From: Gavin Shan <gshan@redhat.com>
To: Salil Mehta <salil.mehta@huawei.com>,
qemu-devel@nongnu.org, qemu-arm@nongnu.org
Cc: maz@kernel.org, jean-philippe@linaro.org,
jonathan.cameron@huawei.com, lpieralisi@kernel.org,
peter.maydell@linaro.org, richard.henderson@linaro.org,
imammedo@redhat.com, andrew.jones@linux.dev, david@redhat.com,
philmd@linaro.org, eric.auger@redhat.com, will@kernel.org,
ardb@kernel.org, oliver.upton@linux.dev, pbonzini@redhat.com,
mst@redhat.com, rafael@kernel.org, borntraeger@linux.ibm.com,
alex.bennee@linaro.org, linux@armlinux.org.uk,
darren@os.amperecomputing.com, ilkka@os.amperecomputing.com,
vishnu@os.amperecomputing.com, karl.heubaum@oracle.com,
miguel.luis@oracle.com, salil.mehta@opnsrc.net,
zhukeqian1@huawei.com, wangxiongfeng2@huawei.com,
wangyanan55@huawei.com, jiakernel2@gmail.com,
maobibo@loongson.cn, lixianglai@loongson.cn
Subject: Re: [PATCH RFC V2 05/37] accel/kvm: Extract common KVM vCPU {creation,parking} code
Date: Wed, 27 Sep 2023 16:51:45 +1000 [thread overview]
Message-ID: <d58c51d2-53e4-3873-7c87-c6ccc3025ed9@redhat.com> (raw)
In-Reply-To: <20230926100436.28284-6-salil.mehta@huawei.com>
Hi Salil,
On 9/26/23 20:04, 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. If the architecture
> supports vCPU hot-{un}plug then this KVM vCPU creation could be deferred to
> later point as well. Some architectures might in any case create KVM vCPUs for
> the yet-to-be plugged vCPUs (i.e. QoM Object & thread does not exists) during VM
> init time and park them.
>
> 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 in Qemu are parked.
>
> Signed-off-by: Salil Mehta <salil.mehta@huawei.com>
> ---
> accel/kvm/kvm-all.c | 61 ++++++++++++++++++++++++++++++++++----------
> include/sysemu/kvm.h | 2 ++
> 2 files changed, 49 insertions(+), 14 deletions(-)
>
The most important point seems missed in the commit log: The KVM vCPU objects,
including those hotpluggable objects, need to be in place before in-host GICv3
is initialized. So we need expose kvm_create_vcpu() to make those KVM vCPU
objects in place, even for those non-present vCPUs.
> diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c
> index 7b3da8dc3a..86e9c9ea60 100644
> --- a/accel/kvm/kvm-all.c
> +++ b/accel/kvm/kvm-all.c
> @@ -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, unsigned long vcpu_id);
>
> static inline void kvm_resample_fd_remove(int gsi)
> {
> @@ -320,11 +321,51 @@ err:
> return ret;
> }
>
> +void kvm_park_vcpu(CPUState *cpu)
> +{
> + unsigned long vcpu_id = cpu->cpu_index;
> + struct KVMParkedVcpu *vcpu;
> +
> + vcpu = g_malloc0(sizeof(*vcpu));
> + vcpu->vcpu_id = vcpu_id;
vcpu->vcpu_id = cpu->cpu_index;
@vcpu_id can be dropped.
> + vcpu->kvm_fd = cpu->kvm_fd;
> + QLIST_INSERT_HEAD(&kvm_state->kvm_parked_vcpus, vcpu, node);
> +}
> +
> +int kvm_create_vcpu(CPUState *cpu)
> +{
> + unsigned long vcpu_id = cpu->cpu_index;
> + KVMState *s = kvm_state;
> + int ret;
> +
> + DPRINTF("kvm_create_vcpu\n");
> +
> + /* check if the KVM vCPU already exist but is parked */
> + ret = kvm_get_vcpu(s, kvm_arch_vcpu_id(cpu));
> + if (ret > 0) {
> + goto found;
> + }
> +
> + /* create a new KVM vcpu */
> + ret = kvm_vm_ioctl(s, KVM_CREATE_VCPU, (void *)vcpu_id);
> + if (ret < 0) {
> + return ret;
> + }
> +
> +found:
> + cpu->vcpu_dirty = true;
> + cpu->kvm_fd = ret;
> + cpu->kvm_state = s;
> + cpu->dirty_pages = 0;
> + cpu->throttle_us_per_full = 0;
> +
> + return 0;
> +}
> +
The found tag can be dropped. @cpu can be initialized if vCPU fd is found
and then bail early.
/* The KVM vCPU may have been existing */
ret = kvm_get_vcpu(s, kvm_arch_vcpu_id(cpu));
if (ret > 0) {
cpu->vcpu_dirty = true;
:
:
return 0;
}
/* Create a new KVM vCPU */
> 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 +394,7 @@ 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;
> }
> @@ -384,7 +422,7 @@ 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 +433,14 @@ 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/include/sysemu/kvm.h b/include/sysemu/kvm.h
> index 115f0cca79..2c34889b01 100644
> --- a/include/sysemu/kvm.h
> +++ b/include/sysemu/kvm.h
> @@ -473,6 +473,8 @@ 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);
> +int kvm_create_vcpu(CPUState *cpu);
> +void kvm_park_vcpu(CPUState *cpu);
>
> #endif /* NEED_CPU_H */
>
Thanks,
Gavin
next prev parent reply other threads:[~2023-09-27 6:52 UTC|newest]
Thread overview: 146+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-09-26 10:03 [PATCH RFC V2 00/37] Support of Virtual CPU Hotplug for ARMv8 Arch Salil Mehta via
2023-09-26 10:04 ` [PATCH RFC V2 01/37] arm/virt, target/arm: Add new ARMCPU {socket, cluster, core, thread}-id property Salil Mehta via
2023-09-26 23:57 ` [PATCH RFC V2 01/37] arm/virt,target/arm: Add new ARMCPU {socket,cluster,core,thread}-id property Gavin Shan
2023-10-02 9:53 ` Salil Mehta via
2023-10-02 9:53 ` Salil Mehta
2023-10-03 5:05 ` Gavin Shan
2023-09-26 10:04 ` [PATCH RFC V2 02/37] cpus-common: Add common CPU utility for possible vCPUs Salil Mehta via
2023-09-27 3:54 ` Gavin Shan
2023-10-02 10:21 ` Salil Mehta via
2023-10-02 10:21 ` Salil Mehta
2023-10-03 5:34 ` Gavin Shan
2023-09-26 10:04 ` [PATCH RFC V2 03/37] hw/arm/virt: Move setting of common CPU properties in a function Salil Mehta via
2023-09-27 5:16 ` Gavin Shan
2023-10-02 10:24 ` Salil Mehta via
2023-10-02 10:24 ` Salil Mehta
2023-10-10 6:46 ` Shaoqin Huang
2023-10-10 9:47 ` Salil Mehta via
2023-10-10 9:47 ` Salil Mehta
2023-09-26 10:04 ` [PATCH RFC V2 04/37] arm/virt, target/arm: Machine init time change common to vCPU {cold|hot}-plug Salil Mehta via
2023-09-27 6:28 ` [PATCH RFC V2 04/37] arm/virt,target/arm: " Gavin Shan
2023-10-02 16:12 ` Salil Mehta via
2023-10-02 16:12 ` Salil Mehta
2024-01-16 15:59 ` Jonathan Cameron via
2023-09-27 6:30 ` Gavin Shan
2023-10-02 10:27 ` Salil Mehta via
2023-10-02 10:27 ` Salil Mehta
2023-09-26 10:04 ` [PATCH RFC V2 05/37] accel/kvm: Extract common KVM vCPU {creation, parking} code Salil Mehta via
2023-09-27 6:51 ` Gavin Shan [this message]
2023-10-02 16:20 ` [PATCH RFC V2 05/37] accel/kvm: Extract common KVM vCPU {creation,parking} code Salil Mehta via
2023-10-02 16:20 ` Salil Mehta
2023-10-03 5:39 ` Gavin Shan
2023-09-26 10:04 ` [PATCH RFC V2 06/37] arm/virt, kvm: Pre-create disabled possible vCPUs @machine init Salil Mehta via
2023-09-27 10:04 ` [PATCH RFC V2 06/37] arm/virt,kvm: " Gavin Shan
2023-10-02 16:39 ` Salil Mehta via
2023-10-02 16:39 ` Salil Mehta
2023-09-26 10:04 ` [PATCH RFC V2 07/37] arm/virt, gicv3: Changes to pre-size GIC with possible vcpus " Salil Mehta via
2023-09-28 0:14 ` Gavin Shan
2023-10-16 16:15 ` Salil Mehta via
2023-10-16 16:15 ` Salil Mehta
2023-09-26 10:04 ` [PATCH RFC V2 08/37] arm/virt: Init PMU at host for all possible vcpus Salil Mehta via
2023-09-26 10:04 ` [PATCH RFC V2 09/37] hw/acpi: Move CPU ctrl-dev MMIO region len macro to common header file Salil Mehta via
2023-09-28 0:19 ` Gavin Shan
2023-10-16 16:20 ` Salil Mehta via
2023-10-16 16:20 ` Salil Mehta
2023-09-26 10:04 ` [PATCH RFC V2 10/37] arm/acpi: Enable ACPI support for vcpu hotplug Salil Mehta via
2023-09-28 0:25 ` Gavin Shan
2023-10-16 21:23 ` Salil Mehta via
2023-10-16 21:23 ` Salil Mehta
2023-09-26 10:04 ` [PATCH RFC V2 11/37] hw/acpi: Add ACPI CPU hotplug init stub Salil Mehta via
2023-09-28 0:28 ` Gavin Shan
2023-10-16 21:27 ` Salil Mehta via
2023-10-16 21:27 ` Salil Mehta
2023-09-26 10:04 ` [PATCH RFC V2 12/37] hw/acpi: Use qemu_present_cpu() API in ACPI CPU hotplug init Salil Mehta via
2023-09-28 0:40 ` Gavin Shan
2023-10-16 21:41 ` Salil Mehta via
2023-10-16 21:41 ` Salil Mehta
2023-09-26 10:04 ` [PATCH RFC V2 13/37] hw/acpi: Init GED framework with cpu hotplug events Salil Mehta via
2023-09-28 0:56 ` Gavin Shan
2023-10-16 21:44 ` Salil Mehta via
2023-10-16 21:44 ` Salil Mehta
2023-09-26 10:04 ` [PATCH RFC V2 14/37] arm/virt: Add cpu hotplug events to GED during creation Salil Mehta via
2023-09-28 1:03 ` Gavin Shan
2023-10-16 21:46 ` Salil Mehta via
2023-10-16 21:46 ` Salil Mehta
2023-09-26 10:04 ` [PATCH RFC V2 15/37] arm/virt: Create GED dev before *disabled* CPU Objs are destroyed Salil Mehta via
2023-09-28 1:08 ` Gavin Shan
2023-10-16 21:54 ` Salil Mehta via
2023-10-16 21:54 ` Salil Mehta
2023-09-26 10:04 ` [PATCH RFC V2 16/37] hw/acpi: Update CPUs AML with cpu-(ctrl)dev change Salil Mehta via
2023-09-28 1:26 ` Gavin Shan
2023-10-16 21:57 ` Salil Mehta via
2023-10-16 21:57 ` Salil Mehta
2023-09-26 10:04 ` [PATCH RFC V2 17/37] arm/virt/acpi: Build CPUs AML with CPU Hotplug support Salil Mehta via
2023-09-28 1:36 ` Gavin Shan
2023-10-16 22:05 ` Salil Mehta via
2023-10-16 22:05 ` Salil Mehta
2023-09-26 10:04 ` [PATCH RFC V2 18/37] arm/virt: Make ARM vCPU *present* status ACPI *persistent* Salil Mehta via
2023-09-28 23:18 ` Gavin Shan
2023-10-16 22:33 ` Salil Mehta via
2023-10-16 22:33 ` Salil Mehta
2023-09-26 10:04 ` [PATCH RFC V2 19/37] hw/acpi: ACPI/AML Changes to reflect the correct _STA.{PRES, ENA} Bits to Guest Salil Mehta via
2023-09-28 23:33 ` [PATCH RFC V2 19/37] hw/acpi: ACPI/AML Changes to reflect the correct _STA.{PRES,ENA} " Gavin Shan
2023-10-16 22:59 ` Salil Mehta via
2023-10-16 22:59 ` Salil Mehta
2024-01-17 21:46 ` [PATCH RFC V2 19/37] hw/acpi: ACPI/AML Changes to reflect the correct _STA.{PRES, ENA} " Jonathan Cameron via
2023-09-26 10:04 ` [PATCH RFC V2 20/37] hw/acpi: Update GED _EVT method AML with cpu scan Salil Mehta via
2023-09-28 23:35 ` Gavin Shan
2023-10-16 23:01 ` Salil Mehta via
2023-10-16 23:01 ` Salil Mehta
2023-09-26 10:04 ` [PATCH RFC V2 21/37] hw/arm: MADT Tbl change to size the guest with possible vCPUs Salil Mehta via
2023-09-28 23:43 ` Gavin Shan
2023-10-16 23:15 ` Salil Mehta via
2023-10-16 23:15 ` Salil Mehta
2023-09-26 10:04 ` [PATCH RFC V2 22/37] hw/acpi: Make _MAT method optional Salil Mehta via
2023-09-28 23:50 ` Gavin Shan
2023-10-16 23:17 ` Salil Mehta via
2023-10-16 23:17 ` Salil Mehta
2023-09-26 10:04 ` [PATCH RFC V2 23/37] arm/virt: Release objects for *disabled* possible vCPUs after init Salil Mehta via
2023-09-28 23:57 ` Gavin Shan
2023-10-16 23:28 ` Salil Mehta via
2023-10-16 23:28 ` Salil Mehta
2023-09-26 10:04 ` [PATCH RFC V2 24/37] hw/acpi: Update ACPI GED framework to support vCPU Hotplug Salil Mehta via
2023-09-26 11:02 ` Michael S. Tsirkin
2023-09-26 11:37 ` Salil Mehta via
2023-09-26 12:00 ` Michael S. Tsirkin
2023-09-26 12:27 ` Salil Mehta via
2023-09-26 13:02 ` lixianglai
2023-09-26 10:04 ` [PATCH RFC V2 25/37] arm/virt: Add/update basic hot-(un)plug framework Salil Mehta via
2023-09-29 0:20 ` Gavin Shan
2023-10-16 23:40 ` Salil Mehta via
2023-10-16 23:40 ` Salil Mehta
2023-09-26 10:04 ` [PATCH RFC V2 26/37] arm/virt: Changes to (un)wire GICC<->vCPU IRQs during hot-(un)plug Salil Mehta via
2023-09-26 10:04 ` [PATCH RFC V2 27/37] hw/arm, gicv3: Changes to update GIC with vCPU hot-plug notification Salil Mehta via
2023-09-26 10:04 ` [PATCH RFC V2 28/37] hw/intc/arm-gicv3*: Changes required to (re)init the vCPU register info Salil Mehta via
2023-09-26 10:04 ` [PATCH RFC V2 29/37] arm/virt: Update the guest(via GED) about CPU hot-(un)plug events Salil Mehta via
2023-09-29 0:30 ` Gavin Shan
2023-10-16 23:48 ` Salil Mehta via
2023-10-16 23:48 ` Salil Mehta
2023-09-26 10:04 ` [PATCH RFC V2 30/37] hw/arm: Changes required for reset and to support next boot Salil Mehta via
2023-09-26 10:04 ` [PATCH RFC V2 31/37] physmem, gdbstub: Common helping funcs/changes to *unrealize* vCPU Salil Mehta via
2023-10-03 6:33 ` [PATCH RFC V2 31/37] physmem,gdbstub: " Philippe Mathieu-Daudé
2023-10-03 10:22 ` Salil Mehta via
2023-10-03 10:22 ` Salil Mehta
2023-10-04 9:17 ` Salil Mehta via
2023-10-04 9:17 ` Salil Mehta
2023-09-26 10:36 ` [PATCH RFC V2 32/37] target/arm: Add support of *unrealize* ARMCPU during vCPU Hot-unplug Salil Mehta via
2023-09-26 10:36 ` [PATCH RFC V2 33/37] target/arm/kvm: Write CPU state back to KVM on reset Salil Mehta via
2023-09-26 10:36 ` [PATCH RFC V2 34/37] target/arm/kvm, tcg: Register/Handle SMCCC hypercall exits to VMM/Qemu Salil Mehta via
2023-09-29 4:15 ` [PATCH RFC V2 34/37] target/arm/kvm,tcg: " Gavin Shan
2023-10-17 0:03 ` Salil Mehta via
2023-10-17 0:03 ` Salil Mehta
2023-09-26 10:36 ` [PATCH RFC V2 35/37] hw/arm: Support hotplug capability check using _OSC method Salil Mehta via
2023-09-29 4:23 ` Gavin Shan
2023-10-17 0:13 ` Salil Mehta via
2023-10-17 0:13 ` Salil Mehta
2023-09-26 10:36 ` [PATCH RFC V2 36/37] tcg/mttcg: enable threads to unregister in tcg_ctxs[] Salil Mehta via
2023-09-26 10:36 ` [PATCH RFC V2 37/37] hw/arm/virt: Expose cold-booted CPUs as MADT GICC Enabled Salil Mehta via
2023-10-11 10:23 ` [PATCH RFC V2 00/37] Support of Virtual CPU Hotplug for ARMv8 Arch Vishnu Pajjuri
2023-10-11 10:32 ` Salil Mehta via
2023-10-11 10:32 ` Salil Mehta
2023-10-11 11:08 ` Vishnu Pajjuri
2023-10-11 20:15 ` Salil Mehta
2023-10-12 17:02 ` Miguel Luis
2023-10-12 17:54 ` Salil Mehta via
2023-10-12 17:54 ` Salil Mehta
2023-10-13 10:43 ` Miguel Luis
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