From b2467e744f89fcb2e723143c2b78bcbaf391828a Mon Sep 17 00:00:00 2001 From: Haozhong Zhang Date: Wed, 25 Nov 2015 17:21:39 +0800 Subject: [PATCH] KVM: nVMX: remove incorrect vpid check in nested invvpid emulation 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 Signed-off-by: Paolo Bonzini --- 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 87acc5221740..af823a388c19 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; -- 2.20.1