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: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 58c35de..cbac9e4b 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -793,9 +793,11 @@
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 @@
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 @@
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 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 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 @@
}
}
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 @@
|| (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_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 @@
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;