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

[Oleksii Kurochko <oleksii.kurochko@xxxxxxxxx>]

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@xxxxxxxxx>
> > > Acked-by: Jan Beulich <jbeulich@xxxxxxxx>
> > > ---
> > > Changes in v2:
> > >    - Add Acked-by: Jan Beulich <jbeulich@xxxxxxxx>.
> > > ---
> > >    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