[PATCH] kvm: nVMX: Reorder error checks for emulated VMXON

[PATCH] kvm: nVMX: Reorder error checks for emulated VMXON

[Jim Mattson]

Checks on the operand to VMXON are performed after the check for
legacy mode operation and the #GP checks, according to the pseudo-code
in Intel's SDM.

Signed-off-by: Jim Mattson <jmattson@google.com>
---
 arch/x86/kvm/vmx.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index a11f5c9..346befd 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -7174,9 +7174,6 @@ static int handle_vmon(struct kvm_vcpu *vcpu)
 		return 1;
 	}
 
-	if (nested_vmx_check_vmptr(vcpu, EXIT_REASON_VMON, NULL))
-		return 1;
-
 	if (vmx->nested.vmxon) {
 		nested_vmx_failValid(vcpu, VMXERR_VMXON_IN_VMX_ROOT_OPERATION);
 		return kvm_skip_emulated_instruction(vcpu);
@@ -7188,6 +7185,9 @@ static int handle_vmon(struct kvm_vcpu *vcpu)
 		return 1;
 	}
 
+	if (nested_vmx_check_vmptr(vcpu, EXIT_REASON_VMON, NULL))
+		return 1;
+
 	if (cpu_has_vmx_msr_bitmap()) {
 		vmx->nested.msr_bitmap =
 				(unsigned long *)__get_free_page(GFP_KERNEL);
-- 
2.8.0.rc3.226.g39d4020

Re: [PATCH] kvm: nVMX: Reorder error checks for emulated VMXON

[David Hildenbrand]

Am 23.12.2016 um 00:49 schrieb Jim Mattson:
> Checks on the operand to VMXON are performed after the check for
> legacy mode operation and the #GP checks, according to the pseudo-code
> in Intel's SDM.
>
> Signed-off-by: Jim Mattson <jmattson@google.com>
> ---
>  arch/x86/kvm/vmx.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
> index a11f5c9..346befd 100644
> --- a/arch/x86/kvm/vmx.c
> +++ b/arch/x86/kvm/vmx.c
> @@ -7174,9 +7174,6 @@ static int handle_vmon(struct kvm_vcpu *vcpu)
>  		return 1;
>  	}
>
> -	if (nested_vmx_check_vmptr(vcpu, EXIT_REASON_VMON, NULL))
> -		return 1;
> -
>  	if (vmx->nested.vmxon) {
>  		nested_vmx_failValid(vcpu, VMXERR_VMXON_IN_VMX_ROOT_OPERATION);
>  		return kvm_skip_emulated_instruction(vcpu);
> @@ -7188,6 +7185,9 @@ static int handle_vmon(struct kvm_vcpu *vcpu)
>  		return 1;
>  	}
>
> +	if (nested_vmx_check_vmptr(vcpu, EXIT_REASON_VMON, NULL))
> +		return 1;
> +
>  	if (cpu_has_vmx_msr_bitmap()) {
>  		vmx->nested.msr_bitmap =
>  				(unsigned long *)__get_free_page(GFP_KERNEL);
>

I also interpret the pseudo code that way (Vol. 3C 30-27). And it also
makes sense to check for the more general error first.

Reviewed-by: David Hildenbrand <david@redhat.com>

-- 

David

Re: [PATCH] kvm: nVMX: Reorder error checks for emulated VMXON

[Radim Krčmář]

2016-12-22 15:49-0800, Jim Mattson:
> Checks on the operand to VMXON are performed after the check for
> legacy mode operation and the #GP checks, according to the pseudo-code
> in Intel's SDM.
> 
> Signed-off-by: Jim Mattson <jmattson@google.com>
> ---

Applied to kvm/queue, thanks.