From: Isaku Yamahata <[email protected]>
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 <[email protected]>
---
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)
{
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;
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
+ * preemption is disabled for historical reason. Disable
+ * preemption until all arch callbacks are fixed.
+ */
+ preempt_disable();
/*
* Abort the CPU online process if hardware virtualization cannot
* be enabled. Otherwise running VMs would encounter unrecoverable
* errors when scheduled to this CPU.
*/
- if (usage_count) {
- WARN_ON_ONCE(atomic_read(&hardware_enable_failed));
+ ret = __hardware_enable((void *)__func__);
+ preempt_enable();
- /*
- * arch callback kvm_arch_hardware_eanble() assumes that
- * preemption is disabled for historical reason. Disable
- * preemption until all arch callbacks are fixed.
- */
- preempt_disable();
- hardware_enable((void *)__func__);
- preempt_enable();
- if (atomic_read(&hardware_enable_failed)) {
- atomic_set(&hardware_enable_failed, 0);
- ret = -EIO;
- }
- }
return ret;
}
@@ -168,7 +168,7 @@ __weak void kvm_arch_resume(int usage_count)
if (usage_count) {
preempt_disable();
- hardware_enable((void *)__func__);
+ (void)__hardware_enable((void *)__func__);
preempt_enable();
}
}
--
2.25.1
On Thu, Sep 08, 2022 at 04:25:32PM -0700, [email protected] wrote:
>From: Isaku Yamahata <[email protected]>
>
>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 <[email protected]>
Reviewed-by: Chao Gao <[email protected]>
>---
> 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
On Fri, Sep 09, 2022 at 02:54:05PM +0800,
Chao Gao <[email protected]> wrote:
> >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.
Do you want to update your patch
"KVM: Provide more information in kernel log if hardware enabling fails"?
--
Isaku Yamahata <[email protected]>