From: Joerg Roedel <joro@8bytes.org>
To: x86@kernel.org, Eric Biederman <ebiederm@xmission.com>
Cc: kexec@lists.infradead.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>,
Joerg Roedel <joro@8bytes.org>,
linux-coco@lists.linux.dev, linux-kernel@vger.kernel.org,
kvm@vger.kernel.org, virtualization@lists.linux-foundation.org
Subject: [PATCH 09/12] x86/sev: Use AP Jump Table blob to stop CPU
Date: Wed, 21 Jul 2021 16:20:12 +0200 [thread overview]
Message-ID: <20210721142015.1401-10-joro@8bytes.org> (raw)
In-Reply-To: <20210721142015.1401-1-joro@8bytes.org>
From: Joerg Roedel <jroedel@suse.de>
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 <jroedel@suse.de>
---
arch/x86/include/asm/sev.h | 7 +++++++
arch/x86/kernel/process.c | 8 ++++++++
arch/x86/kernel/sev.c | 11 ++++++++++-
3 files changed, 25 insertions(+), 1 deletion(-)
diff --git a/arch/x86/include/asm/sev.h b/arch/x86/include/asm/sev.h
index 134a7c9d91b6..cd14b6e10f12 100644
--- a/arch/x86/include/asm/sev.h
+++ b/arch/x86/include/asm/sev.h
@@ -81,12 +81,19 @@ static __always_inline void sev_es_nmi_complete(void)
__sev_es_nmi_complete();
}
extern int __init sev_es_efi_map_ghcbs(pgd_t *pgd);
+void __sev_es_stop_this_cpu(void);
+static __always_inline void sev_es_stop_this_cpu(void)
+{
+ if (static_branch_unlikely(&sev_es_enable_key))
+ __sev_es_stop_this_cpu();
+}
#else
static inline void sev_es_ist_enter(struct pt_regs *regs) { }
static inline void sev_es_ist_exit(void) { }
static inline int sev_es_setup_ap_jump_table(struct real_mode_header *rmh) { return 0; }
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) { }
#endif
#endif
diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c
index 1d9463e3096b..8d9b03923baa 100644
--- a/arch/x86/kernel/process.c
+++ b/arch/x86/kernel/process.c
@@ -43,6 +43,7 @@
#include <asm/io_bitmap.h>
#include <asm/proto.h>
#include <asm/frame.h>
+#include <asm/sev.h>
#include "process.h"
@@ -752,6 +753,13 @@ void stop_this_cpu(void *dummy)
if (boot_cpu_has(X86_FEATURE_SME))
native_wbinvd();
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 20b439986d86..bac9bb4fa54e 100644
--- a/arch/x86/kernel/sev.c
+++ b/arch/x86/kernel/sev.c
@@ -695,7 +695,6 @@ static bool __init sev_es_setup_ghcb(void)
return true;
}
-#ifdef CONFIG_HOTPLUG_CPU
void __noreturn sev_jumptable_ap_park(void)
{
local_irq_disable();
@@ -725,6 +724,16 @@ void __noreturn sev_jumptable_ap_park(void)
}
STACK_FRAME_NON_STANDARD(sev_jumptable_ap_park);
+void __sev_es_stop_this_cpu(void)
+{
+ /* 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;
--
2.31.1
next prev parent reply other threads:[~2021-07-21 14:26 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-21 14:20 [PATCH 00/12] x86/sev: KEXEC/KDUMP support for SEV-ES guests Joerg Roedel
2021-07-21 14:20 ` [PATCH 01/12] kexec: Allow architecture code to opt-out at runtime Joerg Roedel
2022-04-21 13:20 ` Tao Liu
2021-07-21 14:20 ` [PATCH 02/12] x86/kexec/64: Forbid kexec when running as an SEV-ES guest Joerg Roedel
2021-07-21 14:20 ` [PATCH 03/12] x86/sev: Save and print negotiated GHCB protocol version Joerg Roedel
2021-07-21 14:20 ` [PATCH 04/12] x86/sev: Do not hardcode " Joerg Roedel
2021-07-21 21:17 ` Tom Lendacky
2021-07-31 7:18 ` Joerg Roedel
2021-07-21 14:20 ` [PATCH 05/12] x86/sev: Use GHCB protocol version 2 if supported Joerg Roedel
2021-07-21 14:20 ` [PATCH 06/12] x86/sev: Cache AP Jump Table Address Joerg Roedel
2021-07-21 14:20 ` [PATCH 07/12] x86/sev: Setup code to park APs in the AP Jump Table Joerg Roedel
2021-07-21 14:20 ` [PATCH 08/12] x86/sev: Park APs on AP Jump Table with GHCB protocol version 2 Joerg Roedel
2021-07-21 14:20 ` Joerg Roedel [this message]
2021-07-21 14:20 ` [PATCH 10/12] x86/sev: Add MMIO handling support to boot/compressed/ code Joerg Roedel
2021-07-21 14:20 ` [PATCH 11/12] x86/sev: Handle CLFLUSH MMIO events Joerg Roedel
2021-07-30 22:42 ` Sean Christopherson
2021-07-31 7:17 ` Joerg Roedel
2021-07-21 14:20 ` [PATCH 12/12] x86/sev: Support kexec under SEV-ES with AP Jump Table blob Joerg Roedel
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