From 37f6a4e237303549c8676dfe1fd1991ceab512eb Mon Sep 17 00:00:00 2001 From: Marcelo Tosatti Date: Fri, 3 Jan 2014 17:09:32 -0200 Subject: [PATCH] KVM: x86: handle invalid root_hpa everywhere Rom Freiman notes other code paths vulnerable to bug fixed by 989c6b34f6a9480e397b. Signed-off-by: Marcelo Tosatti --- 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 31a5702..e50425d 100644 --- a/arch/x86/kvm/mmu.c +++ b/arch/x86/kvm/mmu.c @@ -2832,6 +2832,9 @@ 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; @@ -3227,6 +3230,9 @@ 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)) @@ -4513,6 +4519,9 @@ 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 ad75d77..cba218a 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; -- 2.7.4