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>,
Tom Lendacky <thomas.lendacky@amd.com>, <kvm@vger.kernel.org>,
<linux-kernel@vger.kernel.org>, <santosh.shukla@amd.com>,
<mlevitsk@redhat.com>
Subject: [PATCHv3 0/8] Virtual NMI feature
Date: Wed, 10 Aug 2022 11:42:18 +0530 [thread overview]
Message-ID: <20220810061226.1286-1-santosh.shukla@amd.com> (raw)
Change History:
v3 (rebased on eb555cb5b794f):
03 - added clear/set_vnmi_mask API for SMM case
04 - added vnmi_pending check so to detect the pending VNMI scenario
05 - removed WARN_ON
06 - handle one of nested case where L1 using vnmi and L2 doesn't
07 - Emulate the VMEXIT(#INVALID) case for nested case
08 - No change.
v2:
https://lore.kernel.org/lkml/20220709134230.2397-7-santosh.shukla@amd.com/T/#m4bf8a131748688fed00ab0fefdcac209a169e202
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.
v1:
https://lore.kernel.org/all/20220602142620.3196-1-santosh.shukla@amd.com/
Description:
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.
If NMI virtualization enabled and NMI_INTERCEPT bit is unset
then HW will exit with #INVALID exit reason.
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 with vGIF enable and disable.
* tested nested env:
- L1+L2 using vnmi
- L1 using vnmi and L2 not
Thanks,
Santosh
[1] https://www.amd.com/system/files/TechDocs/40332.pdf - APM Vol2,
ch-15.20 - "Event Injection".
Santosh Shukla (8):
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: nSVM: emulate VMEXIT_INVALID case for 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 | 32 ++++++++++++++
arch/x86/kvm/svm/svm.c | 44 ++++++++++++++++++-
arch/x86/kvm/svm/svm.h | 68 ++++++++++++++++++++++++++++++
5 files changed, 151 insertions(+), 1 deletion(-)
--
2.25.1
next reply other threads:[~2022-08-10 6:12 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-08-10 6:12 Santosh Shukla [this message]
2022-08-10 6:12 ` [PATCHv3 1/8] x86/cpu: Add CPUID feature bit for VNMI Santosh Shukla
2022-08-10 6:12 ` [PATCHv3 2/8] KVM: SVM: Add VNMI bit definition Santosh Shukla
2022-08-10 6:12 ` [PATCHv3 3/8] KVM: SVM: Add VNMI support in get/set_nmi_mask Santosh Shukla
2022-08-10 6:12 ` [PATCHv3 4/8] KVM: SVM: Report NMI not allowed when Guest busy handling VNMI Santosh Shukla
2022-08-10 6:12 ` [PATCHv3 5/8] KVM: SVM: Add VNMI support in inject_nmi Santosh Shukla
2022-08-10 21:24 ` Maciej S. Szmigiero
2022-08-24 12:13 ` Shukla, Santosh
2022-08-24 12:56 ` Maciej S. Szmigiero
2022-08-25 10:56 ` Shukla, Santosh
2022-08-25 12:45 ` Maciej S. Szmigiero
2022-08-25 14:05 ` Shukla, Santosh
2022-08-25 14:16 ` Maciej S. Szmigiero
2022-08-26 9:35 ` Shukla, Santosh
2022-08-26 12:20 ` Maciej S. Szmigiero
2022-08-26 16:26 ` Shukla, Santosh
2022-08-10 6:12 ` [PATCHv3 6/8] KVM: nSVM: implement nested VNMI Santosh Shukla
2022-08-10 6:12 ` [PATCHv3 7/8] KVM: nSVM: emulate VMEXIT_INVALID case for " Santosh Shukla
2022-08-10 6:12 ` [PATCHv3 8/8] KVM: SVM: Enable VNMI feature Santosh Shukla
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