From: Sean Christopherson seanjc@google.com
commit ee050a577523dfd5fac95e6cc182ebe0293ead59 upstream.
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 seanjc@google.com Message-Id: 20210422022128.3464144-6-seanjc@google.com Signed-off-by: Paolo Bonzini pbonzini@redhat.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- arch/x86/kvm/vmx/nested.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/arch/x86/kvm/vmx/nested.c +++ b/arch/x86/kvm/vmx/nested.c @@ -5750,7 +5750,7 @@ static bool nested_vmx_exit_handled_vmcs
/* 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)