diff for duplicates of <Ynk40U/KA+hLBZRC@google.com>

diff --git a/a/1.txt b/N1/1.txt
index 20134bc..a1a7bec 100644
--- a/a/1.txt
+++ b/N1/1.txt
@@ -41,11 +41,11 @@ Call stacks for the two callers would be very, very helpful.
 > 
 > Fixes: ed72736183c4 ("x86/reboot: Force all cpus to exit VMX root if VMX is supported)
 > Fixes: 0ee59413c967 ("x86/panic: replace smp_send_stop() with kdump friendly version in panic path")
-> Cc: David P. Reed <dpreed@deepplum.com>
-> Cc: Hidehiro Kawai <hidehiro.kawai.ez@hitachi.com>
-> Cc: Paolo Bonzini <pbonzini@redhat.com>
-> Cc: Sean Christopherson <seanjc@google.com>
-> Signed-off-by: Guilherme G. Piccoli <gpiccoli@igalia.com>
+> Cc: David P. Reed <dpreed-UISbPGJNPmdWk0Htik3J/w@public.gmane.org>
+> Cc: Hidehiro Kawai <hidehiro.kawai.ez-FCd8Q96Dh0JBDgjK7y7TUQ@public.gmane.org>
+> Cc: Paolo Bonzini <pbonzini-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
+> Cc: Sean Christopherson <seanjc-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
+> Signed-off-by: Guilherme G. Piccoli <gpiccoli-wEGTBA9jqPzQT0dZR+AlfA@public.gmane.org>
 > ---
 >  arch/x86/include/asm/cpu.h |  1 +
 >  arch/x86/kernel/crash.c    |  8 ++++----
@@ -142,18 +142,4 @@ official mini series.
 >  
 > -- 
 > 2.36.0
-> 
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+>
diff --git a/N1/2.hdr b/N1/2.hdr
new file mode 100644
index 0000000..3482a00
--- /dev/null
+++ b/N1/2.hdr
@@ -0,0 +1,3 @@
+Content-Type: text/x-diff; charset=us-ascii
+Content-Disposition: attachment;
+	filename="0001-x86-crash-Disable-virt-in-core-NMI-crash-handler-to-.patch"
diff --git a/N1/2.txt b/N1/2.txt
new file mode 100644
index 0000000..18fdb45
--- /dev/null
+++ b/N1/2.txt
@@ -0,0 +1,176 @@
+From 8a4573b7cf3a3e49b409ba3a504934de181c259d Mon Sep 17 00:00:00 2001
+From: Sean Christopherson <seanjc-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
+Date: Mon, 9 May 2022 07:36:34 -0700
+Subject: [PATCH 1/2] x86/crash: Disable virt in core NMI crash handler to
+ avoid double list_add
+
+Disable virtualization in crash_nmi_callback() and skip the requested NMI
+shootdown if a shootdown has already occurred, i.e. a callback has been
+registered.  The NMI crash shootdown path doesn't play nice with multiple
+invocations, e.g. attempting to register the NMI handler multiple times
+will trigger a double list_add() and hang the sytem (in addition to
+multiple other issues).  If "crash_kexec_post_notifiers" is specified on
+the kernel command line, panic() will invoke crash_smp_send_stop() and
+result in a second call to nmi_shootdown_cpus() during
+native_machine_emergency_restart().
+
+Invoke the callback _before_ disabling virtualization, as the current
+VMCS needs to be cleared before doing VMXOFF.  Note, this results in a
+subtle change in ordering between disabling virtualization and stopping
+Intel PT on the responding CPUs.  While VMX and Intel PT do interact,
+VMXOFF and writes to MSR_IA32_RTIT_CTL do not induce faults between one
+another, which is all that matters when panicking.
+
+WARN if nmi_shootdown_cpus() is called a second time with anything other
+than the reboot path's "nop" handler, as bailing means the requested
+isn't being invoked.  Punt true handling of multiple shootdown callbacks
+until there's an actual use case for doing so (beyond disabling
+virtualization).
+
+Extract the disabling logic to a common helper to deduplicate code, and
+to prepare for doing the shootdown in the emergency reboot path if SVM
+is supported.
+
+Note, prior to commit ed72736183c4 ("x86/reboot: Force all cpus to exit
+VMX root if VMX is supported), nmi_shootdown_cpus() was subtly protected
+against a second invocation by a cpu_vmx_enabled() check as the kdump
+handler would disable VMX if it ran first.
+
+Fixes: ed72736183c4 ("x86/reboot: Force all cpus to exit VMX root if VMX is supported)
+Cc: stable-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
+Reported-by: Guilherme G. Piccoli <gpiccoli-wEGTBA9jqPzQT0dZR+AlfA@public.gmane.org>
+Signed-off-by: Sean Christopherson <seanjc-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
+---
+ arch/x86/include/asm/reboot.h |  1 +
+ arch/x86/kernel/crash.c       | 16 +--------------
+ arch/x86/kernel/reboot.c      | 38 ++++++++++++++++++++++++++++++++---
+ 3 files changed, 37 insertions(+), 18 deletions(-)
+
+diff --git a/arch/x86/include/asm/reboot.h b/arch/x86/include/asm/reboot.h
+index 04c17be9b5fd..8f2da36435a6 100644
+--- a/arch/x86/include/asm/reboot.h
++++ b/arch/x86/include/asm/reboot.h
+@@ -25,6 +25,7 @@ void __noreturn machine_real_restart(unsigned int type);
+ #define MRR_BIOS	0
+ #define MRR_APM		1
+ 
++void cpu_crash_disable_virtualization(void);
+ typedef void (*nmi_shootdown_cb)(int, struct pt_regs*);
+ void nmi_panic_self_stop(struct pt_regs *regs);
+ void nmi_shootdown_cpus(nmi_shootdown_cb callback);
+diff --git a/arch/x86/kernel/crash.c b/arch/x86/kernel/crash.c
+index e8326a8d1c5d..fe0cf83843ba 100644
+--- a/arch/x86/kernel/crash.c
++++ b/arch/x86/kernel/crash.c
+@@ -81,15 +81,6 @@ static void kdump_nmi_callback(int cpu, struct pt_regs *regs)
+ 	 */
+ 	cpu_crash_vmclear_loaded_vmcss();
+ 
+-	/* Disable VMX or SVM if needed.
+-	 *
+-	 * We need to disable virtualization on all CPUs.
+-	 * Having VMX or SVM enabled on any CPU may break rebooting
+-	 * after the kdump kernel has finished its task.
+-	 */
+-	cpu_emergency_vmxoff();
+-	cpu_emergency_svm_disable();
+-
+ 	/*
+ 	 * Disable Intel PT to stop its logging
+ 	 */
+@@ -148,12 +139,7 @@ void native_machine_crash_shutdown(struct pt_regs *regs)
+ 	 */
+ 	cpu_crash_vmclear_loaded_vmcss();
+ 
+-	/* Booting kdump kernel with VMX or SVM enabled won't work,
+-	 * because (among other limitations) we can't disable paging
+-	 * with the virt flags.
+-	 */
+-	cpu_emergency_vmxoff();
+-	cpu_emergency_svm_disable();
++	cpu_crash_disable_virtualization();
+ 
+ 	/*
+ 	 * Disable Intel PT to stop its logging
+diff --git a/arch/x86/kernel/reboot.c b/arch/x86/kernel/reboot.c
+index fa700b46588e..f9543a4e9b09 100644
+--- a/arch/x86/kernel/reboot.c
++++ b/arch/x86/kernel/reboot.c
+@@ -528,9 +528,9 @@ static inline void kb_wait(void)
+ 	}
+ }
+ 
+-static void vmxoff_nmi(int cpu, struct pt_regs *regs)
++static void nmi_shootdown_nop(int cpu, struct pt_regs *regs)
+ {
+-	cpu_emergency_vmxoff();
++	/* Nothing to do, the NMI shootdown handler disables virtualization. */
+ }
+ 
+ /* Use NMIs as IPIs to tell all CPUs to disable virtualization */
+@@ -554,7 +554,7 @@ static void emergency_vmx_disable_all(void)
+ 		__cpu_emergency_vmxoff();
+ 
+ 		/* Halt and exit VMX root operation on the other CPUs. */
+-		nmi_shootdown_cpus(vmxoff_nmi);
++		nmi_shootdown_cpus(nmi_shootdown_nop);
+ 	}
+ }
+ 
+@@ -802,6 +802,18 @@ static nmi_shootdown_cb shootdown_callback;
+ static atomic_t waiting_for_crash_ipi;
+ static int crash_ipi_issued;
+ 
++void cpu_crash_disable_virtualization(void)
++{
++	/*
++	 * Disable virtualization, i.e. VMX or SVM, so that INIT is recognized
++	 * during reboot.  VMX blocks INIT if the CPU is post-VMXON, and SVM
++	 * blocks INIT if GIF=0.  Note, CLGI #UDs if SVM isn't enabled, so it's
++	 * easier to just disable SVM unconditionally.
++	 */
++	cpu_emergency_vmxoff();
++	cpu_emergency_svm_disable();
++}
++
+ static int crash_nmi_callback(unsigned int val, struct pt_regs *regs)
+ {
+ 	int cpu;
+@@ -819,6 +831,12 @@ static int crash_nmi_callback(unsigned int val, struct pt_regs *regs)
+ 
+ 	shootdown_callback(cpu, regs);
+ 
++	/*
++	 * Prepare the CPU for reboot _after_ invoking the callback so that the
++	 * callback can safely use virtualization instructions, e.g. VMCLEAR.
++	 */
++	cpu_crash_disable_virtualization();
++
+ 	atomic_dec(&waiting_for_crash_ipi);
+ 	/* Assume hlt works */
+ 	halt();
+@@ -840,6 +858,20 @@ void nmi_shootdown_cpus(nmi_shootdown_cb callback)
+ 	unsigned long msecs;
+ 	local_irq_disable();
+ 
++	/*
++	 * Invoking multiple callbacks is not currently supported, registering
++	 * the NMI handler twice will cause a list_add() double add BUG().
++	 * The exception is the "nop" handler in the emergency reboot path,
++	 * which can run after e.g. kdump's shootdown.  Do nothing if the crash
++	 * handler has already run, i.e. has already prepared other CPUs, the
++	 * reboot path doesn't have any work of its to do, it just needs to
++	 * ensure all CPUs have prepared for reboot.
++	 */
++	if (shootdown_callback) {
++		WARN_ON_ONCE(callback != nmi_shootdown_nop);
++		return;
++	}
++
+ 	/* Make a note of crashing cpu. Will be used in NMI callback. */
+ 	crashing_cpu = safe_smp_processor_id();
+ 
+
+base-commit: 2764011106d0436cb44702cfb0981339d68c3509
+-- 
+2.36.0.512.ge40c2bad7a-goog
diff --git a/N1/3.hdr b/N1/3.hdr
new file mode 100644
index 0000000..88c74d8
--- /dev/null
+++ b/N1/3.hdr
@@ -0,0 +1,3 @@
+Content-Type: text/x-diff; charset=us-ascii
+Content-Disposition: attachment;
+	filename="0002-x86-reboot-Disable-virtualization-in-an-emergency-if.patch"
diff --git a/N1/3.txt b/N1/3.txt
new file mode 100644
index 0000000..c0459ff
--- /dev/null
+++ b/N1/3.txt
@@ -0,0 +1,72 @@
+From ce4b8fb50962c00a9bb29663e96501e90d68bd8b Mon Sep 17 00:00:00 2001
+From: Sean Christopherson <seanjc-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
+Date: Mon, 9 May 2022 08:28:14 -0700
+Subject: [PATCH 2/2] x86/reboot: Disable virtualization in an emergency if SVM
+ is supported
+
+Disable SVM on all CPUs via NMI shootdown during an emergency reboot.
+Like VMX, SVM can block INIT and thus prevent bringing up other CPUs via
+INIT-SIPI-SIPI.
+
+Cc: stable-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
+Signed-off-by: Sean Christopherson <seanjc-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
+---
+ arch/x86/kernel/reboot.c | 26 ++++++++++++++------------
+ 1 file changed, 14 insertions(+), 12 deletions(-)
+
+diff --git a/arch/x86/kernel/reboot.c b/arch/x86/kernel/reboot.c
+index f9543a4e9b09..33c1f4883b27 100644
+--- a/arch/x86/kernel/reboot.c
++++ b/arch/x86/kernel/reboot.c
+@@ -533,27 +533,29 @@ static void nmi_shootdown_nop(int cpu, struct pt_regs *regs)
+ 	/* Nothing to do, the NMI shootdown handler disables virtualization. */
+ }
+ 
+-/* Use NMIs as IPIs to tell all CPUs to disable virtualization */
+-static void emergency_vmx_disable_all(void)
++static void emergency_reboot_disable_virtualization(void)
+ {
+ 	/* Just make sure we won't change CPUs while doing this */
+ 	local_irq_disable();
+ 
+ 	/*
+-	 * Disable VMX on all CPUs before rebooting, otherwise we risk hanging
+-	 * the machine, because the CPU blocks INIT when it's in VMX root.
++	 * Disable virtualization on all CPUs before rebooting to avoid hanging
++	 * the system, as VMX and SVM block INIT when running in the host
+ 	 *
+ 	 * We can't take any locks and we may be on an inconsistent state, so
+-	 * use NMIs as IPIs to tell the other CPUs to exit VMX root and halt.
++	 * use NMIs as IPIs to tell the other CPUs to disable VMX/SVM and halt.
+ 	 *
+-	 * Do the NMI shootdown even if VMX if off on _this_ CPU, as that
+-	 * doesn't prevent a different CPU from being in VMX root operation.
++	 * Do the NMI shootdown even if virtualization is off on _this_ CPU, as
++	 * other CPUs may have virtualization enabled.
+ 	 */
+-	if (cpu_has_vmx()) {
+-		/* Safely force _this_ CPU out of VMX root operation. */
+-		__cpu_emergency_vmxoff();
++	if (cpu_has_vmx() || cpu_has_svm(NULL)) {
++		/* Safely force _this_ CPU out of VMX/SVM operation. */
++		if (cpu_has_vmx())
++			__cpu_emergency_vmxoff();
++		else
++			cpu_emergency_svm_disable();
+ 
+-		/* Halt and exit VMX root operation on the other CPUs. */
++		/* Disable VMX/SVM and halt on other CPUs. */
+ 		nmi_shootdown_cpus(nmi_shootdown_nop);
+ 	}
+ }
+@@ -590,7 +592,7 @@ static void native_machine_emergency_restart(void)
+ 	unsigned short mode;
+ 
+ 	if (reboot_emergency)
+-		emergency_vmx_disable_all();
++		emergency_reboot_disable_virtualization();
+ 
+ 	tboot_shutdown(TB_SHUTDOWN_REBOOT);
+ 
+-- 
+2.36.0.512.ge40c2bad7a-goog
diff --git a/a/content_digest b/N1/content_digest
index ec71d3d..d3fa7e3 100644
--- a/a/content_digest
+++ b/N1/content_digest
@@ -1,10 +1,40 @@
  "ref\020220427224924.592546-1-gpiccoli@igalia.com\0"
  "ref\020220427224924.592546-2-gpiccoli@igalia.com\0"
- "From\0Sean Christopherson <seanjc@google.com>\0"
- "Subject\0[PATCH 01/30] x86/crash,reboot: Avoid re-disabling VMX in all CPUs on crash/restart\0"
+ "ref\020220427224924.592546-2-gpiccoli-wEGTBA9jqPzQT0dZR+AlfA@public.gmane.org\0"
+ "From\0Sean Christopherson <seanjc-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>\0"
+ "Subject\0Re: [PATCH 01/30] x86/crash,reboot: Avoid re-disabling VMX in all CPUs on crash/restart\0"
  "Date\0Mon, 9 May 2022 15:52:49 +0000\0"
- "To\0kexec@lists.infradead.org\0"
- "\00:1\0"
+ "To\0Guilherme G. Piccoli <gpiccoli-wEGTBA9jqPzQT0dZR+AlfA@public.gmane.org>\0"
+ "Cc\0akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org"
+  bhe-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org
+  pmladek-IBi9RG/b67k@public.gmane.org
+  kexec-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org
+  linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
+  bcm-kernel-feedback-list-dY08KVG/lbpWk0Htik3J/w@public.gmane.org
+  coresight-cunTk1MwBs8s++Sfvej+rw@public.gmane.org
+  linuxppc-dev-uLR06cmDAlY/bJ5BZ2RsiQ@public.gmane.org
+  linux-alpha-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
+  linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org
+  linux-edac-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
+  linux-hyperv-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
+  linux-leds-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
+  linux-mips-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
+  linux-parisc-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
+  linux-pm-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
+  linux-remoteproc-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
+  linux-s390-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
+  linux-tegra-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
+  linux-um-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org
+  linux-xtensa-PjhNF2WwrV/0Sa2dR60CXw@public.gmane.org
+  netdev-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
+  openipmi-developer-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org
+  rcu-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
+  sparclinux-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
+  xen-devel-GuqFBffKawtpuQazS67q72D2FQJk+8+b@public.gmane.org
+  x86-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org
+  kernel-dev-wEGTBA9jqPzQT0dZR+AlfA@public.gmane.org
+ " k\0"
+ "\01:1\0"
  "b\0"
  "I find the shortlog to be very confusing, the bug has nothing to do with disabling\n"
  "VMX and I distinctly remember wrapping VMXOFF with exception fixup to prevent doom\n"
@@ -49,11 +79,11 @@
  "> \n"
  "> Fixes: ed72736183c4 (\"x86/reboot: Force all cpus to exit VMX root if VMX is supported)\n"
  "> Fixes: 0ee59413c967 (\"x86/panic: replace smp_send_stop() with kdump friendly version in panic path\")\n"
- "> Cc: David P. Reed <dpreed@deepplum.com>\n"
- "> Cc: Hidehiro Kawai <hidehiro.kawai.ez@hitachi.com>\n"
- "> Cc: Paolo Bonzini <pbonzini@redhat.com>\n"
- "> Cc: Sean Christopherson <seanjc@google.com>\n"
- "> Signed-off-by: Guilherme G. Piccoli <gpiccoli@igalia.com>\n"
+ "> Cc: David P. Reed <dpreed-UISbPGJNPmdWk0Htik3J/w@public.gmane.org>\n"
+ "> Cc: Hidehiro Kawai <hidehiro.kawai.ez-FCd8Q96Dh0JBDgjK7y7TUQ@public.gmane.org>\n"
+ "> Cc: Paolo Bonzini <pbonzini-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>\n"
+ "> Cc: Sean Christopherson <seanjc-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>\n"
+ "> Signed-off-by: Guilherme G. Piccoli <gpiccoli-wEGTBA9jqPzQT0dZR+AlfA@public.gmane.org>\n"
  "> ---\n"
  ">  arch/x86/include/asm/cpu.h |  1 +\n"
  ">  arch/x86/kernel/crash.c    |  8 ++++----\n"
@@ -150,20 +180,260 @@
  ">  \n"
  "> -- \n"
  "> 2.36.0\n"
- "> \n"
- "-------------- next part --------------\n"
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- URL: <http://lists.infradead.org/pipermail/kexec/attachments/20220509/5e99544c/attachment-0003.bin>
+ >
+ "\01:2\0"
+ "fn\00001-x86-crash-Disable-virt-in-core-NMI-crash-handler-to-.patch\0"
+ "b\0"
+ "From 8a4573b7cf3a3e49b409ba3a504934de181c259d Mon Sep 17 00:00:00 2001\n"
+ "From: Sean Christopherson <seanjc-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>\n"
+ "Date: Mon, 9 May 2022 07:36:34 -0700\n"
+ "Subject: [PATCH 1/2] x86/crash: Disable virt in core NMI crash handler to\n"
+ " avoid double list_add\n"
+ "\n"
+ "Disable virtualization in crash_nmi_callback() and skip the requested NMI\n"
+ "shootdown if a shootdown has already occurred, i.e. a callback has been\n"
+ "registered.  The NMI crash shootdown path doesn't play nice with multiple\n"
+ "invocations, e.g. attempting to register the NMI handler multiple times\n"
+ "will trigger a double list_add() and hang the sytem (in addition to\n"
+ "multiple other issues).  If \"crash_kexec_post_notifiers\" is specified on\n"
+ "the kernel command line, panic() will invoke crash_smp_send_stop() and\n"
+ "result in a second call to nmi_shootdown_cpus() during\n"
+ "native_machine_emergency_restart().\n"
+ "\n"
+ "Invoke the callback _before_ disabling virtualization, as the current\n"
+ "VMCS needs to be cleared before doing VMXOFF.  Note, this results in a\n"
+ "subtle change in ordering between disabling virtualization and stopping\n"
+ "Intel PT on the responding CPUs.  While VMX and Intel PT do interact,\n"
+ "VMXOFF and writes to MSR_IA32_RTIT_CTL do not induce faults between one\n"
+ "another, which is all that matters when panicking.\n"
+ "\n"
+ "WARN if nmi_shootdown_cpus() is called a second time with anything other\n"
+ "than the reboot path's \"nop\" handler, as bailing means the requested\n"
+ "isn't being invoked.  Punt true handling of multiple shootdown callbacks\n"
+ "until there's an actual use case for doing so (beyond disabling\n"
+ "virtualization).\n"
+ "\n"
+ "Extract the disabling logic to a common helper to deduplicate code, and\n"
+ "to prepare for doing the shootdown in the emergency reboot path if SVM\n"
+ "is supported.\n"
+ "\n"
+ "Note, prior to commit ed72736183c4 (\"x86/reboot: Force all cpus to exit\n"
+ "VMX root if VMX is supported), nmi_shootdown_cpus() was subtly protected\n"
+ "against a second invocation by a cpu_vmx_enabled() check as the kdump\n"
+ "handler would disable VMX if it ran first.\n"
+ "\n"
+ "Fixes: ed72736183c4 (\"x86/reboot: Force all cpus to exit VMX root if VMX is supported)\n"
+ "Cc: stable-u79uwXL29TY76Z2rM5mHXA@public.gmane.org\n"
+ "Reported-by: Guilherme G. Piccoli <gpiccoli-wEGTBA9jqPzQT0dZR+AlfA@public.gmane.org>\n"
+ "Signed-off-by: Sean Christopherson <seanjc-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>\n"
+ "---\n"
+ " arch/x86/include/asm/reboot.h |  1 +\n"
+ " arch/x86/kernel/crash.c       | 16 +--------------\n"
+ " arch/x86/kernel/reboot.c      | 38 ++++++++++++++++++++++++++++++++---\n"
+ " 3 files changed, 37 insertions(+), 18 deletions(-)\n"
+ "\n"
+ "diff --git a/arch/x86/include/asm/reboot.h b/arch/x86/include/asm/reboot.h\n"
+ "index 04c17be9b5fd..8f2da36435a6 100644\n"
+ "--- a/arch/x86/include/asm/reboot.h\n"
+ "+++ b/arch/x86/include/asm/reboot.h\n"
+ "@@ -25,6 +25,7 @@ void __noreturn machine_real_restart(unsigned int type);\n"
+ " #define MRR_BIOS\t0\n"
+ " #define MRR_APM\t\t1\n"
+ " \n"
+ "+void cpu_crash_disable_virtualization(void);\n"
+ " typedef void (*nmi_shootdown_cb)(int, struct pt_regs*);\n"
+ " void nmi_panic_self_stop(struct pt_regs *regs);\n"
+ " void nmi_shootdown_cpus(nmi_shootdown_cb callback);\n"
+ "diff --git a/arch/x86/kernel/crash.c b/arch/x86/kernel/crash.c\n"
+ "index e8326a8d1c5d..fe0cf83843ba 100644\n"
+ "--- a/arch/x86/kernel/crash.c\n"
+ "+++ b/arch/x86/kernel/crash.c\n"
+ "@@ -81,15 +81,6 @@ static void kdump_nmi_callback(int cpu, struct pt_regs *regs)\n"
+ " \t */\n"
+ " \tcpu_crash_vmclear_loaded_vmcss();\n"
+ " \n"
+ "-\t/* Disable VMX or SVM if needed.\n"
+ "-\t *\n"
+ "-\t * We need to disable virtualization on all CPUs.\n"
+ "-\t * Having VMX or SVM enabled on any CPU may break rebooting\n"
+ "-\t * after the kdump kernel has finished its task.\n"
+ "-\t */\n"
+ "-\tcpu_emergency_vmxoff();\n"
+ "-\tcpu_emergency_svm_disable();\n"
+ "-\n"
+ " \t/*\n"
+ " \t * Disable Intel PT to stop its logging\n"
+ " \t */\n"
+ "@@ -148,12 +139,7 @@ void native_machine_crash_shutdown(struct pt_regs *regs)\n"
+ " \t */\n"
+ " \tcpu_crash_vmclear_loaded_vmcss();\n"
+ " \n"
+ "-\t/* Booting kdump kernel with VMX or SVM enabled won't work,\n"
+ "-\t * because (among other limitations) we can't disable paging\n"
+ "-\t * with the virt flags.\n"
+ "-\t */\n"
+ "-\tcpu_emergency_vmxoff();\n"
+ "-\tcpu_emergency_svm_disable();\n"
+ "+\tcpu_crash_disable_virtualization();\n"
+ " \n"
+ " \t/*\n"
+ " \t * Disable Intel PT to stop its logging\n"
+ "diff --git a/arch/x86/kernel/reboot.c b/arch/x86/kernel/reboot.c\n"
+ "index fa700b46588e..f9543a4e9b09 100644\n"
+ "--- a/arch/x86/kernel/reboot.c\n"
+ "+++ b/arch/x86/kernel/reboot.c\n"
+ "@@ -528,9 +528,9 @@ static inline void kb_wait(void)\n"
+ " \t}\n"
+ " }\n"
+ " \n"
+ "-static void vmxoff_nmi(int cpu, struct pt_regs *regs)\n"
+ "+static void nmi_shootdown_nop(int cpu, struct pt_regs *regs)\n"
+ " {\n"
+ "-\tcpu_emergency_vmxoff();\n"
+ "+\t/* Nothing to do, the NMI shootdown handler disables virtualization. */\n"
+ " }\n"
+ " \n"
+ " /* Use NMIs as IPIs to tell all CPUs to disable virtualization */\n"
+ "@@ -554,7 +554,7 @@ static void emergency_vmx_disable_all(void)\n"
+ " \t\t__cpu_emergency_vmxoff();\n"
+ " \n"
+ " \t\t/* Halt and exit VMX root operation on the other CPUs. */\n"
+ "-\t\tnmi_shootdown_cpus(vmxoff_nmi);\n"
+ "+\t\tnmi_shootdown_cpus(nmi_shootdown_nop);\n"
+ " \t}\n"
+ " }\n"
+ " \n"
+ "@@ -802,6 +802,18 @@ static nmi_shootdown_cb shootdown_callback;\n"
+ " static atomic_t waiting_for_crash_ipi;\n"
+ " static int crash_ipi_issued;\n"
+ " \n"
+ "+void cpu_crash_disable_virtualization(void)\n"
+ "+{\n"
+ "+\t/*\n"
+ "+\t * Disable virtualization, i.e. VMX or SVM, so that INIT is recognized\n"
+ "+\t * during reboot.  VMX blocks INIT if the CPU is post-VMXON, and SVM\n"
+ "+\t * blocks INIT if GIF=0.  Note, CLGI #UDs if SVM isn't enabled, so it's\n"
+ "+\t * easier to just disable SVM unconditionally.\n"
+ "+\t */\n"
+ "+\tcpu_emergency_vmxoff();\n"
+ "+\tcpu_emergency_svm_disable();\n"
+ "+}\n"
+ "+\n"
+ " static int crash_nmi_callback(unsigned int val, struct pt_regs *regs)\n"
+ " {\n"
+ " \tint cpu;\n"
+ "@@ -819,6 +831,12 @@ static int crash_nmi_callback(unsigned int val, struct pt_regs *regs)\n"
+ " \n"
+ " \tshootdown_callback(cpu, regs);\n"
+ " \n"
+ "+\t/*\n"
+ "+\t * Prepare the CPU for reboot _after_ invoking the callback so that the\n"
+ "+\t * callback can safely use virtualization instructions, e.g. VMCLEAR.\n"
+ "+\t */\n"
+ "+\tcpu_crash_disable_virtualization();\n"
+ "+\n"
+ " \tatomic_dec(&waiting_for_crash_ipi);\n"
+ " \t/* Assume hlt works */\n"
+ " \thalt();\n"
+ "@@ -840,6 +858,20 @@ void nmi_shootdown_cpus(nmi_shootdown_cb callback)\n"
+ " \tunsigned long msecs;\n"
+ " \tlocal_irq_disable();\n"
+ " \n"
+ "+\t/*\n"
+ "+\t * Invoking multiple callbacks is not currently supported, registering\n"
+ "+\t * the NMI handler twice will cause a list_add() double add BUG().\n"
+ "+\t * The exception is the \"nop\" handler in the emergency reboot path,\n"
+ "+\t * which can run after e.g. kdump's shootdown.  Do nothing if the crash\n"
+ "+\t * handler has already run, i.e. has already prepared other CPUs, the\n"
+ "+\t * reboot path doesn't have any work of its to do, it just needs to\n"
+ "+\t * ensure all CPUs have prepared for reboot.\n"
+ "+\t */\n"
+ "+\tif (shootdown_callback) {\n"
+ "+\t\tWARN_ON_ONCE(callback != nmi_shootdown_nop);\n"
+ "+\t\treturn;\n"
+ "+\t}\n"
+ "+\n"
+ " \t/* Make a note of crashing cpu. Will be used in NMI callback. */\n"
+ " \tcrashing_cpu = safe_smp_processor_id();\n"
+ " \n"
+ "\n"
+ "base-commit: 2764011106d0436cb44702cfb0981339d68c3509\n"
+ "-- \n"
+ 2.36.0.512.ge40c2bad7a-goog
+ "\01:3\0"
+ "fn\00002-x86-reboot-Disable-virtualization-in-an-emergency-if.patch\0"
+ "b\0"
+ "From ce4b8fb50962c00a9bb29663e96501e90d68bd8b Mon Sep 17 00:00:00 2001\n"
+ "From: Sean Christopherson <seanjc-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>\n"
+ "Date: Mon, 9 May 2022 08:28:14 -0700\n"
+ "Subject: [PATCH 2/2] x86/reboot: Disable virtualization in an emergency if SVM\n"
+ " is supported\n"
+ "\n"
+ "Disable SVM on all CPUs via NMI shootdown during an emergency reboot.\n"
+ "Like VMX, SVM can block INIT and thus prevent bringing up other CPUs via\n"
+ "INIT-SIPI-SIPI.\n"
+ "\n"
+ "Cc: stable-u79uwXL29TY76Z2rM5mHXA@public.gmane.org\n"
+ "Signed-off-by: Sean Christopherson <seanjc-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>\n"
+ "---\n"
+ " arch/x86/kernel/reboot.c | 26 ++++++++++++++------------\n"
+ " 1 file changed, 14 insertions(+), 12 deletions(-)\n"
+ "\n"
+ "diff --git a/arch/x86/kernel/reboot.c b/arch/x86/kernel/reboot.c\n"
+ "index f9543a4e9b09..33c1f4883b27 100644\n"
+ "--- a/arch/x86/kernel/reboot.c\n"
+ "+++ b/arch/x86/kernel/reboot.c\n"
+ "@@ -533,27 +533,29 @@ static void nmi_shootdown_nop(int cpu, struct pt_regs *regs)\n"
+ " \t/* Nothing to do, the NMI shootdown handler disables virtualization. */\n"
+ " }\n"
+ " \n"
+ "-/* Use NMIs as IPIs to tell all CPUs to disable virtualization */\n"
+ "-static void emergency_vmx_disable_all(void)\n"
+ "+static void emergency_reboot_disable_virtualization(void)\n"
+ " {\n"
+ " \t/* Just make sure we won't change CPUs while doing this */\n"
+ " \tlocal_irq_disable();\n"
+ " \n"
+ " \t/*\n"
+ "-\t * Disable VMX on all CPUs before rebooting, otherwise we risk hanging\n"
+ "-\t * the machine, because the CPU blocks INIT when it's in VMX root.\n"
+ "+\t * Disable virtualization on all CPUs before rebooting to avoid hanging\n"
+ "+\t * the system, as VMX and SVM block INIT when running in the host\n"
+ " \t *\n"
+ " \t * We can't take any locks and we may be on an inconsistent state, so\n"
+ "-\t * use NMIs as IPIs to tell the other CPUs to exit VMX root and halt.\n"
+ "+\t * use NMIs as IPIs to tell the other CPUs to disable VMX/SVM and halt.\n"
+ " \t *\n"
+ "-\t * Do the NMI shootdown even if VMX if off on _this_ CPU, as that\n"
+ "-\t * doesn't prevent a different CPU from being in VMX root operation.\n"
+ "+\t * Do the NMI shootdown even if virtualization is off on _this_ CPU, as\n"
+ "+\t * other CPUs may have virtualization enabled.\n"
+ " \t */\n"
+ "-\tif (cpu_has_vmx()) {\n"
+ "-\t\t/* Safely force _this_ CPU out of VMX root operation. */\n"
+ "-\t\t__cpu_emergency_vmxoff();\n"
+ "+\tif (cpu_has_vmx() || cpu_has_svm(NULL)) {\n"
+ "+\t\t/* Safely force _this_ CPU out of VMX/SVM operation. */\n"
+ "+\t\tif (cpu_has_vmx())\n"
+ "+\t\t\t__cpu_emergency_vmxoff();\n"
+ "+\t\telse\n"
+ "+\t\t\tcpu_emergency_svm_disable();\n"
+ " \n"
+ "-\t\t/* Halt and exit VMX root operation on the other CPUs. */\n"
+ "+\t\t/* Disable VMX/SVM and halt on other CPUs. */\n"
+ " \t\tnmi_shootdown_cpus(nmi_shootdown_nop);\n"
+ " \t}\n"
+ " }\n"
+ "@@ -590,7 +592,7 @@ static void native_machine_emergency_restart(void)\n"
+ " \tunsigned short mode;\n"
+ " \n"
+ " \tif (reboot_emergency)\n"
+ "-\t\temergency_vmx_disable_all();\n"
+ "+\t\temergency_reboot_disable_virtualization();\n"
+ " \n"
+ " \ttboot_shutdown(TB_SHUTDOWN_REBOOT);\n"
+ " \n"
+ "-- \n"
+ 2.36.0.512.ge40c2bad7a-goog
 
-3be9201c695e4da7cfca208c981473813e543ff3a9120ce19aba847befe8a493
+1aae2f1845de36a34b6901e81ac337ea9cab5cebbd792c2a999f035747a30fde
