From: "Shukla, Santosh" <santosh.shukla@amd.com>
To: Maxim Levitsky <mlevitsk@redhat.com>,
Paolo Bonzini <pbonzini@redhat.com>
Cc: Sean Christopherson <seanjc@google.com>,
Vitaly Kuznetsov <vkuznets@redhat.com>,
Jim Mattson <jmattson@google.com>, Joerg Roedel <joro@8bytes.org>,
Tom Lendacky <thomas.lendacky@amd.com>,
kvm@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/7] KVM: SVM: Add VNMI bit definition
Date: Fri, 17 Jun 2022 20:12:49 +0530 [thread overview]
Message-ID: <737d3bda-0f97-0689-53e9-21bd11ae647e@amd.com> (raw)
In-Reply-To: <bd37180680b3e3ecec85b5151742092b9f1ce9ff.camel@redhat.com>
On 6/7/2022 6:25 PM, Maxim Levitsky wrote:
> On Thu, 2022-06-02 at 19:56 +0530, Santosh Shukla wrote:
>> VNMI exposes 3 capability bits (V_NMI, V_NMI_MASK, and V_NMI_ENABLE) to
>> virtualize NMI and NMI_MASK, Those capability bits are part of
>> VMCB::intr_ctrl -
>> V_NMI(11) - Indicates whether a virtual NMI is pending in the guest.
> So this is like bit in IRR
>
>> V_NMI_MASK(12) - Indicates whether virtual NMI is masked in the guest.
> And that is like bit in ISR.
>
> Question: what are the interactions with GIF/vGIF and this feature?
>
Hi Maxim,
The quick answer is, that V_NMI will respect the VGIF enable controls.
More info about interaction in subsequent patch reply.
Thanks,
Santosh
>> V_NMI_ENABLE(26) - Enables the NMI virtualization feature for the guest.
>>
>> When Hypervisor wants to inject NMI, it will set V_NMI bit, Processor
>> will clear the V_NMI bit and Set the V_NMI_MASK which means the Guest is
>> handling NMI, After the guest handled the NMI, The processor will clear
>> the V_NMI_MASK on the successful completion of IRET instruction Or if
>> VMEXIT occurs while delivering the virtual NMI.
>>
>> To enable the VNMI capability, Hypervisor need to program
>> V_NMI_ENABLE bit 1.
>>
>> Signed-off-by: Santosh Shukla <santosh.shukla@amd.com>
>> ---
>> arch/x86/include/asm/svm.h | 7 +++++++
>> arch/x86/kvm/svm/svm.c | 6 ++++++
>> 2 files changed, 13 insertions(+)
>>
>> diff --git a/arch/x86/include/asm/svm.h b/arch/x86/include/asm/svm.h
>> index 1b07fba11704..22d918555df0 100644
>> --- a/arch/x86/include/asm/svm.h
>> +++ b/arch/x86/include/asm/svm.h
>> @@ -195,6 +195,13 @@ struct __attribute__ ((__packed__)) vmcb_control_area {
>> #define AVIC_ENABLE_SHIFT 31
>> #define AVIC_ENABLE_MASK (1 << AVIC_ENABLE_SHIFT)
>>
>> +#define V_NMI_PENDING_SHIFT 11
>> +#define V_NMI_PENDING (1 << V_NMI_PENDING_SHIFT)
>> +#define V_NMI_MASK_SHIFT 12
>> +#define V_NMI_MASK (1 << V_NMI_MASK_SHIFT)
>> +#define V_NMI_ENABLE_SHIFT 26
>> +#define V_NMI_ENABLE (1 << V_NMI_ENABLE_SHIFT)
>> +
>> #define LBR_CTL_ENABLE_MASK BIT_ULL(0)
>> #define VIRTUAL_VMLOAD_VMSAVE_ENABLE_MASK BIT_ULL(1)
>>
>> diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
>> index 200045f71df0..860f28c668bd 100644
>> --- a/arch/x86/kvm/svm/svm.c
>> +++ b/arch/x86/kvm/svm/svm.c
>> @@ -198,6 +198,8 @@ module_param(dump_invalid_vmcb, bool, 0644);
>> bool intercept_smi = true;
>> module_param(intercept_smi, bool, 0444);
>>
>> +static bool vnmi;
>> +module_param(vnmi, bool, 0444);
>>
>> static bool svm_gp_erratum_intercept = true;
>>
>> @@ -4930,6 +4932,10 @@ static __init int svm_hardware_setup(void)
>> svm_x86_ops.vcpu_get_apicv_inhibit_reasons = NULL;
>> }
>>
>> + vnmi = vnmi && boot_cpu_has(X86_FEATURE_V_NMI);
>> + if (vnmi)
>> + pr_info("V_NMI enabled\n");
>> +
>> if (vls) {
>> if (!npt_enabled ||
>> !boot_cpu_has(X86_FEATURE_V_VMSAVE_VMLOAD) ||
>
>
> Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
>
> Best regards,
> Maxim Levitsky
>
next prev parent reply other threads:[~2022-06-17 14:43 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-06-02 14:26 [PATCH 0/7] Virtual NMI feature Santosh Shukla
2022-06-02 14:26 ` [PATCH 1/7] x86/cpu: Add CPUID feature bit for VNMI Santosh Shukla
2022-06-07 12:32 ` Maxim Levitsky
2022-06-02 14:26 ` [PATCH 2/7] KVM: SVM: Add VNMI bit definition Santosh Shukla
2022-06-07 12:55 ` Maxim Levitsky
2022-06-17 14:42 ` Shukla, Santosh [this message]
2022-06-02 14:26 ` [PATCH 3/7] KVM: SVM: Add VNMI support in get/set_nmi_mask Santosh Shukla
2022-06-07 13:07 ` Maxim Levitsky
2022-06-17 14:45 ` Shukla, Santosh
2022-06-17 14:48 ` Shukla, Santosh
2022-07-10 16:09 ` Maxim Levitsky
2022-07-21 9:25 ` Shukla, Santosh
2022-07-10 18:39 ` Maxim Levitsky
2022-06-02 14:26 ` [PATCH 4/7] KVM: SVM: Report NMI not allowed when Guest busy handling VNMI Santosh Shukla
2022-06-07 13:10 ` Maxim Levitsky
2022-06-07 13:12 ` Maxim Levitsky
2022-06-17 14:59 ` Shukla, Santosh
2022-07-10 16:08 ` Maxim Levitsky
2022-07-21 9:31 ` Shukla, Santosh
2022-07-21 11:56 ` Maxim Levitsky
2022-06-02 14:26 ` [PATCH 5/7] KVM: SVM: Add VNMI support in inject_nmi Santosh Shukla
2022-06-07 13:14 ` Maxim Levitsky
2022-06-17 15:05 ` Shukla, Santosh
2022-07-10 16:07 ` Maxim Levitsky
2022-06-02 14:26 ` [PATCH 6/7] KVM: nSVM: implement nested VNMI Santosh Shukla
2022-06-07 13:22 ` Maxim Levitsky
2022-06-17 15:08 ` Shukla, Santosh
2022-06-02 14:26 ` [PATCH 7/7] KVM: SVM: Enable VNMI feature Santosh Shukla
2022-06-06 23:01 ` [PATCH 0/7] Virtual NMI feature Jim Mattson
2022-06-08 8:23 ` Shukla, Santosh
2022-09-05 19:45 ` Jim Mattson
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