* [PATCH] KVM: x86: handle MSR_IA32_DEBUGCTLMSR with report_ignored_msrs
@ 2020-11-05 15:39 Pankaj Gupta
2020-11-05 17:01 ` Paolo Bonzini
0 siblings, 1 reply; 4+ messages in thread
From: Pankaj Gupta @ 2020-11-05 15:39 UTC (permalink / raw)
To: kvm
Cc: pbonzini, sean.j.christopherson, vkuznets, wanpengli, jmattson,
tglx, oro, mingo, bp, x86, hpa, pankaj.gupta.linux, Pankaj Gupta
From: Pankaj Gupta <pankaj.gupta@cloud.ionos.com>
Guest tries to enable LBR (last branch/interrupt/exception) repeatedly,
thus spamming the host kernel logs. As MSR_IA32_DEBUGCTLMSR is not emulated by
KVM, its better to add the error log only with "report_ignored_msrs".
Signed-off-by: Pankaj Gupta <pankaj.gupta@cloud.ionos.com>
---
arch/x86/kvm/x86.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index f5ede41bf9e6..99c69ae43c69 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -3063,9 +3063,9 @@ int kvm_set_msr_common(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
/* Values other than LBR and BTF are vendor-specific,
thus reserved and should throw a #GP */
return 1;
- }
- vcpu_unimpl(vcpu, "%s: MSR_IA32_DEBUGCTLMSR 0x%llx, nop\n",
- __func__, data);
+ } else if (report_ignored_msrs)
+ vcpu_unimpl(vcpu, "%s: MSR_IA32_DEBUGCTLMSR 0x%llx, nop\n",
+ __func__, data);
break;
case 0x200 ... 0x2ff:
return kvm_mtrr_set_msr(vcpu, msr, data);
--
2.20.1
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH] KVM: x86: handle MSR_IA32_DEBUGCTLMSR with report_ignored_msrs
2020-11-05 15:39 [PATCH] KVM: x86: handle MSR_IA32_DEBUGCTLMSR with report_ignored_msrs Pankaj Gupta
@ 2020-11-05 17:01 ` Paolo Bonzini
2020-11-05 18:58 ` Pankaj Gupta
0 siblings, 1 reply; 4+ messages in thread
From: Paolo Bonzini @ 2020-11-05 17:01 UTC (permalink / raw)
To: Pankaj Gupta, kvm
Cc: sean.j.christopherson, vkuznets, wanpengli, jmattson, tglx, oro,
mingo, bp, x86, hpa, Pankaj Gupta
On 05/11/20 16:39, Pankaj Gupta wrote:
> From: Pankaj Gupta <pankaj.gupta@cloud.ionos.com>
>
> Guest tries to enable LBR (last branch/interrupt/exception) repeatedly,
> thus spamming the host kernel logs. As MSR_IA32_DEBUGCTLMSR is not emulated by
> KVM, its better to add the error log only with "report_ignored_msrs".
>
> Signed-off-by: Pankaj Gupta <pankaj.gupta@cloud.ionos.com>
> ---
> arch/x86/kvm/x86.c | 6 +++---
> 1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> index f5ede41bf9e6..99c69ae43c69 100644
> --- a/arch/x86/kvm/x86.c
> +++ b/arch/x86/kvm/x86.c
> @@ -3063,9 +3063,9 @@ int kvm_set_msr_common(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
> /* Values other than LBR and BTF are vendor-specific,
> thus reserved and should throw a #GP */
> return 1;
> - }
> - vcpu_unimpl(vcpu, "%s: MSR_IA32_DEBUGCTLMSR 0x%llx, nop\n",
> - __func__, data);
> + } else if (report_ignored_msrs)
> + vcpu_unimpl(vcpu, "%s: MSR_IA32_DEBUGCTLMSR 0x%llx, nop\n",
> + __func__, data);
> break;
> case 0x200 ... 0x2ff:
> return kvm_mtrr_set_msr(vcpu, msr, data);
>
Which guest it is? (Patch queued, but I'd like to have a better
description).
Paolo
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] KVM: x86: handle MSR_IA32_DEBUGCTLMSR with report_ignored_msrs
2020-11-05 17:01 ` Paolo Bonzini
@ 2020-11-05 18:58 ` Pankaj Gupta
2020-11-06 10:08 ` Paolo Bonzini
0 siblings, 1 reply; 4+ messages in thread
From: Pankaj Gupta @ 2020-11-05 18:58 UTC (permalink / raw)
To: Paolo Bonzini
Cc: kvm, Sean Christopherson, Vitaly Kuznetsov, Wanpeng Li,
Jim Mattson, Thomas Gleixner, oro, Ingo Molnar, Borislav Petkov,
maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT), H. Peter Anvin,
Pankaj Gupta
> > Guest tries to enable LBR (last branch/interrupt/exception) repeatedly,
> > thus spamming the host kernel logs. As MSR_IA32_DEBUGCTLMSR is not emulated by
> > KVM, its better to add the error log only with "report_ignored_msrs".
> >
> > Signed-off-by: Pankaj Gupta <pankaj.gupta@cloud.ionos.com>
> > ---
> > arch/x86/kvm/x86.c | 6 +++---
> > 1 file changed, 3 insertions(+), 3 deletions(-)
> >
> > diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> > index f5ede41bf9e6..99c69ae43c69 100644
> > --- a/arch/x86/kvm/x86.c
> > +++ b/arch/x86/kvm/x86.c
> > @@ -3063,9 +3063,9 @@ int kvm_set_msr_common(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
> > /* Values other than LBR and BTF are vendor-specific,
> > thus reserved and should throw a #GP */
> > return 1;
> > - }
> > - vcpu_unimpl(vcpu, "%s: MSR_IA32_DEBUGCTLMSR 0x%llx, nop\n",
> > - __func__, data);
> > + } else if (report_ignored_msrs)
> > + vcpu_unimpl(vcpu, "%s: MSR_IA32_DEBUGCTLMSR 0x%llx, nop\n",
> > + __func__, data);
> > break;
> > case 0x200 ... 0x2ff:
> > return kvm_mtrr_set_msr(vcpu, msr, data);
> >
>
> Which guest it is? (Patch queued, but I'd like to have a better
> description).
How about this?
Windows2016 guest tries to enable LBR (last
branch/interrupt/exception) by setting
MSR_IA32_DEBUGCTLMSR. KVM does not emulate MSR_IA32_DEBUGCTLMSR and
spams the host kernel logs with the below error messages.This patch
fixes this by enabling
error logging only with 'report_ignored_msrs'.
"kvm []: vcpu1, guest rIP: 0xfffff800a8b687d3 kvm_set_msr_common:
MSR_IA32_DEBUGCTLMSR 0x1, nop"
Thanks,
Pankaj
>
> Paolo
>
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] KVM: x86: handle MSR_IA32_DEBUGCTLMSR with report_ignored_msrs
2020-11-05 18:58 ` Pankaj Gupta
@ 2020-11-06 10:08 ` Paolo Bonzini
0 siblings, 0 replies; 4+ messages in thread
From: Paolo Bonzini @ 2020-11-06 10:08 UTC (permalink / raw)
To: Pankaj Gupta
Cc: kvm, Sean Christopherson, Vitaly Kuznetsov, Wanpeng Li,
Jim Mattson, Thomas Gleixner, oro, Ingo Molnar, Borislav Petkov,
maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT), H. Peter Anvin,
Pankaj Gupta
On 05/11/20 19:58, Pankaj Gupta wrote:
> Windows2016 guest tries to enable LBR (last
> branch/interrupt/exception) by setting
> MSR_IA32_DEBUGCTLMSR. KVM does not emulate MSR_IA32_DEBUGCTLMSR and
> spams the host kernel logs with the below error messages.This patch
> fixes this by enabling
> error logging only with 'report_ignored_msrs'.
>
> "kvm []: vcpu1, guest rIP: 0xfffff800a8b687d3 kvm_set_msr_common:
> MSR_IA32_DEBUGCTLMSR 0x1, nop"
Sounds good, thanks.
Paolo
^ permalink raw reply [flat|nested] 4+ messages in thread
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2020-11-05 15:39 [PATCH] KVM: x86: handle MSR_IA32_DEBUGCTLMSR with report_ignored_msrs Pankaj Gupta
2020-11-05 17:01 ` Paolo Bonzini
2020-11-05 18:58 ` Pankaj Gupta
2020-11-06 10:08 ` Paolo Bonzini
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