From e4ce333cc66ef8c43c84fc70c0195ac1586dec73 Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Wed, 30 Nov 2022 23:36:50 +0000 Subject: [PATCH] x86/reboot: Disable SVM, not just VMX, when stopping CPUs commit a2b07fa7b93321c059af0c6d492cc9a4f1e390aa upstream. 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.org Reviewed-by: Thomas Gleixner Link: https://lore.kernel.org/r/20221130233650.1404148-5-seanjc@google.com Signed-off-by: Sean Christopherson Signed-off-by: Greg Kroah-Hartman --- arch/x86/kernel/smp.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/arch/x86/kernel/smp.c b/arch/x86/kernel/smp.c index b8d4e9c3c070..31ee37f87b2b 100644 --- a/arch/x86/kernel/smp.c +++ b/arch/x86/kernel/smp.c @@ -31,7 +31,7 @@ #include #include #include -#include +#include /* * Some notes on x86 processor bugs affecting SMP operation: @@ -121,7 +121,7 @@ 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) asmlinkage __visible void smp_reboot_interrupt(void) { ipi_entering_ack_irq(); - cpu_emergency_vmxoff(); + cpu_emergency_disable_virtualization(); stop_this_cpu(NULL); irq_exit(); }