On Thu, Sep 08, 2022 at 04:25:32PM -0700, isaku.yamahata@xxxxxxxxx wrote:
>From: Isaku Yamahata <isaku.yamahata@xxxxxxxxx>
>
>A global variable hardware_enable_failed in kvm_arch.c is used only by
>kvm_arch_add_vm() and hardware_enable(). It doesn't have to be a global
>variable. Make it function local.
>
>Signed-off-by: Isaku Yamahata <isaku.yamahata@xxxxxxxxx>
Reviewed-by: Chao Gao <chao.gao@xxxxxxxxx>
>---
> virt/kvm/kvm_arch.c | 62 ++++++++++++++++++++++-----------------------
> 1 file changed, 31 insertions(+), 31 deletions(-)
>
>diff --git a/virt/kvm/kvm_arch.c b/virt/kvm/kvm_arch.c
>index 4fe16e8ef2e5..ad23537ebe3b 100644
>--- a/virt/kvm/kvm_arch.c
>+++ b/virt/kvm/kvm_arch.c
>@@ -13,14 +13,13 @@
> #include <linux/kvm_host.h>
>
> static cpumask_t cpus_hardware_enabled = CPU_MASK_NONE;
>-static atomic_t hardware_enable_failed;
>
> __weak int kvm_arch_post_init_vm(struct kvm *kvm)
> {
> return 0;
> }
>
>-static void hardware_enable(void *caller_name)
>+static int __hardware_enable(void *caller_name)
nit: caller_name can be dropped and use __builtin_return_address(0) instead.
> {
> int cpu = raw_smp_processor_id();
> int r;
>@@ -28,18 +27,22 @@ static void hardware_enable(void *caller_name)
> WARN_ON_ONCE(preemptible());
>
> if (cpumask_test_cpu(cpu, &cpus_hardware_enabled))
>- return;
>-
>- cpumask_set_cpu(cpu, &cpus_hardware_enabled);
>-
>+ return 0;
> r = kvm_arch_hardware_enable();
>-
>- if (r) {
>- cpumask_clear_cpu(cpu, &cpus_hardware_enabled);
>- atomic_inc(&hardware_enable_failed);
>+ if (r)
> pr_warn("kvm: enabling virtualization on CPU%d failed during %s()\n",
> cpu, (const char *)caller_name);
>- }
>+ else
>+ cpumask_set_cpu(cpu, &cpus_hardware_enabled);
>+ return r;
>+}
>+
>+static void hardware_enable(void *arg)
>+{
>+ atomic_t *failed = arg;
>+
>+ if (__hardware_enable((void *)__func__))
>+ atomic_inc(failed);
> }
>
> static void hardware_disable(void *junk)
>@@ -65,15 +68,16 @@ __weak void kvm_arch_pre_hardware_unsetup(void)
> */
> __weak int kvm_arch_add_vm(struct kvm *kvm, int usage_count)
> {
>+ atomic_t failed;
nit:
atomic_t failed = ATOMIC_INIT(0);
then you can drop the atomic_set() below.
> int r = 0;
>
> if (usage_count != 1)
> return 0;
>
>- atomic_set(&hardware_enable_failed, 0);
>- on_each_cpu(hardware_enable, (void *)__func__, 1);
>+ atomic_set(&failed, 0);
>+ on_each_cpu(hardware_enable, &failed, 1);
>
>- if (atomic_read(&hardware_enable_failed)) {
>+ if (atomic_read(&failed)) {
> r = -EBUSY;
> goto err;
> }
>@@ -96,33 +100,29 @@ __weak int kvm_arch_del_vm(int usage_count)
>
> __weak int kvm_arch_online_cpu(unsigned int cpu, int usage_count)
> {
>- int ret = 0;
>+ int ret;
>
> ret = kvm_arch_check_processor_compat();
> if (ret)
> return ret;
>
>+ if (!usage_count)
>+ return 0;
>+
>+ /*
>+ * arch callback kvm_arch_hardware_eanble() assumes that
^ enable
