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From: Michael Roth <michael.roth@amd.com>
To: <kvm@vger.kernel.org>
Cc: <linux-coco@lists.linux.dev>, <linux-mm@kvack.org>,
	<linux-crypto@vger.kernel.org>, <x86@kernel.org>,
	<linux-kernel@vger.kernel.org>, <tglx@linutronix.de>,
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	<alpergun@google.com>, <jarkko@kernel.org>,
	<ashish.kalra@amd.com>, <nikunj.dadhania@amd.com>,
	<pankaj.gupta@amd.com>, <liam.merwick@oracle.com>,
	Brijesh Singh <brijesh.singh@amd.com>
Subject: [PATCH v14 10/22] KVM: SEV: Add support to handle Page State Change VMGEXIT
Date: Sun, 21 Apr 2024 13:01:10 -0500	[thread overview]
Message-ID: <20240421180122.1650812-11-michael.roth@amd.com> (raw)
In-Reply-To: <20240421180122.1650812-1-michael.roth@amd.com>

From: Brijesh Singh <brijesh.singh@amd.com>

SEV-SNP VMs can ask the hypervisor to change the page state in the RMP
table to be private or shared using the Page State Change NAE event
as defined in the GHCB specification version 2.

Forward these requests to userspace as KVM_EXIT_VMGEXITs, similar to how
it is done for requests that don't use a GHCB page.

Co-developed-by: Michael Roth <michael.roth@amd.com>
Signed-off-by: Michael Roth <michael.roth@amd.com>
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
Signed-off-by: Ashish Kalra <ashish.kalra@amd.com>
---
 Documentation/virt/kvm/api.rst | 14 ++++++++++++++
 arch/x86/kvm/svm/sev.c         | 16 ++++++++++++++++
 include/uapi/linux/kvm.h       |  5 +++++
 3 files changed, 35 insertions(+)

diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst
index 4a7a2945bc78..85099198a10f 100644
--- a/Documentation/virt/kvm/api.rst
+++ b/Documentation/virt/kvm/api.rst
@@ -7065,6 +7065,7 @@ values in kvm_run even if the corresponding bit in kvm_dirty_regs is not set.
 		/* KVM_EXIT_VMGEXIT */
 		struct kvm_user_vmgexit {
 		#define KVM_USER_VMGEXIT_PSC_MSR	1
+		#define KVM_USER_VMGEXIT_PSC		2
 			__u32 type; /* KVM_USER_VMGEXIT_* type */
 			union {
 				struct {
@@ -7074,9 +7075,14 @@ values in kvm_run even if the corresponding bit in kvm_dirty_regs is not set.
 					__u8 op;
 					__u32 ret;
 				} psc_msr;
+				struct {
+					__u64 shared_gpa;
+					__u64 ret;
+				} psc;
 			};
 		};
 
+
 If exit reason is KVM_EXIT_VMGEXIT then it indicates that an SEV-SNP guest
 has issued a VMGEXIT instruction (as documented by the AMD Architecture
 Programmer's Manual (APM)) to the hypervisor that needs to be serviced by
@@ -7094,6 +7100,14 @@ update the private/shared state of the GPA using the corresponding
 KVM_SET_MEMORY_ATTRIBUTES ioctl. The 'ret' field is to be set to 0 by
 userpace on success, or some non-zero value on failure.
 
+For the KVM_USER_VMGEXIT_PSC type, the psc union type is used. The kernel
+will supply the GPA of the Page State Structure defined in the GHCB spec.
+Userspace will process this structure as defined by the GHCB, and issue
+KVM_SET_MEMORY_ATTRIBUTES ioctls to set the GPAs therein to the expected
+private/shared state. Userspace will return a value in 'ret' that is in
+agreement with the GHCB-defined return values that the guest will expect
+in the SW_EXITINFO2 field of the GHCB in response to these requests.
+
 6. Capabilities that can be enabled on vCPUs
 ============================================
 
diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
index f6f54a889fde..e9519af8f14c 100644
--- a/arch/x86/kvm/svm/sev.c
+++ b/arch/x86/kvm/svm/sev.c
@@ -3275,6 +3275,7 @@ static int sev_es_validate_vmgexit(struct vcpu_svm *svm)
 	case SVM_VMGEXIT_AP_JUMP_TABLE:
 	case SVM_VMGEXIT_UNSUPPORTED_EVENT:
 	case SVM_VMGEXIT_HV_FEATURES:
+	case SVM_VMGEXIT_PSC:
 		break;
 	default:
 		reason = GHCB_ERR_INVALID_EVENT;
@@ -3493,6 +3494,15 @@ static int snp_begin_psc_msr(struct kvm_vcpu *vcpu, u64 ghcb_msr)
 	return 0; /* forward request to userspace */
 }
 
+static int snp_complete_psc(struct kvm_vcpu *vcpu)
+{
+	struct vcpu_svm *svm = to_svm(vcpu);
+
+	ghcb_set_sw_exit_info_2(svm->sev_es.ghcb, vcpu->run->vmgexit.psc.ret);
+
+	return 1; /* resume guest */
+}
+
 static int sev_handle_vmgexit_msr_protocol(struct vcpu_svm *svm)
 {
 	struct vmcb_control_area *control = &svm->vmcb->control;
@@ -3730,6 +3740,12 @@ int sev_handle_vmgexit(struct kvm_vcpu *vcpu)
 
 		ret = 1;
 		break;
+	case SVM_VMGEXIT_PSC:
+		vcpu->run->exit_reason = KVM_EXIT_VMGEXIT;
+		vcpu->run->vmgexit.type = KVM_USER_VMGEXIT_PSC;
+		vcpu->run->vmgexit.psc.shared_gpa = svm->sev_es.sw_scratch;
+		vcpu->arch.complete_userspace_io = snp_complete_psc;
+		break;
 	case SVM_VMGEXIT_UNSUPPORTED_EVENT:
 		vcpu_unimpl(vcpu,
 			    "vmgexit: unsupported event - exit_info_1=%#llx, exit_info_2=%#llx\n",
diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
index 54b81e46a9fa..e33c48bfbd67 100644
--- a/include/uapi/linux/kvm.h
+++ b/include/uapi/linux/kvm.h
@@ -137,6 +137,7 @@ struct kvm_xen_exit {
 
 struct kvm_user_vmgexit {
 #define KVM_USER_VMGEXIT_PSC_MSR	1
+#define KVM_USER_VMGEXIT_PSC		2
 	__u32 type; /* KVM_USER_VMGEXIT_* type */
 	union {
 		struct {
@@ -146,6 +147,10 @@ struct kvm_user_vmgexit {
 			__u8 op;
 			__u32 ret;
 		} psc_msr;
+		struct {
+			__u64 shared_gpa;
+			__u64 ret;
+		} psc;
 	};
 };
 
-- 
2.25.1


  parent reply	other threads:[~2024-04-21 18:03 UTC|newest]

Thread overview: 56+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-04-21 18:01 [PATCH v14 00/22] Add AMD Secure Nested Paging (SEV-SNP) Hypervisor Support Michael Roth
2024-04-21 18:01 ` [PATCH v14 01/22] KVM: SEV: Select KVM_GENERIC_PRIVATE_MEM when CONFIG_KVM_AMD_SEV=y Michael Roth
2024-04-21 18:01 ` [PATCH v14 02/22] KVM: SEV: Add support to handle AP reset MSR protocol Michael Roth
2024-04-21 18:01 ` [PATCH v14 03/22] KVM: SEV: Add GHCB handling for Hypervisor Feature Support requests Michael Roth
2024-04-24 20:21   ` Sean Christopherson
2024-04-25 20:52     ` Michael Roth
2024-04-25 21:55       ` Sean Christopherson
2024-04-21 18:01 ` [PATCH v14 04/22] KVM: SEV: Add initial SEV-SNP support Michael Roth
2024-04-21 18:01 ` [PATCH v14 05/22] KVM: SEV: Add KVM_SEV_SNP_LAUNCH_START command Michael Roth
2024-04-24 23:26   ` Sean Christopherson
2024-04-21 18:01 ` [PATCH v14 06/22] KVM: SEV: Add KVM_SEV_SNP_LAUNCH_UPDATE command Michael Roth
2024-04-24 23:58   ` Sean Christopherson
2024-04-21 18:01 ` [PATCH v14 07/22] KVM: SEV: Add KVM_SEV_SNP_LAUNCH_FINISH command Michael Roth
2024-04-21 18:01 ` [PATCH v14 08/22] KVM: SEV: Add support to handle GHCB GPA register VMGEXIT Michael Roth
2024-04-21 18:01 ` [PATCH v14 09/22] KVM: SEV: Add support to handle MSR based Page State Change VMGEXIT Michael Roth
2024-04-24 20:59   ` Sean Christopherson
2024-04-25 22:00     ` Michael Roth
2024-04-25 22:13       ` Sean Christopherson
2024-04-26 17:16         ` Michael Roth
2024-04-26 20:14           ` Sean Christopherson
2024-04-26 22:24             ` Michael Roth
2024-04-26 22:48               ` Michael Roth
2024-04-21 18:01 ` Michael Roth [this message]
2024-04-21 18:01 ` [PATCH v14 11/22] KVM: SEV: Add support to handle RMP nested page faults Michael Roth
2024-04-21 18:01 ` [PATCH v14 12/22] KVM: SEV: Support SEV-SNP AP Creation NAE event Michael Roth
2024-04-21 18:01 ` [PATCH v14 13/22] KVM: SEV: Add support for GHCB-based termination requests Michael Roth
2024-04-21 18:01 ` [PATCH v14 14/22] KVM: SEV: Implement gmem hook for initializing private pages Michael Roth
2024-04-21 18:01 ` [PATCH v14 15/22] KVM: SEV: Implement gmem hook for invalidating " Michael Roth
2024-04-21 18:01 ` [PATCH v14 16/22] KVM: x86: Implement gmem hook for determining max NPT mapping level Michael Roth
2024-04-25  0:45   ` Sean Christopherson
2024-04-21 18:01 ` [PATCH v14 17/22] KVM: SEV: Avoid WBINVD for HVA-based MMU notifications for SNP Michael Roth
2024-04-25  0:17   ` Sean Christopherson
2024-04-21 18:01 ` [PATCH v14 18/22] KVM: SVM: Add module parameter to enable SEV-SNP Michael Roth
2024-04-21 18:01 ` [PATCH v14 19/22] KVM: SEV: Provide support for SNP_GUEST_REQUEST NAE event Michael Roth
2024-04-21 18:01 ` [PATCH v14 20/22] crypto: ccp: Add the SNP_VLEK_LOAD command Michael Roth
2024-04-21 18:01 ` [PATCH v14 21/22] crypto: ccp: Add the SNP_{PAUSE,RESUME}_ATTESTATION commands Michael Roth
2024-04-25  0:15   ` Sean Christopherson
2024-04-26 17:35     ` Michael Roth
2024-04-26 19:57       ` Sean Christopherson
2024-04-26 21:46         ` Michael Roth
2024-04-27  0:10           ` Sean Christopherson
2024-04-27  1:32             ` Michael Roth
2024-04-29 14:27               ` Sean Christopherson
2024-04-21 18:01 ` [PATCH v14 22/22] KVM: SEV: Provide support for SNP_EXTENDED_GUEST_REQUEST NAE event Michael Roth
2024-04-25  0:10   ` Sean Christopherson
2024-04-26 17:57     ` Michael Roth
2024-04-23 16:21 ` [PATCH v14 23/22] [SQUASH] KVM: SEV: Add support to handle GHCB GPA register VMGEXIT Michael Roth
2024-04-23 16:21   ` [PATCH v14 24/22] [SQUASH] KVM: SEV: Add support to handle MSR based Page State Change VMGEXIT Michael Roth
2024-04-23 16:21   ` [PATCH v14 25/22] [SQUASH] KVM: SEV: Add support to handle " Michael Roth
2024-04-23 16:21   ` [PATCH v14 26/22] [SQUASH] KVM: SEV: Add support for GHCB-based termination requests Michael Roth
2024-04-23 16:21   ` [PATCH v14 27/22] [SQUASH] KVM: SEV: Provide support for SNP_GUEST_REQUEST NAE event Michael Roth
2024-04-23 16:21   ` [PATCH v14 28/22] [SQUASH] KVM: SEV: Provide support for SNP_EXTENDED_GUEST_REQUEST " Michael Roth
2024-04-23 21:36     ` Jarkko Sakkinen
2024-04-23 16:21   ` [PATCH v14 29/22] [SQUASH] KVM: SEV: Support SEV-SNP AP Creation " Michael Roth
2024-04-23 16:31 ` [PATCH v14 00/22] Add AMD Secure Nested Paging (SEV-SNP) Hypervisor Support Michael Roth
2024-04-24 16:51   ` Paolo Bonzini

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