linux-kernel - [PATCH v10 22/50] KVM: SEV: Add GHCB handling for Hypervisor Feature Support requests

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Message-ID: <20231016132819.1002933-23-michael.roth@amd.com>
Date:   Mon, 16 Oct 2023 08:27:51 -0500
From:   Michael Roth <michael.roth@....com>
To:     <kvm@...r.kernel.org>
CC:     <linux-coco@...ts.linux.dev>, <linux-mm@...ck.org>,
        <linux-crypto@...r.kernel.org>, <x86@...nel.org>,
        <linux-kernel@...r.kernel.org>, <tglx@...utronix.de>,
        <mingo@...hat.com>, <jroedel@...e.de>, <thomas.lendacky@....com>,
        <hpa@...or.com>, <ardb@...nel.org>, <pbonzini@...hat.com>,
        <seanjc@...gle.com>, <vkuznets@...hat.com>, <jmattson@...gle.com>,
        <luto@...nel.org>, <dave.hansen@...ux.intel.com>, <slp@...hat.com>,
        <pgonda@...gle.com>, <peterz@...radead.org>,
        <srinivas.pandruvada@...ux.intel.com>, <rientjes@...gle.com>,
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        <vbabka@...e.cz>, <kirill@...temov.name>, <ak@...ux.intel.com>,
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        <sathyanarayanan.kuppuswamy@...ux.intel.com>,
        <alpergun@...gle.com>, <jarkko@...nel.org>, <ashish.kalra@....com>,
        <nikunj.dadhania@....com>, <pankaj.gupta@....com>,
        <liam.merwick@...cle.com>, <zhi.a.wang@...el.com>,
        Brijesh Singh <brijesh.singh@....com>
Subject: [PATCH v10 22/50] KVM: SEV: Add GHCB handling for Hypervisor Feature Support requests

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

Version 2 of the GHCB specification introduced advertisement of features
that are supported by the Hypervisor.

Now that KVM supports version 2 of the GHCB specification, bump the
maximum supported protocol version.

Signed-off-by: Brijesh Singh <brijesh.singh@....com>
Signed-off-by: Ashish Kalra <ashish.kalra@....com>
---
 arch/x86/include/asm/sev-common.h |  2 ++
 arch/x86/kvm/svm/sev.c            | 14 ++++++++++++++
 arch/x86/kvm/svm/svm.h            |  3 ++-
 3 files changed, 18 insertions(+), 1 deletion(-)

diff --git a/arch/x86/include/asm/sev-common.h b/arch/x86/include/asm/sev-common.h
index 57ced29264ce..9ba88973a187 100644
--- a/arch/x86/include/asm/sev-common.h
+++ b/arch/x86/include/asm/sev-common.h
@@ -101,6 +101,8 @@ enum psc_op {
 /* GHCB Hypervisor Feature Request/Response */
 #define GHCB_MSR_HV_FT_REQ		0x080
 #define GHCB_MSR_HV_FT_RESP		0x081
+#define GHCB_MSR_HV_FT_POS		12
+#define GHCB_MSR_HV_FT_MASK		GENMASK_ULL(51, 0)
 #define GHCB_MSR_HV_FT_RESP_VAL(v)			\
 	/* GHCBData[63:12] */				\
 	(((u64)(v) & GENMASK_ULL(63, 12)) >> 12)
diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
index 4f895a7201ed..088b32657f46 100644
--- a/arch/x86/kvm/svm/sev.c
+++ b/arch/x86/kvm/svm/sev.c
@@ -2568,6 +2568,7 @@ static int sev_es_validate_vmgexit(struct vcpu_svm *svm)
 	case SVM_VMGEXIT_AP_HLT_LOOP:
 	case SVM_VMGEXIT_AP_JUMP_TABLE:
 	case SVM_VMGEXIT_UNSUPPORTED_EVENT:
+	case SVM_VMGEXIT_HV_FEATURES:
 		break;
 	default:
 		reason = GHCB_ERR_INVALID_EVENT;
@@ -2828,6 +2829,13 @@ static int sev_handle_vmgexit_msr_protocol(struct vcpu_svm *svm)
 				  GHCB_MSR_INFO_MASK,
 				  GHCB_MSR_INFO_POS);
 		break;
+	case GHCB_MSR_HV_FT_REQ: {
+		set_ghcb_msr_bits(svm, GHCB_HV_FT_SUPPORTED,
+				  GHCB_MSR_HV_FT_MASK, GHCB_MSR_HV_FT_POS);
+		set_ghcb_msr_bits(svm, GHCB_MSR_HV_FT_RESP,
+				  GHCB_MSR_INFO_MASK, GHCB_MSR_INFO_POS);
+		break;
+	}
 	case GHCB_MSR_TERM_REQ: {
 		u64 reason_set, reason_code;
 
@@ -2952,6 +2960,12 @@ int sev_handle_vmgexit(struct kvm_vcpu *vcpu)
 		ret = 1;
 		break;
 	}
+	case SVM_VMGEXIT_HV_FEATURES: {
+		ghcb_set_sw_exit_info_2(svm->sev_es.ghcb, GHCB_HV_FT_SUPPORTED);
+
+		ret = 1;
+		break;
+	}
 	case SVM_VMGEXIT_UNSUPPORTED_EVENT:
 		vcpu_unimpl(vcpu,
 			    "vmgexit: unsupported event - exit_info_1=%#llx, exit_info_2=%#llx\n",
diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h
index b74231511493..c13070d00910 100644
--- a/arch/x86/kvm/svm/svm.h
+++ b/arch/x86/kvm/svm/svm.h
@@ -663,9 +663,10 @@ void avic_refresh_virtual_apic_mode(struct kvm_vcpu *vcpu);
 
 /* sev.c */
 
-#define GHCB_VERSION_MAX	1ULL
+#define GHCB_VERSION_MAX	2ULL
 #define GHCB_VERSION_MIN	1ULL
 
+#define GHCB_HV_FT_SUPPORTED	GHCB_HV_FT_SNP
 
 extern unsigned int max_sev_asid;
 
-- 
2.25.1