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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>, <mail@maciej.szmigiero.name>
Subject: [PATCHv4 2/8] KVM: SVM: Add VNMI bit definition
Date: Mon, 29 Aug 2022 15:38:44 +0530	[thread overview]
Message-ID: <20220829100850.1474-3-santosh.shukla@amd.com> (raw)
In-Reply-To: <20220829100850.1474-1-santosh.shukla@amd.com>

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.
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.

Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
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 0361626841bc..73bf97e04fe3 100644
--- a/arch/x86/include/asm/svm.h
+++ b/arch/x86/include/asm/svm.h
@@ -198,6 +198,13 @@ struct __attribute__ ((__packed__)) vmcb_control_area {
 #define X2APIC_MODE_SHIFT 30
 #define X2APIC_MODE_MASK (1 << X2APIC_MODE_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 f3813dbacb9f..38db96121c32 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -229,6 +229,8 @@ module_param(dump_invalid_vmcb, bool, 0644);
 bool intercept_smi = true;
 module_param(intercept_smi, bool, 0444);
 
+bool vnmi = true;
+module_param(vnmi, bool, 0444);
 
 static bool svm_gp_erratum_intercept = true;
 
@@ -5063,6 +5065,10 @@ 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) ||
-- 
2.25.1


  parent reply	other threads:[~2022-08-29 10:10 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-08-29 10:08 [PATCHv4 0/8] Virtual NMI feature Santosh Shukla
2022-08-29 10:08 ` [PATCHv4 1/8] x86/cpu: Add CPUID feature bit for VNMI Santosh Shukla
2022-08-31 23:42   ` Jim Mattson
2022-09-01 12:45     ` Shukla, Santosh
2022-09-01 17:43       ` Jim Mattson
2022-09-05  7:49         ` Shukla, Santosh
2022-08-29 10:08 ` Santosh Shukla [this message]
2022-08-29 10:08 ` [PATCHv4 3/8] KVM: SVM: Add VNMI support in get/set_nmi_mask Santosh Shukla
2022-08-29 10:08 ` [PATCHv4 4/8] KVM: SVM: Report NMI not allowed when Guest busy handling VNMI Santosh Shukla
2022-08-29 10:08 ` [PATCHv4 5/8] KVM: SVM: Add VNMI support in inject_nmi Santosh Shukla
2022-08-29 10:08 ` [PATCHv4 6/8] KVM: nSVM: implement nested VNMI Santosh Shukla
2022-08-29 10:08 ` [PATCHv4 7/8] KVM: nSVM: emulate VMEXIT_INVALID case for " Santosh Shukla
2022-08-29 10:08 ` [PATCHv4 8/8] KVM: SVM: Enable VNMI feature Santosh Shukla
2022-10-06 18:40 ` [PATCHv4 0/8] Virtual NMI feature Sean Christopherson
2022-10-10  5:46   ` Santosh Shukla
2022-10-10 15:51     ` Sean Christopherson
2022-10-16  5:49       ` Santosh Shukla

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