* [PATCH v4] KVM: emulate: Don't inject #GP when emulating RDMPC if CR0.PE=0
@ 2021-10-20 8:52 Wanpeng Li
2021-10-20 9:01 ` Paolo Bonzini
0 siblings, 1 reply; 3+ messages in thread
From: Wanpeng Li @ 2021-10-20 8:52 UTC (permalink / raw)
To: linux-kernel, kvm
Cc: Paolo Bonzini, Sean Christopherson, Vitaly Kuznetsov, Wanpeng Li,
Jim Mattson, Joerg Roedel
From: Wanpeng Li <wanpengli@tencent.com>
SDM mentioned that we should #GP for rdpmc if ECX is not valid or
(CR4.PCE is 0 and CPL is 1, 2, or 3 and CR0.PE is 1).
Let's add the CR0.PE is 1 checking to rdpmc emulate, though this isn't
strictly necessary since it's impossible for CPL to be >0 if CR0.PE=0.
Reviewed-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
---
v3 -> v4:
* add comments instead of pseudocode
v2 -> v3:
* add the missing 'S'
v1 -> v2:
* update patch description
arch/x86/kvm/emulate.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index 9a144ca8e146..ab7ec569e8c9 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -4213,6 +4213,7 @@ static int check_rdtsc(struct x86_emulate_ctxt *ctxt)
static int check_rdpmc(struct x86_emulate_ctxt *ctxt)
{
u64 cr4 = ctxt->ops->get_cr(ctxt, 4);
+ u64 cr0 = ctxt->ops->get_cr(ctxt, 0);
u64 rcx = reg_read(ctxt, VCPU_REGS_RCX);
/*
@@ -4222,7 +4223,7 @@ static int check_rdpmc(struct x86_emulate_ctxt *ctxt)
if (enable_vmware_backdoor && is_vmware_backdoor_pmc(rcx))
return X86EMUL_CONTINUE;
- if ((!(cr4 & X86_CR4_PCE) && ctxt->ops->cpl(ctxt)) ||
+ if ((!(cr4 & X86_CR4_PCE) && ctxt->ops->cpl(ctxt) && (cr0 & X86_CR0_PE)) ||
ctxt->ops->check_pmc(ctxt, rcx))
return emulate_gp(ctxt, 0);
--
2.25.1
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [PATCH v4] KVM: emulate: Don't inject #GP when emulating RDMPC if CR0.PE=0
2021-10-20 8:52 [PATCH v4] KVM: emulate: Don't inject #GP when emulating RDMPC if CR0.PE=0 Wanpeng Li
@ 2021-10-20 9:01 ` Paolo Bonzini
2021-10-20 10:15 ` Wanpeng Li
0 siblings, 1 reply; 3+ messages in thread
From: Paolo Bonzini @ 2021-10-20 9:01 UTC (permalink / raw)
To: Wanpeng Li, linux-kernel, kvm
Cc: Sean Christopherson, Vitaly Kuznetsov, Wanpeng Li, Jim Mattson,
Joerg Roedel
On 20/10/21 10:52, Wanpeng Li wrote:
> From: Wanpeng Li<wanpengli@tencent.com>
>
> SDM mentioned that we should #GP for rdpmc if ECX is not valid or
> (CR4.PCE is 0 and CPL is 1, 2, or 3 and CR0.PE is 1).
>
> Let's add the CR0.PE is 1 checking to rdpmc emulate, though this isn't
> strictly necessary since it's impossible for CPL to be >0 if CR0.PE=0.
>
> Reviewed-by: Sean Christopherson<seanjc@google.com>
> Signed-off-by: Wanpeng Li<wanpengli@tencent.com>
> ---
> v3 -> v4:
> * add comments instead of pseudocode
No, the commit message was fine. What I meant is there's no need to
change the code. Just add a comment about why CR0.PE isn't tested.
Paolo
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH v4] KVM: emulate: Don't inject #GP when emulating RDMPC if CR0.PE=0
2021-10-20 9:01 ` Paolo Bonzini
@ 2021-10-20 10:15 ` Wanpeng Li
0 siblings, 0 replies; 3+ messages in thread
From: Wanpeng Li @ 2021-10-20 10:15 UTC (permalink / raw)
To: Paolo Bonzini
Cc: LKML, kvm, Sean Christopherson, Vitaly Kuznetsov, Wanpeng Li,
Jim Mattson, Joerg Roedel
On Wed, 20 Oct 2021 at 17:02, Paolo Bonzini <pbonzini@redhat.com> wrote:
>
> On 20/10/21 10:52, Wanpeng Li wrote:
> > From: Wanpeng Li<wanpengli@tencent.com>
> >
> > SDM mentioned that we should #GP for rdpmc if ECX is not valid or
> > (CR4.PCE is 0 and CPL is 1, 2, or 3 and CR0.PE is 1).
> >
> > Let's add the CR0.PE is 1 checking to rdpmc emulate, though this isn't
> > strictly necessary since it's impossible for CPL to be >0 if CR0.PE=0.
> >
> > Reviewed-by: Sean Christopherson<seanjc@google.com>
> > Signed-off-by: Wanpeng Li<wanpengli@tencent.com>
> > ---
> > v3 -> v4:
> > * add comments instead of pseudocode
>
> No, the commit message was fine. What I meant is there's no need to
> change the code. Just add a comment about why CR0.PE isn't tested.
Just sent out a new version.
Wanpeng
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2021-10-20 10:16 UTC | newest]
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2021-10-20 8:52 [PATCH v4] KVM: emulate: Don't inject #GP when emulating RDMPC if CR0.PE=0 Wanpeng Li
2021-10-20 9:01 ` Paolo Bonzini
2021-10-20 10:15 ` Wanpeng Li
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