[patch 06/13] KVM: MMU: global page keeping

[Marcelo Tosatti <mtosatti@redhat.com>]

[-- Attachment #1: kvm-oos-global-keeping --]
[-- Type: text/plain, Size: 3848 bytes --]

Account pages that only have global entries. Such pages need to be
synced on cr4 writes, but not cr3 writes.

Index: kvm/arch/x86/kvm/mmu.c
===================================================================
--- kvm.orig/arch/x86/kvm/mmu.c
+++ kvm/arch/x86/kvm/mmu.c
@@ -778,6 +778,7 @@ static struct kvm_mmu_page *kvm_mmu_allo
 	ASSERT(is_empty_shadow_page(sp->spt));
 	sp->slot_bitmap = 0;
 	sp->multimapped = 0;
+	sp->flags = (1 << KVM_PG_global);
 	sp->parent_pte = parent_pte;
 	--vcpu->kvm->arch.n_free_mmu_pages;
 	return sp;
@@ -1147,18 +1148,22 @@ struct page *gva_to_page(struct kvm_vcpu
 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 global, int *ptwrite, int largepage,
+			 gfn_t gfn, pfn_t pfn, bool speculative)
 {
 	u64 spte;
 	int was_rmapped = 0;
 	int was_writeble = is_writeble_pte(*shadow_pte);
+	struct kvm_mmu_page *sp = page_header(__pa(shadow_pte));
 
 	pgprintk("%s: spte %llx access %x write_fault %d"
 		 " user_fault %d gfn %lx\n",
 		 __func__, *shadow_pte, pt_access,
 		 write_fault, user_fault, gfn);
 
+	if (!global)
+		kvm_clear_pg_global(sp);
+
 	if (is_rmap_pte(*shadow_pte)) {
 		/*
 		 * If we overwrite a PTE page pointer with a 2MB PMD, unlink
@@ -1285,7 +1290,7 @@ static int direct_map_entry(struct kvm_s
 	if (level == PT_PAGE_TABLE_LEVEL
 	    || (walk->largepage && level == PT_DIRECTORY_LEVEL)) {
 		mmu_set_spte(vcpu, sptep, ACC_ALL, ACC_ALL,
-			     0, walk->write, 1, &walk->pt_write,
+			     0, walk->write, 1, 0, &walk->pt_write,
 			     walk->largepage, gfn, walk->pfn, false);
 		++vcpu->stat.pf_fixed;
 		return 1;
Index: kvm/include/asm-x86/kvm_host.h
===================================================================
--- kvm.orig/include/asm-x86/kvm_host.h
+++ kvm/include/asm-x86/kvm_host.h
@@ -199,6 +199,7 @@ struct kvm_mmu_page {
 		u64 *parent_pte;               /* !multimapped */
 		struct hlist_head parent_ptes; /* multimapped, kvm_pte_chain */
 	};
+	unsigned long flags;
 };
 
 struct kvm_pv_mmu_op_buffer {
@@ -757,4 +758,20 @@ asmlinkage void kvm_handle_fault_on_rebo
 int kvm_unmap_hva(struct kvm *kvm, unsigned long hva);
 int kvm_age_hva(struct kvm *kvm, unsigned long hva);
 
+enum kvm_page_flags {
+	KVM_PG_global,
+};
+
+#define KVMPGFLAG(name)							\
+static inline int kvm_page_##name(struct kvm_mmu_page *sp)		\
+	{ return test_bit(KVM_PG_##name, &sp->flags); }			\
+static inline void kvm_set_pg_##name(struct kvm_mmu_page *sp)		\
+	{ set_bit(KVM_PG_##name, &sp->flags); }				\
+static inline void kvm_clear_pg_##name(struct kvm_mmu_page *sp)		\
+	{ clear_bit(KVM_PG_##name, &sp->flags); }			\
+static inline int kvm_test_clear_pg_##name(struct kvm_mmu_page *sp)	\
+	{ return test_and_clear_bit(KVM_PG_##name, &sp->flags); }
+
+KVMPGFLAG(global);
+
 #endif
Index: kvm/arch/x86/kvm/paging_tmpl.h
===================================================================
--- kvm.orig/arch/x86/kvm/paging_tmpl.h
+++ kvm/arch/x86/kvm/paging_tmpl.h
@@ -274,8 +274,8 @@ static void FNAME(update_pte)(struct kvm
 		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),
-		     pfn, true);
+		     gpte & PT_DIRTY_MASK, gpte & PT_GLOBAL_MASK, NULL,
+		     largepage, gpte_to_gfn(gpte), pfn, true);
 }
 
 /*
@@ -301,6 +301,7 @@ static int FNAME(shadow_walk_entry)(stru
 		mmu_set_spte(vcpu, sptep, access, gw->pte_access & access,
 			     sw->user_fault, sw->write_fault,
 			     gw->ptes[gw->level-1] & PT_DIRTY_MASK,
+			     gw->ptes[gw->level-1] & PT_GLOBAL_MASK,
 			     sw->ptwrite, sw->largepage, gw->gfn, sw->pfn,
 			     false);
 		sw->sptep = sptep;

--