This patch removes the vpid check when emulating nested invvpid
instruction of type all-contexts invalidation. The existing code is
incorrect because:
(1) According to Intel SDM Vol 3, Section "INVVPID - Invalidate
Translations Based on VPID", invvpid instruction does not check
vpid in the invvpid descriptor when its type is all-contexts
invalidation.
(2) According to the same document, invvpid of type all-contexts
invalidation does not require there is an active VMCS, so/and
get_vmcs12() in the existing code may result in a NULL-pointer
dereference. In practice, it can crash both KVM itself and L1
hypervisors that use invvpid (e.g. Xen).
Signed-off-by: Haozhong Zhang <haozhong.zhang@xxxxxxxxx>
---
arch/x86/kvm/vmx.c | 5 -----
1 file changed, 5 deletions(-)
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 87acc52..af823a3 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -7394,11 +7394,6 @@ static int handle_invvpid(struct kvm_vcpu *vcpu)
switch (type) {
case VMX_VPID_EXTENT_ALL_CONTEXT:
- if (get_vmcs12(vcpu)->virtual_processor_id == 0) {
- nested_vmx_failValid(vcpu,
- VMXERR_INVALID_OPERAND_TO_INVEPT_INVVPID);
- return 1;
- }
__vmx_flush_tlb(vcpu, to_vmx(vcpu)->nested.vpid02);
nested_vmx_succeed(vcpu);
break;
--
2.4.8
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