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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>,
	<mingo@redhat.com>, <jroedel@suse.de>, <thomas.lendacky@amd.com>,
	<hpa@zytor.com>, <ardb@kernel.org>, <pbonzini@redhat.com>,
	<seanjc@google.com>, <vkuznets@redhat.com>, <jmattson@google.com>,
	<luto@kernel.org>, <dave.hansen@linux.intel.com>,
	<slp@redhat.com>, <pgonda@google.com>, <peterz@infradead.org>,
	<srinivas.pandruvada@linux.intel.com>, <rientjes@google.com>,
	<dovmurik@linux.ibm.com>, <tobin@ibm.com>, <bp@alien8.de>,
	<vbabka@suse.cz>, <kirill@shutemov.name>, <ak@linux.intel.com>,
	<tony.luck@intel.com>,
	<sathyanarayanan.kuppuswamy@linux.intel.com>,
	<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>,
	Alexey Kardashevskiy <aik@amd.com>
Subject: [PATCH v15 18/20] KVM: SEV: Provide support for SNP_GUEST_REQUEST NAE event
Date: Wed, 1 May 2024 03:52:08 -0500	[thread overview]
Message-ID: <20240501085210.2213060-19-michael.roth@amd.com> (raw)
In-Reply-To: <20240501085210.2213060-1-michael.roth@amd.com>

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

Version 2 of GHCB specification added support for the SNP Guest Request
Message NAE event. The event allows for an SEV-SNP guest to make
requests to the SEV-SNP firmware through hypervisor using the
SNP_GUEST_REQUEST API defined in the SEV-SNP firmware specification.

This is used by guests primarily to request attestation reports from
firmware. There are other request types are available as well, but the
specifics of what guest requests are being made are opaque to the
hypervisor, which only serves as a proxy for the guest requests and
firmware responses.

Implement handling for these events.

Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
Co-developed-by: Alexey Kardashevskiy <aik@amd.com>
Signed-off-by: Alexey Kardashevskiy <aik@amd.com>
Co-developed-by: Ashish Kalra <ashish.kalra@amd.com>
Signed-off-by: Ashish Kalra <ashish.kalra@amd.com>
Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>
[mdr: ensure FW command failures are indicated to guest, drop extended
 request handling to be re-written as separate patch, massage commit]
Signed-off-by: Michael Roth <michael.roth@amd.com>
---
 arch/x86/kvm/svm/sev.c         | 86 ++++++++++++++++++++++++++++++++++
 include/uapi/linux/sev-guest.h |  9 ++++
 2 files changed, 95 insertions(+)

diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
index 112041ee55e9..5c6262f3232f 100644
--- a/arch/x86/kvm/svm/sev.c
+++ b/arch/x86/kvm/svm/sev.c
@@ -19,6 +19,7 @@
 #include <linux/misc_cgroup.h>
 #include <linux/processor.h>
 #include <linux/trace_events.h>
+#include <uapi/linux/sev-guest.h>
 
 #include <asm/pkru.h>
 #include <asm/trapnr.h>
@@ -3292,6 +3293,10 @@ static int sev_es_validate_vmgexit(struct vcpu_svm *svm)
 		if (!sev_snp_guest(vcpu->kvm) || !kvm_ghcb_sw_scratch_is_valid(svm))
 			goto vmgexit_err;
 		break;
+	case SVM_VMGEXIT_GUEST_REQUEST:
+		if (!sev_snp_guest(vcpu->kvm))
+			goto vmgexit_err;
+		break;
 	default:
 		reason = GHCB_ERR_INVALID_EVENT;
 		goto vmgexit_err;
@@ -3906,6 +3911,83 @@ static int sev_snp_ap_creation(struct vcpu_svm *svm)
 	return ret;
 }
 
+static int snp_setup_guest_buf(struct kvm *kvm, struct sev_data_snp_guest_request *data,
+			       gpa_t req_gpa, gpa_t resp_gpa)
+{
+	struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info;
+	kvm_pfn_t req_pfn, resp_pfn;
+
+	if (!PAGE_ALIGNED(req_gpa) || !PAGE_ALIGNED(resp_gpa))
+		return -EINVAL;
+
+	req_pfn = gfn_to_pfn(kvm, gpa_to_gfn(req_gpa));
+	if (is_error_noslot_pfn(req_pfn))
+		return -EINVAL;
+
+	resp_pfn = gfn_to_pfn(kvm, gpa_to_gfn(resp_gpa));
+	if (is_error_noslot_pfn(resp_pfn))
+		return -EINVAL;
+
+	if (rmp_make_private(resp_pfn, 0, PG_LEVEL_4K, 0, true))
+		return -EINVAL;
+
+	data->gctx_paddr = __psp_pa(sev->snp_context);
+	data->req_paddr = __sme_set(req_pfn << PAGE_SHIFT);
+	data->res_paddr = __sme_set(resp_pfn << PAGE_SHIFT);
+
+	return 0;
+}
+
+static int snp_cleanup_guest_buf(struct sev_data_snp_guest_request *data)
+{
+	u64 pfn = __sme_clr(data->res_paddr) >> PAGE_SHIFT;
+
+	if (snp_page_reclaim(pfn) || rmp_make_shared(pfn, PG_LEVEL_4K))
+		return -EINVAL;
+
+	return 0;
+}
+
+static int __snp_handle_guest_req(struct kvm *kvm, gpa_t req_gpa, gpa_t resp_gpa,
+				  sev_ret_code *fw_err)
+{
+	struct sev_data_snp_guest_request data = {0};
+	struct kvm_sev_info *sev;
+	int ret;
+
+	if (!sev_snp_guest(kvm))
+		return -EINVAL;
+
+	sev = &to_kvm_svm(kvm)->sev_info;
+
+	ret = snp_setup_guest_buf(kvm, &data, req_gpa, resp_gpa);
+	if (ret)
+		return ret;
+
+	ret = sev_issue_cmd(kvm, SEV_CMD_SNP_GUEST_REQUEST, &data, fw_err);
+	if (ret)
+		return ret;
+
+	ret = snp_cleanup_guest_buf(&data);
+	if (ret)
+		return ret;
+
+	return 0;
+}
+
+static void snp_handle_guest_req(struct vcpu_svm *svm, gpa_t req_gpa, gpa_t resp_gpa)
+{
+	struct kvm_vcpu *vcpu = &svm->vcpu;
+	struct kvm *kvm = vcpu->kvm;
+	sev_ret_code fw_err = 0;
+	int vmm_ret = 0;
+
+	if (__snp_handle_guest_req(kvm, req_gpa, resp_gpa, &fw_err))
+		vmm_ret = SNP_GUEST_VMM_ERR_GENERIC;
+
+	ghcb_set_sw_exit_info_2(svm->sev_es.ghcb, SNP_GUEST_ERR(vmm_ret, fw_err));
+}
+
 static int sev_handle_vmgexit_msr_protocol(struct vcpu_svm *svm)
 {
 	struct vmcb_control_area *control = &svm->vmcb->control;
@@ -4178,6 +4260,10 @@ int sev_handle_vmgexit(struct kvm_vcpu *vcpu)
 			ghcb_set_sw_exit_info_2(svm->sev_es.ghcb, GHCB_ERR_INVALID_INPUT);
 		}
 
+		ret = 1;
+		break;
+	case SVM_VMGEXIT_GUEST_REQUEST:
+		snp_handle_guest_req(svm, control->exit_info_1, control->exit_info_2);
 		ret = 1;
 		break;
 	case SVM_VMGEXIT_UNSUPPORTED_EVENT:
diff --git a/include/uapi/linux/sev-guest.h b/include/uapi/linux/sev-guest.h
index 154a87a1eca9..7bd78e258569 100644
--- a/include/uapi/linux/sev-guest.h
+++ b/include/uapi/linux/sev-guest.h
@@ -89,8 +89,17 @@ struct snp_ext_report_req {
 #define SNP_GUEST_FW_ERR_MASK		GENMASK_ULL(31, 0)
 #define SNP_GUEST_VMM_ERR_SHIFT		32
 #define SNP_GUEST_VMM_ERR(x)		(((u64)x) << SNP_GUEST_VMM_ERR_SHIFT)
+#define SNP_GUEST_FW_ERR(x)		((x) & SNP_GUEST_FW_ERR_MASK)
+#define SNP_GUEST_ERR(vmm_err, fw_err)	(SNP_GUEST_VMM_ERR(vmm_err) | \
+					 SNP_GUEST_FW_ERR(fw_err))
 
+/*
+ * The GHCB spec only formally defines INVALID_LEN/BUSY VMM errors, but define
+ * a GENERIC error code such that it won't ever conflict with GHCB-defined
+ * errors if any get added in the future.
+ */
 #define SNP_GUEST_VMM_ERR_INVALID_LEN	1
 #define SNP_GUEST_VMM_ERR_BUSY		2
+#define SNP_GUEST_VMM_ERR_GENERIC	BIT(31)
 
 #endif /* __UAPI_LINUX_SEV_GUEST_H_ */
-- 
2.25.1


  parent reply	other threads:[~2024-05-01  9:05 UTC|newest]

Thread overview: 64+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-05-01  8:51 [PATCH v15 00/20] Add AMD Secure Nested Paging (SEV-SNP) Hypervisor Support Michael Roth
2024-05-01  8:51 ` [PATCH v15 01/20] Revert "KVM: x86: Add gmem hook for determining max NPT mapping level" Michael Roth
2024-05-01  8:51 ` [PATCH v15 02/20] KVM: x86: Add hook for determining max NPT mapping level Michael Roth
2024-05-02 23:11   ` Isaku Yamahata
2024-05-07 17:48   ` Paolo Bonzini
2024-05-01  8:51 ` [PATCH v15 03/20] KVM: SEV: Select KVM_GENERIC_PRIVATE_MEM when CONFIG_KVM_AMD_SEV=y Michael Roth
2024-05-01  8:51 ` [PATCH v15 04/20] KVM: SEV: Add initial SEV-SNP support Michael Roth
2024-05-01  8:51 ` [PATCH v15 05/20] KVM: SEV: Add KVM_SEV_SNP_LAUNCH_START command Michael Roth
2024-05-01  8:51 ` [PATCH v15 06/20] KVM: SEV: Add KVM_SEV_SNP_LAUNCH_UPDATE command Michael Roth
2024-05-01  8:51 ` [PATCH v15 07/20] KVM: SEV: Add KVM_SEV_SNP_LAUNCH_FINISH command Michael Roth
2024-05-01  8:51 ` [PATCH v15 08/20] KVM: SEV: Add support to handle GHCB GPA register VMGEXIT Michael Roth
2024-05-01  8:51 ` [PATCH v15 09/20] KVM: SEV: Add support to handle MSR based Page State Change VMGEXIT Michael Roth
2024-05-16  8:28   ` Binbin Wu
2024-05-16 17:23     ` Paolo Bonzini
2024-05-21  0:49       ` Binbin Wu
2024-05-21 21:49         ` Michael Roth
2024-05-27 12:25           ` Binbin Wu
2024-05-28 10:39             ` Paolo Bonzini
2024-05-29 20:02               ` Sean Christopherson
2024-05-31  1:22                 ` Binbin Wu
2024-05-31 13:10                   ` Paolo Bonzini
2024-05-30 16:47           ` Zhi Wang
2024-05-01  8:52 ` [PATCH v15 10/20] KVM: SEV: Add support to handle " Michael Roth
2024-05-01  8:52 ` [PATCH v15 11/20] KVM: SEV: Add support to handle RMP nested page faults Michael Roth
2024-05-01  8:52 ` [PATCH v15 12/20] KVM: SEV: Support SEV-SNP AP Creation NAE event Michael Roth
2024-05-01  8:52 ` [PATCH v15 13/20] KVM: SEV: Implement gmem hook for initializing private pages Michael Roth
2024-05-20 10:16   ` Huang, Kai
2024-05-20 17:35     ` Sean Christopherson
2024-05-20 21:57       ` Huang, Kai
2024-05-20 23:15         ` Sean Christopherson
2024-05-20 23:41           ` Huang, Kai
2024-05-21  0:30             ` Sean Christopherson
2024-05-20 19:14     ` Isaku Yamahata
2024-05-01  8:52 ` [PATCH v15 14/20] KVM: SEV: Implement gmem hook for invalidating " Michael Roth
2024-05-01  8:52 ` [PATCH v15 15/20] KVM: x86: Implement hook for determining max NPT mapping level Michael Roth
2024-05-01  8:52 ` [PATCH v15 16/20] KVM: SEV: Avoid WBINVD for HVA-based MMU notifications for SNP Michael Roth
2024-05-01  8:52 ` [PATCH v15 17/20] KVM: SVM: Add module parameter to enable SEV-SNP Michael Roth
2024-05-01  8:52 ` Michael Roth [this message]
2024-05-01  8:52 ` [PATCH v15 19/20] KVM: SEV: Provide support for SNP_EXTENDED_GUEST_REQUEST NAE event Michael Roth
2024-05-13 23:48   ` Sean Christopherson
2024-05-14  2:51     ` Michael Roth
2024-05-14 14:36       ` Sean Christopherson
2024-05-15  1:25         ` [PATCH] KVM: SEV: Replace KVM_EXIT_VMGEXIT with KVM_EXIT_SNP_REQ_CERTS Michael Roth
2024-05-01  8:52 ` [PATCH v15 20/20] crypto: ccp: Add the SNP_VLEK_LOAD command Michael Roth
2024-05-07 18:04 ` [PATCH v15 00/20] Add AMD Secure Nested Paging (SEV-SNP) Hypervisor Support Paolo Bonzini
2024-05-07 18:14   ` Michael Roth
2024-05-10  2:34     ` Michael Roth
2024-05-10  1:58 ` [PATCH v15 21/23] KVM: MMU: Disable fast path for private memslots Michael Roth
2024-05-10  1:58   ` [PATCH v15 22/23] KVM: SEV: Fix return code interpretation for RMP nested page faults Michael Roth
2024-05-10 13:58     ` Sean Christopherson
2024-05-10 15:36       ` Michael Roth
2024-05-10 16:01       ` Paolo Bonzini
2024-05-10 16:37         ` Michael Roth
2024-05-10 16:59           ` Paolo Bonzini
2024-05-10 17:25             ` Paolo Bonzini
2024-05-14  8:10             ` Borislav Petkov
2024-05-10  1:58   ` [PATCH v15 23/23] KVM: SEV: Fix PSC handling for SMASH/UNSMASH and partial update ops Michael Roth
2024-05-10 17:09     ` Paolo Bonzini
2024-05-10 19:08       ` Michael Roth
2024-05-10 13:47   ` [PATCH v15 21/23] KVM: MMU: Disable fast path for private memslots Sean Christopherson
2024-05-10 13:50     ` Paolo Bonzini
2024-05-10 15:27       ` Michael Roth
2024-05-10 15:59         ` Sean Christopherson
2024-05-10 17:47           ` Isaku Yamahata

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