd_update_pinned, 1);
	ADD_STATS(pgd_update_batched, paravirt_get_lazy_mode() == PARAVIRT_LAZY_MMU);

819 820 821 822 823 824 825 826 827
	/* If it's pinned, then we can at least batch the kernel and
	   user updates together. */
	xen_mc_batch();

	__xen_set_pgd_hyper(ptr, val);
	if (user_ptr)
		__xen_set_pgd_hyper(user_ptr, val);

	xen_mc_issue(PARAVIRT_LAZY_MMU);
828 829 830
}
#endif	/* PAGETABLE_LEVELS == 4 */

831
/*
832 833 834 835 836 837 838 839 840 841 842 843 844 845
 * (Yet another) pagetable walker.  This one is intended for pinning a
 * pagetable.  This means that it walks a pagetable and calls the
 * callback function on each page it finds making up the page table,
 * at every level.  It walks the entire pagetable, but it only bothers
 * pinning pte pages which are below limit.  In the normal case this
 * will be STACK_TOP_MAX, but at boot we need to pin up to
 * FIXADDR_TOP.
 *
 * For 32-bit the important bit is that we don't pin beyond there,
 * because then we start getting into Xen's ptes.
 *
 * For 64-bit, we must skip the Xen hole in the middle of the address
 * space, just after the big x86-64 virtual hole.
 */
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846 847 848 849
static int __xen_pgd_walk(struct mm_struct *mm, pgd_t *pgd,
			  int (*func)(struct mm_struct *mm, struct page *,
				      enum pt_level),
			  unsigned long limit)
J
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850
{
851
	int flush = 0;
852 853 854
	unsigned hole_low, hole_high;
	unsigned pgdidx_limit, pudidx_limit, pmdidx_limit;
	unsigned pgdidx, pudidx, pmdidx;
855

856 857 858
	/* The limit is the last byte to be touched */
	limit--;
	BUG_ON(limit >= FIXADDR_TOP);
J
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859 860

	if (xen_feature(XENFEAT_auto_translated_physmap))
861 862
		return 0;

863 864 865 866 867
	/*
	 * 64-bit has a great big hole in the middle of the address
	 * space, which contains the Xen mappings.  On 32-bit these
	 * will end up making a zero-sized hole and so is a no-op.
	 */
868
	hole_low = pgd_index(USER_LIMIT);
869 870 871 872 873 874 875 876 877 878 879 880 881 882 883
	hole_high = pgd_index(PAGE_OFFSET);

	pgdidx_limit = pgd_index(limit);
#if PTRS_PER_PUD > 1
	pudidx_limit = pud_index(limit);
#else
	pudidx_limit = 0;
#endif
#if PTRS_PER_PMD > 1
	pmdidx_limit = pmd_index(limit);
#else
	pmdidx_limit = 0;
#endif

	for (pgdidx = 0; pgdidx <= pgdidx_limit; pgdidx++) {
884
		pud_t *pud;
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885

886 887
		if (pgdidx >= hole_low && pgdidx < hole_high)
			continue;
888

889
		if (!pgd_val(pgd[pgdidx]))
J
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890
			continue;
891

892
		pud = pud_offset(&pgd[pgdidx], 0);
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893 894

		if (PTRS_PER_PUD > 1) /* not folded */
895
			flush |= (*func)(mm, virt_to_page(pud), PT_PUD);
896

897
		for (pudidx = 0; pudidx < PTRS_PER_PUD; pudidx++) {
898 899
			pmd_t *pmd;

900 901 902
			if (pgdidx == pgdidx_limit &&
			    pudidx > pudidx_limit)
				goto out;
J
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903

904
			if (pud_none(pud[pudidx]))
J
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905
				continue;
906

907
			pmd = pmd_offset(&pud[pudidx], 0);
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908 909

			if (PTRS_PER_PMD > 1) /* not folded */
910
				flush |= (*func)(mm, virt_to_page(pmd), PT_PMD);
911

912 913 914 915 916 917 918
			for (pmdidx = 0; pmdidx < PTRS_PER_PMD; pmdidx++) {
				struct page *pte;

				if (pgdidx == pgdidx_limit &&
				    pudidx == pudidx_limit &&
				    pmdidx > pmdidx_limit)
					goto out;
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919

920
				if (pmd_none(pmd[pmdidx]))
J
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921 922
					continue;

923
				pte = pmd_page(pmd[pmdidx]);
924
				flush |= (*func)(mm, pte, PT_PTE);
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925 926 927
			}
		}
	}
928

929
out:
930 931
	/* Do the top level last, so that the callbacks can use it as
	   a cue to do final things like tlb flushes. */
932
	flush |= (*func)(mm, virt_to_page(pgd), PT_PGD);
933 934

	return flush;
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935 936
}

I
Ian Campbell 已提交
937 938 939 940 941 942 943 944
static int xen_pgd_walk(struct mm_struct *mm,
			int (*func)(struct mm_struct *mm, struct page *,
				    enum pt_level),
			unsigned long limit)
{
	return __xen_pgd_walk(mm, mm->pgd, func, limit);
}

945 946
/* If we're using split pte locks, then take the page's lock and
   return a pointer to it.  Otherwise return NULL. */
947
static spinlock_t *xen_pte_lock(struct page *page, struct mm_struct *mm)
948 949 950
{
	spinlock_t *ptl = NULL;

951
#if USE_SPLIT_PTLOCKS
952
	ptl = __pte_lockptr(page);
953
	spin_lock_nest_lock(ptl, &mm->page_table_lock);
954 955 956 957 958
#endif

	return ptl;
}

959
static void xen_pte_unlock(void *v)
960 961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976
{
	spinlock_t *ptl = v;
	spin_unlock(ptl);
}

static void xen_do_pin(unsigned level, unsigned long pfn)
{
	struct mmuext_op *op;
	struct multicall_space mcs;

	mcs = __xen_mc_entry(sizeof(*op));
	op = mcs.args;
	op->cmd = level;
	op->arg1.mfn = pfn_to_mfn(pfn);
	MULTI_mmuext_op(mcs.mc, op, 1, NULL, DOMID_SELF);
}

977 978
static int xen_pin_page(struct mm_struct *mm, struct page *page,
			enum pt_level level)
979
{
980
	unsigned pgfl = TestSetPagePinned(page);
981 982 983 984 985 986 987 988 989 990 991 992
	int flush;

	if (pgfl)
		flush = 0;		/* already pinned */
	else if (PageHighMem(page))
		/* kmaps need flushing if we found an unpinned
		   highpage */
		flush = 1;
	else {
		void *pt = lowmem_page_address(page);
		unsigned long pfn = page_to_pfn(page);
		struct multicall_space mcs = __xen_mc_entry(0);
993
		spinlock_t *ptl;
994 995 996

		flush = 0;

997 998 999 1000 1001 1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016
		/*
		 * We need to hold the pagetable lock between the time
		 * we make the pagetable RO and when we actually pin
		 * it.  If we don't, then other users may come in and
		 * attempt to update the pagetable by writing it,
		 * which will fail because the memory is RO but not
		 * pinned, so Xen won't do the trap'n'emulate.
		 *
		 * If we're using split pte locks, we can't hold the
		 * entire pagetable's worth of locks during the
		 * traverse, because we may wrap the preempt count (8
		 * bits).  The solution is to mark RO and pin each PTE
		 * page while holding the lock.  This means the number
		 * of locks we end up holding is never more than a
		 * batch size (~32 entries, at present).
		 *
		 * If we're not using split pte locks, we needn't pin
		 * the PTE pages independently, because we're
		 * protected by the overall pagetable lock.
		 */
1017 1018
		ptl = NULL;
		if (level == PT_PTE)
1019
			ptl = xen_pte_lock(page, mm);
1020

1021 1022
		MULTI_update_va_mapping(mcs.mc, (unsigned long)pt,
					pfn_pte(pfn, PAGE_KERNEL_RO),
1023 1024
					level == PT_PGD ? UVMF_TLB_FLUSH : 0);

1025
		if (ptl) {
1026 1027 1028 1029
			xen_do_pin(MMUEXT_PIN_L1_TABLE, pfn);

			/* Queue a deferred unlock for when this batch
			   is completed. */
1030
			xen_mc_callback(xen_pte_unlock, ptl);
1031
		}
1032 1033 1034 1035
	}

	return flush;
}
J
Jeremy Fitzhardinge 已提交
1036

1037 1038 1039
/* This is called just after a mm has been created, but it has not
   been used yet.  We need to make sure that its pagetable is all
   read-only, and can be pinned. */
1040
static void __xen_pgd_pin(struct mm_struct *mm, pgd_t *pgd)
J
Jeremy Fitzhardinge 已提交
1041
{
1042
	xen_mc_batch();
J
Jeremy Fitzhardinge 已提交
1043

I
Ian Campbell 已提交
1044
	if (__xen_pgd_walk(mm, pgd, xen_pin_page, USER_LIMIT)) {
1045
		/* re-enable interrupts for flushing */
J
Jeremy Fitzhardinge 已提交
1046
		xen_mc_issue(0);
1047

1048
		kmap_flush_unused();
1049

J
Jeremy Fitzhardinge 已提交
1050 1051
		xen_mc_batch();
	}
1052

1053 1054 1055 1056 1057 1058 1059
#ifdef CONFIG_X86_64
	{
		pgd_t *user_pgd = xen_get_user_pgd(pgd);

		xen_do_pin(MMUEXT_PIN_L4_TABLE, PFN_DOWN(__pa(pgd)));

		if (user_pgd) {
1060
			xen_pin_page(mm, virt_to_page(user_pgd), PT_PGD);
T
Tej 已提交
1061 1062
			xen_do_pin(MMUEXT_PIN_L4_TABLE,
				   PFN_DOWN(__pa(user_pgd)));
1063 1064 1065
		}
	}
#else /* CONFIG_X86_32 */
1066 1067
#ifdef CONFIG_X86_PAE
	/* Need to make sure unshared kernel PMD is pinnable */
1068
	xen_pin_page(mm, pgd_page(pgd[pgd_index(TASK_SIZE)]),
1069
		     PT_PMD);
1070
#endif
1071
	xen_do_pin(MMUEXT_PIN_L3_TABLE, PFN_DOWN(__pa(pgd)));
1072
#endif /* CONFIG_X86_64 */
1073
	xen_mc_issue(0);
J
Jeremy Fitzhardinge 已提交
1074 1075
}

1076 1077 1078 1079 1080
static void xen_pgd_pin(struct mm_struct *mm)
{
	__xen_pgd_pin(mm, mm->pgd);
}

1081 1082 1083 1084 1085
/*
 * On save, we need to pin all pagetables to make sure they get their
 * mfns turned into pfns.  Search the list for any unpinned pgds and pin
 * them (unpinned pgds are not currently in use, probably because the
 * process is under construction or destruction).
1086 1087 1088 1089
 *
 * Expected to be called in stop_machine() ("equivalent to taking
 * every spinlock in the system"), so the locking doesn't really
 * matter all that much.
1090 1091 1092 1093 1094
 */
void xen_mm_pin_all(void)
{
	unsigned long flags;
	struct page *page;
1095

1096
	spin_lock_irqsave(&pgd_lock, flags);
1097

1098 1099
	list_for_each_entry(page, &pgd_list, lru) {
		if (!PagePinned(page)) {
1100
			__xen_pgd_pin(&init_mm, (pgd_t *)page_address(page));
1101 1102 1103 1104 1105
			SetPageSavePinned(page);
		}
	}

	spin_unlock_irqrestore(&pgd_lock, flags);
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}

1108 1109 1110 1111 1112
/*
 * The init_mm pagetable is really pinned as soon as its created, but
 * that's before we have page structures to store the bits.  So do all
 * the book-keeping now.
 */
1113 1114
static __init int xen_mark_pinned(struct mm_struct *mm, struct page *page,
				  enum pt_level level)
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{
1116 1117 1118
	SetPagePinned(page);
	return 0;
}
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1120
static void __init xen_mark_init_mm_pinned(void)
1121
{
1122
	xen_pgd_walk(&init_mm, xen_mark_pinned, FIXADDR_TOP);
1123
}
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1125 1126
static int xen_unpin_page(struct mm_struct *mm, struct page *page,
			  enum pt_level level)
1127
{
1128
	unsigned pgfl = TestClearPagePinned(page);
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1130 1131 1132
	if (pgfl && !PageHighMem(page)) {
		void *pt = lowmem_page_address(page);
		unsigned long pfn = page_to_pfn(page);
1133 1134 1135
		spinlock_t *ptl = NULL;
		struct multicall_space mcs;

1136 1137 1138 1139 1140 1141 1142
		/*
		 * Do the converse to pin_page.  If we're using split
		 * pte locks, we must be holding the lock for while
		 * the pte page is unpinned but still RO to prevent
		 * concurrent updates from seeing it in this
		 * partially-pinned state.
		 */
1143
		if (level == PT_PTE) {
1144
			ptl = xen_pte_lock(page, mm);
1145

1146 1147
			if (ptl)
				xen_do_pin(MMUEXT_UNPIN_TABLE, pfn);
1148 1149 1150
		}

		mcs = __xen_mc_entry(0);
1151 1152 1153

		MULTI_update_va_mapping(mcs.mc, (unsigned long)pt,
					pfn_pte(pfn, PAGE_KERNEL),
1154 1155 1156 1157
					level == PT_PGD ? UVMF_TLB_FLUSH : 0);

		if (ptl) {
			/* unlock when batch completed */
1158
			xen_mc_callback(xen_pte_unlock, ptl);
1159
		}
1160 1161 1162
	}

	return 0;		/* never need to flush on unpin */
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}

1165
/* Release a pagetables pages back as normal RW */
1166
static void __xen_pgd_unpin(struct mm_struct *mm, pgd_t *pgd)
1167 1168 1169
{
	xen_mc_batch();

1170
	xen_do_pin(MMUEXT_UNPIN_TABLE, PFN_DOWN(__pa(pgd)));
1171

1172 1173 1174 1175 1176
#ifdef CONFIG_X86_64
	{
		pgd_t *user_pgd = xen_get_user_pgd(pgd);

		if (user_pgd) {
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			xen_do_pin(MMUEXT_UNPIN_TABLE,
				   PFN_DOWN(__pa(user_pgd)));
1179
			xen_unpin_page(mm, virt_to_page(user_pgd), PT_PGD);
1180 1181 1182 1183
		}
	}
#endif

1184 1185
#ifdef CONFIG_X86_PAE
	/* Need to make sure unshared kernel PMD is unpinned */
1186
	xen_unpin_page(mm, pgd_page(pgd[pgd_index(TASK_SIZE)]),
1187
		       PT_PMD);
1188
#endif
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	__xen_pgd_walk(mm, pgd, xen_unpin_page, USER_LIMIT);
1191 1192 1193

	xen_mc_issue(0);
}
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1195 1196 1197 1198 1199
static void xen_pgd_unpin(struct mm_struct *mm)
{
	__xen_pgd_unpin(mm, mm->pgd);
}

1200 1201 1202 1203 1204 1205 1206 1207 1208 1209 1210 1211 1212 1213
/*
 * On resume, undo any pinning done at save, so that the rest of the
 * kernel doesn't see any unexpected pinned pagetables.
 */
void xen_mm_unpin_all(void)
{
	unsigned long flags;
	struct page *page;

	spin_lock_irqsave(&pgd_lock, flags);

	list_for_each_entry(page, &pgd_list, lru) {
		if (PageSavePinned(page)) {
			BUG_ON(!PagePinned(page));
1214
			__xen_pgd_unpin(&init_mm, (pgd_t *)page_address(page));
1215 1216 1217 1218 1219 1220 1221
			ClearPageSavePinned(page);
		}
	}

	spin_unlock_irqrestore(&pgd_lock, flags);
}

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void xen_activate_mm(struct mm_struct *prev, struct mm_struct *next)
{
1224
	spin_lock(&next->page_table_lock);
1225
	xen_pgd_pin(next);
1226
	spin_unlock(&next->page_table_lock);
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}

void xen_dup_mmap(struct mm_struct *oldmm, struct mm_struct *mm)
{
1231
	spin_lock(&mm->page_table_lock);
1232
	xen_pgd_pin(mm);
1233
	spin_unlock(&mm->page_table_lock);
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}


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#ifdef CONFIG_SMP
/* Another cpu may still have their %cr3 pointing at the pagetable, so
   we need to repoint it somewhere else before we can unpin it. */
static void drop_other_mm_ref(void *info)
{
	struct mm_struct *mm = info;
1243
	struct mm_struct *active_mm;
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1245
	active_mm = percpu_read(cpu_tlbstate.active_mm);
1246 1247

	if (active_mm == mm)
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		leave_mm(smp_processor_id());
1249 1250 1251

	/* If this cpu still has a stale cr3 reference, then make sure
	   it has been flushed. */
1252
	if (percpu_read(xen_current_cr3) == __pa(mm->pgd))
1253
		load_cr3(swapper_pg_dir);
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}
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1256
static void xen_drop_mm_ref(struct mm_struct *mm)
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{
1258
	cpumask_var_t mask;
1259 1260
	unsigned cpu;

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1261 1262 1263 1264 1265
	if (current->active_mm == mm) {
		if (current->mm == mm)
			load_cr3(swapper_pg_dir);
		else
			leave_mm(smp_processor_id());
1266 1267 1268
	}

	/* Get the "official" set of cpus referring to our pagetable. */
1269 1270
	if (!alloc_cpumask_var(&mask, GFP_ATOMIC)) {
		for_each_online_cpu(cpu) {
1271
			if (!cpumask_test_cpu(cpu, mm_cpumask(mm))
1272 1273 1274 1275 1276 1277
			    && per_cpu(xen_current_cr3, cpu) != __pa(mm->pgd))
				continue;
			smp_call_function_single(cpu, drop_other_mm_ref, mm, 1);
		}
		return;
	}
1278
	cpumask_copy(mask, mm_cpumask(mm));
1279 1280 1281 1282 1283 1284 1285 1286

	/* It's possible that a vcpu may have a stale reference to our
	   cr3, because its in lazy mode, and it hasn't yet flushed
	   its set of pending hypercalls yet.  In this case, we can
	   look at its actual current cr3 value, and force it to flush
	   if needed. */
	for_each_online_cpu(cpu) {
		if (per_cpu(xen_current_cr3, cpu) == __pa(mm->pgd))
1287
			cpumask_set_cpu(cpu, mask);
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	}

1290 1291 1292
	if (!cpumask_empty(mask))
		smp_call_function_many(mask, drop_other_mm_ref, mm, 1);
	free_cpumask_var(mask);
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}
#else
1295
static void xen_drop_mm_ref(struct mm_struct *mm)
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{
	if (current->active_mm == mm)
		load_cr3(swapper_pg_dir);
}
#endif

/*
 * While a process runs, Xen pins its pagetables, which means that the
 * hypervisor forces it to be read-only, and it controls all updates
 * to it.  This means that all pagetable updates have to go via the
 * hypervisor, which is moderately expensive.
 *
 * Since we're pulling the pagetable down, we switch to use init_mm,
 * unpin old process pagetable and mark it all read-write, which
 * allows further operations on it to be simple memory accesses.
 *
 * The only subtle point is that another CPU may be still using the
 * pagetable because of lazy tlb flushing.  This means we need need to
 * switch all CPUs off this pagetable before we can unpin it.
 */
void xen_exit_mmap(struct mm_struct *mm)
{
	get_cpu();		/* make sure we don't move around */
1319
	xen_drop_mm_ref(mm);
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	put_cpu();
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1322
	spin_lock(&mm->page_table_lock);
1323 1324

	/* pgd may not be pinned in the error exit path of execve */
1325
	if (xen_page_pinned(mm->pgd))
1326
		xen_pgd_unpin(mm);
1327

1328
	spin_unlock(&mm->page_table_lock);
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}
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1331 1332 1333 1334
static __init void xen_pagetable_setup_start(pgd_t *base)
{
}

1335 1336
static void xen_post_allocator_init(void);

1337 1338 1339
static __init void xen_pagetable_setup_done(pgd_t *base)
{
	xen_setup_shared_info();
1340
	xen_post_allocator_init();
1341 1342 1343 1344 1345 1346 1347 1348 1349 1350 1351 1352 1353 1354 1355 1356 1357 1358 1359 1360 1361 1362 1363 1364 1365 1366 1367 1368 1369 1370 1371 1372 1373 1374 1375 1376 1377 1378 1379 1380 1381 1382 1383 1384 1385 1386 1387 1388 1389 1390 1391 1392 1393 1394 1395 1396 1397 1398 1399 1400 1401 1402
}

static void xen_write_cr2(unsigned long cr2)
{
	percpu_read(xen_vcpu)->arch.cr2 = cr2;
}

static unsigned long xen_read_cr2(void)
{
	return percpu_read(xen_vcpu)->arch.cr2;
}

unsigned long xen_read_cr2_direct(void)
{
	return percpu_read(xen_vcpu_info.arch.cr2);
}

static void xen_flush_tlb(void)
{
	struct mmuext_op *op;
	struct multicall_space mcs;

	preempt_disable();

	mcs = xen_mc_entry(sizeof(*op));

	op = mcs.args;
	op->cmd = MMUEXT_TLB_FLUSH_LOCAL;
	MULTI_mmuext_op(mcs.mc, op, 1, NULL, DOMID_SELF);

	xen_mc_issue(PARAVIRT_LAZY_MMU);

	preempt_enable();
}

static void xen_flush_tlb_single(unsigned long addr)
{
	struct mmuext_op *op;
	struct multicall_space mcs;

	preempt_disable();

	mcs = xen_mc_entry(sizeof(*op));
	op = mcs.args;
	op->cmd = MMUEXT_INVLPG_LOCAL;
	op->arg1.linear_addr = addr & PAGE_MASK;
	MULTI_mmuext_op(mcs.mc, op, 1, NULL, DOMID_SELF);

	xen_mc_issue(PARAVIRT_LAZY_MMU);

	preempt_enable();
}

static void xen_flush_tlb_others(const struct cpumask *cpus,
				 struct mm_struct *mm, unsigned long va)
{
	struct {
		struct mmuext_op op;
		DECLARE_BITMAP(mask, NR_CPUS);
	} *args;
	struct multicall_space mcs;

1403 1404
	if (cpumask_empty(cpus))
		return;		/* nothing to do */
1405 1406 1407 1408 1409 1410 1411 1412 1413 1414 1415 1416 1417 1418 1419 1420 1421 1422 1423 1424 1425 1426 1427 1428 1429 1430 1431 1432 1433 1434 1435 1436 1437 1438 1439 1440 1441 1442 1443 1444 1445 1446 1447 1448 1449 1450 1451 1452 1453 1454 1455 1456 1457 1458 1459 1460 1461 1462 1463 1464 1465 1466 1467 1468 1469 1470 1471 1472 1473 1474 1475 1476 1477 1478 1479 1480 1481 1482 1483 1484 1485 1486 1487 1488 1489 1490 1491 1492 1493 1494 1495 1496 1497 1498 1499 1500 1501 1502 1503 1504 1505 1506 1507 1508 1509 1510 1511 1512 1513 1514 1515 1516 1517 1518 1519 1520 1521 1522 1523 1524 1525 1526 1527 1528 1529 1530 1531 1532

	mcs = xen_mc_entry(sizeof(*args));
	args = mcs.args;
	args->op.arg2.vcpumask = to_cpumask(args->mask);

	/* Remove us, and any offline CPUS. */
	cpumask_and(to_cpumask(args->mask), cpus, cpu_online_mask);
	cpumask_clear_cpu(smp_processor_id(), to_cpumask(args->mask));

	if (va == TLB_FLUSH_ALL) {
		args->op.cmd = MMUEXT_TLB_FLUSH_MULTI;
	} else {
		args->op.cmd = MMUEXT_INVLPG_MULTI;
		args->op.arg1.linear_addr = va;
	}

	MULTI_mmuext_op(mcs.mc, &args->op, 1, NULL, DOMID_SELF);

	xen_mc_issue(PARAVIRT_LAZY_MMU);
}

static unsigned long xen_read_cr3(void)
{
	return percpu_read(xen_cr3);
}

static void set_current_cr3(void *v)
{
	percpu_write(xen_current_cr3, (unsigned long)v);
}

static void __xen_write_cr3(bool kernel, unsigned long cr3)
{
	struct mmuext_op *op;
	struct multicall_space mcs;
	unsigned long mfn;

	if (cr3)
		mfn = pfn_to_mfn(PFN_DOWN(cr3));
	else
		mfn = 0;

	WARN_ON(mfn == 0 && kernel);

	mcs = __xen_mc_entry(sizeof(*op));

	op = mcs.args;
	op->cmd = kernel ? MMUEXT_NEW_BASEPTR : MMUEXT_NEW_USER_BASEPTR;
	op->arg1.mfn = mfn;

	MULTI_mmuext_op(mcs.mc, op, 1, NULL, DOMID_SELF);

	if (kernel) {
		percpu_write(xen_cr3, cr3);

		/* Update xen_current_cr3 once the batch has actually
		   been submitted. */
		xen_mc_callback(set_current_cr3, (void *)cr3);
	}
}

static void xen_write_cr3(unsigned long cr3)
{
	BUG_ON(preemptible());

	xen_mc_batch();  /* disables interrupts */

	/* Update while interrupts are disabled, so its atomic with
	   respect to ipis */
	percpu_write(xen_cr3, cr3);

	__xen_write_cr3(true, cr3);

#ifdef CONFIG_X86_64
	{
		pgd_t *user_pgd = xen_get_user_pgd(__va(cr3));
		if (user_pgd)
			__xen_write_cr3(false, __pa(user_pgd));
		else
			__xen_write_cr3(false, 0);
	}
#endif

	xen_mc_issue(PARAVIRT_LAZY_CPU);  /* interrupts restored */
}

static int xen_pgd_alloc(struct mm_struct *mm)
{
	pgd_t *pgd = mm->pgd;
	int ret = 0;

	BUG_ON(PagePinned(virt_to_page(pgd)));

#ifdef CONFIG_X86_64
	{
		struct page *page = virt_to_page(pgd);
		pgd_t *user_pgd;

		BUG_ON(page->private != 0);

		ret = -ENOMEM;

		user_pgd = (pgd_t *)__get_free_page(GFP_KERNEL | __GFP_ZERO);
		page->private = (unsigned long)user_pgd;

		if (user_pgd != NULL) {
			user_pgd[pgd_index(VSYSCALL_START)] =
				__pgd(__pa(level3_user_vsyscall) | _PAGE_TABLE);
			ret = 0;
		}

		BUG_ON(PagePinned(virt_to_page(xen_get_user_pgd(pgd))));
	}
#endif

	return ret;
}

static void xen_pgd_free(struct mm_struct *mm, pgd_t *pgd)
{
#ifdef CONFIG_X86_64
	pgd_t *user_pgd = xen_get_user_pgd(pgd);

	if (user_pgd)
		free_page((unsigned long)user_pgd);
#endif
}

1533 1534 1535 1536 1537 1538 1539 1540 1541 1542 1543 1544 1545 1546 1547 1548 1549 1550 1551 1552
#ifdef CONFIG_X86_32
static __init pte_t mask_rw_pte(pte_t *ptep, pte_t pte)
{
	/* If there's an existing pte, then don't allow _PAGE_RW to be set */
	if (pte_val_ma(*ptep) & _PAGE_PRESENT)
		pte = __pte_ma(((pte_val_ma(*ptep) & _PAGE_RW) | ~_PAGE_RW) &
			       pte_val_ma(pte));

	return pte;
}

/* Init-time set_pte while constructing initial pagetables, which
   doesn't allow RO pagetable pages to be remapped RW */
static __init void xen_set_pte_init(pte_t *ptep, pte_t pte)
{
	pte = mask_rw_pte(ptep, pte);

	xen_set_pte(ptep, pte);
}
#endif
1553

1554 1555 1556 1557 1558 1559 1560 1561 1562
static void pin_pagetable_pfn(unsigned cmd, unsigned long pfn)
{
	struct mmuext_op op;
	op.cmd = cmd;
	op.arg1.mfn = pfn_to_mfn(pfn);
	if (HYPERVISOR_mmuext_op(&op, 1, NULL, DOMID_SELF))
		BUG();
}

1563 1564 1565 1566
/* Early in boot, while setting up the initial pagetable, assume
   everything is pinned. */
static __init void xen_alloc_pte_init(struct mm_struct *mm, unsigned long pfn)
{
1567 1568 1569 1570 1571 1572 1573 1574 1575 1576
#ifdef CONFIG_FLATMEM
	BUG_ON(mem_map);	/* should only be used early */
#endif
	make_lowmem_page_readonly(__va(PFN_PHYS(pfn)));
	pin_pagetable_pfn(MMUEXT_PIN_L1_TABLE, pfn);
}

/* Used for pmd and pud */
static __init void xen_alloc_pmd_init(struct mm_struct *mm, unsigned long pfn)
{
1577 1578 1579 1580 1581 1582 1583 1584
#ifdef CONFIG_FLATMEM
	BUG_ON(mem_map);	/* should only be used early */
#endif
	make_lowmem_page_readonly(__va(PFN_PHYS(pfn)));
}

/* Early release_pte assumes that all pts are pinned, since there's
   only init_mm and anything attached to that is pinned. */
1585
static __init void xen_release_pte_init(unsigned long pfn)
1586
{
1587
	pin_pagetable_pfn(MMUEXT_UNPIN_TABLE, pfn);
1588 1589 1590
	make_lowmem_page_readwrite(__va(PFN_PHYS(pfn)));
}

1591
static __init void xen_release_pmd_init(unsigned long pfn)
1592
{
1593
	make_lowmem_page_readwrite(__va(PFN_PHYS(pfn)));
1594 1595 1596 1597 1598 1599 1600 1601 1602 1603 1604 1605 1606 1607 1608 1609 1610 1611 1612 1613 1614 1615 1616 1617 1618 1619 1620 1621 1622 1623 1624 1625 1626 1627 1628 1629 1630 1631 1632 1633 1634 1635 1636 1637 1638 1639 1640 1641 1642 1643 1644 1645 1646 1647 1648 1649 1650 1651 1652 1653 1654 1655 1656 1657 1658 1659 1660 1661 1662 1663 1664 1665 1666 1667 1668 1669 1670 1671 1672 1673 1674 1675 1676 1677 1678 1679 1680 1681 1682 1683 1684 1685 1686 1687 1688 1689 1690 1691 1692 1693 1694 1695 1696 1697 1698 1699 1700 1701 1702 1703 1704 1705 1706 1707 1708 1709 1710 1711 1712 1713 1714 1715 1716 1717 1718 1719 1720 1721
}

/* This needs to make sure the new pte page is pinned iff its being
   attached to a pinned pagetable. */
static void xen_alloc_ptpage(struct mm_struct *mm, unsigned long pfn, unsigned level)
{
	struct page *page = pfn_to_page(pfn);

	if (PagePinned(virt_to_page(mm->pgd))) {
		SetPagePinned(page);

		if (!PageHighMem(page)) {
			make_lowmem_page_readonly(__va(PFN_PHYS((unsigned long)pfn)));
			if (level == PT_PTE && USE_SPLIT_PTLOCKS)
				pin_pagetable_pfn(MMUEXT_PIN_L1_TABLE, pfn);
		} else {
			/* make sure there are no stray mappings of
			   this page */
			kmap_flush_unused();
		}
	}
}

static void xen_alloc_pte(struct mm_struct *mm, unsigned long pfn)
{
	xen_alloc_ptpage(mm, pfn, PT_PTE);
}

static void xen_alloc_pmd(struct mm_struct *mm, unsigned long pfn)
{
	xen_alloc_ptpage(mm, pfn, PT_PMD);
}

/* This should never happen until we're OK to use struct page */
static void xen_release_ptpage(unsigned long pfn, unsigned level)
{
	struct page *page = pfn_to_page(pfn);

	if (PagePinned(page)) {
		if (!PageHighMem(page)) {
			if (level == PT_PTE && USE_SPLIT_PTLOCKS)
				pin_pagetable_pfn(MMUEXT_UNPIN_TABLE, pfn);
			make_lowmem_page_readwrite(__va(PFN_PHYS(pfn)));
		}
		ClearPagePinned(page);
	}
}

static void xen_release_pte(unsigned long pfn)
{
	xen_release_ptpage(pfn, PT_PTE);
}

static void xen_release_pmd(unsigned long pfn)
{
	xen_release_ptpage(pfn, PT_PMD);
}

#if PAGETABLE_LEVELS == 4
static void xen_alloc_pud(struct mm_struct *mm, unsigned long pfn)
{
	xen_alloc_ptpage(mm, pfn, PT_PUD);
}

static void xen_release_pud(unsigned long pfn)
{
	xen_release_ptpage(pfn, PT_PUD);
}
#endif

void __init xen_reserve_top(void)
{
#ifdef CONFIG_X86_32
	unsigned long top = HYPERVISOR_VIRT_START;
	struct xen_platform_parameters pp;

	if (HYPERVISOR_xen_version(XENVER_platform_parameters, &pp) == 0)
		top = pp.virt_start;

	reserve_top_address(-top);
#endif	/* CONFIG_X86_32 */
}

/*
 * Like __va(), but returns address in the kernel mapping (which is
 * all we have until the physical memory mapping has been set up.
 */
static void *__ka(phys_addr_t paddr)
{
#ifdef CONFIG_X86_64
	return (void *)(paddr + __START_KERNEL_map);
#else
	return __va(paddr);
#endif
}

/* Convert a machine address to physical address */
static unsigned long m2p(phys_addr_t maddr)
{
	phys_addr_t paddr;

	maddr &= PTE_PFN_MASK;
	paddr = mfn_to_pfn(maddr >> PAGE_SHIFT) << PAGE_SHIFT;

	return paddr;
}

/* Convert a machine address to kernel virtual */
static void *m2v(phys_addr_t maddr)
{
	return __ka(m2p(maddr));
}

static void set_page_prot(void *addr, pgprot_t prot)
{
	unsigned long pfn = __pa(addr) >> PAGE_SHIFT;
	pte_t pte = pfn_pte(pfn, prot);

	if (HYPERVISOR_update_va_mapping((unsigned long)addr, pte, 0))
		BUG();
}

static __init void xen_map_identity_early(pmd_t *pmd, unsigned long max_pfn)
{
	unsigned pmdidx, pteidx;
	unsigned ident_pte;
	unsigned long pfn;

1722 1723 1724
	level1_ident_pgt = extend_brk(sizeof(pte_t) * LEVEL1_IDENT_ENTRIES,
				      PAGE_SIZE);

1725 1726 1727 1728 1729 1730 1731 1732 1733 1734
	ident_pte = 0;
	pfn = 0;
	for (pmdidx = 0; pmdidx < PTRS_PER_PMD && pfn < max_pfn; pmdidx++) {
		pte_t *pte_page;

		/* Reuse or allocate a page of ptes */
		if (pmd_present(pmd[pmdidx]))
			pte_page = m2v(pmd[pmdidx].pmd);
		else {
			/* Check for free pte pages */
1735
			if (ident_pte == LEVEL1_IDENT_ENTRIES)
1736 1737 1738 1739 1740 1741 1742 1743 1744 1745 1746 1747 1748 1749 1750 1751 1752 1753 1754 1755 1756 1757 1758 1759 1760 1761 1762 1763 1764 1765 1766 1767 1768 1769 1770 1771 1772 1773 1774 1775 1776 1777 1778 1779 1780 1781 1782 1783 1784 1785 1786 1787 1788 1789 1790 1791 1792 1793 1794 1795 1796 1797 1798 1799 1800 1801 1802 1803 1804 1805 1806 1807 1808 1809 1810 1811 1812 1813 1814 1815 1816 1817 1818 1819 1820 1821 1822 1823 1824 1825 1826 1827 1828 1829 1830 1831 1832 1833 1834 1835 1836 1837 1838 1839 1840 1841 1842 1843 1844 1845 1846 1847 1848 1849
				break;

			pte_page = &level1_ident_pgt[ident_pte];
			ident_pte += PTRS_PER_PTE;

			pmd[pmdidx] = __pmd(__pa(pte_page) | _PAGE_TABLE);
		}

		/* Install mappings */
		for (pteidx = 0; pteidx < PTRS_PER_PTE; pteidx++, pfn++) {
			pte_t pte;

			if (pfn > max_pfn_mapped)
				max_pfn_mapped = pfn;

			if (!pte_none(pte_page[pteidx]))
				continue;

			pte = pfn_pte(pfn, PAGE_KERNEL_EXEC);
			pte_page[pteidx] = pte;
		}
	}

	for (pteidx = 0; pteidx < ident_pte; pteidx += PTRS_PER_PTE)
		set_page_prot(&level1_ident_pgt[pteidx], PAGE_KERNEL_RO);

	set_page_prot(pmd, PAGE_KERNEL_RO);
}

#ifdef CONFIG_X86_64
static void convert_pfn_mfn(void *v)
{
	pte_t *pte = v;
	int i;

	/* All levels are converted the same way, so just treat them
	   as ptes. */
	for (i = 0; i < PTRS_PER_PTE; i++)
		pte[i] = xen_make_pte(pte[i].pte);
}

/*
 * Set up the inital kernel pagetable.
 *
 * We can construct this by grafting the Xen provided pagetable into
 * head_64.S's preconstructed pagetables.  We copy the Xen L2's into
 * level2_ident_pgt, level2_kernel_pgt and level2_fixmap_pgt.  This
 * means that only the kernel has a physical mapping to start with -
 * but that's enough to get __va working.  We need to fill in the rest
 * of the physical mapping once some sort of allocator has been set
 * up.
 */
__init pgd_t *xen_setup_kernel_pagetable(pgd_t *pgd,
					 unsigned long max_pfn)
{
	pud_t *l3;
	pmd_t *l2;

	/* Zap identity mapping */
	init_level4_pgt[0] = __pgd(0);

	/* Pre-constructed entries are in pfn, so convert to mfn */
	convert_pfn_mfn(init_level4_pgt);
	convert_pfn_mfn(level3_ident_pgt);
	convert_pfn_mfn(level3_kernel_pgt);

	l3 = m2v(pgd[pgd_index(__START_KERNEL_map)].pgd);
	l2 = m2v(l3[pud_index(__START_KERNEL_map)].pud);

	memcpy(level2_ident_pgt, l2, sizeof(pmd_t) * PTRS_PER_PMD);
	memcpy(level2_kernel_pgt, l2, sizeof(pmd_t) * PTRS_PER_PMD);

	l3 = m2v(pgd[pgd_index(__START_KERNEL_map + PMD_SIZE)].pgd);
	l2 = m2v(l3[pud_index(__START_KERNEL_map + PMD_SIZE)].pud);
	memcpy(level2_fixmap_pgt, l2, sizeof(pmd_t) * PTRS_PER_PMD);

	/* Set up identity map */
	xen_map_identity_early(level2_ident_pgt, max_pfn);

	/* Make pagetable pieces RO */
	set_page_prot(init_level4_pgt, PAGE_KERNEL_RO);
	set_page_prot(level3_ident_pgt, PAGE_KERNEL_RO);
	set_page_prot(level3_kernel_pgt, PAGE_KERNEL_RO);
	set_page_prot(level3_user_vsyscall, PAGE_KERNEL_RO);
	set_page_prot(level2_kernel_pgt, PAGE_KERNEL_RO);
	set_page_prot(level2_fixmap_pgt, PAGE_KERNEL_RO);

	/* Pin down new L4 */
	pin_pagetable_pfn(MMUEXT_PIN_L4_TABLE,
			  PFN_DOWN(__pa_symbol(init_level4_pgt)));

	/* Unpin Xen-provided one */
	pin_pagetable_pfn(MMUEXT_UNPIN_TABLE, PFN_DOWN(__pa(pgd)));

	/* Switch over */
	pgd = init_level4_pgt;

	/*
	 * At this stage there can be no user pgd, and no page
	 * structure to attach it to, so make sure we just set kernel
	 * pgd.
	 */
	xen_mc_batch();
	__xen_write_cr3(true, __pa(pgd));
	xen_mc_issue(PARAVIRT_LAZY_CPU);

	reserve_early(__pa(xen_start_info->pt_base),
		      __pa(xen_start_info->pt_base +
			   xen_start_info->nr_pt_frames * PAGE_SIZE),
		      "XEN PAGETABLES");

	return pgd;
}
#else	/* !CONFIG_X86_64 */
1850
static RESERVE_BRK_ARRAY(pmd_t, level2_kernel_pgt, PTRS_PER_PMD);
1851 1852 1853 1854 1855 1856

__init pgd_t *xen_setup_kernel_pagetable(pgd_t *pgd,
					 unsigned long max_pfn)
{
	pmd_t *kernel_pmd;

1857 1858
	level2_kernel_pgt = extend_brk(sizeof(pmd_t *) * PTRS_PER_PMD, PAGE_SIZE);

1859 1860 1861
	max_pfn_mapped = PFN_DOWN(__pa(xen_start_info->pt_base) +
				  xen_start_info->nr_pt_frames * PAGE_SIZE +
				  512*1024);
1862 1863 1864 1865 1866 1867 1868 1869 1870 1871 1872 1873 1874 1875 1876 1877 1878 1879 1880 1881

	kernel_pmd = m2v(pgd[KERNEL_PGD_BOUNDARY].pgd);
	memcpy(level2_kernel_pgt, kernel_pmd, sizeof(pmd_t) * PTRS_PER_PMD);

	xen_map_identity_early(level2_kernel_pgt, max_pfn);

	memcpy(swapper_pg_dir, pgd, sizeof(pgd_t) * PTRS_PER_PGD);
	set_pgd(&swapper_pg_dir[KERNEL_PGD_BOUNDARY],
			__pgd(__pa(level2_kernel_pgt) | _PAGE_PRESENT));

	set_page_prot(level2_kernel_pgt, PAGE_KERNEL_RO);
	set_page_prot(swapper_pg_dir, PAGE_KERNEL_RO);
	set_page_prot(empty_zero_page, PAGE_KERNEL_RO);

	pin_pagetable_pfn(MMUEXT_UNPIN_TABLE, PFN_DOWN(__pa(pgd)));

	xen_write_cr3(__pa(swapper_pg_dir));

	pin_pagetable_pfn(MMUEXT_PIN_L3_TABLE, PFN_DOWN(__pa(swapper_pg_dir)));

1882 1883 1884 1885 1886
	reserve_early(__pa(xen_start_info->pt_base),
		      __pa(xen_start_info->pt_base +
			   xen_start_info->nr_pt_frames * PAGE_SIZE),
		      "XEN PAGETABLES");

1887 1888 1889 1890
	return swapper_pg_dir;
}
#endif	/* CONFIG_X86_64 */

1891
static void xen_set_fixmap(unsigned idx, phys_addr_t phys, pgprot_t prot)
1892 1893 1894 1895 1896 1897 1898 1899 1900 1901 1902 1903 1904 1905 1906 1907 1908 1909 1910 1911 1912 1913
{
	pte_t pte;

	phys >>= PAGE_SHIFT;

	switch (idx) {
	case FIX_BTMAP_END ... FIX_BTMAP_BEGIN:
#ifdef CONFIG_X86_F00F_BUG
	case FIX_F00F_IDT:
#endif
#ifdef CONFIG_X86_32
	case FIX_WP_TEST:
	case FIX_VDSO:
# ifdef CONFIG_HIGHMEM
	case FIX_KMAP_BEGIN ... FIX_KMAP_END:
# endif
#else
	case VSYSCALL_LAST_PAGE ... VSYSCALL_FIRST_PAGE:
#endif
#ifdef CONFIG_X86_LOCAL_APIC
	case FIX_APIC_BASE:	/* maps dummy local APIC */
#endif
1914 1915 1916
	case FIX_TEXT_POKE0:
	case FIX_TEXT_POKE1:
		/* All local page mappings */
1917 1918 1919
		pte = pfn_pte(phys, prot);
		break;

1920 1921 1922
	case FIX_PARAVIRT_BOOTMAP:
		/* This is an MFN, but it isn't an IO mapping from the
		   IO domain */
1923 1924
		pte = mfn_pte(phys, prot);
		break;
1925 1926 1927 1928 1929

	default:
		/* By default, set_fixmap is used for hardware mappings */
		pte = mfn_pte(phys, __pgprot(pgprot_val(prot) | _PAGE_IOMAP));
		break;
1930 1931 1932 1933 1934 1935 1936 1937 1938 1939 1940 1941 1942 1943
	}

	__native_set_fixmap(idx, pte);

#ifdef CONFIG_X86_64
	/* Replicate changes to map the vsyscall page into the user
	   pagetable vsyscall mapping. */
	if (idx >= VSYSCALL_LAST_PAGE && idx <= VSYSCALL_FIRST_PAGE) {
		unsigned long vaddr = __fix_to_virt(idx);
		set_pte_vaddr_pud(level3_user_vsyscall, vaddr, pte);
	}
#endif
}

1944
static __init void xen_post_allocator_init(void)
1945 1946 1947 1948 1949 1950 1951 1952 1953 1954 1955 1956 1957 1958 1959 1960 1961 1962 1963 1964 1965 1966 1967 1968 1969
{
	pv_mmu_ops.set_pte = xen_set_pte;
	pv_mmu_ops.set_pmd = xen_set_pmd;
	pv_mmu_ops.set_pud = xen_set_pud;
#if PAGETABLE_LEVELS == 4
	pv_mmu_ops.set_pgd = xen_set_pgd;
#endif

	/* This will work as long as patching hasn't happened yet
	   (which it hasn't) */
	pv_mmu_ops.alloc_pte = xen_alloc_pte;
	pv_mmu_ops.alloc_pmd = xen_alloc_pmd;
	pv_mmu_ops.release_pte = xen_release_pte;
	pv_mmu_ops.release_pmd = xen_release_pmd;
#if PAGETABLE_LEVELS == 4
	pv_mmu_ops.alloc_pud = xen_alloc_pud;
	pv_mmu_ops.release_pud = xen_release_pud;
#endif

#ifdef CONFIG_X86_64
	SetPagePinned(virt_to_page(level3_user_vsyscall));
#endif
	xen_mark_init_mm_pinned();
}

1970 1971
static void xen_leave_lazy_mmu(void)
{
1972
	preempt_disable();
1973 1974
	xen_mc_flush();
	paravirt_leave_lazy_mmu();
1975
	preempt_enable();
1976
}
1977

1978
static const struct pv_mmu_ops xen_mmu_ops __initdata = {
1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997
	.read_cr2 = xen_read_cr2,
	.write_cr2 = xen_write_cr2,

	.read_cr3 = xen_read_cr3,
	.write_cr3 = xen_write_cr3,

	.flush_tlb_user = xen_flush_tlb,
	.flush_tlb_kernel = xen_flush_tlb,
	.flush_tlb_single = xen_flush_tlb_single,
	.flush_tlb_others = xen_flush_tlb_others,

	.pte_update = paravirt_nop,
	.pte_update_defer = paravirt_nop,

	.pgd_alloc = xen_pgd_alloc,
	.pgd_free = xen_pgd_free,

	.alloc_pte = xen_alloc_pte_init,
	.release_pte = xen_release_pte_init,
1998
	.alloc_pmd = xen_alloc_pmd_init,
1999
	.alloc_pmd_clone = paravirt_nop,
2000
	.release_pmd = xen_release_pmd_init,
2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012

#ifdef CONFIG_X86_64
	.set_pte = xen_set_pte,
#else
	.set_pte = xen_set_pte_init,
#endif
	.set_pte_at = xen_set_pte_at,
	.set_pmd = xen_set_pmd_hyper,

	.ptep_modify_prot_start = __ptep_modify_prot_start,
	.ptep_modify_prot_commit = __ptep_modify_prot_commit,

2013 2014
	.pte_val = PV_CALLEE_SAVE(xen_pte_val),
	.pgd_val = PV_CALLEE_SAVE(xen_pgd_val),
2015

2016 2017
	.make_pte = PV_CALLEE_SAVE(xen_make_pte),
	.make_pgd = PV_CALLEE_SAVE(xen_make_pgd),
2018 2019 2020 2021 2022 2023 2024 2025

#ifdef CONFIG_X86_PAE
	.set_pte_atomic = xen_set_pte_atomic,
	.pte_clear = xen_pte_clear,
	.pmd_clear = xen_pmd_clear,
#endif	/* CONFIG_X86_PAE */
	.set_pud = xen_set_pud_hyper,

2026 2027
	.make_pmd = PV_CALLEE_SAVE(xen_make_pmd),
	.pmd_val = PV_CALLEE_SAVE(xen_pmd_val),
2028 2029

#if PAGETABLE_LEVELS == 4
2030 2031
	.pud_val = PV_CALLEE_SAVE(xen_pud_val),
	.make_pud = PV_CALLEE_SAVE(xen_make_pud),
2032 2033
	.set_pgd = xen_set_pgd_hyper,

2034 2035
	.alloc_pud = xen_alloc_pmd_init,
	.release_pud = xen_release_pmd_init,
2036 2037 2038 2039 2040 2041 2042 2043
#endif	/* PAGETABLE_LEVELS == 4 */

	.activate_mm = xen_activate_mm,
	.dup_mmap = xen_dup_mmap,
	.exit_mmap = xen_exit_mmap,

	.lazy_mode = {
		.enter = paravirt_enter_lazy_mmu,
2044
		.leave = xen_leave_lazy_mmu,
2045 2046 2047 2048 2049
	},

	.set_fixmap = xen_set_fixmap,
};

2050 2051 2052 2053 2054
void __init xen_init_mmu_ops(void)
{
	x86_init.paging.pagetable_setup_start = xen_pagetable_setup_start;
	x86_init.paging.pagetable_setup_done = xen_pagetable_setup_done;
	pv_mmu_ops = xen_mmu_ops;
2055 2056

	vmap_lazy_unmap = false;
2057
}
2058

2059 2060 2061 2062 2063 2064 2065 2066 2067 2068 2069 2070 2071 2072 2073 2074 2075 2076 2077 2078 2079 2080 2081 2082 2083 2084 2085 2086 2087 2088 2089 2090 2091 2092 2093 2094 2095 2096 2097 2098 2099 2100 2101 2102 2103 2104 2105 2106 2107 2108 2109 2110 2111 2112 2113 2114 2115 2116 2117 2118 2119 2120 2121 2122 2123 2124 2125 2126 2127 2128 2129 2130 2131 2132 2133 2134 2135 2136 2137 2138 2139 2140 2141 2142 2143 2144 2145 2146 2147 2148 2149 2150 2151 2152 2153 2154 2155 2156 2157 2158 2159 2160 2161 2162 2163 2164 2165 2166 2167 2168 2169 2170 2171 2172 2173 2174 2175 2176 2177 2178 2179 2180 2181 2182 2183 2184 2185 2186 2187 2188 2189 2190 2191 2192 2193 2194 2195 2196 2197 2198 2199 2200 2201 2202 2203 2204 2205 2206 2207 2208 2209 2210 2211 2212 2213 2214 2215 2216 2217 2218 2219 2220 2221 2222 2223 2224 2225 2226 2227 2228 2229 2230 2231 2232 2233 2234 2235 2236 2237 2238 2239 2240 2241 2242 2243 2244 2245 2246 2247 2248 2249 2250 2251
/* Protected by xen_reservation_lock. */
#define MAX_CONTIG_ORDER 9 /* 2MB */
static unsigned long discontig_frames[1<<MAX_CONTIG_ORDER];

#define VOID_PTE (mfn_pte(0, __pgprot(0)))
static void xen_zap_pfn_range(unsigned long vaddr, unsigned int order,
				unsigned long *in_frames,
				unsigned long *out_frames)
{
	int i;
	struct multicall_space mcs;

	xen_mc_batch();
	for (i = 0; i < (1UL<<order); i++, vaddr += PAGE_SIZE) {
		mcs = __xen_mc_entry(0);

		if (in_frames)
			in_frames[i] = virt_to_mfn(vaddr);

		MULTI_update_va_mapping(mcs.mc, vaddr, VOID_PTE, 0);
		set_phys_to_machine(virt_to_pfn(vaddr), INVALID_P2M_ENTRY);

		if (out_frames)
			out_frames[i] = virt_to_pfn(vaddr);
	}
	xen_mc_issue(0);
}

/*
 * Update the pfn-to-mfn mappings for a virtual address range, either to
 * point to an array of mfns, or contiguously from a single starting
 * mfn.
 */
static void xen_remap_exchanged_ptes(unsigned long vaddr, int order,
				     unsigned long *mfns,
				     unsigned long first_mfn)
{
	unsigned i, limit;
	unsigned long mfn;

	xen_mc_batch();

	limit = 1u << order;
	for (i = 0; i < limit; i++, vaddr += PAGE_SIZE) {
		struct multicall_space mcs;
		unsigned flags;

		mcs = __xen_mc_entry(0);
		if (mfns)
			mfn = mfns[i];
		else
			mfn = first_mfn + i;

		if (i < (limit - 1))
			flags = 0;
		else {
			if (order == 0)
				flags = UVMF_INVLPG | UVMF_ALL;
			else
				flags = UVMF_TLB_FLUSH | UVMF_ALL;
		}

		MULTI_update_va_mapping(mcs.mc, vaddr,
				mfn_pte(mfn, PAGE_KERNEL), flags);

		set_phys_to_machine(virt_to_pfn(vaddr), mfn);
	}

	xen_mc_issue(0);
}

/*
 * Perform the hypercall to exchange a region of our pfns to point to
 * memory with the required contiguous alignment.  Takes the pfns as
 * input, and populates mfns as output.
 *
 * Returns a success code indicating whether the hypervisor was able to
 * satisfy the request or not.
 */
static int xen_exchange_memory(unsigned long extents_in, unsigned int order_in,
			       unsigned long *pfns_in,
			       unsigned long extents_out,
			       unsigned int order_out,
			       unsigned long *mfns_out,
			       unsigned int address_bits)
{
	long rc;
	int success;

	struct xen_memory_exchange exchange = {
		.in = {
			.nr_extents   = extents_in,
			.extent_order = order_in,
			.extent_start = pfns_in,
			.domid        = DOMID_SELF
		},
		.out = {
			.nr_extents   = extents_out,
			.extent_order = order_out,
			.extent_start = mfns_out,
			.address_bits = address_bits,
			.domid        = DOMID_SELF
		}
	};

	BUG_ON(extents_in << order_in != extents_out << order_out);

	rc = HYPERVISOR_memory_op(XENMEM_exchange, &exchange);
	success = (exchange.nr_exchanged == extents_in);

	BUG_ON(!success && ((exchange.nr_exchanged != 0) || (rc == 0)));
	BUG_ON(success && (rc != 0));

	return success;
}

int xen_create_contiguous_region(unsigned long vstart, unsigned int order,
				 unsigned int address_bits)
{
	unsigned long *in_frames = discontig_frames, out_frame;
	unsigned long  flags;
	int            success;

	/*
	 * Currently an auto-translated guest will not perform I/O, nor will
	 * it require PAE page directories below 4GB. Therefore any calls to
	 * this function are redundant and can be ignored.
	 */

	if (xen_feature(XENFEAT_auto_translated_physmap))
		return 0;

	if (unlikely(order > MAX_CONTIG_ORDER))
		return -ENOMEM;

	memset((void *) vstart, 0, PAGE_SIZE << order);

	spin_lock_irqsave(&xen_reservation_lock, flags);

	/* 1. Zap current PTEs, remembering MFNs. */
	xen_zap_pfn_range(vstart, order, in_frames, NULL);

	/* 2. Get a new contiguous memory extent. */
	out_frame = virt_to_pfn(vstart);
	success = xen_exchange_memory(1UL << order, 0, in_frames,
				      1, order, &out_frame,
				      address_bits);

	/* 3. Map the new extent in place of old pages. */
	if (success)
		xen_remap_exchanged_ptes(vstart, order, NULL, out_frame);
	else
		xen_remap_exchanged_ptes(vstart, order, in_frames, 0);

	spin_unlock_irqrestore(&xen_reservation_lock, flags);

	return success ? 0 : -ENOMEM;
}
EXPORT_SYMBOL_GPL(xen_create_contiguous_region);

void xen_destroy_contiguous_region(unsigned long vstart, unsigned int order)
{
	unsigned long *out_frames = discontig_frames, in_frame;
	unsigned long  flags;
	int success;

	if (xen_feature(XENFEAT_auto_translated_physmap))
		return;

	if (unlikely(order > MAX_CONTIG_ORDER))
		return;

	memset((void *) vstart, 0, PAGE_SIZE << order);

	spin_lock_irqsave(&xen_reservation_lock, flags);

	/* 1. Find start MFN of contiguous extent. */
	in_frame = virt_to_mfn(vstart);

	/* 2. Zap current PTEs. */
	xen_zap_pfn_range(vstart, order, NULL, out_frames);

	/* 3. Do the exchange for non-contiguous MFNs. */
	success = xen_exchange_memory(1, order, &in_frame, 1UL << order,
					0, out_frames, 0);

	/* 4. Map new pages in place of old pages. */
	if (success)
		xen_remap_exchanged_ptes(vstart, order, out_frames, 0);
	else
		xen_remap_exchanged_ptes(vstart, order, NULL, in_frame);

	spin_unlock_irqrestore(&xen_reservation_lock, flags);
2252
}
2253
EXPORT_SYMBOL_GPL(xen_destroy_contiguous_region);
2254

2255
#ifdef CONFIG_XEN_PVHVM
2256 2257 2258 2259 2260 2261 2262 2263 2264 2265 2266 2267 2268 2269 2270 2271 2272 2273 2274 2275 2276 2277 2278 2279 2280 2281 2282 2283 2284 2285 2286
static void xen_hvm_exit_mmap(struct mm_struct *mm)
{
	struct xen_hvm_pagetable_dying a;
	int rc;

	a.domid = DOMID_SELF;
	a.gpa = __pa(mm->pgd);
	rc = HYPERVISOR_hvm_op(HVMOP_pagetable_dying, &a);
	WARN_ON_ONCE(rc < 0);
}

static int is_pagetable_dying_supported(void)
{
	struct xen_hvm_pagetable_dying a;
	int rc = 0;

	a.domid = DOMID_SELF;
	a.gpa = 0x00;
	rc = HYPERVISOR_hvm_op(HVMOP_pagetable_dying, &a);
	if (rc < 0) {
		printk(KERN_DEBUG "HVMOP_pagetable_dying not supported\n");
		return 0;
	}
	return 1;
}

void __init xen_hvm_init_mmu_ops(void)
{
	if (is_pagetable_dying_supported())
		pv_mmu_ops.exit_mmap = xen_hvm_exit_mmap;
}
2287
#endif
2288

J
Jeremy Fitzhardinge 已提交
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#ifdef CONFIG_XEN_DEBUG_FS

static struct dentry *d_mmu_debug;

static int __init xen_mmu_debugfs(void)
{
	struct dentry *d_xen = xen_init_debugfs();

	if (d_xen == NULL)
		return -ENOMEM;

	d_mmu_debug = debugfs_create_dir("mmu", d_xen);

	debugfs_create_u8("zero_stats", 0644, d_mmu_debug, &zero_stats);

	debugfs_create_u32("pgd_update", 0444, d_mmu_debug, &mmu_stats.pgd_update);
	debugfs_create_u32("pgd_update_pinned", 0444, d_mmu_debug,
			   &mmu_stats.pgd_update_pinned);
	debugfs_create_u32("pgd_update_batched", 0444, d_mmu_debug,
			   &mmu_stats.pgd_update_pinned);

	debugfs_create_u32("pud_update", 0444, d_mmu_debug, &mmu_stats.pud_update);
	debugfs_create_u32("pud_update_pinned", 0444, d_mmu_debug,
			   &mmu_stats.pud_update_pinned);
	debugfs_create_u32("pud_update_batched", 0444, d_mmu_debug,
			   &mmu_stats.pud_update_pinned);

	debugfs_create_u32("pmd_update", 0444, d_mmu_debug, &mmu_stats.pmd_update);
	debugfs_create_u32("pmd_update_pinned", 0444, d_mmu_debug,
			   &mmu_stats.pmd_update_pinned);
	debugfs_create_u32("pmd_update_batched", 0444, d_mmu_debug,
			   &mmu_stats.pmd_update_pinned);

	debugfs_create_u32("pte_update", 0444, d_mmu_debug, &mmu_stats.pte_update);
//	debugfs_create_u32("pte_update_pinned", 0444, d_mmu_debug,
//			   &mmu_stats.pte_update_pinned);
	debugfs_create_u32("pte_update_batched", 0444, d_mmu_debug,
			   &mmu_stats.pte_update_pinned);

	debugfs_create_u32("mmu_update", 0444, d_mmu_debug, &mmu_stats.mmu_update);
	debugfs_create_u32("mmu_update_extended", 0444, d_mmu_debug,
			   &mmu_stats.mmu_update_extended);
	xen_debugfs_create_u32_array("mmu_update_histo", 0444, d_mmu_debug,
				     mmu_stats.mmu_update_histo, 20);

	debugfs_create_u32("set_pte_at", 0444, d_mmu_debug, &mmu_stats.set_pte_at);
	debugfs_create_u32("set_pte_at_batched", 0444, d_mmu_debug,
			   &mmu_stats.set_pte_at_batched);
	debugfs_create_u32("set_pte_at_current", 0444, d_mmu_debug,
			   &mmu_stats.set_pte_at_current);
	debugfs_create_u32("set_pte_at_kernel", 0444, d_mmu_debug,
			   &mmu_stats.set_pte_at_kernel);

	debugfs_create_u32("prot_commit", 0444, d_mmu_debug, &mmu_stats.prot_commit);
	debugfs_create_u32("prot_commit_batched", 0444, d_mmu_debug,
			   &mmu_stats.prot_commit_batched);

	return 0;
}
fs_initcall(xen_mmu_debugfs);

#endif	/* CONFIG_XEN_DEBUG_FS */