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[PATCH v2 09/16] xen/riscv: introduce vcpu_kick() implementation

Oleksii Kurochko posted 16 patches 5 months, 3 weeks ago
There is a newer version of this series
[PATCH v2 09/16] xen/riscv: introduce vcpu_kick() implementation
Posted by Oleksii Kurochko 5 months, 3 weeks ago 
Add a RISC-V implementation of vcpu_kick(), which unblocks the target
vCPU and sends an event check IPI if the vCPU was running on another
processor. This mirrors the behavior of Arm and enables proper vCPU
wakeup handling on RISC-V.

Remove the stub implementation from stubs.c, as it is now provided by
arch/riscv/domain.c.

Signed-off-by: Oleksii Kurochko <oleksii.kurochko@gmail.com>
Acked-by: Jan Beulich <jbeulich@suse.com>
---
Changes in v2:
 - Add Acked-by: Jan Beulich <jbeulich@suse.com>.
---
 xen/arch/riscv/domain.c | 14 ++++++++++++++
 xen/arch/riscv/stubs.c  |  5 -----
 2 files changed, 14 insertions(+), 5 deletions(-)

diff --git a/xen/arch/riscv/domain.c b/xen/arch/riscv/domain.c
index e38c0db62cac..13ac384c4b76 100644
--- a/xen/arch/riscv/domain.c
+++ b/xen/arch/riscv/domain.c
@@ -1,8 +1,10 @@
 /* SPDX-License-Identifier: GPL-2.0-only */
 
+#include <xen/cpumask.h>
 #include <xen/init.h>
 #include <xen/mm.h>
 #include <xen/sched.h>
+#include <xen/smp.h>
 #include <xen/vmap.h>
 
 #include <asm/bitops.h>
@@ -240,3 +242,15 @@ void vcpu_sync_interrupts(struct vcpu *v)
 #   error "Update vsieh"
 #endif
 }
+
+void vcpu_kick(struct vcpu *v)
+{
+    bool running = v->is_running;
+
+    vcpu_unblock(v);
+    if ( running && v != current )
+    {
+        perfc_incr(vcpu_kick);
+        smp_send_event_check_mask(cpumask_of(v->processor));
+    }
+}
diff --git a/xen/arch/riscv/stubs.c b/xen/arch/riscv/stubs.c
index c5784a436574..1f0add97b361 100644
--- a/xen/arch/riscv/stubs.c
+++ b/xen/arch/riscv/stubs.c
@@ -208,11 +208,6 @@ void vcpu_block_unless_event_pending(struct vcpu *v)
     BUG_ON("unimplemented");
 }
 
-void vcpu_kick(struct vcpu *v)
-{
-    BUG_ON("unimplemented");
-}
-
 unsigned long
 hypercall_create_continuation(unsigned int op, const char *format, ...)
 {
-- 
2.52.0
Re: [PATCH v2 09/16] xen/riscv: introduce vcpu_kick() implementation
Posted by Oleksii Kurochko 5 months, 1 week ago 
On 1/22/26 5:47 PM, Oleksii Kurochko wrote:
> Add a RISC-V implementation of vcpu_kick(), which unblocks the target
> vCPU and sends an event check IPI if the vCPU was running on another
> processor. This mirrors the behavior of Arm and enables proper vCPU
> wakeup handling on RISC-V.
>
> Remove the stub implementation from stubs.c, as it is now provided by
> arch/riscv/domain.c.
>
> Signed-off-by: Oleksii Kurochko <oleksii.kurochko@gmail.com>
> Acked-by: Jan Beulich <jbeulich@suse.com>
> ---
> Changes in v2:
>   - Add Acked-by: Jan Beulich <jbeulich@suse.com>.
> ---
>   xen/arch/riscv/domain.c | 14 ++++++++++++++
>   xen/arch/riscv/stubs.c  |  5 -----
>   2 files changed, 14 insertions(+), 5 deletions(-)
>
> diff --git a/xen/arch/riscv/domain.c b/xen/arch/riscv/domain.c
> index e38c0db62cac..13ac384c4b76 100644
> --- a/xen/arch/riscv/domain.c
> +++ b/xen/arch/riscv/domain.c
> @@ -1,8 +1,10 @@
>   /* SPDX-License-Identifier: GPL-2.0-only */
>   
> +#include <xen/cpumask.h>
>   #include <xen/init.h>
>   #include <xen/mm.h>
>   #include <xen/sched.h>
> +#include <xen/smp.h>
>   #include <xen/vmap.h>
>   
>   #include <asm/bitops.h>
> @@ -240,3 +242,15 @@ void vcpu_sync_interrupts(struct vcpu *v)
>   #   error "Update vsieh"
>   #endif
>   }
> +
> +void vcpu_kick(struct vcpu *v)
> +{
> +    bool running = v->is_running;
> +
> +    vcpu_unblock(v);
> +    if ( running && v != current )
> +    {
> +        perfc_incr(vcpu_kick);

Because of this it is needed to introduce:
   PERFCOUNTER(vcpu_kick, "vcpu: notify other vcpu")
Otherwise randconfig build will fail when CONFIG_PERF_COUNTERS=y.

I would like to ask if it would be okay to add it xen/include/xen/perfc_defn.h
just after PERFCOUNTER(need_flush_tlb_flush,...) or would it be better to have
it in arch specific perfc_defn.h?

~ Oleksii
Re: [PATCH v2 09/16] xen/riscv: introduce vcpu_kick() implementation
Posted by Jan Beulich 5 months ago 
On 06.02.2026 17:36, Oleksii Kurochko wrote:
> 
> On 1/22/26 5:47 PM, Oleksii Kurochko wrote:
>> Add a RISC-V implementation of vcpu_kick(), which unblocks the target
>> vCPU and sends an event check IPI if the vCPU was running on another
>> processor. This mirrors the behavior of Arm and enables proper vCPU
>> wakeup handling on RISC-V.
>>
>> Remove the stub implementation from stubs.c, as it is now provided by
>> arch/riscv/domain.c.
>>
>> Signed-off-by: Oleksii Kurochko <oleksii.kurochko@gmail.com>
>> Acked-by: Jan Beulich <jbeulich@suse.com>
>> ---
>> Changes in v2:
>>   - Add Acked-by: Jan Beulich <jbeulich@suse.com>.
>> ---
>>   xen/arch/riscv/domain.c | 14 ++++++++++++++
>>   xen/arch/riscv/stubs.c  |  5 -----
>>   2 files changed, 14 insertions(+), 5 deletions(-)
>>
>> diff --git a/xen/arch/riscv/domain.c b/xen/arch/riscv/domain.c
>> index e38c0db62cac..13ac384c4b76 100644
>> --- a/xen/arch/riscv/domain.c
>> +++ b/xen/arch/riscv/domain.c
>> @@ -1,8 +1,10 @@
>>   /* SPDX-License-Identifier: GPL-2.0-only */
>>   
>> +#include <xen/cpumask.h>
>>   #include <xen/init.h>
>>   #include <xen/mm.h>
>>   #include <xen/sched.h>
>> +#include <xen/smp.h>
>>   #include <xen/vmap.h>
>>   
>>   #include <asm/bitops.h>
>> @@ -240,3 +242,15 @@ void vcpu_sync_interrupts(struct vcpu *v)
>>   #   error "Update vsieh"
>>   #endif
>>   }
>> +
>> +void vcpu_kick(struct vcpu *v)
>> +{
>> +    bool running = v->is_running;
>> +
>> +    vcpu_unblock(v);
>> +    if ( running && v != current )
>> +    {
>> +        perfc_incr(vcpu_kick);
> 
> Because of this it is needed to introduce:
>    PERFCOUNTER(vcpu_kick, "vcpu: notify other vcpu")
> Otherwise randconfig build will fail when CONFIG_PERF_COUNTERS=y.
> 
> I would like to ask if it would be okay to add it xen/include/xen/perfc_defn.h
> just after PERFCOUNTER(need_flush_tlb_flush,...) or would it be better to have
> it in arch specific perfc_defn.h?

Arch-specific please - it's not used by x86 nor ppc.

Jan
Re: [PATCH v2 09/16] xen/riscv: introduce vcpu_kick() implementation
Posted by Oleksii Kurochko 5 months ago 
On 2/9/26 10:07 AM, Jan Beulich wrote:
> On 06.02.2026 17:36, Oleksii Kurochko wrote:
>> On 1/22/26 5:47 PM, Oleksii Kurochko wrote:
>>> Add a RISC-V implementation of vcpu_kick(), which unblocks the target
>>> vCPU and sends an event check IPI if the vCPU was running on another
>>> processor. This mirrors the behavior of Arm and enables proper vCPU
>>> wakeup handling on RISC-V.
>>>
>>> Remove the stub implementation from stubs.c, as it is now provided by
>>> arch/riscv/domain.c.
>>>
>>> Signed-off-by: Oleksii Kurochko <oleksii.kurochko@gmail.com>
>>> Acked-by: Jan Beulich <jbeulich@suse.com>
>>> ---
>>> Changes in v2:
>>>    - Add Acked-by: Jan Beulich <jbeulich@suse.com>.
>>> ---
>>>    xen/arch/riscv/domain.c | 14 ++++++++++++++
>>>    xen/arch/riscv/stubs.c  |  5 -----
>>>    2 files changed, 14 insertions(+), 5 deletions(-)
>>>
>>> diff --git a/xen/arch/riscv/domain.c b/xen/arch/riscv/domain.c
>>> index e38c0db62cac..13ac384c4b76 100644
>>> --- a/xen/arch/riscv/domain.c
>>> +++ b/xen/arch/riscv/domain.c
>>> @@ -1,8 +1,10 @@
>>>    /* SPDX-License-Identifier: GPL-2.0-only */
>>>    
>>> +#include <xen/cpumask.h>
>>>    #include <xen/init.h>
>>>    #include <xen/mm.h>
>>>    #include <xen/sched.h>
>>> +#include <xen/smp.h>
>>>    #include <xen/vmap.h>
>>>    
>>>    #include <asm/bitops.h>
>>> @@ -240,3 +242,15 @@ void vcpu_sync_interrupts(struct vcpu *v)
>>>    #   error "Update vsieh"
>>>    #endif
>>>    }
>>> +
>>> +void vcpu_kick(struct vcpu *v)
>>> +{
>>> +    bool running = v->is_running;
>>> +
>>> +    vcpu_unblock(v);
>>> +    if ( running && v != current )
>>> +    {
>>> +        perfc_incr(vcpu_kick);
>> Because of this it is needed to introduce:
>>     PERFCOUNTER(vcpu_kick, "vcpu: notify other vcpu")
>> Otherwise randconfig build will fail when CONFIG_PERF_COUNTERS=y.
>>
>> I would like to ask if it would be okay to add it xen/include/xen/perfc_defn.h
>> just after PERFCOUNTER(need_flush_tlb_flush,...) or would it be better to have
>> it in arch specific perfc_defn.h?
> Arch-specific please - it's not used by x86 nor ppc.

Then I will do the following changes:

diff --git a/xen/arch/riscv/include/asm/Makefile b/xen/arch/riscv/include/asm/Makefile
index 3824f31c395c..86c56251d5d7 100644
--- a/xen/arch/riscv/include/asm/Makefile
+++ b/xen/arch/riscv/include/asm/Makefile
@@ -7,7 +7,6 @@ generic-y += hypercall.h
  generic-y += iocap.h
  generic-y += irq-dt.h
  generic-y += percpu.h
-generic-y += perfc_defn.h
  generic-y += random.h
  generic-y += softirq.h
  generic-y += vm_event.h
diff --git a/xen/arch/riscv/include/asm/perfc_defn.h b/xen/arch/riscv/include/asm/perfc_defn.h
new file mode 100644
index 000000000000..4fc161f1abad
--- /dev/null
+++ b/xen/arch/riscv/include/asm/perfc_defn.h
@@ -0,0 +1,7 @@
+/* This file is intended to be included multiple times. */
+/*#ifndef __XEN_PERFC_DEFN_H__*/
+/*#define __XEN_PERFC_DEFN_H__*/
+
+PERFCOUNTER(vcpu_kick, "vcpu: notify other vcpu")
+
+/*#endif*/ /* __XEN_PERFC_DEFN_H__ */

and add the following to commit message:
     Since vcpu_kick() calls perfc_incr(vcpu_kick), add perfcounter for
     vcpu_kick to handle the case when CONFIG_PERF_COUNTERS=y. Although
     CONFIG_PERF_COUNTERS is not enabled by default, it can be enabled,
     for example, by randconfig what will lead to CI build issues.

Note that I keep __XEN_PERFC_DEFN_H__ as other archictectures use the same,
not something like ASM__<arch>__PERFC_DEFN_H.

Let me know if these changes are okay for you and if I can keep your
Acked-by for this patch.

~ Oleksii
Re: [PATCH v2 09/16] xen/riscv: introduce vcpu_kick() implementation
Posted by Jan Beulich 5 months ago 
On 09.02.2026 10:40, Oleksii Kurochko wrote:
> 
> On 2/9/26 10:07 AM, Jan Beulich wrote:
>> On 06.02.2026 17:36, Oleksii Kurochko wrote:
>>> On 1/22/26 5:47 PM, Oleksii Kurochko wrote:
>>>> Add a RISC-V implementation of vcpu_kick(), which unblocks the target
>>>> vCPU and sends an event check IPI if the vCPU was running on another
>>>> processor. This mirrors the behavior of Arm and enables proper vCPU
>>>> wakeup handling on RISC-V.
>>>>
>>>> Remove the stub implementation from stubs.c, as it is now provided by
>>>> arch/riscv/domain.c.
>>>>
>>>> Signed-off-by: Oleksii Kurochko <oleksii.kurochko@gmail.com>
>>>> Acked-by: Jan Beulich <jbeulich@suse.com>
>>>> ---
>>>> Changes in v2:
>>>>    - Add Acked-by: Jan Beulich <jbeulich@suse.com>.
>>>> ---
>>>>    xen/arch/riscv/domain.c | 14 ++++++++++++++
>>>>    xen/arch/riscv/stubs.c  |  5 -----
>>>>    2 files changed, 14 insertions(+), 5 deletions(-)
>>>>
>>>> diff --git a/xen/arch/riscv/domain.c b/xen/arch/riscv/domain.c
>>>> index e38c0db62cac..13ac384c4b76 100644
>>>> --- a/xen/arch/riscv/domain.c
>>>> +++ b/xen/arch/riscv/domain.c
>>>> @@ -1,8 +1,10 @@
>>>>    /* SPDX-License-Identifier: GPL-2.0-only */
>>>>    
>>>> +#include <xen/cpumask.h>
>>>>    #include <xen/init.h>
>>>>    #include <xen/mm.h>
>>>>    #include <xen/sched.h>
>>>> +#include <xen/smp.h>
>>>>    #include <xen/vmap.h>
>>>>    
>>>>    #include <asm/bitops.h>
>>>> @@ -240,3 +242,15 @@ void vcpu_sync_interrupts(struct vcpu *v)
>>>>    #   error "Update vsieh"
>>>>    #endif
>>>>    }
>>>> +
>>>> +void vcpu_kick(struct vcpu *v)
>>>> +{
>>>> +    bool running = v->is_running;
>>>> +
>>>> +    vcpu_unblock(v);
>>>> +    if ( running && v != current )
>>>> +    {
>>>> +        perfc_incr(vcpu_kick);
>>> Because of this it is needed to introduce:
>>>     PERFCOUNTER(vcpu_kick, "vcpu: notify other vcpu")
>>> Otherwise randconfig build will fail when CONFIG_PERF_COUNTERS=y.
>>>
>>> I would like to ask if it would be okay to add it xen/include/xen/perfc_defn.h
>>> just after PERFCOUNTER(need_flush_tlb_flush,...) or would it be better to have
>>> it in arch specific perfc_defn.h?
>> Arch-specific please - it's not used by x86 nor ppc.
> 
> Then I will do the following changes:
> 
> diff --git a/xen/arch/riscv/include/asm/Makefile b/xen/arch/riscv/include/asm/Makefile
> index 3824f31c395c..86c56251d5d7 100644
> --- a/xen/arch/riscv/include/asm/Makefile
> +++ b/xen/arch/riscv/include/asm/Makefile
> @@ -7,7 +7,6 @@ generic-y += hypercall.h
>   generic-y += iocap.h
>   generic-y += irq-dt.h
>   generic-y += percpu.h
> -generic-y += perfc_defn.h
>   generic-y += random.h
>   generic-y += softirq.h
>   generic-y += vm_event.h
> diff --git a/xen/arch/riscv/include/asm/perfc_defn.h b/xen/arch/riscv/include/asm/perfc_defn.h
> new file mode 100644
> index 000000000000..4fc161f1abad
> --- /dev/null
> +++ b/xen/arch/riscv/include/asm/perfc_defn.h
> @@ -0,0 +1,7 @@
> +/* This file is intended to be included multiple times. */
> +/*#ifndef __XEN_PERFC_DEFN_H__*/
> +/*#define __XEN_PERFC_DEFN_H__*/
> +
> +PERFCOUNTER(vcpu_kick, "vcpu: notify other vcpu")
> +
> +/*#endif*/ /* __XEN_PERFC_DEFN_H__ */
> 
> and add the following to commit message:
>      Since vcpu_kick() calls perfc_incr(vcpu_kick), add perfcounter for
>      vcpu_kick to handle the case when CONFIG_PERF_COUNTERS=y. Although
>      CONFIG_PERF_COUNTERS is not enabled by default, it can be enabled,
>      for example, by randconfig what will lead to CI build issues.
> 
> Note that I keep __XEN_PERFC_DEFN_H__ as other archictectures use the same,
> not something like ASM__<arch>__PERFC_DEFN_H.

Please don't copy this mistake. I actually question the commented-out pre-
processor directives altogether: Misra also has a rule against commented-
out code (directive 4.4, which we didn't accept [yet], but which exists
nevertheless). Yet at the very least what's commented out should not be
obviously wrong.

Jan
Re: [PATCH v2 09/16] xen/riscv: introduce vcpu_kick() implementation
Posted by Oleksii Kurochko 5 months ago 
On 2/9/26 10:51 AM, Jan Beulich wrote:
> On 09.02.2026 10:40, Oleksii Kurochko wrote:
>> On 2/9/26 10:07 AM, Jan Beulich wrote:
>>> On 06.02.2026 17:36, Oleksii Kurochko wrote:
>>>> On 1/22/26 5:47 PM, Oleksii Kurochko wrote:
>>>>> Add a RISC-V implementation of vcpu_kick(), which unblocks the target
>>>>> vCPU and sends an event check IPI if the vCPU was running on another
>>>>> processor. This mirrors the behavior of Arm and enables proper vCPU
>>>>> wakeup handling on RISC-V.
>>>>>
>>>>> Remove the stub implementation from stubs.c, as it is now provided by
>>>>> arch/riscv/domain.c.
>>>>>
>>>>> Signed-off-by: Oleksii Kurochko <oleksii.kurochko@gmail.com>
>>>>> Acked-by: Jan Beulich <jbeulich@suse.com>
>>>>> ---
>>>>> Changes in v2:
>>>>>     - Add Acked-by: Jan Beulich <jbeulich@suse.com>.
>>>>> ---
>>>>>     xen/arch/riscv/domain.c | 14 ++++++++++++++
>>>>>     xen/arch/riscv/stubs.c  |  5 -----
>>>>>     2 files changed, 14 insertions(+), 5 deletions(-)
>>>>>
>>>>> diff --git a/xen/arch/riscv/domain.c b/xen/arch/riscv/domain.c
>>>>> index e38c0db62cac..13ac384c4b76 100644
>>>>> --- a/xen/arch/riscv/domain.c
>>>>> +++ b/xen/arch/riscv/domain.c
>>>>> @@ -1,8 +1,10 @@
>>>>>     /* SPDX-License-Identifier: GPL-2.0-only */
>>>>>     
>>>>> +#include <xen/cpumask.h>
>>>>>     #include <xen/init.h>
>>>>>     #include <xen/mm.h>
>>>>>     #include <xen/sched.h>
>>>>> +#include <xen/smp.h>
>>>>>     #include <xen/vmap.h>
>>>>>     
>>>>>     #include <asm/bitops.h>
>>>>> @@ -240,3 +242,15 @@ void vcpu_sync_interrupts(struct vcpu *v)
>>>>>     #   error "Update vsieh"
>>>>>     #endif
>>>>>     }
>>>>> +
>>>>> +void vcpu_kick(struct vcpu *v)
>>>>> +{
>>>>> +    bool running = v->is_running;
>>>>> +
>>>>> +    vcpu_unblock(v);
>>>>> +    if ( running && v != current )
>>>>> +    {
>>>>> +        perfc_incr(vcpu_kick);
>>>> Because of this it is needed to introduce:
>>>>      PERFCOUNTER(vcpu_kick, "vcpu: notify other vcpu")
>>>> Otherwise randconfig build will fail when CONFIG_PERF_COUNTERS=y.
>>>>
>>>> I would like to ask if it would be okay to add it xen/include/xen/perfc_defn.h
>>>> just after PERFCOUNTER(need_flush_tlb_flush,...) or would it be better to have
>>>> it in arch specific perfc_defn.h?
>>> Arch-specific please - it's not used by x86 nor ppc.
>> Then I will do the following changes:
>>
>> diff --git a/xen/arch/riscv/include/asm/Makefile b/xen/arch/riscv/include/asm/Makefile
>> index 3824f31c395c..86c56251d5d7 100644
>> --- a/xen/arch/riscv/include/asm/Makefile
>> +++ b/xen/arch/riscv/include/asm/Makefile
>> @@ -7,7 +7,6 @@ generic-y += hypercall.h
>>    generic-y += iocap.h
>>    generic-y += irq-dt.h
>>    generic-y += percpu.h
>> -generic-y += perfc_defn.h
>>    generic-y += random.h
>>    generic-y += softirq.h
>>    generic-y += vm_event.h
>> diff --git a/xen/arch/riscv/include/asm/perfc_defn.h b/xen/arch/riscv/include/asm/perfc_defn.h
>> new file mode 100644
>> index 000000000000..4fc161f1abad
>> --- /dev/null
>> +++ b/xen/arch/riscv/include/asm/perfc_defn.h
>> @@ -0,0 +1,7 @@
>> +/* This file is intended to be included multiple times. */
>> +/*#ifndef __XEN_PERFC_DEFN_H__*/
>> +/*#define __XEN_PERFC_DEFN_H__*/
>> +
>> +PERFCOUNTER(vcpu_kick, "vcpu: notify other vcpu")
>> +
>> +/*#endif*/ /* __XEN_PERFC_DEFN_H__ */
>>
>> and add the following to commit message:
>>       Since vcpu_kick() calls perfc_incr(vcpu_kick), add perfcounter for
>>       vcpu_kick to handle the case when CONFIG_PERF_COUNTERS=y. Although
>>       CONFIG_PERF_COUNTERS is not enabled by default, it can be enabled,
>>       for example, by randconfig what will lead to CI build issues.
>>
>> Note that I keep __XEN_PERFC_DEFN_H__ as other archictectures use the same,
>> not something like ASM__<arch>__PERFC_DEFN_H.
> Please don't copy this mistake. I actually question the commented-out pre-
> processor directives altogether: Misra also has a rule against commented-
> out code (directive 4.4, which we didn't accept [yet], but which exists
> nevertheless). Yet at the very least what's commented out should not be
> obviously wrong.

Do I understand correctly that it would be acceptable to simply drop the
commented-out preprocessor directives and keep only /* This file is intended
to be included multiple times. */ ?

~ Oleksii
Re: [PATCH v2 09/16] xen/riscv: introduce vcpu_kick() implementation
Posted by Jan Beulich 5 months ago 
On 09.02.2026 13:35, Oleksii Kurochko wrote:
> On 2/9/26 10:51 AM, Jan Beulich wrote:
>> On 09.02.2026 10:40, Oleksii Kurochko wrote:
>>> On 2/9/26 10:07 AM, Jan Beulich wrote:
>>>> On 06.02.2026 17:36, Oleksii Kurochko wrote:
>>>>> On 1/22/26 5:47 PM, Oleksii Kurochko wrote:
>>>>>> Add a RISC-V implementation of vcpu_kick(), which unblocks the target
>>>>>> vCPU and sends an event check IPI if the vCPU was running on another
>>>>>> processor. This mirrors the behavior of Arm and enables proper vCPU
>>>>>> wakeup handling on RISC-V.
>>>>>>
>>>>>> Remove the stub implementation from stubs.c, as it is now provided by
>>>>>> arch/riscv/domain.c.
>>>>>>
>>>>>> Signed-off-by: Oleksii Kurochko <oleksii.kurochko@gmail.com>
>>>>>> Acked-by: Jan Beulich <jbeulich@suse.com>
>>>>>> ---
>>>>>> Changes in v2:
>>>>>>     - Add Acked-by: Jan Beulich <jbeulich@suse.com>.
>>>>>> ---
>>>>>>     xen/arch/riscv/domain.c | 14 ++++++++++++++
>>>>>>     xen/arch/riscv/stubs.c  |  5 -----
>>>>>>     2 files changed, 14 insertions(+), 5 deletions(-)
>>>>>>
>>>>>> diff --git a/xen/arch/riscv/domain.c b/xen/arch/riscv/domain.c
>>>>>> index e38c0db62cac..13ac384c4b76 100644
>>>>>> --- a/xen/arch/riscv/domain.c
>>>>>> +++ b/xen/arch/riscv/domain.c
>>>>>> @@ -1,8 +1,10 @@
>>>>>>     /* SPDX-License-Identifier: GPL-2.0-only */
>>>>>>     
>>>>>> +#include <xen/cpumask.h>
>>>>>>     #include <xen/init.h>
>>>>>>     #include <xen/mm.h>
>>>>>>     #include <xen/sched.h>
>>>>>> +#include <xen/smp.h>
>>>>>>     #include <xen/vmap.h>
>>>>>>     
>>>>>>     #include <asm/bitops.h>
>>>>>> @@ -240,3 +242,15 @@ void vcpu_sync_interrupts(struct vcpu *v)
>>>>>>     #   error "Update vsieh"
>>>>>>     #endif
>>>>>>     }
>>>>>> +
>>>>>> +void vcpu_kick(struct vcpu *v)
>>>>>> +{
>>>>>> +    bool running = v->is_running;
>>>>>> +
>>>>>> +    vcpu_unblock(v);
>>>>>> +    if ( running && v != current )
>>>>>> +    {
>>>>>> +        perfc_incr(vcpu_kick);
>>>>> Because of this it is needed to introduce:
>>>>>      PERFCOUNTER(vcpu_kick, "vcpu: notify other vcpu")
>>>>> Otherwise randconfig build will fail when CONFIG_PERF_COUNTERS=y.
>>>>>
>>>>> I would like to ask if it would be okay to add it xen/include/xen/perfc_defn.h
>>>>> just after PERFCOUNTER(need_flush_tlb_flush,...) or would it be better to have
>>>>> it in arch specific perfc_defn.h?
>>>> Arch-specific please - it's not used by x86 nor ppc.
>>> Then I will do the following changes:
>>>
>>> diff --git a/xen/arch/riscv/include/asm/Makefile b/xen/arch/riscv/include/asm/Makefile
>>> index 3824f31c395c..86c56251d5d7 100644
>>> --- a/xen/arch/riscv/include/asm/Makefile
>>> +++ b/xen/arch/riscv/include/asm/Makefile
>>> @@ -7,7 +7,6 @@ generic-y += hypercall.h
>>>    generic-y += iocap.h
>>>    generic-y += irq-dt.h
>>>    generic-y += percpu.h
>>> -generic-y += perfc_defn.h
>>>    generic-y += random.h
>>>    generic-y += softirq.h
>>>    generic-y += vm_event.h
>>> diff --git a/xen/arch/riscv/include/asm/perfc_defn.h b/xen/arch/riscv/include/asm/perfc_defn.h
>>> new file mode 100644
>>> index 000000000000..4fc161f1abad
>>> --- /dev/null
>>> +++ b/xen/arch/riscv/include/asm/perfc_defn.h
>>> @@ -0,0 +1,7 @@
>>> +/* This file is intended to be included multiple times. */
>>> +/*#ifndef __XEN_PERFC_DEFN_H__*/
>>> +/*#define __XEN_PERFC_DEFN_H__*/
>>> +
>>> +PERFCOUNTER(vcpu_kick, "vcpu: notify other vcpu")
>>> +
>>> +/*#endif*/ /* __XEN_PERFC_DEFN_H__ */
>>>
>>> and add the following to commit message:
>>>       Since vcpu_kick() calls perfc_incr(vcpu_kick), add perfcounter for
>>>       vcpu_kick to handle the case when CONFIG_PERF_COUNTERS=y. Although
>>>       CONFIG_PERF_COUNTERS is not enabled by default, it can be enabled,
>>>       for example, by randconfig what will lead to CI build issues.
>>>
>>> Note that I keep __XEN_PERFC_DEFN_H__ as other archictectures use the same,
>>> not something like ASM__<arch>__PERFC_DEFN_H.
>> Please don't copy this mistake. I actually question the commented-out pre-
>> processor directives altogether: Misra also has a rule against commented-
>> out code (directive 4.4, which we didn't accept [yet], but which exists
>> nevertheless). Yet at the very least what's commented out should not be
>> obviously wrong.
> 
> Do I understand correctly that it would be acceptable to simply drop the
> commented-out preprocessor directives and keep only /* This file is intended
> to be included multiple times. */ ?

I think so, yes. You could simply check how the same situation is covered
for elsewhere.

Jan

Patchew 2.1-devel-ea86937

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