Bugzilla: 924916
Upstream-status: Queued for 3.14 in kvm tree
From 989c6b34f6a9480e397b170cc62237e89bf4fdb9 Mon Sep 17 00:00:00 2001
From: Marcelo Tosatti <mtosatti@redhat.com>
Date: Thu, 19 Dec 2013 17:28:51 +0000
Subject: KVM: MMU: handle invalid root_hpa at __direct_map
It is possible for __direct_map to be called on invalid root_hpa
(-1), two examples:
1) try_async_pf -> can_do_async_pf
-> vmx_interrupt_allowed -> nested_vmx_vmexit
2) vmx_handle_exit -> vmx_interrupt_allowed -> nested_vmx_vmexit
Then to load_vmcs12_host_state and kvm_mmu_reset_context.
Check for this possibility, let fault exception be regenerated.
BZ: https://bugzilla.redhat.com/show_bug.cgi?id=924916
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 40772ef..31a5702 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -2659,6 +2659,9 @@ static int __direct_map(struct kvm_vcpu *vcpu, gpa_t v, int write,
int emulate = 0;
gfn_t pseudo_gfn;
+ if (!VALID_PAGE(vcpu->arch.mmu.root_hpa))
+ return 0;
+
for_each_shadow_entry(vcpu, (u64)gfn << PAGE_SHIFT, iterator) {
if (iterator.level == level) {
mmu_set_spte(vcpu, iterator.sptep, ACC_ALL,
--
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