diff --git a/arch/x86/include/asm/xen/page.h b/arch/x86/include/asm/xen/page.h index e9f52fe2d56a0ca47a3dc2df957fb2087ed06956..358dcd33891582a2da1d07d0b75a11333091a1a9 100644 --- a/arch/x86/include/asm/xen/page.h +++ b/arch/x86/include/asm/xen/page.h @@ -57,7 +57,6 @@ extern int set_foreign_p2m_mapping(struct gnttab_map_grant_ref *map_ops, extern int clear_foreign_p2m_mapping(struct gnttab_unmap_grant_ref *unmap_ops, struct gnttab_unmap_grant_ref *kunmap_ops, struct page **pages, unsigned int count); -extern unsigned long m2p_find_override_pfn(unsigned long mfn, unsigned long pfn); /* * Helper functions to write or read unsigned long values to/from @@ -154,21 +153,12 @@ static inline unsigned long mfn_to_pfn(unsigned long mfn) return mfn; pfn = mfn_to_pfn_no_overrides(mfn); - if (__pfn_to_mfn(pfn) != mfn) { - /* - * If this appears to be a foreign mfn (because the pfn - * doesn't map back to the mfn), then check the local override - * table to see if there's a better pfn to use. - * - * m2p_find_override_pfn returns ~0 if it doesn't find anything. - */ - pfn = m2p_find_override_pfn(mfn, ~0); - } + if (__pfn_to_mfn(pfn) != mfn) + pfn = ~0; /* - * pfn is ~0 if there are no entries in the m2p for mfn or if the - * entry doesn't map back to the mfn and m2p_override doesn't have a - * valid entry for it. + * pfn is ~0 if there are no entries in the m2p for mfn or the + * entry doesn't map back to the mfn. */ if (pfn == ~0 && __pfn_to_mfn(mfn) == IDENTITY_FRAME(mfn)) pfn = mfn; diff --git a/arch/x86/xen/p2m.c b/arch/x86/xen/p2m.c index df40b2888eae25fd5940f725809411b8e962dc51..c9bc53f64359b921c76a777d2b3280af71eecb57 100644 --- a/arch/x86/xen/p2m.c +++ b/arch/x86/xen/p2m.c @@ -84,8 +84,6 @@ #define PMDS_PER_MID_PAGE (P2M_MID_PER_PAGE / PTRS_PER_PTE) -static void __init m2p_override_init(void); - unsigned long *xen_p2m_addr __read_mostly; EXPORT_SYMBOL_GPL(xen_p2m_addr); unsigned long xen_p2m_size __read_mostly; @@ -402,8 +400,6 @@ void __init xen_vmalloc_p2m_tree(void) xen_p2m_size = xen_max_p2m_pfn; xen_inv_extra_mem(); - - m2p_override_init(); } unsigned long get_phys_to_machine(unsigned long pfn) @@ -652,100 +648,21 @@ bool set_phys_to_machine(unsigned long pfn, unsigned long mfn) return true; } -#define M2P_OVERRIDE_HASH_SHIFT 10 -#define M2P_OVERRIDE_HASH (1 << M2P_OVERRIDE_HASH_SHIFT) - -static struct list_head *m2p_overrides; -static DEFINE_SPINLOCK(m2p_override_lock); - -static void __init m2p_override_init(void) -{ - unsigned i; - - m2p_overrides = alloc_bootmem_align( - sizeof(*m2p_overrides) * M2P_OVERRIDE_HASH, - sizeof(unsigned long)); - - for (i = 0; i < M2P_OVERRIDE_HASH; i++) - INIT_LIST_HEAD(&m2p_overrides[i]); -} - -static unsigned long mfn_hash(unsigned long mfn) -{ - return hash_long(mfn, M2P_OVERRIDE_HASH_SHIFT); -} - -/* Add an MFN override for a particular page */ -static int m2p_add_override(unsigned long mfn, struct page *page, - struct gnttab_map_grant_ref *kmap_op) -{ - unsigned long flags; - unsigned long pfn; - unsigned long uninitialized_var(address); - unsigned level; - pte_t *ptep = NULL; - - pfn = page_to_pfn(page); - if (!PageHighMem(page)) { - address = (unsigned long)__va(pfn << PAGE_SHIFT); - ptep = lookup_address(address, &level); - if (WARN(ptep == NULL || level != PG_LEVEL_4K, - "m2p_add_override: pfn %lx not mapped", pfn)) - return -EINVAL; - } - - if (kmap_op != NULL) { - if (!PageHighMem(page)) { - struct multicall_space mcs = - xen_mc_entry(sizeof(*kmap_op)); - - MULTI_grant_table_op(mcs.mc, - GNTTABOP_map_grant_ref, kmap_op, 1); - - xen_mc_issue(PARAVIRT_LAZY_MMU); - } - } - spin_lock_irqsave(&m2p_override_lock, flags); - list_add(&page->lru, &m2p_overrides[mfn_hash(mfn)]); - spin_unlock_irqrestore(&m2p_override_lock, flags); - - /* p2m(m2p(mfn)) == mfn: the mfn is already present somewhere in - * this domain. Set the FOREIGN_FRAME_BIT in the p2m for the other - * pfn so that the following mfn_to_pfn(mfn) calls will return the - * pfn from the m2p_override (the backend pfn) instead. - * We need to do this because the pages shared by the frontend - * (xen-blkfront) can be already locked (lock_page, called by - * do_read_cache_page); when the userspace backend tries to use them - * with direct_IO, mfn_to_pfn returns the pfn of the frontend, so - * do_blockdev_direct_IO is going to try to lock the same pages - * again resulting in a deadlock. - * As a side effect get_user_pages_fast might not be safe on the - * frontend pages while they are being shared with the backend, - * because mfn_to_pfn (that ends up being called by GUPF) will - * return the backend pfn rather than the frontend pfn. */ - pfn = mfn_to_pfn_no_overrides(mfn); - if (__pfn_to_mfn(pfn) == mfn) - set_phys_to_machine(pfn, FOREIGN_FRAME(mfn)); - - return 0; -} - int set_foreign_p2m_mapping(struct gnttab_map_grant_ref *map_ops, struct gnttab_map_grant_ref *kmap_ops, struct page **pages, unsigned int count) { int i, ret = 0; - bool lazy = false; pte_t *pte; if (xen_feature(XENFEAT_auto_translated_physmap)) return 0; - if (kmap_ops && - !in_interrupt() && - paravirt_get_lazy_mode() == PARAVIRT_LAZY_NONE) { - arch_enter_lazy_mmu_mode(); - lazy = true; + if (kmap_ops) { + ret = HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, + kmap_ops, count); + if (ret) + goto out; } for (i = 0; i < count; i++) { @@ -773,160 +690,22 @@ int set_foreign_p2m_mapping(struct gnttab_map_grant_ref *map_ops, ret = -ENOMEM; goto out; } - - if (kmap_ops) { - ret = m2p_add_override(mfn, pages[i], &kmap_ops[i]); - if (ret) - goto out; - } } out: - if (lazy) - arch_leave_lazy_mmu_mode(); - return ret; } EXPORT_SYMBOL_GPL(set_foreign_p2m_mapping); -static struct page *m2p_find_override(unsigned long mfn) -{ - unsigned long flags; - struct list_head *bucket; - struct page *p, *ret; - - if (unlikely(!m2p_overrides)) - return NULL; - - ret = NULL; - bucket = &m2p_overrides[mfn_hash(mfn)]; - - spin_lock_irqsave(&m2p_override_lock, flags); - - list_for_each_entry(p, bucket, lru) { - if (page_private(p) == mfn) { - ret = p; - break; - } - } - - spin_unlock_irqrestore(&m2p_override_lock, flags); - - return ret; -} - -static int m2p_remove_override(struct page *page, - struct gnttab_unmap_grant_ref *kunmap_op, - unsigned long mfn) -{ - unsigned long flags; - unsigned long pfn; - unsigned long uninitialized_var(address); - unsigned level; - pte_t *ptep = NULL; - - pfn = page_to_pfn(page); - - if (!PageHighMem(page)) { - address = (unsigned long)__va(pfn << PAGE_SHIFT); - ptep = lookup_address(address, &level); - - if (WARN(ptep == NULL || level != PG_LEVEL_4K, - "m2p_remove_override: pfn %lx not mapped", pfn)) - return -EINVAL; - } - - spin_lock_irqsave(&m2p_override_lock, flags); - list_del(&page->lru); - spin_unlock_irqrestore(&m2p_override_lock, flags); - - if (kunmap_op != NULL) { - if (!PageHighMem(page)) { - struct multicall_space mcs; - struct gnttab_unmap_and_replace *unmap_op; - struct page *scratch_page = get_balloon_scratch_page(); - unsigned long scratch_page_address = (unsigned long) - __va(page_to_pfn(scratch_page) << PAGE_SHIFT); - - /* - * It might be that we queued all the m2p grant table - * hypercalls in a multicall, then m2p_remove_override - * get called before the multicall has actually been - * issued. In this case handle is going to -1 because - * it hasn't been modified yet. - */ - if (kunmap_op->handle == -1) - xen_mc_flush(); - /* - * Now if kmap_op->handle is negative it means that the - * hypercall actually returned an error. - */ - if (kunmap_op->handle == GNTST_general_error) { - pr_warn("m2p_remove_override: pfn %lx mfn %lx, failed to modify kernel mappings", - pfn, mfn); - put_balloon_scratch_page(); - return -1; - } - - xen_mc_batch(); - - mcs = __xen_mc_entry( - sizeof(struct gnttab_unmap_and_replace)); - unmap_op = mcs.args; - unmap_op->host_addr = kunmap_op->host_addr; - unmap_op->new_addr = scratch_page_address; - unmap_op->handle = kunmap_op->handle; - - MULTI_grant_table_op(mcs.mc, - GNTTABOP_unmap_and_replace, unmap_op, 1); - - mcs = __xen_mc_entry(0); - MULTI_update_va_mapping(mcs.mc, scratch_page_address, - pfn_pte(page_to_pfn(scratch_page), - PAGE_KERNEL_RO), 0); - - xen_mc_issue(PARAVIRT_LAZY_MMU); - - put_balloon_scratch_page(); - } - } - - /* p2m(m2p(mfn)) == FOREIGN_FRAME(mfn): the mfn is already present - * somewhere in this domain, even before being added to the - * m2p_override (see comment above in m2p_add_override). - * If there are no other entries in the m2p_override corresponding - * to this mfn, then remove the FOREIGN_FRAME_BIT from the p2m for - * the original pfn (the one shared by the frontend): the backend - * cannot do any IO on this page anymore because it has been - * unshared. Removing the FOREIGN_FRAME_BIT from the p2m entry of - * the original pfn causes mfn_to_pfn(mfn) to return the frontend - * pfn again. */ - mfn &= ~FOREIGN_FRAME_BIT; - pfn = mfn_to_pfn_no_overrides(mfn); - if (__pfn_to_mfn(pfn) == FOREIGN_FRAME(mfn) && - m2p_find_override(mfn) == NULL) - set_phys_to_machine(pfn, mfn); - - return 0; -} - int clear_foreign_p2m_mapping(struct gnttab_unmap_grant_ref *unmap_ops, struct gnttab_unmap_grant_ref *kunmap_ops, struct page **pages, unsigned int count) { int i, ret = 0; - bool lazy = false; if (xen_feature(XENFEAT_auto_translated_physmap)) return 0; - if (kunmap_ops && - !in_interrupt() && - paravirt_get_lazy_mode() == PARAVIRT_LAZY_NONE) { - arch_enter_lazy_mmu_mode(); - lazy = true; - } - for (i = 0; i < count; i++) { unsigned long mfn = __pfn_to_mfn(page_to_pfn(pages[i])); unsigned long pfn = page_to_pfn(pages[i]); @@ -940,32 +719,15 @@ int clear_foreign_p2m_mapping(struct gnttab_unmap_grant_ref *unmap_ops, WARN_ON(!PagePrivate(pages[i])); ClearPagePrivate(pages[i]); set_phys_to_machine(pfn, pages[i]->index); - - if (kunmap_ops) - ret = m2p_remove_override(pages[i], &kunmap_ops[i], mfn); - if (ret) - goto out; } - + if (kunmap_ops) + ret = HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, + kunmap_ops, count); out: - if (lazy) - arch_leave_lazy_mmu_mode(); return ret; } EXPORT_SYMBOL_GPL(clear_foreign_p2m_mapping); -unsigned long m2p_find_override_pfn(unsigned long mfn, unsigned long pfn) -{ - struct page *p = m2p_find_override(mfn); - unsigned long ret = pfn; - - if (p) - ret = page_to_pfn(p); - - return ret; -} -EXPORT_SYMBOL_GPL(m2p_find_override_pfn); - #ifdef CONFIG_XEN_DEBUG_FS #include #include "debugfs.h" diff --git a/drivers/xen/balloon.c b/drivers/xen/balloon.c index 3860d02729dcc4909798d778fa28f3c71c6eec8f..0b52d92cb2e52d03899dd410d8a58e7640c8d8d5 100644 --- a/drivers/xen/balloon.c +++ b/drivers/xen/balloon.c @@ -92,7 +92,6 @@ EXPORT_SYMBOL_GPL(balloon_stats); /* We increase/decrease in batches which fit in a page */ static xen_pfn_t frame_list[PAGE_SIZE / sizeof(unsigned long)]; -static DEFINE_PER_CPU(struct page *, balloon_scratch_page); /* List of ballooned pages, threaded through the mem_map array. */ @@ -423,22 +422,12 @@ static enum bp_state decrease_reservation(unsigned long nr_pages, gfp_t gfp) page = pfn_to_page(pfn); #ifdef CONFIG_XEN_HAVE_PVMMU - /* - * Ballooned out frames are effectively replaced with - * a scratch frame. Ensure direct mappings and the - * p2m are consistent. - */ if (!xen_feature(XENFEAT_auto_translated_physmap)) { if (!PageHighMem(page)) { - struct page *scratch_page = get_balloon_scratch_page(); - ret = HYPERVISOR_update_va_mapping( (unsigned long)__va(pfn << PAGE_SHIFT), - pfn_pte(page_to_pfn(scratch_page), - PAGE_KERNEL_RO), 0); + __pte_ma(0), 0); BUG_ON(ret); - - put_balloon_scratch_page(); } __set_phys_to_machine(pfn, INVALID_P2M_ENTRY); } @@ -500,18 +489,6 @@ static void balloon_process(struct work_struct *work) mutex_unlock(&balloon_mutex); } -struct page *get_balloon_scratch_page(void) -{ - struct page *ret = get_cpu_var(balloon_scratch_page); - BUG_ON(ret == NULL); - return ret; -} - -void put_balloon_scratch_page(void) -{ - put_cpu_var(balloon_scratch_page); -} - /* Resets the Xen limit, sets new target, and kicks off processing. */ void balloon_set_new_target(unsigned long target) { @@ -605,61 +582,13 @@ static void __init balloon_add_region(unsigned long start_pfn, } } -static int alloc_balloon_scratch_page(int cpu) -{ - if (per_cpu(balloon_scratch_page, cpu) != NULL) - return 0; - - per_cpu(balloon_scratch_page, cpu) = alloc_page(GFP_KERNEL); - if (per_cpu(balloon_scratch_page, cpu) == NULL) { - pr_warn("Failed to allocate balloon_scratch_page for cpu %d\n", cpu); - return -ENOMEM; - } - - return 0; -} - - -static int balloon_cpu_notify(struct notifier_block *self, - unsigned long action, void *hcpu) -{ - int cpu = (long)hcpu; - switch (action) { - case CPU_UP_PREPARE: - if (alloc_balloon_scratch_page(cpu)) - return NOTIFY_BAD; - break; - default: - break; - } - return NOTIFY_OK; -} - -static struct notifier_block balloon_cpu_notifier = { - .notifier_call = balloon_cpu_notify, -}; - static int __init balloon_init(void) { - int i, cpu; + int i; if (!xen_domain()) return -ENODEV; - if (!xen_feature(XENFEAT_auto_translated_physmap)) { - register_cpu_notifier(&balloon_cpu_notifier); - - get_online_cpus(); - for_each_online_cpu(cpu) { - if (alloc_balloon_scratch_page(cpu)) { - put_online_cpus(); - unregister_cpu_notifier(&balloon_cpu_notifier); - return -ENOMEM; - } - } - put_online_cpus(); - } - pr_info("Initialising balloon driver\n"); balloon_stats.current_pages = xen_pv_domain() @@ -696,15 +625,4 @@ static int __init balloon_init(void) subsys_initcall(balloon_init); -static int __init balloon_clear(void) -{ - int cpu; - - for_each_possible_cpu(cpu) - per_cpu(balloon_scratch_page, cpu) = NULL; - - return 0; -} -early_initcall(balloon_clear); - MODULE_LICENSE("GPL");