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Commit 6cffe8ca authored by Marcelo Tosatti's avatar Marcelo Tosatti Committed by Avi Kivity
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KVM: MMU: skip global pgtables on sync due to cr3 switch 



Skip syncing global pages on cr3 switch (but not on cr4/cr0). This is
important for Linux 32-bit guests with PAE, where the kmap page is
marked as global.

Signed-off-by: default avatarMarcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: default avatarAvi Kivity <avi@redhat.com>
parent b1a36821

arch/x86/include/asm/kvm_host.h

+6 −0
Original line number Diff line number Diff line
@@ -182,6 +182,8 @@ struct kvm_mmu_page { 
	struct list_head link;

	struct hlist_node hash_link;



	struct list_head oos_link;



	/*

	 * The following two entries are used to key the shadow page in the

	 * hash table.
@@ -200,6 +202,7 @@ struct kvm_mmu_page { 
	int multimapped;         /* More than one parent_pte? */

	int root_count;          /* Currently serving as active root */

	bool unsync;

	bool global;

	unsigned int unsync_children;

	union {

		u64 *parent_pte;               /* !multimapped */
@@ -356,6 +359,7 @@ struct kvm_arch{ 
	 */

	struct list_head active_mmu_pages;

	struct list_head assigned_dev_head;

	struct list_head oos_global_pages;

	struct dmar_domain *intel_iommu_domain;

	struct kvm_pic *vpic;

	struct kvm_ioapic *vioapic;
@@ -385,6 +389,7 @@ struct kvm_vm_stat { 
	u32 mmu_recycled;

	u32 mmu_cache_miss;

	u32 mmu_unsync;

	u32 mmu_unsync_global;

	u32 remote_tlb_flush;

	u32 lpages;

};
@@ -603,6 +608,7 @@ void __kvm_mmu_free_some_pages(struct kvm_vcpu *vcpu); 
int kvm_mmu_load(struct kvm_vcpu *vcpu);

void kvm_mmu_unload(struct kvm_vcpu *vcpu);

void kvm_mmu_sync_roots(struct kvm_vcpu *vcpu);

void kvm_mmu_sync_global(struct kvm_vcpu *vcpu);



int kvm_emulate_hypercall(struct kvm_vcpu *vcpu);

arch/x86/kvm/mmu.c

+47 −6
Original line number Diff line number Diff line
@@ -793,9 +793,11 @@ static struct kvm_mmu_page *kvm_mmu_alloc_page(struct kvm_vcpu *vcpu, 
	sp->gfns = mmu_memory_cache_alloc(&vcpu->arch.mmu_page_cache, PAGE_SIZE);

	set_page_private(virt_to_page(sp->spt), (unsigned long)sp);

	list_add(&sp->link, &vcpu->kvm->arch.active_mmu_pages);

	INIT_LIST_HEAD(&sp->oos_link);

	ASSERT(is_empty_shadow_page(sp->spt));

	bitmap_zero(sp->slot_bitmap, KVM_MEMORY_SLOTS + KVM_PRIVATE_MEM_SLOTS);

	sp->multimapped = 0;

	sp->global = 1;

	sp->parent_pte = parent_pte;

	--vcpu->kvm->arch.n_free_mmu_pages;

	return sp;
@@ -1066,10 +1068,18 @@ static struct kvm_mmu_page *kvm_mmu_lookup_page(struct kvm *kvm, gfn_t gfn) 
	return NULL;

}



static void kvm_unlink_unsync_global(struct kvm *kvm, struct kvm_mmu_page *sp)

{

	list_del(&sp->oos_link);

	--kvm->stat.mmu_unsync_global;

}



static void kvm_unlink_unsync_page(struct kvm *kvm, struct kvm_mmu_page *sp)

{

	WARN_ON(!sp->unsync);

	sp->unsync = 0;

	if (sp->global)

		kvm_unlink_unsync_global(kvm, sp);

	--kvm->stat.mmu_unsync;

}
@@ -1615,9 +1625,15 @@ static int kvm_unsync_page(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp) 
		if (s->role.word != sp->role.word)

			return 1;

	}

	kvm_mmu_mark_parents_unsync(vcpu, sp);

	++vcpu->kvm->stat.mmu_unsync;

	sp->unsync = 1;



	if (sp->global) {

		list_add(&sp->oos_link, &vcpu->kvm->arch.oos_global_pages);

		++vcpu->kvm->stat.mmu_unsync_global;

	} else

		kvm_mmu_mark_parents_unsync(vcpu, sp);



	mmu_convert_notrap(sp);

	return 0;

}
@@ -1643,12 +1659,21 @@ static int mmu_need_write_protect(struct kvm_vcpu *vcpu, gfn_t gfn, 
static int set_spte(struct kvm_vcpu *vcpu, u64 *shadow_pte,

		    unsigned pte_access, int user_fault,

		    int write_fault, int dirty, int largepage,

		    gfn_t gfn, pfn_t pfn, bool speculative,

		    int global, gfn_t gfn, pfn_t pfn, bool speculative,

		    bool can_unsync)

{

	u64 spte;

	int ret = 0;

	u64 mt_mask = shadow_mt_mask;

	struct kvm_mmu_page *sp = page_header(__pa(shadow_pte));



	if (!global && sp->global) {

		sp->global = 0;

		if (sp->unsync) {

			kvm_unlink_unsync_global(vcpu->kvm, sp);

			kvm_mmu_mark_parents_unsync(vcpu, sp);

		}

	}



	/*

	 * We don't set the accessed bit, since we sometimes want to see
@@ -1717,8 +1742,8 @@ static int set_spte(struct kvm_vcpu *vcpu, u64 *shadow_pte, 
static void mmu_set_spte(struct kvm_vcpu *vcpu, u64 *shadow_pte,

			 unsigned pt_access, unsigned pte_access,

			 int user_fault, int write_fault, int dirty,

			 int *ptwrite, int largepage, gfn_t gfn,

			 pfn_t pfn, bool speculative)

			 int *ptwrite, int largepage, int global,

			 gfn_t gfn, pfn_t pfn, bool speculative)

{

	int was_rmapped = 0;

	int was_writeble = is_writeble_pte(*shadow_pte);
@@ -1751,7 +1776,7 @@ static void mmu_set_spte(struct kvm_vcpu *vcpu, u64 *shadow_pte, 
		}

	}

	if (set_spte(vcpu, shadow_pte, pte_access, user_fault, write_fault,

		      dirty, largepage, gfn, pfn, speculative, true)) {

		      dirty, largepage, global, gfn, pfn, speculative, true)) {

		if (write_fault)

			*ptwrite = 1;

		kvm_x86_ops->tlb_flush(vcpu);
@@ -1808,7 +1833,7 @@ static int direct_map_entry(struct kvm_shadow_walk *_walk, 
	    || (walk->largepage && level == PT_DIRECTORY_LEVEL)) {

		mmu_set_spte(vcpu, sptep, ACC_ALL, ACC_ALL,

			     0, walk->write, 1, &walk->pt_write,

			     walk->largepage, gfn, walk->pfn, false);

			     walk->largepage, 0, gfn, walk->pfn, false);

		++vcpu->stat.pf_fixed;

		return 1;

	}
@@ -1995,6 +2020,15 @@ static void mmu_sync_roots(struct kvm_vcpu *vcpu) 
	}

}



static void mmu_sync_global(struct kvm_vcpu *vcpu)

{

	struct kvm *kvm = vcpu->kvm;

	struct kvm_mmu_page *sp, *n;



	list_for_each_entry_safe(sp, n, &kvm->arch.oos_global_pages, oos_link)

		kvm_sync_page(vcpu, sp);

}



void kvm_mmu_sync_roots(struct kvm_vcpu *vcpu)

{

	spin_lock(&vcpu->kvm->mmu_lock);
@@ -2002,6 +2036,13 @@ void kvm_mmu_sync_roots(struct kvm_vcpu *vcpu) 
	spin_unlock(&vcpu->kvm->mmu_lock);

}



void kvm_mmu_sync_global(struct kvm_vcpu *vcpu)

{

	spin_lock(&vcpu->kvm->mmu_lock);

	mmu_sync_global(vcpu);

	spin_unlock(&vcpu->kvm->mmu_lock);

}



static gpa_t nonpaging_gva_to_gpa(struct kvm_vcpu *vcpu, gva_t vaddr)

{

	return vaddr;

arch/x86/kvm/paging_tmpl.h

+6 −4
Original line number Diff line number Diff line
@@ -274,7 +274,8 @@ static void FNAME(update_pte)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *page, 
		return;

	kvm_get_pfn(pfn);

	mmu_set_spte(vcpu, spte, page->role.access, pte_access, 0, 0,

		     gpte & PT_DIRTY_MASK, NULL, largepage, gpte_to_gfn(gpte),

		     gpte & PT_DIRTY_MASK, NULL, largepage,

		     gpte & PT_GLOBAL_MASK, gpte_to_gfn(gpte),

		     pfn, true);

}
@@ -301,8 +302,9 @@ static int FNAME(shadow_walk_entry)(struct kvm_shadow_walk *_sw, 
		mmu_set_spte(vcpu, sptep, access, gw->pte_access & access,

			     sw->user_fault, sw->write_fault,

			     gw->ptes[gw->level-1] & PT_DIRTY_MASK,

			     sw->ptwrite, sw->largepage, gw->gfn, sw->pfn,

			     false);

			     sw->ptwrite, sw->largepage,

			     gw->ptes[gw->level-1] & PT_GLOBAL_MASK,

			     gw->gfn, sw->pfn, false);

		sw->sptep = sptep;

		return 1;

	}
@@ -580,7 +582,7 @@ static int FNAME(sync_page)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp) 
		nr_present++;

		pte_access = sp->role.access & FNAME(gpte_access)(vcpu, gpte);

		set_spte(vcpu, &sp->spt[i], pte_access, 0, 0,

			 is_dirty_pte(gpte), 0, gfn,

			 is_dirty_pte(gpte), 0, gpte & PT_GLOBAL_MASK, gfn,

			 spte_to_pfn(sp->spt[i]), true, false);

	}

arch/x86/kvm/x86.c

+4 −0
Original line number Diff line number Diff line
@@ -104,6 +104,7 @@ struct kvm_stats_debugfs_item debugfs_entries[] = { 
	{ "mmu_recycled", VM_STAT(mmu_recycled) },

	{ "mmu_cache_miss", VM_STAT(mmu_cache_miss) },

	{ "mmu_unsync", VM_STAT(mmu_unsync) },

	{ "mmu_unsync_global", VM_STAT(mmu_unsync_global) },

	{ "remote_tlb_flush", VM_STAT(remote_tlb_flush) },

	{ "largepages", VM_STAT(lpages) },

	{ NULL }
@@ -315,6 +316,7 @@ void kvm_set_cr0(struct kvm_vcpu *vcpu, unsigned long cr0) 
	kvm_x86_ops->set_cr0(vcpu, cr0);

	vcpu->arch.cr0 = cr0;



	kvm_mmu_sync_global(vcpu);

	kvm_mmu_reset_context(vcpu);

	return;

}
@@ -358,6 +360,7 @@ void kvm_set_cr4(struct kvm_vcpu *vcpu, unsigned long cr4) 
	}

	kvm_x86_ops->set_cr4(vcpu, cr4);

	vcpu->arch.cr4 = cr4;

	kvm_mmu_sync_global(vcpu);

	kvm_mmu_reset_context(vcpu);

}

EXPORT_SYMBOL_GPL(kvm_set_cr4);
@@ -4113,6 +4116,7 @@ struct kvm *kvm_arch_create_vm(void) 
		return ERR_PTR(-ENOMEM);



	INIT_LIST_HEAD(&kvm->arch.active_mmu_pages);

	INIT_LIST_HEAD(&kvm->arch.oos_global_pages);

	INIT_LIST_HEAD(&kvm->arch.assigned_dev_head);



	/* Reserve bit 0 of irq_sources_bitmap for userspace irq source */