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Received-SPF: Pass (protection.outlook.com: domain of amd.com designates 165.204.84.17 as permitted sender) receiver=protection.outlook.com; client-ip=165.204.84.17; helo=SATLEXMB04.amd.com; pr=C Received: from SATLEXMB04.amd.com (165.204.84.17) by MWH0EPF000971E2.mail.protection.outlook.com (10.167.243.69) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.20.7228.16 via Frontend Transport; Fri, 26 Jan 2024 04:44:39 +0000 Received: from localhost (10.180.168.240) by SATLEXMB04.amd.com (10.181.40.145) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.34; Thu, 25 Jan 2024 22:44:38 -0600 From: Michael Roth To: CC: , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , Subject: [PATCH v2 20/25] crypto: ccp: Add panic notifier for SEV/SNP firmware shutdown on kdump Date: Thu, 25 Jan 2024 22:11:20 -0600 Message-ID: <20240126041126.1927228-21-michael.roth@amd.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20240126041126.1927228-1-michael.roth@amd.com> References: <20240126041126.1927228-1-michael.roth@amd.com> Precedence: bulk X-Mailing-List: linux-crypto@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-ClientProxiedBy: SATLEXMB04.amd.com (10.181.40.145) To SATLEXMB04.amd.com (10.181.40.145) X-EOPAttributedMessage: 0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: MWH0EPF000971E2:EE_|DS0PR12MB7533:EE_ X-MS-Office365-Filtering-Correlation-Id: 57beac15-2d24-4074-f700-08dc1e298188 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0; 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CAT:NONE; SFS:(13230031)(4636009)(376002)(39860400002)(136003)(346002)(396003)(230273577357003)(230922051799003)(230173577357003)(64100799003)(82310400011)(186009)(1800799012)(451199024)(40470700004)(46966006)(36840700001)(36860700001)(47076005)(36756003)(2906002)(86362001)(41300700001)(356005)(82740400003)(81166007)(6916009)(54906003)(316002)(70586007)(70206006)(478600001)(6666004)(336012)(426003)(5660300002)(4326008)(44832011)(2616005)(8676002)(7416002)(16526019)(1076003)(26005)(8936002)(7406005)(83380400001)(40480700001)(40460700003)(36900700001); DIR:OUT; SFP:1101; X-OriginatorOrg: amd.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 26 Jan 2024 04:44:39.3778 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: 57beac15-2d24-4074-f700-08dc1e298188 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=[SATLEXMB04.amd.com] X-MS-Exchange-CrossTenant-AuthSource: MWH0EPF000971E2.namprd02.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: DS0PR12MB7533 From: Ashish Kalra Add a kdump safe version of sev_firmware_shutdown() and register it as a crash_kexec_post_notifier so it will be invoked during panic/crash to do SEV/SNP shutdown. This is required for transitioning all IOMMU pages to reclaim/hypervisor state, otherwise re-init of IOMMU pages during crashdump kernel boot fails and panics the crashdump kernel. This panic notifier runs in atomic context, hence it ensures not to acquire any locks/mutexes and polls for PSP command completion instead of depending on PSP command completion interrupt. Signed-off-by: Ashish Kalra [mdr: remove use of "we" in comments] Signed-off-by: Michael Roth --- arch/x86/include/asm/sev.h | 2 + arch/x86/kernel/crash.c | 3 + arch/x86/kernel/sev.c | 10 ++++ arch/x86/virt/svm/sev.c | 6 ++ drivers/crypto/ccp/sev-dev.c | 111 +++++++++++++++++++++++++---------- 5 files changed, 102 insertions(+), 30 deletions(-) diff --git a/arch/x86/include/asm/sev.h b/arch/x86/include/asm/sev.h index 435ba9bc4510..b3ba32c6fc9f 100644 --- a/arch/x86/include/asm/sev.h +++ b/arch/x86/include/asm/sev.h @@ -227,6 +227,7 @@ int snp_issue_guest_request(u64 exit_code, struct snp_req_data *input, struct sn void snp_accept_memory(phys_addr_t start, phys_addr_t end); u64 snp_get_unsupported_features(u64 status); u64 sev_get_status(void); +void kdump_sev_callback(void); #else static inline void sev_es_ist_enter(struct pt_regs *regs) { } static inline void sev_es_ist_exit(void) { } @@ -255,6 +256,7 @@ static inline int snp_issue_guest_request(u64 exit_code, struct snp_req_data *in static inline void snp_accept_memory(phys_addr_t start, phys_addr_t end) { } static inline u64 snp_get_unsupported_features(u64 status) { return 0; } static inline u64 sev_get_status(void) { return 0; } +static inline void kdump_sev_callback(void) { } #endif #ifdef CONFIG_KVM_AMD_SEV diff --git a/arch/x86/kernel/crash.c b/arch/x86/kernel/crash.c index b6b044356f1b..d184c29398db 100644 --- a/arch/x86/kernel/crash.c +++ b/arch/x86/kernel/crash.c @@ -40,6 +40,7 @@ #include #include #include +#include /* Used while preparing memory map entries for second kernel */ struct crash_memmap_data { @@ -59,6 +60,8 @@ static void kdump_nmi_callback(int cpu, struct pt_regs *regs) */ cpu_emergency_stop_pt(); + kdump_sev_callback(); + disable_local_APIC(); } diff --git a/arch/x86/kernel/sev.c b/arch/x86/kernel/sev.c index 1ec753331524..002af6c30601 100644 --- a/arch/x86/kernel/sev.c +++ b/arch/x86/kernel/sev.c @@ -2265,3 +2265,13 @@ static int __init snp_init_platform_device(void) return 0; } device_initcall(snp_init_platform_device); + +void kdump_sev_callback(void) +{ + /* + * Do wbinvd() on remote CPUs when SNP is enabled in order to + * safely do SNP_SHUTDOWN on the local CPU. + */ + if (cpu_feature_enabled(X86_FEATURE_SEV_SNP)) + wbinvd(); +} diff --git a/arch/x86/virt/svm/sev.c b/arch/x86/virt/svm/sev.c index 649ac1bb6b0e..3d33b75b4606 100644 --- a/arch/x86/virt/svm/sev.c +++ b/arch/x86/virt/svm/sev.c @@ -216,6 +216,12 @@ static int __init snp_rmptable_init(void) cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "x86/rmptable_init:online", __snp_enable, NULL); + /* + * Setting crash_kexec_post_notifiers to 'true' to ensure that SNP panic + * notifier is invoked to do SNP IOMMU shutdown before kdump. + */ + crash_kexec_post_notifiers = true; + return 0; nosnp: diff --git a/drivers/crypto/ccp/sev-dev.c b/drivers/crypto/ccp/sev-dev.c index d26bff55ec93..9a395f0f9b10 100644 --- a/drivers/crypto/ccp/sev-dev.c +++ b/drivers/crypto/ccp/sev-dev.c @@ -21,6 +21,7 @@ #include #include #include +#include #include #include #include @@ -143,6 +144,25 @@ static int sev_wait_cmd_ioc(struct sev_device *sev, { int ret; + /* + * If invoked during panic handling, local interrupts are disabled, + * so the PSP command completion interrupt can't be used. Poll for + * PSP command completion instead. + */ + if (irqs_disabled()) { + unsigned long timeout_usecs = (timeout * USEC_PER_SEC) / 10; + + /* Poll for SEV command completion: */ + while (timeout_usecs--) { + *reg = ioread32(sev->io_regs + sev->vdata->cmdresp_reg); + if (*reg & PSP_CMDRESP_RESP) + return 0; + + udelay(10); + } + return -ETIMEDOUT; + } + ret = wait_event_timeout(sev->int_queue, sev->int_rcvd, timeout * HZ); if (!ret) @@ -1316,17 +1336,6 @@ static int __sev_platform_shutdown_locked(int *error) return ret; } -static int sev_platform_shutdown(int *error) -{ - int rc; - - mutex_lock(&sev_cmd_mutex); - rc = __sev_platform_shutdown_locked(NULL); - mutex_unlock(&sev_cmd_mutex); - - return rc; -} - static int sev_get_platform_state(int *state, int *error) { struct sev_user_data_status data; @@ -1602,7 +1611,7 @@ static int sev_update_firmware(struct device *dev) return ret; } -static int __sev_snp_shutdown_locked(int *error) +static int __sev_snp_shutdown_locked(int *error, bool panic) { struct sev_device *sev = psp_master->sev_data; struct sev_data_snp_shutdown_ex data; @@ -1615,7 +1624,16 @@ static int __sev_snp_shutdown_locked(int *error) data.len = sizeof(data); data.iommu_snp_shutdown = 1; - wbinvd_on_all_cpus(); + /* + * If invoked during panic handling, local interrupts are disabled + * and all CPUs are stopped, so wbinvd_on_all_cpus() can't be called. + * In that case, a wbinvd() is done on remote CPUs via the NMI + * callback, so only a local wbinvd() is needed here. + */ + if (!panic) + wbinvd_on_all_cpus(); + else + wbinvd(); ret = __sev_do_cmd_locked(SEV_CMD_SNP_SHUTDOWN_EX, &data, error); /* SHUTDOWN may require DF_FLUSH */ @@ -1659,17 +1677,6 @@ static int __sev_snp_shutdown_locked(int *error) return ret; } -static int sev_snp_shutdown(int *error) -{ - int rc; - - mutex_lock(&sev_cmd_mutex); - rc = __sev_snp_shutdown_locked(error); - mutex_unlock(&sev_cmd_mutex); - - return rc; -} - static int sev_ioctl_do_pek_import(struct sev_issue_cmd *argp, bool writable) { struct sev_device *sev = psp_master->sev_data; @@ -2117,19 +2124,28 @@ int sev_dev_init(struct psp_device *psp) return ret; } -static void sev_firmware_shutdown(struct sev_device *sev) +static void __sev_firmware_shutdown(struct sev_device *sev, bool panic) { int error; - sev_platform_shutdown(NULL); + __sev_platform_shutdown_locked(NULL); if (sev_es_tmr) { - /* The TMR area was encrypted, flush it from the cache */ - wbinvd_on_all_cpus(); + /* + * The TMR area was encrypted, flush it from the cache + * + * If invoked during panic handling, local interrupts are + * disabled and all CPUs are stopped, so wbinvd_on_all_cpus() + * can't be used. In that case, wbinvd() is done on remote CPUs + * via the NMI callback, and done for this CPU later during + * SNP shutdown, so wbinvd_on_all_cpus() can be skipped. + */ + if (!panic) + wbinvd_on_all_cpus(); __snp_free_firmware_pages(virt_to_page(sev_es_tmr), get_order(sev_es_tmr_size), - false); + true); sev_es_tmr = NULL; } @@ -2145,7 +2161,14 @@ static void sev_firmware_shutdown(struct sev_device *sev) snp_range_list = NULL; } - sev_snp_shutdown(&error); + __sev_snp_shutdown_locked(&error, panic); +} + +static void sev_firmware_shutdown(struct sev_device *sev) +{ + mutex_lock(&sev_cmd_mutex); + __sev_firmware_shutdown(sev, false); + mutex_unlock(&sev_cmd_mutex); } void sev_dev_destroy(struct psp_device *psp) @@ -2163,6 +2186,29 @@ void sev_dev_destroy(struct psp_device *psp) psp_clear_sev_irq_handler(psp); } +static int snp_shutdown_on_panic(struct notifier_block *nb, + unsigned long reason, void *arg) +{ + struct sev_device *sev = psp_master->sev_data; + + /* + * If sev_cmd_mutex is already acquired, then it's likely + * another PSP command is in flight and issuing a shutdown + * would fail in unexpected ways. Rather than create even + * more confusion during a panic, just bail out here. + */ + if (mutex_is_locked(&sev_cmd_mutex)) + return NOTIFY_DONE; + + __sev_firmware_shutdown(sev, true); + + return NOTIFY_DONE; +} + +static struct notifier_block snp_panic_notifier = { + .notifier_call = snp_shutdown_on_panic, +}; + int sev_issue_cmd_external_user(struct file *filep, unsigned int cmd, void *data, int *error) { @@ -2200,6 +2246,8 @@ void sev_pci_init(void) dev_info(sev->dev, "SEV%s API:%d.%d build:%d\n", sev->snp_initialized ? "-SNP" : "", sev->api_major, sev->api_minor, sev->build); + atomic_notifier_chain_register(&panic_notifier_list, + &snp_panic_notifier); return; err: @@ -2214,4 +2262,7 @@ void sev_pci_exit(void) return; sev_firmware_shutdown(sev); + + atomic_notifier_chain_unregister(&panic_notifier_list, + &snp_panic_notifier); }