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Subject[patch 61/88] KVM: MMU: Fix aliased gfns treated as unaliased

2.6.28-stable review patch. If anyone has any objections, please let us know.

------------------

From: Izik Eidus <ieidus@redhat.com>

(cherry picked from 2843099fee32a6020e1caa95c6026f28b5d43bff)

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---
arch/x86/include/asm/kvm_host.h | 2 ++
arch/x86/kvm/mmu.c | 14 ++++++++++----
virt/kvm/kvm_main.c | 9 +++++----
3 files changed, 17 insertions(+), 8 deletions(-)

--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -609,6 +609,8 @@ 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);
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -384,7 +384,9 @@ static void account_shadowed(struct kvm
{
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;
}

@@ -392,16 +394,20 @@ static void unaccount_shadowed(struct kv
{
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;
@@ -2860,8 +2866,8 @@ static void audit_write_protection(struc
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"
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -918,7 +918,7 @@ 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;

@@ -931,11 +931,12 @@ static struct kvm_memory_slot *__gfn_to_
}
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)
@@ -959,7 +960,7 @@ unsigned long gfn_to_hva(struct kvm *kvm
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);
@@ -1210,7 +1211,7 @@ void mark_page_dirty(struct kvm *kvm, gf
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;




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