From: Marcelo Tosatti <mtosatti@xxxxxxxxxx>
3.12-stable review patch. If anyone has any objections, please let me know.
===============
commit 37f6a4e237303549c8676dfe1fd1991ceab512eb upstream.
Rom Freiman <rom@xxxxxxxxxxxxxxx> notes other code paths vulnerable to
bug fixed by 989c6b34f6a9480e397b.
Signed-off-by: Marcelo Tosatti <mtosatti@xxxxxxxxxx>
Cc: Josh Boyer <jwboyer@xxxxxxxxxxxxxxxxx>
Signed-off-by: Jiri Slaby <jslaby@xxxxxxx>
---
arch/x86/kvm/mmu.c | 9 +++++++++
arch/x86/kvm/paging_tmpl.h | 8 ++++++++
2 files changed, 17 insertions(+)
diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 0af8490eb9a9..74dd12952ea8 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -2837,6 +2837,9 @@ static bool fast_page_fault(struct kvm_vcpu *vcpu, gva_t gva, int level,
bool ret = false;
u64 spte = 0ull;
+ if (!VALID_PAGE(vcpu->arch.mmu.root_hpa))
+ return false;
+
if (!page_fault_can_be_fast(error_code))
return false;
@@ -3232,6 +3235,9 @@ static u64 walk_shadow_page_get_mmio_spte(struct kvm_vcpu *vcpu, u64 addr)
struct kvm_shadow_walk_iterator iterator;
u64 spte = 0ull;
+ if (!VALID_PAGE(vcpu->arch.mmu.root_hpa))
+ return spte;
+
walk_shadow_page_lockless_begin(vcpu);
for_each_shadow_entry_lockless(vcpu, addr, iterator, spte)
if (!is_shadow_present_pte(spte))
@@ -4560,6 +4566,9 @@ int kvm_mmu_get_spte_hierarchy(struct kvm_vcpu *vcpu, u64 addr, u64 sptes[4])
u64 spte;
int nr_sptes = 0;
+ if (!VALID_PAGE(vcpu->arch.mmu.root_hpa))
+ return nr_sptes;
+
walk_shadow_page_lockless_begin(vcpu);
for_each_shadow_entry_lockless(vcpu, addr, iterator, spte) {
sptes[iterator.level-1] = spte;
diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h
index ad75d77999d0..cba218a2f08d 100644
--- a/arch/x86/kvm/paging_tmpl.h
+++ b/arch/x86/kvm/paging_tmpl.h
@@ -569,6 +569,9 @@ static int FNAME(fetch)(struct kvm_vcpu *vcpu, gva_t addr,
if (FNAME(gpte_changed)(vcpu, gw, top_level))
goto out_gpte_changed;
+ if (!VALID_PAGE(vcpu->arch.mmu.root_hpa))
+ goto out_gpte_changed;
+
for (shadow_walk_init(&it, vcpu, addr);
shadow_walk_okay(&it) && it.level > gw->level;
shadow_walk_next(&it)) {
@@ -820,6 +823,11 @@ static void FNAME(invlpg)(struct kvm_vcpu *vcpu, gva_t gva)
*/
mmu_topup_memory_caches(vcpu);
+ if (!VALID_PAGE(vcpu->arch.mmu.root_hpa)) {
+ WARN_ON(1);
+ return;
+ }
+
spin_lock(&vcpu->kvm->mmu_lock);
for_each_shadow_entry(vcpu, gva, iterator) {
level = iterator.level;
--
1.9.1
--
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