> From: Igor Mammedov <imamm...@redhat.com>
> Sent: Monday, July 15, 2024 2:28 PM
> To: Salil Mehta <salil.me...@huawei.com>
>
> On Mon, 15 Jul 2024 14:49:25 +0200
> Igor Mammedov <imamm...@redhat.com> wrote:
>
> > On Sat, 13 Jul 2024 19:25:10 +0100
> > Salil Mehta <salil.me...@huawei.com> wrote:
> >
> > > KVM vCPU creation is done once during the vCPU realization when Qemu
> > > vCPU thread is spawned. This is common to all the architectures as of
> now.
> > >
> > > Hot-unplug of vCPU results in destruction of the vCPU object in QOM
> > > but the corresponding KVM vCPU object in the Host KVM is not
> > > destroyed as KVM doesn't support vCPU removal. Therefore, its
> > > representative KVM vCPU object/context in Qemu is parked.
> > >
> > > Refactor architecture common logic so that some APIs could be reused
> > > by vCPU Hotplug code of some architectures likes ARM, Loongson etc.
> > > Update new/old APIs with trace events. New APIs
> > > qemu_{create,park,unpark}_vcpu() can be externally called. No
> functional change is intended here.
> > >
> > > Signed-off-by: Salil Mehta <salil.me...@huawei.com>
> > > Reviewed-by: Gavin Shan <gs...@redhat.com>
> > > Tested-by: Vishnu Pajjuri <vis...@os.amperecomputing.com>
> > > Reviewed-by: Jonathan Cameron <jonathan.came...@huawei.com>
> > > Tested-by: Xianglai Li <lixiang...@loongson.cn>
> > > Tested-by: Miguel Luis <miguel.l...@oracle.com>
> > > Reviewed-by: Shaoqin Huang <shahu...@redhat.com>
> > > Reviewed-by: Vishnu Pajjuri <vis...@os.amperecomputing.com>
> > > Reviewed-by: Nicholas Piggin <npig...@gmail.com>
> > > Tested-by: Zhao Liu <zhao1....@intel.com>
> > > Reviewed-by: Zhao Liu <zhao1....@intel.com>
> > > Reviewed-by: Harsh Prateek Bora <hars...@linux.ibm.com>
> >
> > Reviewed-by: Igor Mammedov <imamm...@redhat.com>
>
> this needs fixing, to make checkpatch happy
>
> Checking 0001-accel-kvm-Extract-common-KVM-vCPU-creation-parking-
> c.patch...
> WARNING: line over 80 characters
> #120: FILE: accel/kvm/kvm-all.c:368:
> + trace_kvm_unpark_vcpu(vcpu_id, kvm_fd > 0 ? "unparked" : "not found
> + parked");
Thanks. I will fix this as well.
>
> total: 0 errors, 1 warnings, 183 lines checked
>
> >
> > > ---
> > > accel/kvm/kvm-all.c | 95 ++++++++++++++++++++++++++++----------
> ----
> > > accel/kvm/kvm-cpus.h | 1 -
> > > accel/kvm/trace-events | 5 ++-
> > > include/sysemu/kvm.h | 25 +++++++++++
> > > 4 files changed, 92 insertions(+), 34 deletions(-)
> > >
> > > diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c index
> > > 2b4ab89679..e446d18944 100644
> > > --- a/accel/kvm/kvm-all.c
> > > +++ b/accel/kvm/kvm-all.c
> > > @@ -340,14 +340,71 @@ err:
> > > return ret;
> > > }
> > >
> > > +void kvm_park_vcpu(CPUState *cpu)
> > > +{
> > > + struct KVMParkedVcpu *vcpu;
> > > +
> > > + trace_kvm_park_vcpu(cpu->cpu_index, kvm_arch_vcpu_id(cpu));
> > > +
> > > + vcpu = g_malloc0(sizeof(*vcpu));
> > > + vcpu->vcpu_id = kvm_arch_vcpu_id(cpu);
> > > + vcpu->kvm_fd = cpu->kvm_fd;
> > > + QLIST_INSERT_HEAD(&kvm_state->kvm_parked_vcpus, vcpu,
> node); }
> > > +
> > > +int kvm_unpark_vcpu(KVMState *s, unsigned long vcpu_id) {
> > > + struct KVMParkedVcpu *cpu;
> > > + int kvm_fd = -ENOENT;
> > > +
> > > + QLIST_FOREACH(cpu, &s->kvm_parked_vcpus, node) {
> > > + if (cpu->vcpu_id == vcpu_id) {
> > > + QLIST_REMOVE(cpu, node);
> > > + kvm_fd = cpu->kvm_fd;
> > > + g_free(cpu);
> > > + }
> > > + }
> > > +
> > > + trace_kvm_unpark_vcpu(vcpu_id, kvm_fd > 0 ? "unparked" : "not
> > > + found parked");
> > > +
> > > + return kvm_fd;
> > > +}
> > > +
> > > +int kvm_create_vcpu(CPUState *cpu)
> > > +{
> > > + unsigned long vcpu_id = kvm_arch_vcpu_id(cpu);
> > > + KVMState *s = kvm_state;
> > > + int kvm_fd;
> > > +
> > > + /* check if the KVM vCPU already exist but is parked */
> > > + kvm_fd = kvm_unpark_vcpu(s, vcpu_id);
> > > + if (kvm_fd < 0) {
> > > + /* vCPU not parked: create a new KVM vCPU */
> > > + kvm_fd = kvm_vm_ioctl(s, KVM_CREATE_VCPU, vcpu_id);
> > > + if (kvm_fd < 0) {
> > > + error_report("KVM_CREATE_VCPU IOCTL failed for vCPU %lu",
> vcpu_id);
> > > + return kvm_fd;
> > > + }
> > > + }
> > > +
> > > + cpu->kvm_fd = kvm_fd;
> > > + cpu->kvm_state = s;
> > > + cpu->vcpu_dirty = true;
> > > + cpu->dirty_pages = 0;
> > > + cpu->throttle_us_per_full = 0;
> > > +
> > > + trace_kvm_create_vcpu(cpu->cpu_index, vcpu_id, kvm_fd);
> > > +
> > > + return 0;
> > > +}
> > > +
> > > static int do_kvm_destroy_vcpu(CPUState *cpu) {
> > > KVMState *s = kvm_state;
> > > long mmap_size;
> > > - struct KVMParkedVcpu *vcpu = NULL;
> > > int ret = 0;
> > >
> > > - trace_kvm_destroy_vcpu();
> > > + trace_kvm_destroy_vcpu(cpu->cpu_index,
> kvm_arch_vcpu_id(cpu));
> > >
> > > ret = kvm_arch_destroy_vcpu(cpu);
> > > if (ret < 0) {
> > > @@ -373,10 +430,7 @@ static int do_kvm_destroy_vcpu(CPUState
> *cpu)
> > > }
> > > }
> > >
> > > - vcpu = g_malloc0(sizeof(*vcpu));
> > > - vcpu->vcpu_id = kvm_arch_vcpu_id(cpu);
> > > - vcpu->kvm_fd = cpu->kvm_fd;
> > > - QLIST_INSERT_HEAD(&kvm_state->kvm_parked_vcpus, vcpu, node);
> > > + kvm_park_vcpu(cpu);
> > > err:
> > > return ret;
> > > }
> > > @@ -389,24 +443,6 @@ void kvm_destroy_vcpu(CPUState *cpu)
> > > }
> > > }
> > >
> > > -static int kvm_get_vcpu(KVMState *s, unsigned long vcpu_id) -{
> > > - struct KVMParkedVcpu *cpu;
> > > -
> > > - QLIST_FOREACH(cpu, &s->kvm_parked_vcpus, node) {
> > > - if (cpu->vcpu_id == vcpu_id) {
> > > - int kvm_fd;
> > > -
> > > - QLIST_REMOVE(cpu, node);
> > > - kvm_fd = cpu->kvm_fd;
> > > - g_free(cpu);
> > > - return kvm_fd;
> > > - }
> > > - }
> > > -
> > > - return kvm_vm_ioctl(s, KVM_CREATE_VCPU, (void *)vcpu_id);
> > > -}
> > > -
> > > int kvm_init_vcpu(CPUState *cpu, Error **errp) {
> > > KVMState *s = kvm_state;
> > > @@ -415,19 +451,14 @@ int kvm_init_vcpu(CPUState *cpu, Error
> **errp)
> > >
> > > trace_kvm_init_vcpu(cpu->cpu_index, kvm_arch_vcpu_id(cpu));
> > >
> > > - ret = kvm_get_vcpu(s, kvm_arch_vcpu_id(cpu));
> > > + ret = kvm_create_vcpu(cpu);
> > > if (ret < 0) {
> > > - error_setg_errno(errp, -ret, "kvm_init_vcpu: kvm_get_vcpu failed
> (%lu)",
> > > + error_setg_errno(errp, -ret,
> > > + "kvm_init_vcpu: kvm_create_vcpu failed
> > > + (%lu)",
> > > kvm_arch_vcpu_id(cpu));
> > > goto err;
> > > }
> > >
> > > - cpu->kvm_fd = ret;
> > > - cpu->kvm_state = s;
> > > - cpu->vcpu_dirty = true;
> > > - cpu->dirty_pages = 0;
> > > - cpu->throttle_us_per_full = 0;
> > > -
> > > mmap_size = kvm_ioctl(s, KVM_GET_VCPU_MMAP_SIZE, 0);
> > > if (mmap_size < 0) {
> > > ret = mmap_size;
> > > diff --git a/accel/kvm/kvm-cpus.h b/accel/kvm/kvm-cpus.h index
> > > ca40add32c..171b22fd29 100644
> > > --- a/accel/kvm/kvm-cpus.h
> > > +++ b/accel/kvm/kvm-cpus.h
> > > @@ -22,5 +22,4 @@ bool kvm_supports_guest_debug(void); int
> > > kvm_insert_breakpoint(CPUState *cpu, int type, vaddr addr, vaddr
> > > len); int kvm_remove_breakpoint(CPUState *cpu, int type, vaddr
> > > addr, vaddr len); void kvm_remove_all_breakpoints(CPUState *cpu);
> > > -
> > > #endif /* KVM_CPUS_H */
> > > diff --git a/accel/kvm/trace-events b/accel/kvm/trace-events index
> > > 681ccb667d..37626c1ac5 100644
> > > --- a/accel/kvm/trace-events
> > > +++ b/accel/kvm/trace-events
> > > @@ -9,6 +9,10 @@ kvm_device_ioctl(int fd, int type, void *arg) "dev fd
> %d, type 0x%x, arg %p"
> > > kvm_failed_reg_get(uint64_t id, const char *msg) "Warning: Unable to
> retrieve ONEREG %" PRIu64 " from KVM: %s"
> > > kvm_failed_reg_set(uint64_t id, const char *msg) "Warning: Unable to
> set ONEREG %" PRIu64 " to KVM: %s"
> > > kvm_init_vcpu(int cpu_index, unsigned long arch_cpu_id) "index: %d
> id: %lu"
> > > +kvm_create_vcpu(int cpu_index, unsigned long arch_cpu_id, int
> kvm_fd) "index: %d, id: %lu, kvm fd: %d"
> > > +kvm_destroy_vcpu(int cpu_index, unsigned long arch_cpu_id) "index:
> %d id: %lu"
> > > +kvm_park_vcpu(int cpu_index, unsigned long arch_cpu_id) "index: %d
> id: %lu"
> > > +kvm_unpark_vcpu(unsigned long arch_cpu_id, const char *msg) "id:
> %lu %s"
> > > kvm_irqchip_commit_routes(void) ""
> > > kvm_irqchip_add_msi_route(char *name, int vector, int virq) "dev %s
> vector %d virq %d"
> > > kvm_irqchip_update_msi_route(int virq) "Updating MSI route virq=%d"
> > > @@ -25,7 +29,6 @@ kvm_dirty_ring_reaper(const char *s) "%s"
> > > kvm_dirty_ring_reap(uint64_t count, int64_t t) "reaped %"PRIu64"
> pages (took %"PRIi64" us)"
> > > kvm_dirty_ring_reaper_kick(const char *reason) "%s"
> > > kvm_dirty_ring_flush(int finished) "%d"
> > > -kvm_destroy_vcpu(void) ""
> > > kvm_failed_get_vcpu_mmap_size(void) ""
> > > kvm_cpu_exec(void) ""
> > > kvm_interrupt_exit_request(void) ""
> > > diff --git a/include/sysemu/kvm.h b/include/sysemu/kvm.h index
> > > c31d9c7356..c4a914b3d8 100644
> > > --- a/include/sysemu/kvm.h
> > > +++ b/include/sysemu/kvm.h
> > > @@ -313,6 +313,31 @@ int kvm_create_device(KVMState *s, uint64_t
> type, bool test);
> > > */
> > > bool kvm_device_supported(int vmfd, uint64_t type);
> > >
> > > +/**
> > > + * kvm_create_vcpu - Gets a parked KVM vCPU or creates a KVM vCPU
> > > + * @cpu: QOM CPUState object for which KVM vCPU has to be
> fetched/created.
> > > + *
> > > + * @returns: 0 when success, errno (<0) when failed.
> > > + */
> > > +int kvm_create_vcpu(CPUState *cpu);
> > > +
> > > +/**
> > > + * kvm_park_vcpu - Park QEMU KVM vCPU context
> > > + * @cpu: QOM CPUState object for which QEMU KVM vCPU context
> has to be parked.
> > > + *
> > > + * @returns: none
> > > + */
> > > +void kvm_park_vcpu(CPUState *cpu);
> > > +
> > > +/**
> > > + * kvm_unpark_vcpu - unpark QEMU KVM vCPU context
> > > + * @s: KVM State
> > > + * @vcpu_id: Architecture vCPU ID of the parked vCPU
> > > + *
> > > + * @returns: KVM fd
> > > + */
> > > +int kvm_unpark_vcpu(KVMState *s, unsigned long vcpu_id);
> > > +
> > > /* Arch specific hooks */
> > >
> > > extern const KVMCapabilityInfo kvm_arch_required_capabilities[];
> >
>
