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Subject[PATCH 3.13 37/46] KVM: x86: handle invalid root_hpa everywhere
Date
3.13-stable review patch.  If anyone has any objections, please let me know.

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

From: Marcelo Tosatti <mtosatti@redhat.com>

commit 37f6a4e237303549c8676dfe1fd1991ceab512eb upstream.

Rom Freiman <rom@stratoscale.com> notes other code paths vulnerable to
bug fixed by 989c6b34f6a9480e397b.

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Josh Boyer <jwboyer@fedoraproject.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
arch/x86/kvm/mmu.c | 9 +++++++++
arch/x86/kvm/paging_tmpl.h | 8 ++++++++
2 files changed, 17 insertions(+)

--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -2832,6 +2832,9 @@ static bool fast_page_fault(struct kvm_v
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;

@@ -3227,6 +3230,9 @@ static u64 walk_shadow_page_get_mmio_spt
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))
@@ -4513,6 +4519,9 @@ int kvm_mmu_get_spte_hierarchy(struct kv
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;
--- 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
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_vcp
*/
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;



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