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: 354c3b95d8f3 ("x86/reboot: Turn off KVM when halting a CPU")
Cc: stable@vger.kernel.org
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20221130233650.1404148-5-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/arch/x86/kernel/smp.c b/arch/x86/kernel/smp.c
index b8d4e9c3c070c07dc94f429dc21df25787a49a75..31ee37f87b2b370b4a6cb1204ec04e4fce71c958 100644 (file)
--- a/arch/x86/kernel/smp.c
+++ b/arch/x86/kernel/smp.c
@@ -31,7 +31,7 @@
 #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:
@@ -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();
 }