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* [PATCH] KVM: nVMX: Add VM-Enter failed tracepoints for super early checks
@ 2020-08-12 18:06 Sean Christopherson
       [not found] ` <87v9gxx5z8.fsf@vitty.brq.redhat.com>
  2020-09-23 16:03 ` Paolo Bonzini
  0 siblings, 2 replies; 3+ messages in thread
From: Sean Christopherson @ 2020-08-12 18:06 UTC (permalink / raw)
  To: Paolo Bonzini
  Cc: Sean Christopherson, Vitaly Kuznetsov, Wanpeng Li, Jim Mattson,
	Joerg Roedel, kvm, linux-kernel

Add tracepoints for the early consistency checks in nested_vmx_run().
The "VMLAUNCH vs. VMRESUME" check in particular is useful to trace, as
there is no architectural way to check VMCS.LAUNCH_STATE, and subtle
bugs such as VMCLEAR on the wrong HPA can lead to confusing errors in
the L1 VMM.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
---
 arch/x86/kvm/vmx/nested.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
index 23b58c28a1c92..fb37f0972e78a 100644
--- a/arch/x86/kvm/vmx/nested.c
+++ b/arch/x86/kvm/vmx/nested.c
@@ -3468,11 +3468,11 @@ static int nested_vmx_run(struct kvm_vcpu *vcpu, bool launch)
 	if (evmptrld_status == EVMPTRLD_ERROR) {
 		kvm_queue_exception(vcpu, UD_VECTOR);
 		return 1;
-	} else if (evmptrld_status == EVMPTRLD_VMFAIL) {
+	} else if (CC(evmptrld_status == EVMPTRLD_VMFAIL)) {
 		return nested_vmx_failInvalid(vcpu);
 	}
 
-	if (!vmx->nested.hv_evmcs && vmx->nested.current_vmptr == -1ull)
+	if (CC(!vmx->nested.hv_evmcs && vmx->nested.current_vmptr == -1ull))
 		return nested_vmx_failInvalid(vcpu);
 
 	vmcs12 = get_vmcs12(vcpu);
@@ -3483,7 +3483,7 @@ static int nested_vmx_run(struct kvm_vcpu *vcpu, bool launch)
 	 * rather than RFLAGS.ZF, and no error number is stored to the
 	 * VM-instruction error field.
 	 */
-	if (vmcs12->hdr.shadow_vmcs)
+	if (CC(vmcs12->hdr.shadow_vmcs))
 		return nested_vmx_failInvalid(vcpu);
 
 	if (vmx->nested.hv_evmcs) {
@@ -3504,10 +3504,10 @@ static int nested_vmx_run(struct kvm_vcpu *vcpu, bool launch)
 	 * for misconfigurations which will anyway be caught by the processor
 	 * when using the merged vmcs02.
 	 */
-	if (interrupt_shadow & KVM_X86_SHADOW_INT_MOV_SS)
+	if (CC(interrupt_shadow & KVM_X86_SHADOW_INT_MOV_SS))
 		return nested_vmx_fail(vcpu, VMXERR_ENTRY_EVENTS_BLOCKED_BY_MOV_SS);
 
-	if (vmcs12->launch_state == launch)
+	if (CC(vmcs12->launch_state == launch))
 		return nested_vmx_fail(vcpu,
 			launch ? VMXERR_VMLAUNCH_NONCLEAR_VMCS
 			       : VMXERR_VMRESUME_NONLAUNCHED_VMCS);
-- 
2.28.0


^ permalink raw reply related	[flat|nested] 3+ messages in thread
* Re: [PATCH] KVM: nVMX: Add VM-Enter failed tracepoints for super early checks
       [not found] ` <87v9gxx5z8.fsf@vitty.brq.redhat.com>
@ 2020-09-02 22:14   ` Sean Christopherson
  0 siblings, 0 replies; 3+ messages in thread
From: Sean Christopherson @ 2020-09-02 22:14 UTC (permalink / raw)
  To: Vitaly Kuznetsov
  Cc: Paolo Bonzini, Wanpeng Li, Jim Mattson, Joerg Roedel, kvm, linux-kernel

On Tue, Sep 01, 2020 at 10:21:15AM +0200, Vitaly Kuznetsov wrote:
> Sean Christopherson <sean.j.christopherson@intel.com> writes:
> 
> > Add tracepoints for the early consistency checks in nested_vmx_run().
> > The "VMLAUNCH vs. VMRESUME" check in particular is useful to trace, as
> > there is no architectural way to check VMCS.LAUNCH_STATE, and subtle
> > bugs such as VMCLEAR on the wrong HPA can lead to confusing errors in
> > the L1 VMM.
> >
> > Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
> > ---
> >  arch/x86/kvm/vmx/nested.c | 10 +++++-----
> >  1 file changed, 5 insertions(+), 5 deletions(-)
> >
> > diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
> > index 23b58c28a1c92..fb37f0972e78a 100644
> > --- a/arch/x86/kvm/vmx/nested.c
> > +++ b/arch/x86/kvm/vmx/nested.c
> > @@ -3468,11 +3468,11 @@ static int nested_vmx_run(struct kvm_vcpu *vcpu, bool launch)
> >  	if (evmptrld_status == EVMPTRLD_ERROR) {
> 
> Would it make sense to add 'CC' here too for, em, consistency? :-) #UD
> is probably easy to spot anyway..

I'd prefer not to, purely because it's a #UD and not a VM-Fail.

^ permalink raw reply	[flat|nested] 3+ messages in thread
* Re: [PATCH] KVM: nVMX: Add VM-Enter failed tracepoints for super early checks
  2020-08-12 18:06 [PATCH] KVM: nVMX: Add VM-Enter failed tracepoints for super early checks Sean Christopherson
       [not found] ` <87v9gxx5z8.fsf@vitty.brq.redhat.com>
@ 2020-09-23 16:03 ` Paolo Bonzini
  1 sibling, 0 replies; 3+ messages in thread
From: Paolo Bonzini @ 2020-09-23 16:03 UTC (permalink / raw)
  To: Sean Christopherson
  Cc: Vitaly Kuznetsov, Wanpeng Li, Jim Mattson, Joerg Roedel, kvm,
	linux-kernel

On 12/08/20 20:06, Sean Christopherson wrote:
> Add tracepoints for the early consistency checks in nested_vmx_run().
> The "VMLAUNCH vs. VMRESUME" check in particular is useful to trace, as
> there is no architectural way to check VMCS.LAUNCH_STATE, and subtle
> bugs such as VMCLEAR on the wrong HPA can lead to confusing errors in
> the L1 VMM.
> 
> Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
> ---
>  arch/x86/kvm/vmx/nested.c | 10 +++++-----
>  1 file changed, 5 insertions(+), 5 deletions(-)
> 
> diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
> index 23b58c28a1c92..fb37f0972e78a 100644
> --- a/arch/x86/kvm/vmx/nested.c
> +++ b/arch/x86/kvm/vmx/nested.c
> @@ -3468,11 +3468,11 @@ static int nested_vmx_run(struct kvm_vcpu *vcpu, bool launch)
>  	if (evmptrld_status == EVMPTRLD_ERROR) {
>  		kvm_queue_exception(vcpu, UD_VECTOR);
>  		return 1;
> -	} else if (evmptrld_status == EVMPTRLD_VMFAIL) {
> +	} else if (CC(evmptrld_status == EVMPTRLD_VMFAIL)) {
>  		return nested_vmx_failInvalid(vcpu);
>  	}
>  
> -	if (!vmx->nested.hv_evmcs && vmx->nested.current_vmptr == -1ull)
> +	if (CC(!vmx->nested.hv_evmcs && vmx->nested.current_vmptr == -1ull))
>  		return nested_vmx_failInvalid(vcpu);
>  
>  	vmcs12 = get_vmcs12(vcpu);
> @@ -3483,7 +3483,7 @@ static int nested_vmx_run(struct kvm_vcpu *vcpu, bool launch)
>  	 * rather than RFLAGS.ZF, and no error number is stored to the
>  	 * VM-instruction error field.
>  	 */
> -	if (vmcs12->hdr.shadow_vmcs)
> +	if (CC(vmcs12->hdr.shadow_vmcs))
>  		return nested_vmx_failInvalid(vcpu);
>  
>  	if (vmx->nested.hv_evmcs) {
> @@ -3504,10 +3504,10 @@ static int nested_vmx_run(struct kvm_vcpu *vcpu, bool launch)
>  	 * for misconfigurations which will anyway be caught by the processor
>  	 * when using the merged vmcs02.
>  	 */
> -	if (interrupt_shadow & KVM_X86_SHADOW_INT_MOV_SS)
> +	if (CC(interrupt_shadow & KVM_X86_SHADOW_INT_MOV_SS))
>  		return nested_vmx_fail(vcpu, VMXERR_ENTRY_EVENTS_BLOCKED_BY_MOV_SS);
>  
> -	if (vmcs12->launch_state == launch)
> +	if (CC(vmcs12->launch_state == launch))
>  		return nested_vmx_fail(vcpu,
>  			launch ? VMXERR_VMLAUNCH_NONCLEAR_VMCS
>  			       : VMXERR_VMRESUME_NONLAUNCHED_VMCS);
> 

Queued, thanks.

Paolo


^ permalink raw reply	[flat|nested] 3+ messages in thread
end of thread, other threads:[~2020-09-23 16:03 UTC | newest]

Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
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2020-08-12 18:06 [PATCH] KVM: nVMX: Add VM-Enter failed tracepoints for super early checks Sean Christopherson
     [not found] ` <87v9gxx5z8.fsf@vitty.brq.redhat.com>
2020-09-02 22:14   ` Sean Christopherson
2020-09-23 16:03 ` Paolo Bonzini

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