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AJvYcCVR9hGF84qTP6N2ml8/uDBI6adwq42LaFSMAfm7UenX77btz3JQxjbrua2CZGIgb6w9cPhxa0/mmAAc4uuStkP2sEhCoAV4VY/DJQ== X-Gm-Message-State: AOJu0Yy2CEKsgbE+9yFCYRDDS603J5QRCefb76mPE0tu+K2uZb7XsEIZ TYeQXTdXfR2u4as78V8MI903y4tTtldrgRJHebyZhPxlpSFGKInl X-Google-Smtp-Source: AGHT+IHdxdRKuyogtANKix0xsfVIxJjqfkRL3xOpZ/E6JkPe6fFXU/lAH+e1wKvVax66n9KjcPMJqg== X-Received: by 2002:a05:600c:5026:b0:413:d95:bb2c with SMTP id n38-20020a05600c502600b004130d95bb2cmr705386wmr.33.1710173860999; Mon, 11 Mar 2024 09:17:40 -0700 (PDT) Received: from vasant-suse.suse.cz ([2001:9e8:ab47:8200:c3b9:43af:f8e1:76f9]) by smtp.gmail.com with ESMTPSA id ba14-20020a0560001c0e00b0033e96fe9479sm2823815wrb.89.2024.03.11.09.17.39 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 11 Mar 2024 09:17:40 -0700 (PDT) From: Vasant Karasulli To: x86@kernel.org Cc: joro@8bytes.org, cfir@google.com, dan.j.williams@intel.com, dave.hansen@linux.intel.com, ebiederm@xmission.com, erdemaktas@google.com, hpa@zytor.com, jgross@suse.com, jslaby@suse.cz, keescook@chromium.org, kexec@lists.infradead.org, kvm@vger.kernel.org, linux-coco@lists.linux.dev, linux-kernel@vger.kernel.org, luto@kernel.org, martin.b.radev@gmail.com, mhiramat@kernel.org, mstunes@vmware.com, nivedita@alum.mit.edu, peterz@infradead.org, rientjes@google.com, seanjc@google.com, stable@vger.kernel.org, thomas.lendacky@amd.com, virtualization@lists.linux-foundation.org, Joerg Roedel , Vasant Karasulli Subject: [PATCH v4 6/9] x86/sev: Use AP Jump Table blob to stop CPU Date: Mon, 11 Mar 2024 17:17:24 +0100 Message-Id: <20240311161727.14916-7-vsntk18@gmail.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20240311161727.14916-1-vsntk18@gmail.com> References: <20240311161727.14916-1-vsntk18@gmail.com> Precedence: bulk X-Mailing-List: linux-coco@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Joerg Roedel To support kexec under SEV-ES the APs can't be parked with HLT. Upon wakeup the AP needs to find its way to execute at the reset vector set by the new kernel and in real-mode. This is what the AP jump table blob provides, so stop the APs the SEV-ES way by calling the AP-reset-hold VMGEXIT from the AP jump table. Signed-off-by: Joerg Roedel Signed-off-by: Vasant Karasulli --- arch/x86/include/asm/sev.h | 2 ++ arch/x86/kernel/process.c | 8 ++++++++ arch/x86/kernel/sev.c | 15 ++++++++++++++- 3 files changed, 24 insertions(+), 1 deletion(-) diff --git a/arch/x86/include/asm/sev.h b/arch/x86/include/asm/sev.h index c48db0bfb707..2dbd2238325a 100644 --- a/arch/x86/include/asm/sev.h +++ b/arch/x86/include/asm/sev.h @@ -216,6 +216,7 @@ 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 sev_es_stop_this_cpu(void); #else static inline void sev_es_ist_enter(struct pt_regs *regs) { } static inline void sev_es_ist_exit(void) { } @@ -244,6 +245,7 @@ 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 sev_es_stop_this_cpu(void) { } #endif #endif diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c index ab49ade31b0d..ddc3fa076f4d 100644 --- a/arch/x86/kernel/process.c +++ b/arch/x86/kernel/process.c @@ -52,6 +52,7 @@ #include #include #include +#include #include "process.h" @@ -836,6 +837,13 @@ void __noreturn stop_this_cpu(void *dummy) cpumask_clear_cpu(cpu, &cpus_stop_mask); for (;;) { + /* + * SEV-ES guests need a special stop routine to support + * kexec. Try this first, if it fails the function will + * return and native_halt() is used. + */ + sev_es_stop_this_cpu(); + /* * Use native_halt() so that memory contents don't change * (stack usage and variables) after possibly issuing the diff --git a/arch/x86/kernel/sev.c b/arch/x86/kernel/sev.c index 08bf897361b9..10f4294904b4 100644 --- a/arch/x86/kernel/sev.c +++ b/arch/x86/kernel/sev.c @@ -1350,7 +1350,6 @@ void setup_ghcb(void) snp_register_ghcb_early(__pa(&boot_ghcb_page)); } -#ifdef CONFIG_HOTPLUG_CPU void __noreturn sev_jumptable_ap_park(void) { local_irq_disable(); @@ -1383,6 +1382,20 @@ void __noreturn sev_jumptable_ap_park(void) } STACK_FRAME_NON_STANDARD(sev_jumptable_ap_park); +void sev_es_stop_this_cpu(void) +{ + if (!(cc_vendor == CC_VENDOR_AMD) || + !cc_platform_has(CC_ATTR_GUEST_STATE_ENCRYPT)) + return; + + /* Only park in the AP jump table when the code has been installed */ + if (!sev_ap_jumptable_blob_installed) + return; + + sev_jumptable_ap_park(); +} + +#ifdef CONFIG_HOTPLUG_CPU static void sev_es_ap_hlt_loop(void) { struct ghcb_state state; -- 2.34.1