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* [PATCH] kvm: fix wrong exception emulation in check_rdtsc
@ 2021-08-18  3:36 Hou Wenlong
  2021-08-18 21:07 ` Jim Mattson
                   ` (2 more replies)
  0 siblings, 3 replies; 4+ messages in thread
From: Hou Wenlong @ 2021-08-18  3:36 UTC (permalink / raw)
  To: kvm
  Cc: Paolo Bonzini, Sean Christopherson, Vitaly Kuznetsov, Wanpeng Li,
	Jim Mattson, Joerg Roedel, Thomas Gleixner, Ingo Molnar,
	Borislav Petkov, x86, H. Peter Anvin, Avi Kivity, linux-kernel

According to Intel's SDM Vol2 and AMD's APM Vol3, when
CR4.TSD is set, use rdtsc/rdtscp instruction above privilege
level 0 should trigger a #GP.

Fixes: d7eb82030699e ("KVM: SVM: Add intercept checks for remaining group7 instructions")
Signed-off-by: Hou Wenlong <houwenlong93@linux.alibaba.com>
---
 arch/x86/kvm/emulate.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index 2837110e66ed..c589ac832265 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -4206,7 +4206,7 @@ static int check_rdtsc(struct x86_emulate_ctxt *ctxt)
 	u64 cr4 = ctxt->ops->get_cr(ctxt, 4);
 
 	if (cr4 & X86_CR4_TSD && ctxt->ops->cpl(ctxt))
-		return emulate_ud(ctxt);
+		return emulate_gp(ctxt, 0);
 
 	return X86EMUL_CONTINUE;
 }
-- 
2.31.1


^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: [PATCH] kvm: fix wrong exception emulation in check_rdtsc
  2021-08-18  3:36 [PATCH] kvm: fix wrong exception emulation in check_rdtsc Hou Wenlong
@ 2021-08-18 21:07 ` Jim Mattson
  2021-08-18 21:43 ` Sean Christopherson
  2021-09-21 18:00 ` Paolo Bonzini
  2 siblings, 0 replies; 4+ messages in thread
From: Jim Mattson @ 2021-08-18 21:07 UTC (permalink / raw)
  To: Hou Wenlong
  Cc: kvm, Paolo Bonzini, Sean Christopherson, Vitaly Kuznetsov,
	Wanpeng Li, Joerg Roedel, Thomas Gleixner, Ingo Molnar,
	Borislav Petkov, x86, H. Peter Anvin, Avi Kivity, linux-kernel

On Tue, Aug 17, 2021 at 8:36 PM Hou Wenlong
<houwenlong93@linux.alibaba.com> wrote:
>
> According to Intel's SDM Vol2 and AMD's APM Vol3, when
> CR4.TSD is set, use rdtsc/rdtscp instruction above privilege
> level 0 should trigger a #GP.
>
> Fixes: d7eb82030699e ("KVM: SVM: Add intercept checks for remaining group7 instructions")
> Signed-off-by: Hou Wenlong <houwenlong93@linux.alibaba.com>
Reviewed-by: Jim Mattson <jmattson@google.com>

^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: [PATCH] kvm: fix wrong exception emulation in check_rdtsc
  2021-08-18  3:36 [PATCH] kvm: fix wrong exception emulation in check_rdtsc Hou Wenlong
  2021-08-18 21:07 ` Jim Mattson
@ 2021-08-18 21:43 ` Sean Christopherson
  2021-09-21 18:00 ` Paolo Bonzini
  2 siblings, 0 replies; 4+ messages in thread
From: Sean Christopherson @ 2021-08-18 21:43 UTC (permalink / raw)
  To: Hou Wenlong
  Cc: kvm, Paolo Bonzini, Vitaly Kuznetsov, Wanpeng Li, Jim Mattson,
	Joerg Roedel, Thomas Gleixner, Ingo Molnar, Borislav Petkov, x86,
	H. Peter Anvin, Avi Kivity, linux-kernel

On Wed, Aug 18, 2021, Hou Wenlong wrote:
> According to Intel's SDM Vol2 and AMD's APM Vol3, when
> CR4.TSD is set, use rdtsc/rdtscp instruction above privilege
> level 0 should trigger a #GP.
> 
> Fixes: d7eb82030699e ("KVM: SVM: Add intercept checks for remaining group7 instructions")
> Signed-off-by: Hou Wenlong <houwenlong93@linux.alibaba.com>
> ---
>  arch/x86/kvm/emulate.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
> index 2837110e66ed..c589ac832265 100644
> --- a/arch/x86/kvm/emulate.c
> +++ b/arch/x86/kvm/emulate.c
> @@ -4206,7 +4206,7 @@ static int check_rdtsc(struct x86_emulate_ctxt *ctxt)
>  	u64 cr4 = ctxt->ops->get_cr(ctxt, 4);
>  
>  	if (cr4 & X86_CR4_TSD && ctxt->ops->cpl(ctxt))
> -		return emulate_ud(ctxt);
> +		return emulate_gp(ctxt, 0);

Heh, I was having some serious deja vu, but the fix I was thinking of was
for em_rdpid, and that was changing #GP -> #UD (commit a9e2e0ae6860).

Reviewed-by: Sean Christopherson <seanjc@google.com>

>  	return X86EMUL_CONTINUE;
>  }
> -- 
> 2.31.1
> 

^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: [PATCH] kvm: fix wrong exception emulation in check_rdtsc
  2021-08-18  3:36 [PATCH] kvm: fix wrong exception emulation in check_rdtsc Hou Wenlong
  2021-08-18 21:07 ` Jim Mattson
  2021-08-18 21:43 ` Sean Christopherson
@ 2021-09-21 18:00 ` Paolo Bonzini
  2 siblings, 0 replies; 4+ messages in thread
From: Paolo Bonzini @ 2021-09-21 18:00 UTC (permalink / raw)
  To: Hou Wenlong, kvm
  Cc: Sean Christopherson, Vitaly Kuznetsov, Wanpeng Li, Jim Mattson,
	Joerg Roedel, Thomas Gleixner, Ingo Molnar, Borislav Petkov, x86,
	H. Peter Anvin, Avi Kivity, linux-kernel

On 18/08/21 05:36, Hou Wenlong wrote:
> According to Intel's SDM Vol2 and AMD's APM Vol3, when
> CR4.TSD is set, use rdtsc/rdtscp instruction above privilege
> level 0 should trigger a #GP.
> 
> Fixes: d7eb82030699e ("KVM: SVM: Add intercept checks for remaining group7 instructions")
> Signed-off-by: Hou Wenlong <houwenlong93@linux.alibaba.com>
> ---
>   arch/x86/kvm/emulate.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
> index 2837110e66ed..c589ac832265 100644
> --- a/arch/x86/kvm/emulate.c
> +++ b/arch/x86/kvm/emulate.c
> @@ -4206,7 +4206,7 @@ static int check_rdtsc(struct x86_emulate_ctxt *ctxt)
>   	u64 cr4 = ctxt->ops->get_cr(ctxt, 4);
>   
>   	if (cr4 & X86_CR4_TSD && ctxt->ops->cpl(ctxt))
> -		return emulate_ud(ctxt);
> +		return emulate_gp(ctxt, 0);
>   
>   	return X86EMUL_CONTINUE;
>   }
> 

Queued, thanks.

Paolo


^ permalink raw reply	[flat|nested] 4+ messages in thread

end of thread, other threads:[~2021-09-21 18:01 UTC | newest]

Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
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2021-08-18  3:36 [PATCH] kvm: fix wrong exception emulation in check_rdtsc Hou Wenlong
2021-08-18 21:07 ` Jim Mattson
2021-08-18 21:43 ` Sean Christopherson
2021-09-21 18:00 ` Paolo Bonzini

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