From ee050a577523dfd5fac95e6cc182ebe0293ead59 Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Wed, 21 Apr 2021 19:21:24 -0700 Subject: [PATCH] KVM: nVMX: Truncate bits 63:32 of VMCS field on nested check in !64-bit Drop bits 63:32 of the VMCS field encoding when checking for a nested VM-Exit on VMREAD/VMWRITE in !64-bit mode. VMREAD and VMWRITE always use 32-bit operands outside of 64-bit mode. The actual emulation of VMREAD/VMWRITE does the right thing, this bug is purely limited to incorrectly causing a nested VM-Exit if a GPR happens to have bits 63:32 set outside of 64-bit mode. Fixes: a7cde481b6e8 ("KVM: nVMX: Do not forward VMREAD/VMWRITE VMExits to L1 if required so by vmcs12 vmread/vmwrite bitmaps") Cc: stable@vger.kernel.org Signed-off-by: Sean Christopherson Message-Id: <20210422022128.3464144-6-seanjc@google.com> Signed-off-by: Paolo Bonzini --- arch/x86/kvm/vmx/nested.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c index 0f8c118e..f93ff23 100644 --- a/arch/x86/kvm/vmx/nested.c +++ b/arch/x86/kvm/vmx/nested.c @@ -5745,7 +5745,7 @@ static bool nested_vmx_exit_handled_vmcs_access(struct kvm_vcpu *vcpu, /* Decode instruction info and find the field to access */ vmx_instruction_info = vmcs_read32(VMX_INSTRUCTION_INFO); - field = kvm_register_read(vcpu, (((vmx_instruction_info) >> 28) & 0xf)); + field = kvm_register_readl(vcpu, (((vmx_instruction_info) >> 28) & 0xf)); /* Out-of-range fields always cause a VM exit from L2 to L1 */ if (field >> 15) -- 2.7.4