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[213.175.37.10]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-36789a02631sm11590075f8f.1.2024.07.06.06.11.55 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 06 Jul 2024 06:11:56 -0700 (PDT) Date: Sat, 6 Jul 2024 15:11:54 +0200 From: Igor Mammedov To: Salil Mehta Cc: , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , Shaoqin Huang , Zhao Liu Subject: Re: [PATCH V13 1/8] accel/kvm: Extract common KVM vCPU {creation,parking} code Message-ID: <20240706151154.7c430b0a@imammedo.users.ipa.redhat.com> In-Reply-To: <20240607115649.214622-2-salil.mehta@huawei.com> References: <20240607115649.214622-1-salil.mehta@huawei.com> <20240607115649.214622-2-salil.mehta@huawei.com> X-Mailer: Claws Mail 4.2.0 (GTK 3.24.42; x86_64-redhat-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Received-SPF: pass client-ip=170.10.133.124; envelope-from=imammedo@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org On Fri, 7 Jun 2024 12:56:42 +0100 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. No functional change is intended here. > > Signed-off-by: Salil Mehta > Reviewed-by: Gavin Shan > Tested-by: Vishnu Pajjuri > Reviewed-by: Jonathan Cameron > Tested-by: Xianglai Li > Tested-by: Miguel Luis > Reviewed-by: Shaoqin Huang > Reviewed-by: Vishnu Pajjuri > Reviewed-by: Nicholas Piggin > Tested-by: Zhao Liu > Reviewed-by: Zhao Liu > Reviewed-by: Harsh Prateek Bora > --- > 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 c0be9f5eed..8f9128bb92 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; > +} Is there any reason why you are embedding/hiding kvm_state in new API instead of passing it as argument (all callers have it defined, so why not reuse that)? otherwise patch lgtm > + > 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[];