KVM: Ensure CPU is stable during low level hardware enable/disable

Use the non-raw smp_processor_id() in the low hardware enable/disable
helpers as KVM absolutely relies on the CPU being stable, e.g. KVM would
end up with incorrect state if the task were migrated between accessing
cpus_hardware_enabled and actually enabling/disabling hardware.

Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20221130230934.1014142-44-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 2d6203e..0c3b9d6 100644 (file)
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -5097,7 +5097,7 @@ static struct miscdevice kvm_dev = {
 
 static void hardware_enable_nolock(void *junk)
 {
-       int cpu = raw_smp_processor_id();
+       int cpu = smp_processor_id();
        int r;
 
        if (cpumask_test_cpu(cpu, cpus_hardware_enabled))
@@ -5139,7 +5139,7 @@ static int kvm_online_cpu(unsigned int cpu)
 
 static void hardware_disable_nolock(void *junk)
 {
-       int cpu = raw_smp_processor_id();
+       int cpu = smp_processor_id();
 
        if (!cpumask_test_cpu(cpu, cpus_hardware_enabled))
                return;