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 3/7] KVM: SVM: Add VNMI support in get/set_nmi_mask
Date: Fri, 17 Jun 2022 20:18:27 +0530 [thread overview]
Message-ID: <fcf79616-ccbe-1137-6080-57d00773ff83@amd.com> (raw)
In-Reply-To: <91c551a2-11fc-202f-2a8f-75b6374286b6@amd.com>
On 6/17/2022 8:15 PM, Shukla, Santosh wrote:
>
>
> On 6/7/2022 6:37 PM, Maxim Levitsky wrote:
>> On Thu, 2022-06-02 at 19:56 +0530, Santosh Shukla wrote:
>>> VMCB intr_ctrl bit12 (V_NMI_MASK) is set by the processor when handling
>>> NMI in guest and is cleared after the NMI is handled. Treat V_NMI_MASK as
>>> read-only in the hypervisor and do not populate set accessors.
>>>
>>> Signed-off-by: Santosh Shukla <santosh.shukla@amd.com>
>>> ---
>>> arch/x86/kvm/svm/svm.c | 20 +++++++++++++++++++-
>>> 1 file changed, 19 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
>>> index 860f28c668bd..d67a54517d95 100644
>>> --- a/arch/x86/kvm/svm/svm.c
>>> +++ b/arch/x86/kvm/svm/svm.c
>>> @@ -323,6 +323,16 @@ static int is_external_interrupt(u32 info)
>>> return info == (SVM_EVTINJ_VALID | SVM_EVTINJ_TYPE_INTR);
>>> }
>>>
>>> +static bool is_vnmi_enabled(struct vmcb *vmcb)
>>> +{
>>> + return vnmi && (vmcb->control.int_ctl & V_NMI_ENABLE);
>>> +}
>>
>> Following Paolo's suggestion I recently removed vgif_enabled(),
>> based on the logic that vgif_enabled == vgif, because
>> we always enable vGIF for L1 as long as 'vgif' module param is set,
>> which is set unless either hardware or user cleared it.
>>
> Yes. In v2, Thanks!.
>
>> Note that here vmcb is the current vmcb, which can be vmcb02,
>> and it might be wrong
>>
>>> +
>>> +static bool is_vnmi_mask_set(struct vmcb *vmcb)
>>> +{
>>> + return !!(vmcb->control.int_ctl & V_NMI_MASK);
>>> +}
>>> +
>>> static u32 svm_get_interrupt_shadow(struct kvm_vcpu *vcpu)
>>> {
>>> struct vcpu_svm *svm = to_svm(vcpu);
>>> @@ -3502,13 +3512,21 @@ static int svm_nmi_allowed(struct kvm_vcpu *vcpu, bool for_injection)
>>>
>>> static bool svm_get_nmi_mask(struct kvm_vcpu *vcpu)
>>> {
>>> - return !!(vcpu->arch.hflags & HF_NMI_MASK);
>>> + struct vcpu_svm *svm = to_svm(vcpu);
>>> +
>>> + if (is_vnmi_enabled(svm->vmcb))
>>> + return is_vnmi_mask_set(svm->vmcb);
>>> + else
>>> + return !!(vcpu->arch.hflags & HF_NMI_MASK);
>>> }
>>>
>>> static void svm_set_nmi_mask(struct kvm_vcpu *vcpu, bool masked)
>>> {
>>> struct vcpu_svm *svm = to_svm(vcpu);
>>>
>>> + if (is_vnmi_enabled(svm->vmcb))
>>> + return;
>>
>> What if the KVM wants to mask NMI, shoudn't we update the
>> V_NMI_MASK value in int_ctl instead of doing nothing?
>>
V_NMI_MASK is cpu controlled meaning HW sets the mask while processing
event and clears right after processing, so in away its Read-only for hypervisor.
>> Best regards,
>> Maxim Levitsky
>>
>>
>>> +
>>> if (masked) {
>>> vcpu->arch.hflags |= HF_NMI_MASK;
>>> if (!sev_es_guest(vcpu->kvm))
>>
>>
next prev parent reply other threads:[~2022-06-17 14:48 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
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 [this message]
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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