[PATCH v2 19/19] RFC: KVM: Remove cpus_hardware_enabled and related sanity check

isaku.yamahata
2022-08-30T12:03:28Z

cpus_hardware_enabled mask seems incomplete protection against other kernel
component using CPU virtualization feature. Because it's obscure and
incomplete, remove the check.

Signed-off-by: Isaku Yamahata <isaku.yamahata@intel.com>
---
virt/kvm/kvm_arch.c | 16 ++--------------
1 file changed, 2 insertions(+), 14 deletions(-)

diff --git a/virt/kvm/kvm_arch.c b/virt/kvm/kvm_arch.c
index 8f2d920a2a8f..cbad0181c177 100644
--- a/virt/kvm/kvm_arch.c
+++ b/virt/kvm/kvm_arch.c
@@ -12,22 +12,16 @@

#include <linux/kvm_host.h>

-static cpumask_t cpus_hardware_enabled = CPU_MASK_NONE;
-
static int __hardware_enable(void)
{
- int cpu = raw_smp_processor_id();
int r;

WARN_ON_ONCE(preemptible());

- if (cpumask_test_cpu(cpu, &cpus_hardware_enabled))
- return 0;
r = kvm_arch_hardware_enable();
if (r)
- pr_info("kvm: enabling virtualization on CPU%d failed\n", cpu);
- else
- cpumask_set_cpu(cpu, &cpus_hardware_enabled);
+ pr_info("kvm: enabling virtualization on CPU%d failed\n",
+ smp_processor_id());
return r;
}

@@ -41,13 +35,7 @@ static void hardware_enable(void *arg)

static void hardware_disable(void *junk)
{
- int cpu = raw_smp_processor_id();
-
WARN_ON_ONCE(preemptible());
-
- if (!cpumask_test_cpu(cpu, &cpus_hardware_enabled))
- return;
- cpumask_clear_cpu(cpu, &cpus_hardware_enabled);
kvm_arch_hardware_disable();
}

--
2.25.1