Hi Nick, > From: Nicholas Piggin <npig...@gmail.com> > Sent: Monday, May 20, 2024 9:04 AM > To: Salil Mehta <salil.me...@huawei.com>; qemu-devel@nongnu.org; > qemu-...@nongnu.org > > On Mon May 20, 2024 at 7:06 AM AEST, Salil Mehta 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 instead of DPRINTF. No functional > change is intended here. > > This is a nice cleanup and helps with ppc hotplug as well.
Thanks and glad that it is of help. > > Has there been any architecture code posted yet? Yes, I created one in April/early May. It contains arch specific patch-set stacked up on the arch agnostic patch-set V8. Arch specific patch-set contains patches from the RFC V2 I floated last year. https://github.com/salil-mehta/qemu/commits/virt-cpuhp-armv8/rfc-v3-rc1/ As such, a complete code of RFC V2 was posted last year. There is no clear separation of architecture agnostic and specific patch-set in this version. and can be found at below repository. https://lore.kernel.org/qemu-devel/20230926100436.28284-1-salil.me...@huawei.com/ I shall be floating RFC V3 soon which will have only ARM architecture specific part and yes will also have TCG code but there are some issues to be fixed for TCG and we are working towards it. Hence, we have disabled TCG by default for now. Thanks Salil. > > Just a few minor thing: > > > > > 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> > > --- > > accel/kvm/kvm-all.c | 64 ++++++++++++++++++++++++++++++++------ > ---- > > accel/kvm/kvm-cpus.h | 14 +++++++++ > > accel/kvm/trace-events | 5 +++- > > 3 files changed, 67 insertions(+), 16 deletions(-) > > > > diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c index > > c0be9f5eed..9cd7d69bde 100644 > > --- a/accel/kvm/kvm-all.c > > +++ b/accel/kvm/kvm-all.c > > @@ -128,6 +128,7 @@ static QemuMutex kml_slots_lock; #define > > kvm_slots_unlock() qemu_mutex_unlock(&kml_slots_lock) > > > > static void kvm_slot_init_dirty_bitmap(KVMSlot *mem); > > +static int kvm_get_vcpu(KVMState *s, unsigned long vcpu_id); > > > > static inline void kvm_resample_fd_remove(int gsi) { @@ -340,14 > > +341,53 @@ 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); } > > Could you move kvm_get_vcpu up here so it's next to kvm_park_vcpu, and > then you don't need to forward declare it. Call it kvm_unpark_vcpu() for > symmetry with park. > > Thanks, > Nick
