diff mbox series

[v4,4/4] x86/reboot: Disable SVM, not just VMX, when stopping CPUs

Message ID 20221130233650.1404148-5-seanjc@google.com
State New
Headers
Series x86/crash: Fix double NMI shootdown bug |

Commit Message

Sean Christopherson Nov. 30, 2022, 11:36 p.m. UTC 
  Disable SVM and more importantly force GIF=1 when halting a CPU or
rebooting the machine.  Similar to VMX, SVM allows software to block
INITs via CLGI, and thus can be problematic for a crash/reboot.  The
window for failure is smaller with SVM as INIT is only blocked while
GIF=0, i.e. between CLGI and STGI, but the window does exist.

Fixes: fba4f472b33a ("x86/reboot: Turn off KVM when halting a CPU")
Cc: stable@vger.kernel
Signed-off-by: Sean Christopherson <seanjc@google.com>
---
 arch/x86/kernel/smp.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

Comments

Sean Christopherson Nov. 30, 2022, 11:38 p.m. UTC | #1 
On Wed, Nov 30, 2022, Sean Christopherson wrote:
> Disable SVM and more importantly force GIF=1 when halting a CPU or
> rebooting the machine.  Similar to VMX, SVM allows software to block
> INITs via CLGI, and thus can be problematic for a crash/reboot.  The
> window for failure is smaller with SVM as INIT is only blocked while
> GIF=0, i.e. between CLGI and STGI, but the window does exist.
> 
> Fixes: fba4f472b33a ("x86/reboot: Turn off KVM when halting a CPU")
> Cc: stable@vger.kernel

Argh, forgot the .org, and of course my scripts then failed to filter out the
address.
diff mbox series

Patch

diff --git a/arch/x86/kernel/smp.c b/arch/x86/kernel/smp.c
index 06db901fabe8..375b33ecafa2 100644
--- a/arch/x86/kernel/smp.c
+++ b/arch/x86/kernel/smp.c
@@ -32,7 +32,7 @@ 
 #include <asm/mce.h>
 #include <asm/trace/irq_vectors.h>
 #include <asm/kexec.h>
-#include <asm/virtext.h>
+#include <asm/reboot.h>
 
 /*
  *	Some notes on x86 processor bugs affecting SMP operation:
@@ -122,7 +122,7 @@  static int smp_stop_nmi_callback(unsigned int val, struct pt_regs *regs)
 	if (raw_smp_processor_id() == atomic_read(&stopping_cpu))
 		return NMI_HANDLED;
 
-	cpu_emergency_vmxoff();
+	cpu_emergency_disable_virtualization();
 	stop_this_cpu(NULL);
 
 	return NMI_HANDLED;
@@ -134,7 +134,7 @@  static int smp_stop_nmi_callback(unsigned int val, struct pt_regs *regs)
 DEFINE_IDTENTRY_SYSVEC(sysvec_reboot)
 {
 	ack_APIC_irq();
-	cpu_emergency_vmxoff();
+	cpu_emergency_disable_virtualization();
 	stop_this_cpu(NULL);
 }