From: Shuo Liu <[email protected]>
279dcf693ac7 ("virt: acrn: Introduce an interface for Service VM to
control vCPU") introduced {add,remove}_cpu() usage and it hit below
error with !CONFIG_SMP:
../drivers/virt/acrn/hsm.c: In function ‘remove_cpu_store’:
../drivers/virt/acrn/hsm.c:389:3: error: implicit declaration of function ‘remove_cpu’; [-Werror=implicit-function-declaration]
remove_cpu(cpu);
../drivers/virt/acrn/hsm.c:402:2: error: implicit declaration of function ‘add_cpu’; [-Werror=implicit-function-declaration]
add_cpu(cpu);
Add add_cpu() function prototypes with !CONFIG_SMP and remove_cpu() with
!CONFIG_HOTPLUG_CPU for such usage.
Fixes: 279dcf693ac7 ("virt: acrn: Introduce an interface for Service VM to control vCPU")
Reported-by: Randy Dunlap <[email protected]>
Signed-off-by: Shuo Liu <[email protected]>
---
I followed Greg's idea that add {add,remove}_cpu() functions prototypes.
The v2 solution is different from the v1, so i removed Randy's Acked-by.
Randy, please help have a look on v2.
v2:
- Drop the #ifdef in .c solution. Add {add,remove}_cpu() prototypes. (Suggested by Greg)
include/linux/cpu.h | 3 +++
1 file changed, 3 insertions(+)
diff --git a/include/linux/cpu.h b/include/linux/cpu.h
index 3aaa0687e8df..94a578a96202 100644
--- a/include/linux/cpu.h
+++ b/include/linux/cpu.h
@@ -108,6 +108,8 @@ static inline void cpu_maps_update_done(void)
{
}
+static inline int add_cpu(unsigned int cpu) { return 0;}
+
#endif /* CONFIG_SMP */
extern struct bus_type cpu_subsys;
@@ -137,6 +139,7 @@ static inline int cpus_read_trylock(void) { return true; }
static inline void lockdep_assert_cpus_held(void) { }
static inline void cpu_hotplug_disable(void) { }
static inline void cpu_hotplug_enable(void) { }
+static inline int remove_cpu(unsigned int cpu) { return -EPERM; }
static inline void smp_shutdown_nonboot_cpus(unsigned int primary_cpu) { }
#endif /* !CONFIG_HOTPLUG_CPU */
base-commit: 671176b0016c80b3943cb5387312c886aba3308d
--
2.28.0
From: Shuo Liu <[email protected]>
Without cpu hotplug support, vCPU cannot be removed from a Service VM.
Don't expose remove_cpu sysfs when CONFIG_HOTPLUG_CPU disabled.
Signed-off-by: Shuo Liu <[email protected]>
---
drivers/virt/acrn/hsm.c | 9 +++++++++
1 file changed, 9 insertions(+)
diff --git a/drivers/virt/acrn/hsm.c b/drivers/virt/acrn/hsm.c
index 1f6b7c54a1a4..6996ea6219e5 100644
--- a/drivers/virt/acrn/hsm.c
+++ b/drivers/virt/acrn/hsm.c
@@ -404,6 +404,14 @@ static ssize_t remove_cpu_store(struct device *dev,
}
static DEVICE_ATTR_WO(remove_cpu);
+static umode_t acrn_attr_visible(struct kobject *kobj, struct attribute *a, int n)
+{
+ if (a == &dev_attr_remove_cpu.attr)
+ return IS_ENABLED(CONFIG_HOTPLUG_CPU) ? a->mode : 0;
+
+ return a->mode;
+}
+
static struct attribute *acrn_attrs[] = {
&dev_attr_remove_cpu.attr,
NULL
@@ -411,6 +419,7 @@ static struct attribute *acrn_attrs[] = {
static struct attribute_group acrn_attr_group = {
.attrs = acrn_attrs,
+ .is_visible = acrn_attr_visible,
};
static const struct attribute_group *acrn_attr_groups[] = {
--
2.28.0
On 2/12/21 8:55 AM, [email protected] wrote:
> From: Shuo Liu <[email protected]>
>
> Without cpu hotplug support, vCPU cannot be removed from a Service VM.
> Don't expose remove_cpu sysfs when CONFIG_HOTPLUG_CPU disabled.
>
> Signed-off-by: Shuo Liu <[email protected]>
Acked-by: Randy Dunlap <[email protected]> # build-tested
Thanks.
> ---
> drivers/virt/acrn/hsm.c | 9 +++++++++
> 1 file changed, 9 insertions(+)
>
> diff --git a/drivers/virt/acrn/hsm.c b/drivers/virt/acrn/hsm.c
> index 1f6b7c54a1a4..6996ea6219e5 100644
> --- a/drivers/virt/acrn/hsm.c
> +++ b/drivers/virt/acrn/hsm.c
> @@ -404,6 +404,14 @@ static ssize_t remove_cpu_store(struct device *dev,
> }
> static DEVICE_ATTR_WO(remove_cpu);
>
> +static umode_t acrn_attr_visible(struct kobject *kobj, struct attribute *a, int n)
> +{
> + if (a == &dev_attr_remove_cpu.attr)
> + return IS_ENABLED(CONFIG_HOTPLUG_CPU) ? a->mode : 0;
> +
> + return a->mode;
> +}
> +
> static struct attribute *acrn_attrs[] = {
> &dev_attr_remove_cpu.attr,
> NULL
> @@ -411,6 +419,7 @@ static struct attribute *acrn_attrs[] = {
>
> static struct attribute_group acrn_attr_group = {
> .attrs = acrn_attrs,
> + .is_visible = acrn_attr_visible,
> };
>
> static const struct attribute_group *acrn_attr_groups[] = {
>
--
~Randy
On 2/12/21 8:55 AM, [email protected] wrote:
> From: Shuo Liu <[email protected]>
>
> 279dcf693ac7 ("virt: acrn: Introduce an interface for Service VM to
> control vCPU") introduced {add,remove}_cpu() usage and it hit below
> error with !CONFIG_SMP:
>
> ../drivers/virt/acrn/hsm.c: In function ‘remove_cpu_store’:
> ../drivers/virt/acrn/hsm.c:389:3: error: implicit declaration of function ‘remove_cpu’; [-Werror=implicit-function-declaration]
> remove_cpu(cpu);
>
> ../drivers/virt/acrn/hsm.c:402:2: error: implicit declaration of function ‘add_cpu’; [-Werror=implicit-function-declaration]
> add_cpu(cpu);
>
> Add add_cpu() function prototypes with !CONFIG_SMP and remove_cpu() with
> !CONFIG_HOTPLUG_CPU for such usage.
>
> Fixes: 279dcf693ac7 ("virt: acrn: Introduce an interface for Service VM to control vCPU")
> Reported-by: Randy Dunlap <[email protected]>
> Signed-off-by: Shuo Liu <[email protected]>
> ---
> I followed Greg's idea that add {add,remove}_cpu() functions prototypes.
> The v2 solution is different from the v1, so i removed Randy's Acked-by.
> Randy, please help have a look on v2.
>
> v2:
> - Drop the #ifdef in .c solution. Add {add,remove}_cpu() prototypes. (Suggested by Greg)
>
> include/linux/cpu.h | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/include/linux/cpu.h b/include/linux/cpu.h
> index 3aaa0687e8df..94a578a96202 100644
> --- a/include/linux/cpu.h
> +++ b/include/linux/cpu.h
> @@ -108,6 +108,8 @@ static inline void cpu_maps_update_done(void)
> {
> }
>
> +static inline int add_cpu(unsigned int cpu) { return 0;}
> +
> #endif /* CONFIG_SMP */
> extern struct bus_type cpu_subsys;
>
> @@ -137,6 +139,7 @@ static inline int cpus_read_trylock(void) { return true; }
> static inline void lockdep_assert_cpus_held(void) { }
> static inline void cpu_hotplug_disable(void) { }
> static inline void cpu_hotplug_enable(void) { }
> +static inline int remove_cpu(unsigned int cpu) { return -EPERM; }
I would have done: return 0;
Anyway:
Acked-by: Randy Dunlap <[email protected]> # build-tested
> static inline void smp_shutdown_nonboot_cpus(unsigned int primary_cpu) { }
> #endif /* !CONFIG_HOTPLUG_CPU */
thanks.
--
~Randy