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From: Joerg Roedel <joro@8bytes.org>
To: x86@kernel.org
Cc: Joerg Roedel <joro@8bytes.org>, Joerg Roedel <jroedel@suse.de>,
	hpa@zytor.com, Andy Lutomirski <luto@kernel.org>,
	Dave Hansen <dave.hansen@linux.intel.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Jiri Slaby <jslaby@suse.cz>,
	Dan Williams <dan.j.williams@intel.com>,
	Tom Lendacky <thomas.lendacky@amd.com>,
	Juergen Gross <jgross@suse.com>,
	Kees Cook <keescook@chromium.org>,
	David Rientjes <rientjes@google.com>,
	Cfir Cohen <cfir@google.com>, Erdem Aktas <erdemaktas@google.com>,
	Masami Hiramatsu <mhiramat@kernel.org>,
	Mike Stunes <mstunes@vmware.com>,
	Sean Christopherson <seanjc@google.com>,
	Martin Radev <martin.b.radev@gmail.com>,
	Arvind Sankar <nivedita@alum.mit.edu>,
	linux-coco@lists.linux.dev, linux-kernel@vger.kernel.org,
	kvm@vger.kernel.org, virtualization@lists.linux-foundation.org
Subject: [RFC PATCH 12/12] x86/sev: Support kexec under SEV-ES with AP Jump Table blob
Date: Mon,  5 Jul 2021 10:24:43 +0200	[thread overview]
Message-ID: <20210705082443.14721-13-joro@8bytes.org> (raw)
In-Reply-To: <20210705082443.14721-1-joro@8bytes.org>

From: Joerg Roedel <jroedel@suse.de>

When the AP Jump Table blob is installed the kernel can hand over the
APs from the old to the new kernel. Enable kexec when the AP Jump
Table blob has been installed.

Signed-off-by: Joerg Roedel <jroedel@suse.de>
---
 arch/x86/include/asm/sev.h         |  2 ++
 arch/x86/kernel/machine_kexec_64.c |  6 +++++-
 arch/x86/kernel/sev.c              | 12 ++++++++++++
 3 files changed, 19 insertions(+), 1 deletion(-)

diff --git a/arch/x86/include/asm/sev.h b/arch/x86/include/asm/sev.h
index cd14b6e10f12..61910caf2a0d 100644
--- a/arch/x86/include/asm/sev.h
+++ b/arch/x86/include/asm/sev.h
@@ -87,6 +87,7 @@ static __always_inline void sev_es_stop_this_cpu(void)
 	if (static_branch_unlikely(&sev_es_enable_key))
 		__sev_es_stop_this_cpu();
 }
+bool sev_kexec_supported(void);
 #else
 static inline void sev_es_ist_enter(struct pt_regs *regs) { }
 static inline void sev_es_ist_exit(void) { }
@@ -94,6 +95,7 @@ static inline int sev_es_setup_ap_jump_table(struct real_mode_header *rmh) { ret
 static inline void sev_es_nmi_complete(void) { }
 static inline int sev_es_efi_map_ghcbs(pgd_t *pgd) { return 0; }
 static inline void sev_es_stop_this_cpu(void) { }
+static bool sev_kexec_supported(void) { return true; }
 #endif
 
 #endif
diff --git a/arch/x86/kernel/machine_kexec_64.c b/arch/x86/kernel/machine_kexec_64.c
index f902cc9cc634..d08eae4f7694 100644
--- a/arch/x86/kernel/machine_kexec_64.c
+++ b/arch/x86/kernel/machine_kexec_64.c
@@ -26,6 +26,7 @@
 #include <asm/kexec-bzimage64.h>
 #include <asm/setup.h>
 #include <asm/set_memory.h>
+#include <asm/sev.h>
 
 #ifdef CONFIG_ACPI
 /*
@@ -626,5 +627,8 @@ void arch_kexec_pre_free_pages(void *vaddr, unsigned int pages)
  */
 bool arch_kexec_supported(void)
 {
-	return !sev_es_active();
+	if (!sev_kexec_supported())
+		return false;
+
+	return true;
 }
diff --git a/arch/x86/kernel/sev.c b/arch/x86/kernel/sev.c
index 113903ba3095..731bbf941a82 100644
--- a/arch/x86/kernel/sev.c
+++ b/arch/x86/kernel/sev.c
@@ -901,6 +901,18 @@ static int __init sev_es_setup_ap_jump_table_blob(void)
 }
 core_initcall(sev_es_setup_ap_jump_table_blob);
 
+bool sev_kexec_supported(void)
+{
+	/*
+	 * KEXEC with SEV-ES and more than one CPU is only supported
+	 * when the AP Jump Table is installed.
+	 */
+	if (num_possible_cpus() > 1)
+		return !sev_es_active() || sev_ap_jumptable_blob_installed;
+	else
+		return true;
+}
+
 static void __init alloc_runtime_data(int cpu)
 {
 	struct sev_es_runtime_data *data;
-- 
2.31.1


      parent reply	other threads:[~2021-07-05  8:28 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-05  8:24 [RFC PATCH 00/12] x86/sev: KEXEC/KDUMP support for SEV-ES guests Joerg Roedel
2021-07-05  8:24 ` [RFC PATCH 01/12] kexec: Allow architecture code to opt-out at runtime Joerg Roedel
2021-07-05  8:24 ` [RFC PATCH 02/12] x86/kexec/64: Forbid kexec when running as an SEV-ES guest Joerg Roedel
2021-07-05  8:24 ` [RFC PATCH 03/12] x86/sev: Save and print negotiated GHCB protocol version Joerg Roedel
2021-07-05  8:24 ` [RFC PATCH 04/12] x86/sev: Do not hardcode " Joerg Roedel
2021-07-05  8:24 ` [RFC PATCH 05/12] x86/sev: Use GHCB protocol version 2 if supported Joerg Roedel
2021-07-05  8:24 ` [RFC PATCH 06/12] x86/sev: Cache AP Jump Table Address Joerg Roedel
2021-07-05  8:24 ` [RFC PATCH 07/12] x86/sev: Setup code to park APs in the AP Jump Table Joerg Roedel
2021-07-05  8:24 ` [RFC PATCH 08/12] x86/sev: Park APs on AP Jump Table with GHCB protocol version 2 Joerg Roedel
2021-07-05  8:24 ` [RFC PATCH 09/12] x86/sev: Use AP Jump Table blob to stop CPU Joerg Roedel
2021-07-05  8:24 ` [RFC PATCH 10/12] x86/sev: Add MMIO handling support to boot/compressed/ code Joerg Roedel
2021-07-05  8:24 ` [RFC PATCH 11/12] x86/sev: Handle CLFLUSH MMIO events Joerg Roedel
2021-07-05  8:24 ` Joerg Roedel [this message]

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