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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 DS1PEPF00017099.mail.protection.outlook.com (10.167.18.103) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.20.7159.9 via Frontend Transport; Sat, 30 Dec 2023 16:26:17 +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; Sat, 30 Dec 2023 10:26:16 -0600 From: Michael Roth To: CC: , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , Subject: [PATCH v1 21/26] crypto: ccp: Add panic notifier for SEV/SNP firmware shutdown on kdump Date: Sat, 30 Dec 2023 10:19:49 -0600 Message-ID: <20231230161954.569267-22-michael.roth@amd.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20231230161954.569267-1-michael.roth@amd.com> References: <20231230161954.569267-1-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: SATLEXMB03.amd.com (10.181.40.144) To SATLEXMB04.amd.com (10.181.40.145) X-EOPAttributedMessage: 0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: DS1PEPF00017099:EE_|SN7PR12MB6741:EE_ X-MS-Office365-Filtering-Correlation-Id: 6b965103-d486-49b9-1063-08dc09540c8a X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0; 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X-OriginatorOrg: amd.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 30 Dec 2023 16:26:17.1264 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: 6b965103-d486-49b9-1063-08dc09540c8a 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: DS1PEPF00017099.namprd05.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: SN7PR12MB6741 From: Ashish Kalra Add a kdump safe version of sev_firmware_shutdown() registered as a crash_kexec_post_notifier, which is 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/kernel/crash.c | 7 +++ drivers/crypto/ccp/sev-dev.c | 112 +++++++++++++++++++++++++---------- 2 files changed, 89 insertions(+), 30 deletions(-) diff --git a/arch/x86/kernel/crash.c b/arch/x86/kernel/crash.c index cbffb27f6468..b8c44c492d43 100644 --- a/arch/x86/kernel/crash.c +++ b/arch/x86/kernel/crash.c @@ -59,6 +59,13 @@ static void kdump_nmi_callback(int cpu, struct pt_regs *regs) */ cpu_emergency_stop_pt(); + /* + * for SNP do wbinvd() on remote CPUs to + * safely do SNP_SHUTDOWN on the local CPU. + */ + if (cpu_feature_enabled(X86_FEATURE_SEV_SNP)) + wbinvd(); + disable_local_APIC(); } diff --git a/drivers/crypto/ccp/sev-dev.c b/drivers/crypto/ccp/sev-dev.c index 9792c7af3005..598878e760bc 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 @@ -144,6 +145,26 @@ 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) @@ -1358,17 +1379,6 @@ 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; @@ -1644,7 +1654,7 @@ 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 in_panic) { struct sev_device *sev = psp_master->sev_data; struct sev_data_snp_shutdown_ex data; @@ -1657,7 +1667,16 @@ static int __sev_snp_shutdown_locked(int *error) data.length = 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 (!in_panic) + wbinvd_on_all_cpus(); + else + wbinvd(); ret = __sev_do_cmd_locked(SEV_CMD_SNP_SHUTDOWN_EX, &data, error); /* SHUTDOWN may require DF_FLUSH */ @@ -1701,17 +1720,6 @@ 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; @@ -2191,19 +2199,29 @@ 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 in_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, so a local wbinvd() is sufficient here. + */ + if (!in_panic) + wbinvd_on_all_cpus(); + else + wbinvd(); __snp_free_firmware_pages(virt_to_page(sev_es_tmr), get_order(sev_es_tmr_size), - false); + true); sev_es_tmr = NULL; } @@ -2219,7 +2237,14 @@ static void sev_firmware_shutdown(struct sev_device *sev) snp_range_list = NULL; } - sev_snp_shutdown(&error); + __sev_snp_shutdown_locked(&error, in_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) @@ -2237,6 +2262,28 @@ void sev_dev_destroy(struct psp_device *psp) psp_clear_sev_irq_handler(psp); } +static int sev_snp_shutdown_on_panic(struct notifier_block *nb, + unsigned long reason, void *arg) +{ + struct sev_device *sev = psp_master->sev_data; + + /* + * Panic callbacks are executed with all other CPUs stopped, + * so don't wait for sev_cmd_mutex to be released since it + * would block here forever. + */ + if (mutex_is_locked(&sev_cmd_mutex)) + return NOTIFY_DONE; + + __sev_firmware_shutdown(sev, true); + + return NOTIFY_DONE; +} + +static struct notifier_block sev_snp_panic_notifier = { + .notifier_call = sev_snp_shutdown_on_panic, +}; + int sev_issue_cmd_external_user(struct file *filep, unsigned int cmd, void *data, int *error) { @@ -2274,6 +2321,8 @@ 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, + &sev_snp_panic_notifier); return; err: @@ -2288,4 +2337,7 @@ void sev_pci_exit(void) return; sev_firmware_shutdown(sev); + + atomic_notifier_chain_unregister(&panic_notifier_list, + &sev_snp_panic_notifier); }