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AJvYcCXx3L8QwzrOtKbbOz6QsX521UEHTeKl3MRxdOpKubS4WQ8PGuhYN3EitacYvdI+MX8UlZCk4WR6rW+XNFo3Owt4uYFVd/Pjqv2HAg== X-Gm-Message-State: AOJu0YycipPl3vbVzrBzzr/OuK5g8z/iilwflHyIBXkaslNYRBw5dLOD 6uZfvFDXgiKGtOI8pUS+UtP4syA33wiXQQdbIJ6h71oZb6+ek3Ws X-Google-Smtp-Source: AGHT+IESMzVFf+AerzXltPGxT0c2xQkXFKXDrzd1HTo0VAZxc9MRROEt3iL3xUr1my5F1e40MBIekw== X-Received: by 2002:a17:907:7e9d:b0:a6f:17a9:947a with SMTP id a640c23a62f3a-a6f17a9f1bemr225645366b.71.1718014895432; Mon, 10 Jun 2024 03:21:35 -0700 (PDT) Received: from vasant-suse.fritz.box ([2001:9e8:ab68:af00:6f43:17ee:43bd:e0a9]) by smtp.gmail.com with ESMTPSA id a640c23a62f3a-a6f0d7b35d5sm290887766b.192.2024.06.10.03.21.33 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 10 Jun 2024 03:21:35 -0700 (PDT) From: vsntk18@gmail.com To: vsntk18@gmail.com Cc: x86@kernel.org, Borislav.Petkov@amd.com, Dhaval.Giani@amd.com, ashish.kalra@amd.com, 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, jroedel@suse.de, 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, michael.roth@amd.com, 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, vkarasulli@suse.de Subject: [PATCH v6 06/10] x86/sev: Use AP Jump Table blob to stop CPU Date: Mon, 10 Jun 2024 12:21:09 +0200 Message-Id: <20240610102113.20969-7-vsntk18@gmail.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20240610102113.20969-1-vsntk18@gmail.com> References: <20240610102113.20969-1-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 963d51dcf0e6..6f681ced6594 100644 --- a/arch/x86/include/asm/sev.h +++ b/arch/x86/include/asm/sev.h @@ -232,6 +232,7 @@ 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_show_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) { } @@ -261,6 +262,7 @@ 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_show_status(void) { } +static inline void sev_es_stop_this_cpu(void) { } #endif #ifdef CONFIG_KVM_AMD_SEV diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c index b8441147eb5e..0bc615d69c0e 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 84b79630f065..8d3cc5cd7e11 100644 --- a/arch/x86/kernel/sev.c +++ b/arch/x86/kernel/sev.c @@ -1357,7 +1357,6 @@ 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(); @@ -1390,6 +1389,20 @@ 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