From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id A52AAE784BE for ; Mon, 2 Oct 2023 15:53:47 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1qnLEr-0006cx-7g; Mon, 02 Oct 2023 11:53:42 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1qnLEh-00068I-Bj; Mon, 02 Oct 2023 11:53:31 -0400 Received: from frasgout.his.huawei.com ([185.176.79.56]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1qnLEe-0006Bt-DE; Mon, 02 Oct 2023 11:53:31 -0400 Received: from lhrpeml500005.china.huawei.com (unknown [172.18.147.201]) by frasgout.his.huawei.com (SkyGuard) with ESMTP id 4Rzlm61kfJz6HJZM; Mon, 2 Oct 2023 23:50:46 +0800 (CST) Received: from localhost (10.202.227.76) by lhrpeml500005.china.huawei.com (7.191.163.240) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.31; Mon, 2 Oct 2023 16:53:23 +0100 Date: Mon, 2 Oct 2023 16:53:22 +0100 To: Salil Mehta CC: , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , Subject: Re: [PATCH V2 01/10] accel/kvm: Extract common KVM vCPU {creation,parking} code Message-ID: <20231002165322.00003a2e@Huawei.com> In-Reply-To: <20230930001933.2660-2-salil.mehta@huawei.com> References: <20230930001933.2660-1-salil.mehta@huawei.com> <20230930001933.2660-2-salil.mehta@huawei.com> Organization: Huawei Technologies Research and Development (UK) Ltd. X-Mailer: Claws Mail 4.1.0 (GTK 3.24.33; x86_64-w64-mingw32) MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.202.227.76] X-ClientProxiedBy: lhrpeml100006.china.huawei.com (7.191.160.224) To lhrpeml500005.china.huawei.com (7.191.163.240) X-CFilter-Loop: Reflected Received-SPF: pass client-ip=185.176.79.56; envelope-from=jonathan.cameron@huawei.com; helo=frasgout.his.huawei.com X-Spam_score_int: -41 X-Spam_score: -4.2 X-Spam_bar: ---- X-Spam_report: (-4.2 / 5.0 requ) BAYES_00=-1.9, RCVD_IN_DNSWL_MED=-2.3, RCVD_IN_MSPIKE_H5=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: , Reply-to: Jonathan Cameron From: Jonathan Cameron via Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org On Sat, 30 Sep 2023 01:19:24 +0100 Salil Mehta wrote: > KVM vCPU creation is done once during the initialization of the VM when Qemu > threads are spawned. This is common to all the architectures. > > Hot-unplug of vCPU results in destruction of the vCPU objects in QOM but > the KVM vCPU objects in the Host KVM are not destroyed and their representative > KVM vCPU objects/context in Qemu are parked. > > Refactor common logic so that some APIs could be reused by vCPU Hotplug code. > > Signed-off-by: Salil Mehta Hi Salil, A few trivial things inline, plus a question about why cpu->cpu_index can now be used but kvm_arch_vcpu_id(cpu); was previously needed. Thanks, Jonathan > --- > accel/kvm/kvm-all.c | 63 +++++++++++++++++++++++++++++++++----------- > include/sysemu/kvm.h | 14 ++++++++++ > 2 files changed, 61 insertions(+), 16 deletions(-) > > diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c > index ff1578bb32..b8c36ba50a 100644 > --- a/accel/kvm/kvm-all.c > +++ b/accel/kvm/kvm-all.c > @@ -80,7 +80,7 @@ > #endif > > struct KVMParkedVcpu { > - unsigned long vcpu_id; > + int vcpu_id; > int kvm_fd; > QLIST_ENTRY(KVMParkedVcpu) node; > }; > @@ -137,6 +137,7 @@ 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, int vcpu_id); > > static inline void kvm_resample_fd_remove(int gsi) > { > @@ -320,11 +321,49 @@ err: > return ret; > } > > +void kvm_park_vcpu(CPUState *cpu) > +{ > + int vcpu_id = cpu->cpu_index; > + struct KVMParkedVcpu *vcpu; > + > + vcpu = g_malloc0(sizeof(*vcpu)); > + vcpu->vcpu_id = vcpu_id; As vcpu_id is only used here why have the local variable? Maybe that changes in later patches, in which case ignore this. vcpu->vcpu_id = cpu->cpu_index; Why is kvm_arch_vcpu_id() not necessary here any more but was before? > + vcpu->kvm_fd = cpu->kvm_fd; > + QLIST_INSERT_HEAD(&kvm_state->kvm_parked_vcpus, vcpu, node); > +} > + > +int kvm_create_vcpu(CPUState *cpu) > +{ > + int vcpu_id = cpu->cpu_index; See below. I'm not sure why it's safe not to use kvm_arch_vcpu_id() Seems a few architectures have less than trivial implementations of that function currently. > + KVMState *s = kvm_state; > + int kvm_fd; > + > + DPRINTF("kvm_create_vcpu\n"); > + > + /* check if the KVM vCPU already exist but is parked */ > + kvm_fd = kvm_get_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 %d", vcpu_id); > + return kvm_fd; > + } > + } > + > + cpu->vcpu_dirty = true; > + cpu->kvm_fd = kvm_fd; > + cpu->kvm_state = s; > + cpu->dirty_pages = 0; > + cpu->throttle_us_per_full = 0; Trivial but I would have maintained the order wrt to the code removed below just to avoid a reviewer having to check the two bits of code do the same thing after the reorder. > + > + return 0; > +} > + > static int do_kvm_destroy_vcpu(CPUState *cpu) > { > KVMState *s = kvm_state; > long mmap_size; > - struct KVMParkedVcpu *vcpu = NULL; > int ret = 0; > > DPRINTF("kvm_destroy_vcpu\n"); > @@ -353,10 +392,7 @@ 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; > } > @@ -369,7 +405,7 @@ void kvm_destroy_vcpu(CPUState *cpu) > } > } > > -static int kvm_get_vcpu(KVMState *s, unsigned long vcpu_id) > +static int kvm_get_vcpu(KVMState *s, int vcpu_id) > { > struct KVMParkedVcpu *cpu; > > @@ -384,7 +420,7 @@ static int kvm_get_vcpu(KVMState *s, unsigned long vcpu_id) > } > } > > - return kvm_vm_ioctl(s, KVM_CREATE_VCPU, (void *)vcpu_id); > + return -1; > } > > int kvm_init_vcpu(CPUState *cpu, Error **errp) > @@ -395,19 +431,14 @@ 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); The switch from kvm_arch_vcpu_id(cpu) to using int vcpu_id = cpu->cpu_index; Seems like a functional change on some arch. > 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)", The rewrap of the lines above seems like an unrelated change. > 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/include/sysemu/kvm.h b/include/sysemu/kvm.h > index ee9025f8e9..785f3ed083 100644 > --- a/include/sysemu/kvm.h > +++ b/include/sysemu/kvm.h > @@ -464,6 +464,20 @@ void kvm_set_sigmask_len(KVMState *s, unsigned int sigmask_len); > > int kvm_physical_memory_addr_from_host(KVMState *s, void *ram_addr, > hwaddr *phys_addr); > +/** > + * kvm_create_vcpu - Gets a parked KVM vCPU or creates a KVM vCPU > + * @cpu: QOM CPUState object for which KVM vCPU has to be created/fetched. Extra space before QOM (same below) > + * > + * @returns: 0 when success, errno (<0) when failed. > + */ > +int kvm_create_vcpu(CPUState *cpu); Blank line here perhaps. > +/** > + * kvm_park_vcpu - Gets a parked KVM vCPU if it exists > + * @cpu: QOM CPUState object for which parked KVM vCPU has to be fetched. We aren't returning anything, so why fetch? > + * > + * @returns: kvm_fd (>0) when success, -1 when failed. > + */ > +void kvm_park_vcpu(CPUState *cpu); > > #endif /* NEED_CPU_H */ > From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from list by lists.gnu.org with archive (Exim 4.90_1) id 1qnLEr-0006lI-NL for mharc-qemu-devel@gnu.org; Mon, 02 Oct 2023 11:53:42 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1qnLEh-00068I-Bj; Mon, 02 Oct 2023 11:53:31 -0400 Received: from frasgout.his.huawei.com ([185.176.79.56]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1qnLEe-0006Bt-DE; Mon, 02 Oct 2023 11:53:31 -0400 Received: from lhrpeml500005.china.huawei.com (unknown [172.18.147.201]) by frasgout.his.huawei.com (SkyGuard) with ESMTP id 4Rzlm61kfJz6HJZM; Mon, 2 Oct 2023 23:50:46 +0800 (CST) Received: from localhost (10.202.227.76) by lhrpeml500005.china.huawei.com (7.191.163.240) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.31; Mon, 2 Oct 2023 16:53:23 +0100 Date: Mon, 2 Oct 2023 16:53:22 +0100 From: Jonathan Cameron To: Salil Mehta CC: , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , Subject: Re: [PATCH V2 01/10] accel/kvm: Extract common KVM vCPU {creation,parking} code Message-ID: <20231002165322.00003a2e@Huawei.com> In-Reply-To: <20230930001933.2660-2-salil.mehta@huawei.com> References: <20230930001933.2660-1-salil.mehta@huawei.com> <20230930001933.2660-2-salil.mehta@huawei.com> Organization: Huawei Technologies Research and Development (UK) Ltd. X-Mailer: Claws Mail 4.1.0 (GTK 3.24.33; x86_64-w64-mingw32) MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.202.227.76] X-ClientProxiedBy: lhrpeml100006.china.huawei.com (7.191.160.224) To lhrpeml500005.china.huawei.com (7.191.163.240) X-CFilter-Loop: Reflected Received-SPF: pass client-ip=185.176.79.56; envelope-from=jonathan.cameron@huawei.com; helo=frasgout.his.huawei.com X-Spam_score_int: -41 X-Spam_score: -4.2 X-Spam_bar: ---- X-Spam_report: (-4.2 / 5.0 requ) BAYES_00=-1.9, RCVD_IN_DNSWL_MED=-2.3, RCVD_IN_MSPIKE_H5=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: , X-List-Received-Date: Mon, 02 Oct 2023 15:53:33 -0000 Message-ID: <20231002155322.J-_qW9EqY8_FVaMK6nBCHdtDAbfQy5IqFsflpSdhgXE@z> On Sat, 30 Sep 2023 01:19:24 +0100 Salil Mehta wrote: > KVM vCPU creation is done once during the initialization of the VM when Qemu > threads are spawned. This is common to all the architectures. > > Hot-unplug of vCPU results in destruction of the vCPU objects in QOM but > the KVM vCPU objects in the Host KVM are not destroyed and their representative > KVM vCPU objects/context in Qemu are parked. > > Refactor common logic so that some APIs could be reused by vCPU Hotplug code. > > Signed-off-by: Salil Mehta Hi Salil, A few trivial things inline, plus a question about why cpu->cpu_index can now be used but kvm_arch_vcpu_id(cpu); was previously needed. Thanks, Jonathan > --- > accel/kvm/kvm-all.c | 63 +++++++++++++++++++++++++++++++++----------- > include/sysemu/kvm.h | 14 ++++++++++ > 2 files changed, 61 insertions(+), 16 deletions(-) > > diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c > index ff1578bb32..b8c36ba50a 100644 > --- a/accel/kvm/kvm-all.c > +++ b/accel/kvm/kvm-all.c > @@ -80,7 +80,7 @@ > #endif > > struct KVMParkedVcpu { > - unsigned long vcpu_id; > + int vcpu_id; > int kvm_fd; > QLIST_ENTRY(KVMParkedVcpu) node; > }; > @@ -137,6 +137,7 @@ 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, int vcpu_id); > > static inline void kvm_resample_fd_remove(int gsi) > { > @@ -320,11 +321,49 @@ err: > return ret; > } > > +void kvm_park_vcpu(CPUState *cpu) > +{ > + int vcpu_id = cpu->cpu_index; > + struct KVMParkedVcpu *vcpu; > + > + vcpu = g_malloc0(sizeof(*vcpu)); > + vcpu->vcpu_id = vcpu_id; As vcpu_id is only used here why have the local variable? Maybe that changes in later patches, in which case ignore this. vcpu->vcpu_id = cpu->cpu_index; Why is kvm_arch_vcpu_id() not necessary here any more but was before? > + vcpu->kvm_fd = cpu->kvm_fd; > + QLIST_INSERT_HEAD(&kvm_state->kvm_parked_vcpus, vcpu, node); > +} > + > +int kvm_create_vcpu(CPUState *cpu) > +{ > + int vcpu_id = cpu->cpu_index; See below. I'm not sure why it's safe not to use kvm_arch_vcpu_id() Seems a few architectures have less than trivial implementations of that function currently. > + KVMState *s = kvm_state; > + int kvm_fd; > + > + DPRINTF("kvm_create_vcpu\n"); > + > + /* check if the KVM vCPU already exist but is parked */ > + kvm_fd = kvm_get_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 %d", vcpu_id); > + return kvm_fd; > + } > + } > + > + cpu->vcpu_dirty = true; > + cpu->kvm_fd = kvm_fd; > + cpu->kvm_state = s; > + cpu->dirty_pages = 0; > + cpu->throttle_us_per_full = 0; Trivial but I would have maintained the order wrt to the code removed below just to avoid a reviewer having to check the two bits of code do the same thing after the reorder. > + > + return 0; > +} > + > static int do_kvm_destroy_vcpu(CPUState *cpu) > { > KVMState *s = kvm_state; > long mmap_size; > - struct KVMParkedVcpu *vcpu = NULL; > int ret = 0; > > DPRINTF("kvm_destroy_vcpu\n"); > @@ -353,10 +392,7 @@ 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; > } > @@ -369,7 +405,7 @@ void kvm_destroy_vcpu(CPUState *cpu) > } > } > > -static int kvm_get_vcpu(KVMState *s, unsigned long vcpu_id) > +static int kvm_get_vcpu(KVMState *s, int vcpu_id) > { > struct KVMParkedVcpu *cpu; > > @@ -384,7 +420,7 @@ static int kvm_get_vcpu(KVMState *s, unsigned long vcpu_id) > } > } > > - return kvm_vm_ioctl(s, KVM_CREATE_VCPU, (void *)vcpu_id); > + return -1; > } > > int kvm_init_vcpu(CPUState *cpu, Error **errp) > @@ -395,19 +431,14 @@ 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); The switch from kvm_arch_vcpu_id(cpu) to using int vcpu_id = cpu->cpu_index; Seems like a functional change on some arch. > 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)", The rewrap of the lines above seems like an unrelated change. > 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/include/sysemu/kvm.h b/include/sysemu/kvm.h > index ee9025f8e9..785f3ed083 100644 > --- a/include/sysemu/kvm.h > +++ b/include/sysemu/kvm.h > @@ -464,6 +464,20 @@ void kvm_set_sigmask_len(KVMState *s, unsigned int sigmask_len); > > int kvm_physical_memory_addr_from_host(KVMState *s, void *ram_addr, > hwaddr *phys_addr); > +/** > + * kvm_create_vcpu - Gets a parked KVM vCPU or creates a KVM vCPU > + * @cpu: QOM CPUState object for which KVM vCPU has to be created/fetched. Extra space before QOM (same below) > + * > + * @returns: 0 when success, errno (<0) when failed. > + */ > +int kvm_create_vcpu(CPUState *cpu); Blank line here perhaps. > +/** > + * kvm_park_vcpu - Gets a parked KVM vCPU if it exists > + * @cpu: QOM CPUState object for which parked KVM vCPU has to be fetched. We aren't returning anything, so why fetch? > + * > + * @returns: kvm_fd (>0) when success, -1 when failed. > + */ > +void kvm_park_vcpu(CPUState *cpu); > > #endif /* NEED_CPU_H */ >