From: Santosh Shukla <santosh.shukla@amd.com>
To: 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>,
Maxim Levitsky <mlevitsk@redhat.com>,
Tom Lendacky <thomas.lendacky@amd.com>, <kvm@vger.kernel.org>,
<linux-kernel@vger.kernel.org>, <Santosh.Shukla@amd.com>
Subject: [PATCHv2 0/7] Virtual NMI feature
Date: Sat, 9 Jul 2022 19:12:23 +0530 [thread overview]
Message-ID: <20220709134230.2397-1-santosh.shukla@amd.com> (raw)
Currently, NMI is delivered to the guest using the Event Injection
mechanism [1]. The Event Injection mechanism does not block the delivery
of subsequent NMIs. So the Hypervisor needs to track the NMI delivery
and its completion(by intercepting IRET) before sending a new NMI.
Virtual NMI (VNMI) allows the hypervisor to inject the NMI into the guest
w/o using Event Injection mechanism meaning not required to track the
guest NMI and intercepting the IRET. To achieve that,
VNMI feature provides virtualized NMI and NMI_MASK capability bits in
VMCB intr_control -
V_NMI(11) - Indicates whether a virtual NMI is pending in the guest.
V_NMI_MASK(12) - Indicates whether virtual NMI is masked in the guest.
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.
The presence of this feature is indicated via the CPUID function
0x8000000A_EDX[25].
Testing -
* Used qemu's `inject_nmi` for testing.
* tested with and w/o AVIC case.
* tested with kvm-unit-test
* tested injecting NMI event from L1 to L2 guest (nested env).
v2:
01, 02 - added maxim reviwed-by.
03 - Added get_vnmi_vmcb API to return vmcb for l1 and l2.
04 - Moved vnmi check after is_guest_mode() in func svm_nmi_blocked().
05 - Added WARN_ON check for vnmi pending.
06 - Save the V_NMI_PENDING/MASK state in vmcb12 on vmexit.
07 - No change.
Thanks,
Santosh
[1] https://www.amd.com/system/files/TechDocs/40332.pdf - APM Vol2,
ch-15.20 - "Event Injection".
Santosh Shukla (7):
x86/cpu: Add CPUID feature bit for VNMI
KVM: SVM: Add VNMI bit definition
KVM: SVM: Add VNMI support in get/set_nmi_mask
KVM: SVM: Report NMI not allowed when Guest busy handling VNMI
KVM: SVM: Add VNMI support in inject_nmi
KVM: nSVM: implement nested VNMI
KVM: SVM: Enable VNMI feature
arch/x86/include/asm/cpufeatures.h | 1 +
arch/x86/include/asm/svm.h | 7 ++++++
arch/x86/kvm/svm/nested.c | 16 +++++++++++-
arch/x86/kvm/svm/svm.c | 40 ++++++++++++++++++++++++++++--
arch/x86/kvm/svm/svm.h | 38 ++++++++++++++++++++++++++++
5 files changed, 99 insertions(+), 3 deletions(-)
--
2.25.1
next reply other threads:[~2022-07-09 13:42 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-07-09 13:42 Santosh Shukla [this message]
2022-07-09 13:42 ` [PATCHv2 1/7] x86/cpu: Add CPUID feature bit for VNMI Santosh Shukla
2022-07-09 13:42 ` [PATCHv2 2/7] KVM: SVM: Add VNMI bit definition Santosh Shukla
2022-07-09 13:42 ` [PATCHv2 3/7] KVM: SVM: Add VNMI support in get/set_nmi_mask Santosh Shukla
2022-07-10 16:15 ` Maxim Levitsky
2022-07-21 9:34 ` Shukla, Santosh
2022-07-21 12:01 ` Maxim Levitsky
2022-07-21 13:12 ` Shukla, Santosh
2022-07-21 15:48 ` Maxim Levitsky
2022-07-09 13:42 ` [PATCHv2 4/7] KVM: SVM: Report NMI not allowed when Guest busy handling VNMI Santosh Shukla
2022-07-20 21:54 ` Sean Christopherson
2022-07-21 12:05 ` Maxim Levitsky
2022-07-21 14:59 ` Sean Christopherson
2022-07-21 15:31 ` Maxim Levitsky
2022-07-21 16:08 ` Sean Christopherson
2022-07-21 16:17 ` Maxim Levitsky
2022-07-21 16:25 ` Sean Christopherson
2022-07-29 5:51 ` Shukla, Santosh
2022-07-29 14:41 ` Sean Christopherson
2022-08-04 9:51 ` Shukla, Santosh
2022-07-09 13:42 ` [PATCHv2 5/7] KVM: SVM: Add VNMI support in inject_nmi Santosh Shukla
2022-07-20 21:41 ` Sean Christopherson
2022-07-20 22:46 ` Jim Mattson
2022-07-20 23:04 ` Sean Christopherson
2022-07-29 6:06 ` Shukla, Santosh
2022-07-29 13:53 ` Sean Christopherson
2022-07-29 13:55 ` Shukla, Santosh
2022-07-09 13:42 ` [PATCHv2 6/7] KVM: nSVM: implement nested VNMI Santosh Shukla
2022-07-09 13:42 ` [PATCHv2 7/7] KVM: SVM: Enable VNMI feature Santosh Shukla
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