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Peter Anvin" , Ard Biesheuvel , Paolo Bonzini , Sean Christopherson , "Vitaly Kuznetsov" , Jim Mattson , "Andy Lutomirski" , Dave Hansen , Sergio Lopez , Peter Gonda , "Peter Zijlstra" , Srinivas Pandruvada , David Rientjes , Dov Murik , Tobin Feldman-Fitzthum , Borislav Petkov , Michael Roth , Vlastimil Babka , "Kirill A . Shutemov" , Andi Kleen , "Dr . David Alan Gilbert" , , , , Brijesh Singh Subject: [PATCH v8 31/40] x86/compressed: add SEV-SNP feature detection/setup Date: Fri, 10 Dec 2021 09:43:23 -0600 Message-ID: <20211210154332.11526-32-brijesh.singh@amd.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20211210154332.11526-1-brijesh.singh@amd.com> References: <20211210154332.11526-1-brijesh.singh@amd.com> MIME-Version: 1.0 X-Originating-IP: [10.180.168.240] X-ClientProxiedBy: SATLEXMB03.amd.com (10.181.40.144) To SATLEXMB03.amd.com (10.181.40.144) X-EOPAttributedMessage: 0 X-MS-PublicTrafficType: Email X-MS-Office365-Filtering-Correlation-Id: e7b70b9e-220b-4c44-91c3-08d9bbf3f9df X-MS-TrafficTypeDiagnostic: DM6PR12MB3915:EE_ X-Microsoft-Antispam-PRVS: X-MS-Oob-TLC-OOBClassifiers: OLM:8882; X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0; X-Microsoft-Antispam-Message-Info: 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 X-Forefront-Antispam-Report: CIP:165.204.84.17; CTRY:US; LANG:en; SCL:1; SRV:; IPV:CAL; SFV:NSPM; H:SATLEXMB03.amd.com; PTR:InfoDomainNonexistent; CAT:NONE; SFS:(4636009)(36840700001)(46966006)(40470700001)(47076005)(36860700001)(2616005)(2906002)(36756003)(44832011)(5660300002)(54906003)(7696005)(186003)(356005)(4326008)(82310400004)(40460700001)(81166007)(110136005)(83380400001)(426003)(26005)(316002)(336012)(16526019)(8676002)(8936002)(70586007)(6666004)(70206006)(1076003)(7406005)(86362001)(7416002)(508600001)(36900700001)(2101003); DIR:OUT; SFP:1101; X-OriginatorOrg: amd.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 10 Dec 2021 15:44:39.2792 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: e7b70b9e-220b-4c44-91c3-08d9bbf3f9df X-MS-Exchange-CrossTenant-Id: 3dd8961f-e488-4e60-8e11-a82d994e183d X-MS-Exchange-CrossTenant-OriginalAttributedTenantConnectingIp: TenantId=3dd8961f-e488-4e60-8e11-a82d994e183d; Ip=[165.204.84.17]; Helo=[SATLEXMB03.amd.com] X-MS-Exchange-CrossTenant-AuthSource: BN8NAM11FT048.eop-nam11.prod.protection.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: DM6PR12MB3915 Precedence: bulk List-ID: X-Mailing-List: linux-efi@vger.kernel.org From: Michael Roth Initial/preliminary detection of SEV-SNP is done via the Confidential Computing blob. Check for it prior to the normal SEV/SME feature initialization, and add some sanity checks to confirm it agrees with SEV-SNP CPUID/MSR bits. Signed-off-by: Michael Roth Signed-off-by: Brijesh Singh --- arch/x86/boot/compressed/sev.c | 91 +++++++++++++++++++++++++++++++++- arch/x86/include/asm/sev.h | 13 +++++ arch/x86/kernel/sev-shared.c | 34 +++++++++++++ 3 files changed, 137 insertions(+), 1 deletion(-) diff --git a/arch/x86/boot/compressed/sev.c b/arch/x86/boot/compressed/sev.c index 3514feb5b226..93e125da12cf 100644 --- a/arch/x86/boot/compressed/sev.c +++ b/arch/x86/boot/compressed/sev.c @@ -291,6 +291,13 @@ static void enforce_vmpl0(void) void sev_enable(struct boot_params *bp) { unsigned int eax, ebx, ecx, edx; + bool snp; + + /* + * Setup/preliminary detection of SEV-SNP. This will be sanity-checked + * against CPUID/MSR values later. + */ + snp = snp_init(bp); /* Check for the SME/SEV support leaf */ eax = 0x80000000; @@ -311,8 +318,11 @@ void sev_enable(struct boot_params *bp) ecx = 0; native_cpuid(&eax, &ebx, &ecx, &edx); /* Check whether SEV is supported */ - if (!(eax & BIT(1))) + if (!(eax & BIT(1))) { + if (snp) + error("SEV-SNP support indicated by CC blob, but not CPUID."); return; + } /* Set the SME mask if this is an SEV guest. */ sev_status = rd_sev_status_msr(); @@ -337,5 +347,84 @@ void sev_enable(struct boot_params *bp) enforce_vmpl0(); } + if (snp && !(sev_status & MSR_AMD64_SEV_SNP_ENABLED)) + error("SEV-SNP supported indicated by CC blob, but not SEV status MSR."); + sme_me_mask = BIT_ULL(ebx & 0x3f); } + +/* Search for Confidential Computing blob in the EFI config table. */ +static struct cc_blob_sev_info *snp_find_cc_blob_efi(struct boot_params *bp) +{ + struct cc_blob_sev_info *cc_info; + unsigned long conf_table_pa; + unsigned int conf_table_len; + bool efi_64; + int ret; + + ret = efi_get_conf_table(bp, &conf_table_pa, &conf_table_len, &efi_64); + if (ret) + return NULL; + + ret = efi_find_vendor_table(conf_table_pa, conf_table_len, + EFI_CC_BLOB_GUID, efi_64, + (unsigned long *)&cc_info); + if (ret) + return NULL; + + return cc_info; +} + +/* + * Initial set up of SEV-SNP relies on information provided by the + * Confidential Computing blob, which can be passed to the boot kernel + * by firmware/bootloader in the following ways: + * + * - via an entry in the EFI config table + * - via a setup_data structure, as defined by the Linux Boot Protocol + * + * Scan for the blob in that order. + */ +static struct cc_blob_sev_info *snp_find_cc_blob(struct boot_params *bp) +{ + struct cc_blob_sev_info *cc_info; + + cc_info = snp_find_cc_blob_efi(bp); + if (cc_info) + goto found_cc_info; + + cc_info = snp_find_cc_blob_setup_data(bp); + if (!cc_info) + return NULL; + +found_cc_info: + if (cc_info->magic != CC_BLOB_SEV_HDR_MAGIC) + sev_es_terminate(0, GHCB_SNP_UNSUPPORTED); + + return cc_info; +} + +bool snp_init(struct boot_params *bp) +{ + struct cc_blob_sev_info *cc_info; + + if (!bp) + return false; + + cc_info = snp_find_cc_blob(bp); + if (!cc_info) + return false; + + /* + * Pass run-time kernel a pointer to CC info via boot_params so EFI + * config table doesn't need to be searched again during early startup + * phase. + */ + bp->cc_blob_address = (u32)(unsigned long)cc_info; + + /* + * Indicate SEV-SNP based on presence of SEV-SNP-specific CC blob. + * Subsequent checks will verify SEV-SNP CPUID/MSR bits. + */ + return true; +} diff --git a/arch/x86/include/asm/sev.h b/arch/x86/include/asm/sev.h index f42fbe3c332f..cd189c20bcc4 100644 --- a/arch/x86/include/asm/sev.h +++ b/arch/x86/include/asm/sev.h @@ -11,6 +11,7 @@ #include #include #include +#include #define GHCB_PROTOCOL_MIN 1ULL #define GHCB_PROTOCOL_MAX 2ULL @@ -145,6 +146,17 @@ void __init snp_prep_memory(unsigned long paddr, unsigned int sz, enum psc_op op void snp_set_memory_shared(unsigned long vaddr, unsigned int npages); void snp_set_memory_private(unsigned long vaddr, unsigned int npages); void snp_set_wakeup_secondary_cpu(void); +bool snp_init(struct boot_params *bp); +/* + * TODO: These are exported only temporarily while boot/compressed/sev.c is + * the only user. This is to avoid unused function warnings for kernel/sev.c + * during the build of kernel proper. + * + * Once the code is added to consume these in kernel proper these functions + * can be moved back to being statically-scoped to units that pull in + * sev-shared.c via #include and these declarations can be dropped. + */ +struct cc_blob_sev_info *snp_find_cc_blob_setup_data(struct boot_params *bp); #else static inline void sev_es_ist_enter(struct pt_regs *regs) { } static inline void sev_es_ist_exit(void) { } @@ -162,6 +174,7 @@ static inline void __init snp_prep_memory(unsigned long paddr, unsigned int sz, static inline void snp_set_memory_shared(unsigned long vaddr, unsigned int npages) { } static inline void snp_set_memory_private(unsigned long vaddr, unsigned int npages) { } static inline void snp_set_wakeup_secondary_cpu(void) { } +static inline bool snp_init(struct boot_params *bp) { return false; } #endif #endif diff --git a/arch/x86/kernel/sev-shared.c b/arch/x86/kernel/sev-shared.c index dabb425498e0..bd58a4ce29c8 100644 --- a/arch/x86/kernel/sev-shared.c +++ b/arch/x86/kernel/sev-shared.c @@ -934,3 +934,37 @@ static enum es_result vc_handle_rdtsc(struct ghcb *ghcb, return ES_OK; } + +struct cc_setup_data { + struct setup_data header; + u32 cc_blob_address; +}; + +static struct cc_setup_data *get_cc_setup_data(struct boot_params *bp) +{ + struct setup_data *hdr = (struct setup_data *)bp->hdr.setup_data; + + while (hdr) { + if (hdr->type == SETUP_CC_BLOB) + return (struct cc_setup_data *)hdr; + hdr = (struct setup_data *)hdr->next; + } + + return NULL; +} + +/* + * Search for a Confidential Computing blob passed in as a setup_data entry + * via the Linux Boot Protocol. + */ +struct cc_blob_sev_info * +snp_find_cc_blob_setup_data(struct boot_params *bp) +{ + struct cc_setup_data *sd; + + sd = get_cc_setup_data(bp); + if (!sd) + return NULL; + + return (struct cc_blob_sev_info *)(unsigned long)sd->cc_blob_address; +}