Re: [PATCH] KVM: x86: Add emulation of MSR_SMI_COUNT

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On 15/11/2017 12:43, Liran Alon wrote:
> This MSR returns the number of #SMIs that occurred on CPU since
> boot.
> 
> It was seen to be used frequently by ESXi guest.
> 
> Patch adds a new vcpu-arch specific var called smi_count to
> save the number of #SMIs which occurred on CPU since boot.
> It is exposed as a read-only MSR to guest (causing #GP
> on wrmsr) in RDMSR/WRMSR emulation code.
> MSR_SMI_COUNT is also added to emulated_msrs[] to make sure
> user-space can save/restore it for migration purposes.
> 
> Signed-off-by: Liran Alon <liran.alon@xxxxxxxxxx>
> Suggested-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
> Reviewed-by: Nikita Leshenko <nikita.leshchenko@xxxxxxxxxx>
> Reviewed-by: Bhavesh Davda <bhavesh.davda@xxxxxxxxxx>
> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
> ---
> 
> Notes:
>     To make vmsave/vload work for MSR_SMI_COUNT (for migration purposes),
>     a patch for QEMU is also required.
>     We have written such patch and verified that it works.
>     It will be submitted seperately to the QEMU mailing list.
> 
>  arch/x86/include/asm/kvm_host.h |  1 +
>  arch/x86/kvm/x86.c              | 11 +++++++++++
>  2 files changed, 12 insertions(+)
> 
> diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
> index c73e493adf07..089856eeac5d 100644
> --- a/arch/x86/include/asm/kvm_host.h
> +++ b/arch/x86/include/asm/kvm_host.h
> @@ -504,6 +504,7 @@ struct kvm_vcpu_arch {
>  	int mp_state;
>  	u64 ia32_misc_enable_msr;
>  	u64 smbase;
> +	u64 smi_count;
>  	bool tpr_access_reporting;
>  	u64 ia32_xss;
>  
> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> index 21c00594f230..dedf5539f924 100644
> --- a/arch/x86/kvm/x86.c
> +++ b/arch/x86/kvm/x86.c
> @@ -1036,6 +1036,7 @@ bool kvm_rdpmc(struct kvm_vcpu *vcpu)
>  	MSR_IA32_MCG_CTL,
>  	MSR_IA32_MCG_EXT_CTL,
>  	MSR_IA32_SMBASE,
> +	MSR_SMI_COUNT,
>  	MSR_PLATFORM_INFO,
>  	MSR_MISC_FEATURES_ENABLES,
>  };
> @@ -2217,6 +2218,11 @@ int kvm_set_msr_common(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
>  			return 1;
>  		vcpu->arch.smbase = data;
>  		break;
> +	case MSR_SMI_COUNT:
> +		if (!msr_info->host_initiated)
> +			return 1;
> +		vcpu->arch.smi_count = data;
> +		break;
>  	case MSR_KVM_WALL_CLOCK_NEW:
>  	case MSR_KVM_WALL_CLOCK:
>  		vcpu->kvm->arch.wall_clock = data;
> @@ -2491,6 +2497,9 @@ int kvm_get_msr_common(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
>  			return 1;
>  		msr_info->data = vcpu->arch.smbase;
>  		break;
> +	case MSR_SMI_COUNT:
> +		msr_info->data = vcpu->arch.smi_count;
> +		break;
>  	case MSR_IA32_PERF_STATUS:
>  		/* TSC increment by tick */
>  		msr_info->data = 1000ULL;
> @@ -6437,6 +6446,7 @@ static int inject_pending_event(struct kvm_vcpu *vcpu, bool req_int_win)
>  		kvm_x86_ops->queue_exception(vcpu);
>  	} else if (vcpu->arch.smi_pending && !is_smm(vcpu)) {
>  		vcpu->arch.smi_pending = false;
> +		++vcpu->arch.smi_count;
>  		enter_smm(vcpu);
>  	} else if (vcpu->arch.nmi_pending && kvm_x86_ops->nmi_allowed(vcpu)) {
>  		--vcpu->arch.nmi_pending;
> @@ -7781,6 +7791,7 @@ void kvm_vcpu_reset(struct kvm_vcpu *vcpu, bool init_event)
>  	vcpu->arch.hflags = 0;
>  
>  	vcpu->arch.smi_pending = 0;
> +	vcpu->arch.smi_count = 0;
>  	atomic_set(&vcpu->arch.nmi_queued, 0);
>  	vcpu->arch.nmi_pending = 0;
>  	vcpu->arch.nmi_injected = false;
> 

Reviewed-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>



[Index of Archives]     [KVM ARM]     [KVM ia64]     [KVM ppc]     [Virtualization Tools]     [Spice Development]     [Libvirt]     [Libvirt Users]     [Linux USB Devel]     [Linux Audio Users]     [Yosemite Questions]     [Linux Kernel]     [Linux SCSI]     [XFree86]

  Powered by Linux