mmu.c 57.0 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 <linux/memblock.h>
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#include <linux/seq_file.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/init.h>
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#include <asm/pat.h>
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#include <asm/smp.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"

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

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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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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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}
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EXPORT_SYMBOL_GPL(arbitrary_virt_to_machine);
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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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	if (pte == NULL)
		return;		/* vaddr missing */
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	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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	if (pte == NULL)
		return;		/* vaddr missing */
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	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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void xen_set_domain_pte(pte_t *ptep, pte_t pteval, unsigned domid)
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{
	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 */
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	u->ptr = virt_to_machine(ptep).maddr;
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	u->val = pte_val_ma(pteval);

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	MULTI_mmu_update(mcs.mc, mcs.args, 1, NULL, domid);
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	xen_mc_issue(PARAVIRT_LAZY_MMU);
}
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EXPORT_SYMBOL_GPL(xen_set_domain_pte);

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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) {
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		mcs.mc->args[1]++;
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	} else {
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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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	u = mcs.args;
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	*u = *update;
}

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static void xen_set_pmd_hyper(pmd_t *ptr, pmd_t val)
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{
	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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	xen_mc_issue(PARAVIRT_LAZY_MMU);

	preempt_enable();
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}

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static void xen_set_pmd(pmd_t *ptr, pmd_t val)
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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;
	}

	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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}

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static bool xen_batched_set_pte(pte_t *ptep, pte_t pteval)
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{
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	struct mmu_update u;
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	if (paravirt_get_lazy_mode() != PARAVIRT_LAZY_MMU)
		return false;
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	xen_mc_batch();
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	u.ptr = virt_to_machine(ptep).maddr | MMU_NORMAL_PT_UPDATE;
	u.val = pte_val_ma(pteval);
	xen_extend_mmu_update(&u);
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	xen_mc_issue(PARAVIRT_LAZY_MMU);
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	return true;
}

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static void xen_set_pte(pte_t *ptep, pte_t pteval)
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{
	if (!xen_batched_set_pte(ptep, pteval))
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		native_set_pte(ptep, pteval);
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}

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static void xen_set_pte_at(struct mm_struct *mm, unsigned long addr,
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		    pte_t *ptep, pte_t pteval)
{
	xen_set_pte(ptep, pteval);
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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 = 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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	xen_mc_issue(PARAVIRT_LAZY_MMU);
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}

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/* 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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{
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	if (val & _PAGE_PRESENT) {
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		unsigned long mfn = (val & PTE_PFN_MASK) >> PAGE_SHIFT;
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		pteval_t flags = val & PTE_FLAGS_MASK;
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		val = ((pteval_t)mfn_to_pfn(mfn) << PAGE_SHIFT) | flags;
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	}
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	return val;
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}

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static pteval_t pte_pfn_to_mfn(pteval_t val)
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{
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	if (val & _PAGE_PRESENT) {
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		unsigned long pfn = (val & PTE_PFN_MASK) >> PAGE_SHIFT;
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		pteval_t flags = val & PTE_FLAGS_MASK;
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		unsigned long mfn;
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		if (!xen_feature(XENFEAT_auto_translated_physmap))
			mfn = get_phys_to_machine(pfn);
		else
			mfn = pfn;
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		/*
		 * If there's no mfn for the pfn, then just create an
		 * empty non-present pte.  Unfortunately this loses
		 * information about the original pfn, so
		 * pte_mfn_to_pfn is asymmetric.
		 */
		if (unlikely(mfn == INVALID_P2M_ENTRY)) {
			mfn = 0;
			flags = 0;
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		} else {
			/*
			 * Paramount to do this test _after_ the
			 * INVALID_P2M_ENTRY as INVALID_P2M_ENTRY &
			 * IDENTITY_FRAME_BIT resolves to true.
			 */
			mfn &= ~FOREIGN_FRAME_BIT;
			if (mfn & IDENTITY_FRAME_BIT) {
				mfn &= ~IDENTITY_FRAME_BIT;
				flags |= _PAGE_IOMAP;
			}
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		}
		val = ((pteval_t)mfn << PAGE_SHIFT) | flags;
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	}

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	return val;
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}

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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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static pteval_t xen_pte_val(pte_t pte)
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{
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	pteval_t pteval = pte.pte;
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	/* If this is a WC pte, convert back from Xen WC to Linux WC */
	if ((pteval & (_PAGE_PAT | _PAGE_PCD | _PAGE_PWT)) == _PAGE_PAT) {
		WARN_ON(!pat_enabled);
		pteval = (pteval & ~_PAGE_PAT) | _PAGE_PWT;
	}
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	if (xen_initial_domain() && (pteval & _PAGE_IOMAP))
		return pteval;

	return pte_mfn_to_pfn(pteval);
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}
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PV_CALLEE_SAVE_REGS_THUNK(xen_pte_val);
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static pgdval_t xen_pgd_val(pgd_t pgd)
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{
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	return pte_mfn_to_pfn(pgd.pgd);
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}
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PV_CALLEE_SAVE_REGS_THUNK(xen_pgd_val);
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/*
 * Xen's PAT setup is part of its ABI, though I assume entries 6 & 7
 * are reserved for now, to correspond to the Intel-reserved PAT
 * types.
 *
 * We expect Linux's PAT set as follows:
 *
 * Idx  PTE flags        Linux    Xen    Default
 * 0                     WB       WB     WB
 * 1            PWT      WC       WT     WT
 * 2        PCD          UC-      UC-    UC-
 * 3        PCD PWT      UC       UC     UC
 * 4    PAT              WB       WC     WB
 * 5    PAT     PWT      WC       WP     WT
 * 6    PAT PCD          UC-      UC     UC-
 * 7    PAT PCD PWT      UC       UC     UC
 */

void xen_set_pat(u64 pat)
{
	/* We expect Linux to use a PAT setting of
	 * UC UC- WC WB (ignoring the PAT flag) */
	WARN_ON(pat != 0x0007010600070106ull);
}

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static pte_t xen_make_pte(pteval_t pte)
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{
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	phys_addr_t addr = (pte & PTE_PFN_MASK);

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	/* If Linux is trying to set a WC pte, then map to the Xen WC.
	 * If _PAGE_PAT is set, then it probably means it is really
	 * _PAGE_PSE, so avoid fiddling with the PAT mapping and hope
	 * things work out OK...
	 *
	 * (We should never see kernel mappings with _PAGE_PSE set,
	 * but we could see hugetlbfs mappings, I think.).
	 */
	if (pat_enabled && !WARN_ON(pte & _PAGE_PAT)) {
		if ((pte & (_PAGE_PCD | _PAGE_PWT)) == _PAGE_PWT)
			pte = (pte & ~(_PAGE_PCD | _PAGE_PWT)) | _PAGE_PAT;
	}

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	/*
	 * 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)) {
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		pte = iomap_pte(pte);
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	} else {
		pte &= ~_PAGE_IOMAP;
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		pte = pte_pfn_to_mfn(pte);
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	}
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	return native_make_pte(pte);
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}
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PV_CALLEE_SAVE_REGS_THUNK(xen_make_pte);
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#ifdef CONFIG_XEN_DEBUG
pte_t xen_make_pte_debug(pteval_t pte)
{
	phys_addr_t addr = (pte & PTE_PFN_MASK);
	phys_addr_t other_addr;
	bool io_page = false;
	pte_t _pte;

	if (pte & _PAGE_IOMAP)
		io_page = true;

	_pte = xen_make_pte(pte);

	if (!addr)
		return _pte;

	if (io_page &&
	    (xen_initial_domain() || addr >= ISA_END_ADDRESS)) {
		other_addr = pfn_to_mfn(addr >> PAGE_SHIFT) << PAGE_SHIFT;
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		WARN_ONCE(addr != other_addr,
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			"0x%lx is using VM_IO, but it is 0x%lx!\n",
			(unsigned long)addr, (unsigned long)other_addr);
	} else {
		pteval_t iomap_set = (_pte.pte & PTE_FLAGS_MASK) & _PAGE_IOMAP;
		other_addr = (_pte.pte & PTE_PFN_MASK);
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		WARN_ONCE((addr == other_addr) && (!io_page) && (!iomap_set),
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			"0x%lx is missing VM_IO (and wasn't fixed)!\n",
			(unsigned long)addr);
	}

	return _pte;
}
PV_CALLEE_SAVE_REGS_THUNK(xen_make_pte_debug);
#endif

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static pgd_t xen_make_pgd(pgdval_t pgd)
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{
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	pgd = pte_pfn_to_mfn(pgd);
	return native_make_pgd(pgd);
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}
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PV_CALLEE_SAVE_REGS_THUNK(xen_make_pgd);
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static pmdval_t xen_pmd_val(pmd_t pmd)
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{
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	return pte_mfn_to_pfn(pmd.pmd);
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}
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PV_CALLEE_SAVE_REGS_THUNK(xen_pmd_val);
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static void xen_set_pud_hyper(pud_t *ptr, pud_t val)
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{
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	struct mmu_update u;
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	preempt_disable();

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	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 = pud_val_ma(val);
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	xen_extend_mmu_update(&u);
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	xen_mc_issue(PARAVIRT_LAZY_MMU);

	preempt_enable();
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}

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static void xen_set_pud(pud_t *ptr, pud_t val)
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{
	/* If page is not pinned, we can just update the entry
	   directly */
535
	if (!xen_page_pinned(ptr)) {
536 537 538 539 540 541 542
		*ptr = val;
		return;
	}

	xen_set_pud_hyper(ptr, val);
}

543
#ifdef CONFIG_X86_PAE
544
static void xen_set_pte_atomic(pte_t *ptep, pte_t pte)
J
Jeremy Fitzhardinge 已提交
545
{
546
	set_64bit((u64 *)ptep, native_pte_val(pte));
J
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547 548
}

549
static void xen_pte_clear(struct mm_struct *mm, unsigned long addr, pte_t *ptep)
J
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550
{
551 552
	if (!xen_batched_set_pte(ptep, native_make_pte(0)))
		native_pte_clear(mm, addr, ptep);
J
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553 554
}

555
static void xen_pmd_clear(pmd_t *pmdp)
J
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556
{
557
	set_pmd(pmdp, __pmd(0));
J
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558
}
559
#endif	/* CONFIG_X86_PAE */
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560

561
static pmd_t xen_make_pmd(pmdval_t pmd)
J
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562
{
J
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563
	pmd = pte_pfn_to_mfn(pmd);
J
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564
	return native_make_pmd(pmd);
J
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565
}
566
PV_CALLEE_SAVE_REGS_THUNK(xen_make_pmd);
J
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567

568
#if PAGETABLE_LEVELS == 4
569
static pudval_t xen_pud_val(pud_t pud)
570 571 572
{
	return pte_mfn_to_pfn(pud.pud);
}
573
PV_CALLEE_SAVE_REGS_THUNK(xen_pud_val);
574

575
static pud_t xen_make_pud(pudval_t pud)
576 577 578 579 580
{
	pud = pte_pfn_to_mfn(pud);

	return native_make_pud(pud);
}
581
PV_CALLEE_SAVE_REGS_THUNK(xen_make_pud);
582

583
static pgd_t *xen_get_user_pgd(pgd_t *pgd)
584
{
585 586 587
	pgd_t *pgd_page = (pgd_t *)(((unsigned long)pgd) & PAGE_MASK);
	unsigned offset = pgd - pgd_page;
	pgd_t *user_ptr = NULL;
588

589 590 591 592 593 594
	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;
	}
595

596 597 598 599 600 601
	return user_ptr;
}

static void __xen_set_pgd_hyper(pgd_t *ptr, pgd_t val)
{
	struct mmu_update u;
602 603 604

	u.ptr = virt_to_machine(ptr).maddr;
	u.val = pgd_val_ma(val);
605
	xen_extend_mmu_update(&u);
606 607 608 609 610 611 612 613 614
}

/*
 * 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
 */
615
static void __init xen_set_pgd_hyper(pgd_t *ptr, pgd_t val)
616 617 618 619 620 621
{
	preempt_disable();

	xen_mc_batch();

	__xen_set_pgd_hyper(ptr, val);
622 623 624 625 626 627

	xen_mc_issue(PARAVIRT_LAZY_MMU);

	preempt_enable();
}

628
static void xen_set_pgd(pgd_t *ptr, pgd_t val)
629
{
630 631
	pgd_t *user_ptr = xen_get_user_pgd(ptr);

632 633
	/* If page is not pinned, we can just update the entry
	   directly */
634
	if (!xen_page_pinned(ptr)) {
635
		*ptr = val;
636
		if (user_ptr) {
637
			WARN_ON(xen_page_pinned(user_ptr));
638 639
			*user_ptr = val;
		}
640 641 642
		return;
	}

643 644 645 646 647 648 649 650 651
	/* 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);
652 653 654
}
#endif	/* PAGETABLE_LEVELS == 4 */

655
/*
656 657 658 659 660 661 662 663 664 665 666 667 668 669
 * (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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Ian Campbell 已提交
670 671 672 673
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
Jeremy Fitzhardinge 已提交
674
{
675
	int flush = 0;
676 677 678
	unsigned hole_low, hole_high;
	unsigned pgdidx_limit, pudidx_limit, pmdidx_limit;
	unsigned pgdidx, pudidx, pmdidx;
679

680 681 682
	/* The limit is the last byte to be touched */
	limit--;
	BUG_ON(limit >= FIXADDR_TOP);
J
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683 684

	if (xen_feature(XENFEAT_auto_translated_physmap))
685 686
		return 0;

687 688 689 690 691
	/*
	 * 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.
	 */
692
	hole_low = pgd_index(USER_LIMIT);
693 694 695 696 697 698 699 700 701 702 703 704 705 706 707
	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++) {
708
		pud_t *pud;
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709

710 711
		if (pgdidx >= hole_low && pgdidx < hole_high)
			continue;
712

713
		if (!pgd_val(pgd[pgdidx]))
J
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714
			continue;
715

716
		pud = pud_offset(&pgd[pgdidx], 0);
J
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717 718

		if (PTRS_PER_PUD > 1) /* not folded */
719
			flush |= (*func)(mm, virt_to_page(pud), PT_PUD);
720

721
		for (pudidx = 0; pudidx < PTRS_PER_PUD; pudidx++) {
722 723
			pmd_t *pmd;

724 725 726
			if (pgdidx == pgdidx_limit &&
			    pudidx > pudidx_limit)
				goto out;
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727

728
			if (pud_none(pud[pudidx]))
J
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729
				continue;
730

731
			pmd = pmd_offset(&pud[pudidx], 0);
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732 733

			if (PTRS_PER_PMD > 1) /* not folded */
734
				flush |= (*func)(mm, virt_to_page(pmd), PT_PMD);
735

736 737 738 739 740 741 742
			for (pmdidx = 0; pmdidx < PTRS_PER_PMD; pmdidx++) {
				struct page *pte;

				if (pgdidx == pgdidx_limit &&
				    pudidx == pudidx_limit &&
				    pmdidx > pmdidx_limit)
					goto out;
J
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743

744
				if (pmd_none(pmd[pmdidx]))
J
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745 746
					continue;

747
				pte = pmd_page(pmd[pmdidx]);
748
				flush |= (*func)(mm, pte, PT_PTE);
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749 750 751
			}
		}
	}
752

753
out:
754 755
	/* Do the top level last, so that the callbacks can use it as
	   a cue to do final things like tlb flushes. */
756
	flush |= (*func)(mm, virt_to_page(pgd), PT_PGD);
757 758

	return flush;
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759 760
}

I
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761 762 763 764 765 766 767 768
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);
}

769 770
/* If we're using split pte locks, then take the page's lock and
   return a pointer to it.  Otherwise return NULL. */
771
static spinlock_t *xen_pte_lock(struct page *page, struct mm_struct *mm)
772 773 774
{
	spinlock_t *ptl = NULL;

775
#if USE_SPLIT_PTLOCKS
776
	ptl = __pte_lockptr(page);
777
	spin_lock_nest_lock(ptl, &mm->page_table_lock);
778 779 780 781 782
#endif

	return ptl;
}

783
static void xen_pte_unlock(void *v)
784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800
{
	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);
}

801 802
static int xen_pin_page(struct mm_struct *mm, struct page *page,
			enum pt_level level)
803
{
804
	unsigned pgfl = TestSetPagePinned(page);
805 806 807 808 809 810 811 812 813 814 815 816
	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);
817
		spinlock_t *ptl;
818 819 820

		flush = 0;

821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840
		/*
		 * 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.
		 */
841 842
		ptl = NULL;
		if (level == PT_PTE)
843
			ptl = xen_pte_lock(page, mm);
844

845 846
		MULTI_update_va_mapping(mcs.mc, (unsigned long)pt,
					pfn_pte(pfn, PAGE_KERNEL_RO),
847 848
					level == PT_PGD ? UVMF_TLB_FLUSH : 0);

849
		if (ptl) {
850 851 852 853
			xen_do_pin(MMUEXT_PIN_L1_TABLE, pfn);

			/* Queue a deferred unlock for when this batch
			   is completed. */
854
			xen_mc_callback(xen_pte_unlock, ptl);
855
		}
856 857 858 859
	}

	return flush;
}
J
Jeremy Fitzhardinge 已提交
860

861 862 863
/* 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. */
864
static void __xen_pgd_pin(struct mm_struct *mm, pgd_t *pgd)
J
Jeremy Fitzhardinge 已提交
865
{
866
	xen_mc_batch();
J
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867

I
Ian Campbell 已提交
868
	if (__xen_pgd_walk(mm, pgd, xen_pin_page, USER_LIMIT)) {
869
		/* re-enable interrupts for flushing */
J
Jeremy Fitzhardinge 已提交
870
		xen_mc_issue(0);
871

872
		kmap_flush_unused();
873

J
Jeremy Fitzhardinge 已提交
874 875
		xen_mc_batch();
	}
876

877 878 879 880 881 882 883
#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) {
884
			xen_pin_page(mm, virt_to_page(user_pgd), PT_PGD);
T
Tej 已提交
885 886
			xen_do_pin(MMUEXT_PIN_L4_TABLE,
				   PFN_DOWN(__pa(user_pgd)));
887 888 889
		}
	}
#else /* CONFIG_X86_32 */
890 891
#ifdef CONFIG_X86_PAE
	/* Need to make sure unshared kernel PMD is pinnable */
892
	xen_pin_page(mm, pgd_page(pgd[pgd_index(TASK_SIZE)]),
893
		     PT_PMD);
894
#endif
895
	xen_do_pin(MMUEXT_PIN_L3_TABLE, PFN_DOWN(__pa(pgd)));
896
#endif /* CONFIG_X86_64 */
897
	xen_mc_issue(0);
J
Jeremy Fitzhardinge 已提交
898 899
}

900 901 902 903 904
static void xen_pgd_pin(struct mm_struct *mm)
{
	__xen_pgd_pin(mm, mm->pgd);
}

905 906 907 908 909
/*
 * 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).
910 911 912 913
 *
 * 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.
914 915 916 917
 */
void xen_mm_pin_all(void)
{
	struct page *page;
918

A
Andrea Arcangeli 已提交
919
	spin_lock(&pgd_lock);
920

921 922
	list_for_each_entry(page, &pgd_list, lru) {
		if (!PagePinned(page)) {
923
			__xen_pgd_pin(&init_mm, (pgd_t *)page_address(page));
924 925 926 927
			SetPageSavePinned(page);
		}
	}

A
Andrea Arcangeli 已提交
928
	spin_unlock(&pgd_lock);
J
Jeremy Fitzhardinge 已提交
929 930
}

931 932 933 934 935
/*
 * 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.
 */
936
static int __init xen_mark_pinned(struct mm_struct *mm, struct page *page,
937
				  enum pt_level level)
J
Jeremy Fitzhardinge 已提交
938
{
939 940 941
	SetPagePinned(page);
	return 0;
}
J
Jeremy Fitzhardinge 已提交
942

943
static void __init xen_mark_init_mm_pinned(void)
944
{
945
	xen_pgd_walk(&init_mm, xen_mark_pinned, FIXADDR_TOP);
946
}
J
Jeremy Fitzhardinge 已提交
947

948 949
static int xen_unpin_page(struct mm_struct *mm, struct page *page,
			  enum pt_level level)
950
{
951
	unsigned pgfl = TestClearPagePinned(page);
J
Jeremy Fitzhardinge 已提交
952

953 954 955
	if (pgfl && !PageHighMem(page)) {
		void *pt = lowmem_page_address(page);
		unsigned long pfn = page_to_pfn(page);
956 957 958
		spinlock_t *ptl = NULL;
		struct multicall_space mcs;

959 960 961 962 963 964 965
		/*
		 * 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.
		 */
966
		if (level == PT_PTE) {
967
			ptl = xen_pte_lock(page, mm);
968

969 970
			if (ptl)
				xen_do_pin(MMUEXT_UNPIN_TABLE, pfn);
971 972 973
		}

		mcs = __xen_mc_entry(0);
974 975 976

		MULTI_update_va_mapping(mcs.mc, (unsigned long)pt,
					pfn_pte(pfn, PAGE_KERNEL),
977 978 979 980
					level == PT_PGD ? UVMF_TLB_FLUSH : 0);

		if (ptl) {
			/* unlock when batch completed */
981
			xen_mc_callback(xen_pte_unlock, ptl);
982
		}
983 984 985
	}

	return 0;		/* never need to flush on unpin */
J
Jeremy Fitzhardinge 已提交
986 987
}

988
/* Release a pagetables pages back as normal RW */
989
static void __xen_pgd_unpin(struct mm_struct *mm, pgd_t *pgd)
990 991 992
{
	xen_mc_batch();

993
	xen_do_pin(MMUEXT_UNPIN_TABLE, PFN_DOWN(__pa(pgd)));
994

995 996 997 998 999
#ifdef CONFIG_X86_64
	{
		pgd_t *user_pgd = xen_get_user_pgd(pgd);

		if (user_pgd) {
T
Tej 已提交
1000 1001
			xen_do_pin(MMUEXT_UNPIN_TABLE,
				   PFN_DOWN(__pa(user_pgd)));
1002
			xen_unpin_page(mm, virt_to_page(user_pgd), PT_PGD);
1003 1004 1005 1006
		}
	}
#endif

1007 1008
#ifdef CONFIG_X86_PAE
	/* Need to make sure unshared kernel PMD is unpinned */
1009
	xen_unpin_page(mm, pgd_page(pgd[pgd_index(TASK_SIZE)]),
1010
		       PT_PMD);
1011
#endif
1012

I
Ian Campbell 已提交
1013
	__xen_pgd_walk(mm, pgd, xen_unpin_page, USER_LIMIT);
1014 1015 1016

	xen_mc_issue(0);
}
J
Jeremy Fitzhardinge 已提交
1017

1018 1019 1020 1021 1022
static void xen_pgd_unpin(struct mm_struct *mm)
{
	__xen_pgd_unpin(mm, mm->pgd);
}

1023 1024 1025 1026 1027 1028 1029 1030
/*
 * 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)
{
	struct page *page;

A
Andrea Arcangeli 已提交
1031
	spin_lock(&pgd_lock);
1032 1033 1034 1035

	list_for_each_entry(page, &pgd_list, lru) {
		if (PageSavePinned(page)) {
			BUG_ON(!PagePinned(page));
1036
			__xen_pgd_unpin(&init_mm, (pgd_t *)page_address(page));
1037 1038 1039 1040
			ClearPageSavePinned(page);
		}
	}

A
Andrea Arcangeli 已提交
1041
	spin_unlock(&pgd_lock);
1042 1043
}

1044
static void xen_activate_mm(struct mm_struct *prev, struct mm_struct *next)
J
Jeremy Fitzhardinge 已提交
1045
{
1046
	spin_lock(&next->page_table_lock);
1047
	xen_pgd_pin(next);
1048
	spin_unlock(&next->page_table_lock);
J
Jeremy Fitzhardinge 已提交
1049 1050
}

1051
static void xen_dup_mmap(struct mm_struct *oldmm, struct mm_struct *mm)
J
Jeremy Fitzhardinge 已提交
1052
{
1053
	spin_lock(&mm->page_table_lock);
1054
	xen_pgd_pin(mm);
1055
	spin_unlock(&mm->page_table_lock);
J
Jeremy Fitzhardinge 已提交
1056 1057 1058
}


J
Jeremy Fitzhardinge 已提交
1059 1060 1061 1062 1063 1064
#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;
1065
	struct mm_struct *active_mm;
J
Jeremy Fitzhardinge 已提交
1066

1067
	active_mm = percpu_read(cpu_tlbstate.active_mm);
1068

1069
	if (active_mm == mm && percpu_read(cpu_tlbstate.state) != TLBSTATE_OK)
J
Jeremy Fitzhardinge 已提交
1070
		leave_mm(smp_processor_id());
1071 1072 1073

	/* If this cpu still has a stale cr3 reference, then make sure
	   it has been flushed. */
1074
	if (percpu_read(xen_current_cr3) == __pa(mm->pgd))
1075
		load_cr3(swapper_pg_dir);
J
Jeremy Fitzhardinge 已提交
1076
}
J
Jeremy Fitzhardinge 已提交
1077

1078
static void xen_drop_mm_ref(struct mm_struct *mm)
J
Jeremy Fitzhardinge 已提交
1079
{
1080
	cpumask_var_t mask;
1081 1082
	unsigned cpu;

J
Jeremy Fitzhardinge 已提交
1083 1084 1085 1086 1087
	if (current->active_mm == mm) {
		if (current->mm == mm)
			load_cr3(swapper_pg_dir);
		else
			leave_mm(smp_processor_id());
1088 1089 1090
	}

	/* Get the "official" set of cpus referring to our pagetable. */
1091 1092
	if (!alloc_cpumask_var(&mask, GFP_ATOMIC)) {
		for_each_online_cpu(cpu) {
1093
			if (!cpumask_test_cpu(cpu, mm_cpumask(mm))
1094 1095 1096 1097 1098 1099
			    && per_cpu(xen_current_cr3, cpu) != __pa(mm->pgd))
				continue;
			smp_call_function_single(cpu, drop_other_mm_ref, mm, 1);
		}
		return;
	}
1100
	cpumask_copy(mask, mm_cpumask(mm));
1101 1102 1103 1104 1105 1106 1107 1108

	/* 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))
1109
			cpumask_set_cpu(cpu, mask);
J
Jeremy Fitzhardinge 已提交
1110 1111
	}

1112 1113 1114
	if (!cpumask_empty(mask))
		smp_call_function_many(mask, drop_other_mm_ref, mm, 1);
	free_cpumask_var(mask);
J
Jeremy Fitzhardinge 已提交
1115 1116
}
#else
1117
static void xen_drop_mm_ref(struct mm_struct *mm)
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Jeremy Fitzhardinge 已提交
1118 1119 1120 1121 1122 1123 1124 1125 1126 1127 1128 1129 1130 1131 1132 1133 1134 1135 1136 1137
{
	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.
 */
1138
static void xen_exit_mmap(struct mm_struct *mm)
J
Jeremy Fitzhardinge 已提交
1139 1140
{
	get_cpu();		/* make sure we don't move around */
1141
	xen_drop_mm_ref(mm);
J
Jeremy Fitzhardinge 已提交
1142
	put_cpu();
J
Jeremy Fitzhardinge 已提交
1143

1144
	spin_lock(&mm->page_table_lock);
1145 1146

	/* pgd may not be pinned in the error exit path of execve */
1147
	if (xen_page_pinned(mm->pgd))
1148
		xen_pgd_unpin(mm);
1149

1150
	spin_unlock(&mm->page_table_lock);
J
Jeremy Fitzhardinge 已提交
1151
}
J
Jeremy Fitzhardinge 已提交
1152

1153
static void __init xen_pagetable_setup_start(pgd_t *base)
1154 1155 1156
{
}

1157 1158 1159 1160 1161 1162 1163 1164 1165 1166 1167 1168 1169 1170
static __init void xen_mapping_pagetable_reserve(u64 start, u64 end)
{
	/* reserve the range used */
	native_pagetable_reserve(start, end);

	/* set as RW the rest */
	printk(KERN_DEBUG "xen: setting RW the range %llx - %llx\n", end,
			PFN_PHYS(pgt_buf_top));
	while (end < PFN_PHYS(pgt_buf_top)) {
		make_lowmem_page_readwrite(__va(end));
		end += PAGE_SIZE;
	}
}

1171 1172
static void xen_post_allocator_init(void);

1173
static void __init xen_pagetable_setup_done(pgd_t *base)
1174 1175
{
	xen_setup_shared_info();
1176
	xen_post_allocator_init();
1177 1178 1179 1180 1181 1182 1183 1184 1185 1186 1187 1188 1189 1190 1191 1192 1193 1194 1195 1196 1197 1198 1199 1200 1201 1202 1203 1204 1205 1206 1207 1208 1209 1210 1211 1212 1213 1214 1215 1216 1217 1218 1219 1220 1221 1222 1223 1224 1225 1226 1227 1228 1229 1230 1231 1232 1233 1234
}

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;
A
Andrew Jones 已提交
1235
		DECLARE_BITMAP(mask, num_processors);
1236 1237 1238
	} *args;
	struct multicall_space mcs;

1239 1240
	if (cpumask_empty(cpus))
		return;		/* nothing to do */
1241 1242 1243 1244 1245 1246 1247 1248 1249 1250 1251 1252 1253 1254 1255 1256 1257 1258 1259 1260 1261 1262 1263 1264 1265 1266 1267 1268 1269 1270 1271 1272 1273 1274 1275 1276 1277 1278 1279 1280 1281 1282 1283 1284 1285 1286 1287 1288 1289 1290 1291 1292 1293 1294 1295 1296 1297 1298 1299 1300 1301 1302 1303 1304 1305 1306 1307 1308 1309 1310 1311 1312 1313 1314 1315 1316 1317 1318 1319 1320 1321 1322 1323 1324 1325 1326 1327 1328 1329 1330 1331 1332 1333 1334 1335 1336 1337 1338 1339 1340 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

	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
}

1369
#ifdef CONFIG_X86_32
1370
static pte_t __init mask_rw_pte(pte_t *ptep, pte_t pte)
1371 1372 1373 1374 1375
{
	/* 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));
1376 1377 1378 1379

	return pte;
}
#else /* CONFIG_X86_64 */
1380
static pte_t __init mask_rw_pte(pte_t *ptep, pte_t pte)
1381 1382
{
	unsigned long pfn = pte_pfn(pte);
1383 1384 1385 1386

	/*
	 * If the new pfn is within the range of the newly allocated
	 * kernel pagetable, and it isn't being mapped into an
1387 1388
	 * early_ioremap fixmap slot as a freshly allocated page, make sure
	 * it is RO.
1389
	 */
1390
	if (((!is_early_ioremap_ptep(ptep) &&
1391
			pfn >= pgt_buf_start && pfn < pgt_buf_top)) ||
1392
			(is_early_ioremap_ptep(ptep) && pfn != (pgt_buf_end - 1)))
1393
		pte = pte_wrprotect(pte);
1394 1395 1396

	return pte;
}
1397
#endif /* CONFIG_X86_64 */
1398 1399 1400

/* Init-time set_pte while constructing initial pagetables, which
   doesn't allow RO pagetable pages to be remapped RW */
1401
static void __init xen_set_pte_init(pte_t *ptep, pte_t pte)
1402 1403 1404 1405 1406
{
	pte = mask_rw_pte(ptep, pte);

	xen_set_pte(ptep, pte);
}
1407

1408 1409 1410 1411 1412 1413 1414 1415 1416
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();
}

1417 1418
/* Early in boot, while setting up the initial pagetable, assume
   everything is pinned. */
1419
static void __init xen_alloc_pte_init(struct mm_struct *mm, unsigned long pfn)
1420
{
1421 1422 1423 1424 1425 1426 1427 1428
#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 */
1429
static void __init xen_alloc_pmd_init(struct mm_struct *mm, unsigned long pfn)
1430
{
1431 1432 1433 1434 1435 1436 1437 1438
#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. */
1439
static void __init xen_release_pte_init(unsigned long pfn)
1440
{
1441
	pin_pagetable_pfn(MMUEXT_UNPIN_TABLE, pfn);
1442 1443 1444
	make_lowmem_page_readwrite(__va(PFN_PHYS(pfn)));
}

1445
static void __init xen_release_pmd_init(unsigned long pfn)
1446
{
1447
	make_lowmem_page_readwrite(__va(PFN_PHYS(pfn)));
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 1533 1534 1535 1536 1537 1538 1539 1540 1541 1542 1543 1544 1545 1546 1547 1548 1549 1550 1551 1552 1553 1554 1555 1556 1557 1558 1559 1560
}

/* 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));
}

1561
/* Set the page permissions on an identity-mapped pages */
1562 1563 1564 1565 1566 1567 1568 1569 1570
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();
}

1571
static void __init xen_map_identity_early(pmd_t *pmd, unsigned long max_pfn)
1572 1573 1574 1575 1576
{
	unsigned pmdidx, pteidx;
	unsigned ident_pte;
	unsigned long pfn;

1577 1578 1579
	level1_ident_pgt = extend_brk(sizeof(pte_t) * LEVEL1_IDENT_ENTRIES,
				      PAGE_SIZE);

1580 1581 1582 1583 1584 1585 1586 1587 1588 1589
	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 */
1590
			if (ident_pte == LEVEL1_IDENT_ENTRIES)
1591 1592 1593 1594 1595 1596 1597 1598 1599 1600 1601 1602
				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;

1603 1604 1605 1606 1607
#ifdef CONFIG_X86_32
			if (pfn > max_pfn_mapped)
				max_pfn_mapped = pfn;
#endif

1608 1609 1610 1611 1612 1613 1614 1615 1616 1617 1618 1619 1620 1621
			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);
}

1622 1623 1624 1625 1626 1627 1628 1629 1630 1631 1632 1633 1634 1635
void __init xen_setup_machphys_mapping(void)
{
	struct xen_machphys_mapping mapping;
	unsigned long machine_to_phys_nr_ents;

	if (HYPERVISOR_memory_op(XENMEM_machphys_mapping, &mapping) == 0) {
		machine_to_phys_mapping = (unsigned long *)mapping.v_start;
		machine_to_phys_nr_ents = mapping.max_mfn + 1;
	} else {
		machine_to_phys_nr_ents = MACH2PHYS_NR_ENTRIES;
	}
	machine_to_phys_order = fls(machine_to_phys_nr_ents - 1);
}

1636 1637 1638 1639 1640 1641 1642 1643 1644 1645 1646 1647 1648
#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);
}

/*
L
Lucas De Marchi 已提交
1649
 * Set up the initial kernel pagetable.
1650 1651 1652 1653 1654 1655 1656 1657 1658
 *
 * 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.
 */
1659
pgd_t * __init xen_setup_kernel_pagetable(pgd_t *pgd,
1660 1661 1662 1663 1664
					 unsigned long max_pfn)
{
	pud_t *l3;
	pmd_t *l2;

1665 1666 1667 1668 1669 1670
	/* max_pfn_mapped is the last pfn mapped in the initial memory
	 * mappings. Considering that on Xen after the kernel mappings we
	 * have the mappings of some pages that don't exist in pfn space, we
	 * set max_pfn_mapped to the last real pfn mapped. */
	max_pfn_mapped = PFN_DOWN(__pa(xen_start_info->mfn_list));

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
	/* 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);

1719
	memblock_x86_reserve_range(__pa(xen_start_info->pt_base),
1720 1721 1722 1723 1724 1725 1726
		      __pa(xen_start_info->pt_base +
			   xen_start_info->nr_pt_frames * PAGE_SIZE),
		      "XEN PAGETABLES");

	return pgd;
}
#else	/* !CONFIG_X86_64 */
1727 1728 1729
static RESERVE_BRK_ARRAY(pmd_t, initial_kernel_pmd, PTRS_PER_PMD);
static RESERVE_BRK_ARRAY(pmd_t, swapper_kernel_pmd, PTRS_PER_PMD);

1730
static void __init xen_write_cr3_init(unsigned long cr3)
1731 1732 1733 1734 1735 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
{
	unsigned long pfn = PFN_DOWN(__pa(swapper_pg_dir));

	BUG_ON(read_cr3() != __pa(initial_page_table));
	BUG_ON(cr3 != __pa(swapper_pg_dir));

	/*
	 * We are switching to swapper_pg_dir for the first time (from
	 * initial_page_table) and therefore need to mark that page
	 * read-only and then pin it.
	 *
	 * Xen disallows sharing of kernel PMDs for PAE
	 * guests. Therefore we must copy the kernel PMD from
	 * initial_page_table into a new kernel PMD to be used in
	 * swapper_pg_dir.
	 */
	swapper_kernel_pmd =
		extend_brk(sizeof(pmd_t) * PTRS_PER_PMD, PAGE_SIZE);
	memcpy(swapper_kernel_pmd, initial_kernel_pmd,
	       sizeof(pmd_t) * PTRS_PER_PMD);
	swapper_pg_dir[KERNEL_PGD_BOUNDARY] =
		__pgd(__pa(swapper_kernel_pmd) | _PAGE_PRESENT);
	set_page_prot(swapper_kernel_pmd, PAGE_KERNEL_RO);

	set_page_prot(swapper_pg_dir, PAGE_KERNEL_RO);
	xen_write_cr3(cr3);
	pin_pagetable_pfn(MMUEXT_PIN_L3_TABLE, pfn);

	pin_pagetable_pfn(MMUEXT_UNPIN_TABLE,
			  PFN_DOWN(__pa(initial_page_table)));
	set_page_prot(initial_page_table, PAGE_KERNEL);
	set_page_prot(initial_kernel_pmd, PAGE_KERNEL);

	pv_mmu_ops.write_cr3 = &xen_write_cr3;
}
1766

1767
pgd_t * __init xen_setup_kernel_pagetable(pgd_t *pgd,
1768 1769 1770 1771
					 unsigned long max_pfn)
{
	pmd_t *kernel_pmd;

1772 1773
	initial_kernel_pmd =
		extend_brk(sizeof(pmd_t) * PTRS_PER_PMD, PAGE_SIZE);
1774

1775 1776 1777
	max_pfn_mapped = PFN_DOWN(__pa(xen_start_info->pt_base) +
				  xen_start_info->nr_pt_frames * PAGE_SIZE +
				  512*1024);
1778 1779

	kernel_pmd = m2v(pgd[KERNEL_PGD_BOUNDARY].pgd);
1780
	memcpy(initial_kernel_pmd, kernel_pmd, sizeof(pmd_t) * PTRS_PER_PMD);
1781

1782
	xen_map_identity_early(initial_kernel_pmd, max_pfn);
1783

1784 1785 1786
	memcpy(initial_page_table, pgd, sizeof(pgd_t) * PTRS_PER_PGD);
	initial_page_table[KERNEL_PGD_BOUNDARY] =
		__pgd(__pa(initial_kernel_pmd) | _PAGE_PRESENT);
1787

1788 1789
	set_page_prot(initial_kernel_pmd, PAGE_KERNEL_RO);
	set_page_prot(initial_page_table, PAGE_KERNEL_RO);
1790 1791 1792 1793
	set_page_prot(empty_zero_page, PAGE_KERNEL_RO);

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

1794 1795 1796
	pin_pagetable_pfn(MMUEXT_PIN_L3_TABLE,
			  PFN_DOWN(__pa(initial_page_table)));
	xen_write_cr3(__pa(initial_page_table));
1797

1798
	memblock_x86_reserve_range(__pa(xen_start_info->pt_base),
1799 1800 1801 1802
		      __pa(xen_start_info->pt_base +
			   xen_start_info->nr_pt_frames * PAGE_SIZE),
		      "XEN PAGETABLES");

1803
	return initial_page_table;
1804 1805 1806
}
#endif	/* CONFIG_X86_64 */

1807 1808
static unsigned char dummy_mapping[PAGE_SIZE] __page_aligned_bss;

1809
static void xen_set_fixmap(unsigned idx, phys_addr_t phys, pgprot_t prot)
1810 1811 1812 1813 1814 1815 1816 1817 1818 1819 1820 1821 1822 1823 1824 1825 1826 1827 1828
{
	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
1829 1830 1831
	case FIX_TEXT_POKE0:
	case FIX_TEXT_POKE1:
		/* All local page mappings */
1832 1833 1834
		pte = pfn_pte(phys, prot);
		break;

1835 1836 1837 1838 1839 1840 1841 1842 1843 1844 1845 1846 1847 1848 1849 1850
#ifdef CONFIG_X86_LOCAL_APIC
	case FIX_APIC_BASE:	/* maps dummy local APIC */
		pte = pfn_pte(PFN_DOWN(__pa(dummy_mapping)), PAGE_KERNEL);
		break;
#endif

#ifdef CONFIG_X86_IO_APIC
	case FIX_IO_APIC_BASE_0 ... FIX_IO_APIC_BASE_END:
		/*
		 * We just don't map the IO APIC - all access is via
		 * hypercalls.  Keep the address in the pte for reference.
		 */
		pte = pfn_pte(PFN_DOWN(__pa(dummy_mapping)), PAGE_KERNEL);
		break;
#endif

1851 1852 1853
	case FIX_PARAVIRT_BOOTMAP:
		/* This is an MFN, but it isn't an IO mapping from the
		   IO domain */
1854 1855
		pte = mfn_pte(phys, prot);
		break;
1856 1857 1858 1859 1860

	default:
		/* By default, set_fixmap is used for hardware mappings */
		pte = mfn_pte(phys, __pgprot(pgprot_val(prot) | _PAGE_IOMAP));
		break;
1861 1862 1863 1864 1865 1866 1867 1868 1869 1870 1871 1872 1873 1874
	}

	__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
}

1875
void __init xen_ident_map_ISA(void)
1876 1877 1878 1879 1880 1881 1882 1883 1884 1885 1886 1887 1888 1889 1890 1891 1892 1893 1894 1895 1896 1897
{
	unsigned long pa;

	/*
	 * If we're dom0, then linear map the ISA machine addresses into
	 * the kernel's address space.
	 */
	if (!xen_initial_domain())
		return;

	xen_raw_printk("Xen: setup ISA identity maps\n");

	for (pa = ISA_START_ADDRESS; pa < ISA_END_ADDRESS; pa += PAGE_SIZE) {
		pte_t pte = mfn_pte(PFN_DOWN(pa), PAGE_KERNEL_IO);

		if (HYPERVISOR_update_va_mapping(PAGE_OFFSET + pa, pte, 0))
			BUG();
	}

	xen_flush_tlb();
}

1898
static void __init xen_post_allocator_init(void)
1899
{
1900 1901 1902
#ifdef CONFIG_XEN_DEBUG
	pv_mmu_ops.make_pte = PV_CALLEE_SAVE(xen_make_pte_debug);
#endif
1903 1904 1905 1906 1907 1908 1909 1910 1911 1912 1913 1914 1915 1916 1917 1918 1919 1920 1921 1922 1923 1924 1925 1926
	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();
}

1927 1928
static void xen_leave_lazy_mmu(void)
{
1929
	preempt_disable();
1930 1931
	xen_mc_flush();
	paravirt_leave_lazy_mmu();
1932
	preempt_enable();
1933
}
1934

1935
static const struct pv_mmu_ops xen_mmu_ops __initconst = {
1936 1937 1938 1939
	.read_cr2 = xen_read_cr2,
	.write_cr2 = xen_write_cr2,

	.read_cr3 = xen_read_cr3,
1940 1941 1942
#ifdef CONFIG_X86_32
	.write_cr3 = xen_write_cr3_init,
#else
1943
	.write_cr3 = xen_write_cr3,
1944
#endif
1945 1946 1947 1948 1949 1950 1951 1952 1953 1954 1955 1956 1957 1958

	.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,
1959 1960
	.alloc_pmd = xen_alloc_pmd_init,
	.release_pmd = xen_release_pmd_init,
1961 1962 1963 1964 1965 1966 1967 1968

	.set_pte = xen_set_pte_init,
	.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,

1969 1970
	.pte_val = PV_CALLEE_SAVE(xen_pte_val),
	.pgd_val = PV_CALLEE_SAVE(xen_pgd_val),
1971

1972 1973
	.make_pte = PV_CALLEE_SAVE(xen_make_pte),
	.make_pgd = PV_CALLEE_SAVE(xen_make_pgd),
1974 1975 1976 1977 1978 1979 1980 1981

#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,

1982 1983
	.make_pmd = PV_CALLEE_SAVE(xen_make_pmd),
	.pmd_val = PV_CALLEE_SAVE(xen_pmd_val),
1984 1985

#if PAGETABLE_LEVELS == 4
1986 1987
	.pud_val = PV_CALLEE_SAVE(xen_pud_val),
	.make_pud = PV_CALLEE_SAVE(xen_make_pud),
1988 1989
	.set_pgd = xen_set_pgd_hyper,

1990 1991
	.alloc_pud = xen_alloc_pmd_init,
	.release_pud = xen_release_pmd_init,
1992 1993 1994 1995 1996 1997 1998 1999
#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,
2000
		.leave = xen_leave_lazy_mmu,
2001 2002 2003 2004 2005
	},

	.set_fixmap = xen_set_fixmap,
};

2006 2007
void __init xen_init_mmu_ops(void)
{
2008
	x86_init.mapping.pagetable_reserve = xen_mapping_pagetable_reserve;
2009 2010 2011
	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;
2012

2013
	memset(dummy_mapping, 0xff, PAGE_SIZE);
2014
}
2015

2016 2017 2018 2019 2020 2021 2022 2023 2024 2025 2026 2027 2028 2029 2030 2031 2032 2033 2034 2035
/* 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);
2036
		__set_phys_to_machine(virt_to_pfn(vaddr), INVALID_P2M_ENTRY);
2037 2038 2039 2040 2041 2042 2043 2044 2045 2046 2047 2048 2049 2050 2051 2052 2053 2054 2055 2056 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

		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);
2209
}
2210
EXPORT_SYMBOL_GPL(xen_destroy_contiguous_region);
2211

2212
#ifdef CONFIG_XEN_PVHVM
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
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;
}
2244
#endif
2245

2246 2247 2248 2249 2250 2251 2252 2253 2254 2255 2256 2257 2258 2259
#define REMAP_BATCH_SIZE 16

struct remap_data {
	unsigned long mfn;
	pgprot_t prot;
	struct mmu_update *mmu_update;
};

static int remap_area_mfn_pte_fn(pte_t *ptep, pgtable_t token,
				 unsigned long addr, void *data)
{
	struct remap_data *rmd = data;
	pte_t pte = pte_mkspecial(pfn_pte(rmd->mfn++, rmd->prot));

2260
	rmd->mmu_update->ptr = virt_to_machine(ptep).maddr;
2261 2262 2263 2264 2265 2266 2267 2268 2269 2270 2271 2272 2273 2274 2275 2276 2277 2278 2279
	rmd->mmu_update->val = pte_val_ma(pte);
	rmd->mmu_update++;

	return 0;
}

int xen_remap_domain_mfn_range(struct vm_area_struct *vma,
			       unsigned long addr,
			       unsigned long mfn, int nr,
			       pgprot_t prot, unsigned domid)
{
	struct remap_data rmd;
	struct mmu_update mmu_update[REMAP_BATCH_SIZE];
	int batch;
	unsigned long range;
	int err = 0;

	prot = __pgprot(pgprot_val(prot) | _PAGE_IOMAP);

2280 2281
	BUG_ON(!((vma->vm_flags & (VM_PFNMAP | VM_RESERVED | VM_IO)) ==
				(VM_PFNMAP | VM_RESERVED | VM_IO)));
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	rmd.mfn = mfn;
	rmd.prot = prot;

	while (nr) {
		batch = min(REMAP_BATCH_SIZE, nr);
		range = (unsigned long)batch << PAGE_SHIFT;

		rmd.mmu_update = mmu_update;
		err = apply_to_page_range(vma->vm_mm, addr, range,
					  remap_area_mfn_pte_fn, &rmd);
		if (err)
			goto out;

		err = -EFAULT;
		if (HYPERVISOR_mmu_update(mmu_update, batch, NULL, domid) < 0)
			goto out;

		nr -= batch;
		addr += range;
	}

	err = 0;
out:

	flush_tlb_all();

	return err;
}
EXPORT_SYMBOL_GPL(xen_remap_domain_mfn_range);

J
Jeremy Fitzhardinge 已提交
2313
#ifdef CONFIG_XEN_DEBUG_FS
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static int p2m_dump_open(struct inode *inode, struct file *filp)
{
	return single_open(filp, p2m_dump_show, NULL);
}

static const struct file_operations p2m_dump_fops = {
	.open		= p2m_dump_open,
	.read		= seq_read,
	.llseek		= seq_lseek,
	.release	= single_release,
};
2325
#endif /* CONFIG_XEN_DEBUG_FS */