KVM: MMU: Fix aliased gfns treated as unaliased

Some areas of kvm x86 mmu are using gfn offset inside a slot without
unaliasing the gfn first.  This patch makes sure that the gfn will be
unaliased and add gfn_to_memslot_unaliased() to save the calculating
of the gfn unaliasing in case we have it unaliased already.

Signed-off-by: Izik Eidus <ieidus@redhat.com>
Acked-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 09e6c56..99e3cc1 100644 (file)
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -617,6 +617,8 @@ void kvm_disable_tdp(void);
 int load_pdptrs(struct kvm_vcpu *vcpu, unsigned long cr3);
 int complete_pio(struct kvm_vcpu *vcpu);
 
+struct kvm_memory_slot *gfn_to_memslot_unaliased(struct kvm *kvm, gfn_t gfn);
+
 static inline struct kvm_mmu_page *page_header(hpa_t shadow_page)
 {
        struct page *page = pfn_to_page(shadow_page >> PAGE_SHIFT);

diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 8687758..8904e8a 100644 (file)
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -386,7 +386,9 @@ static void account_shadowed(struct kvm *kvm, gfn_t gfn)
 {
        int *write_count;
 
-       write_count = slot_largepage_idx(gfn, gfn_to_memslot(kvm, gfn));
+       gfn = unalias_gfn(kvm, gfn);
+       write_count = slot_largepage_idx(gfn,
+                                        gfn_to_memslot_unaliased(kvm, gfn));
        *write_count += 1;
 }
 
@@ -394,16 +396,20 @@ static void unaccount_shadowed(struct kvm *kvm, gfn_t gfn)
 {
        int *write_count;
 
-       write_count = slot_largepage_idx(gfn, gfn_to_memslot(kvm, gfn));
+       gfn = unalias_gfn(kvm, gfn);
+       write_count = slot_largepage_idx(gfn,
+                                        gfn_to_memslot_unaliased(kvm, gfn));
        *write_count -= 1;
        WARN_ON(*write_count < 0);
 }
 
 static int has_wrprotected_page(struct kvm *kvm, gfn_t gfn)
 {
-       struct kvm_memory_slot *slot = gfn_to_memslot(kvm, gfn);
+       struct kvm_memory_slot *slot;
        int *largepage_idx;
 
+       gfn = unalias_gfn(kvm, gfn);
+       slot = gfn_to_memslot_unaliased(kvm, gfn);
        if (slot) {
                largepage_idx = slot_largepage_idx(gfn, slot);
                return *largepage_idx;
@@ -2973,8 +2979,8 @@ static void audit_write_protection(struct kvm_vcpu *vcpu)
                if (sp->role.metaphysical)
                        continue;
 
-               slot = gfn_to_memslot(vcpu->kvm, sp->gfn);
                gfn = unalias_gfn(vcpu->kvm, sp->gfn);
+               slot = gfn_to_memslot_unaliased(vcpu->kvm, sp->gfn);
                rmapp = &slot->rmap[gfn - slot->base_gfn];
                if (*rmapp)
                        printk(KERN_ERR "%s: (%s) shadow page has writable"

diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 1838052..a65baa9 100644 (file)
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -923,7 +923,7 @@ int kvm_is_error_hva(unsigned long addr)
 }
 EXPORT_SYMBOL_GPL(kvm_is_error_hva);
 
-static struct kvm_memory_slot *__gfn_to_memslot(struct kvm *kvm, gfn_t gfn)
+struct kvm_memory_slot *gfn_to_memslot_unaliased(struct kvm *kvm, gfn_t gfn)
 {
        int i;
 
@@ -936,11 +936,12 @@ static struct kvm_memory_slot *__gfn_to_memslot(struct kvm *kvm, gfn_t gfn)
        }
        return NULL;
 }
+EXPORT_SYMBOL_GPL(gfn_to_memslot_unaliased);
 
 struct kvm_memory_slot *gfn_to_memslot(struct kvm *kvm, gfn_t gfn)
 {
        gfn = unalias_gfn(kvm, gfn);
-       return __gfn_to_memslot(kvm, gfn);
+       return gfn_to_memslot_unaliased(kvm, gfn);
 }
 
 int kvm_is_visible_gfn(struct kvm *kvm, gfn_t gfn)
@@ -964,7 +965,7 @@ unsigned long gfn_to_hva(struct kvm *kvm, gfn_t gfn)
        struct kvm_memory_slot *slot;
 
        gfn = unalias_gfn(kvm, gfn);
-       slot = __gfn_to_memslot(kvm, gfn);
+       slot = gfn_to_memslot_unaliased(kvm, gfn);
        if (!slot)
                return bad_hva();
        return (slot->userspace_addr + (gfn - slot->base_gfn) * PAGE_SIZE);
@@ -1215,7 +1216,7 @@ void mark_page_dirty(struct kvm *kvm, gfn_t gfn)
        struct kvm_memory_slot *memslot;
 
        gfn = unalias_gfn(kvm, gfn);
-       memslot = __gfn_to_memslot(kvm, gfn);
+       memslot = gfn_to_memslot_unaliased(kvm, gfn);
        if (memslot && memslot->dirty_bitmap) {
                unsigned long rel_gfn = gfn - memslot->base_gfn;