In the ARMv8 architecture, the GIC must know all the CPUs it is connected to
during its initialization, and this cannot change afterward. This must be
ensured during the initialization of the VGIC as well in KVM, which requires all
vCPUs to be created and present during its initialization. This is necessary
because:
1. The association between GICC and MPIDR must be fixed at VM initialization
time. This is represented by the register `GIC_TYPER(mp_affinity, proc_num)`.
2. GICC (CPU interfaces), GICR (redistributors), etc., must all be initialized
at boot time.
3. Memory regions associated with GICR, etc., cannot be changed (added, deleted,
or modified) after the VM has been initialized.
This patch adds support to pre-create all possible vCPUs within the host using
the KVM interface as part of the virtual machine initialization. These vCPUs can
later be attached to QOM/ACPI when they are actually hot-plugged and made
present.
Co-developed-by: Keqian Zhu <zhukeqian1@huawei.com>
Signed-off-by: Keqian Zhu <zhukeqian1@huawei.com>
Signed-off-by: Salil Mehta <salil.mehta@huawei.com>
Reported-by: Vishnu Pajjuri <vishnu@os.amperecomputing.com>
[VP: Identified CPU stall issue & suggested probable fix]
---
hw/arm/virt.c | 56 +++++++++++++++++++++++++++++++++++--------
include/hw/core/cpu.h | 1 +
target/arm/cpu64.c | 1 +
target/arm/kvm.c | 41 ++++++++++++++++++++++++++++++-
target/arm/kvm_arm.h | 11 +++++++++
5 files changed, 99 insertions(+), 11 deletions(-)
diff --git a/hw/arm/virt.c b/hw/arm/virt.c
index a285139165..81e7a27786 100644
--- a/hw/arm/virt.c
+++ b/hw/arm/virt.c
@@ -2383,14 +2383,8 @@ static void machvirt_init(MachineState *machine)
Object *cpuobj;
CPUState *cs;
- if (n >= smp_cpus) {
- break;
- }
-
cpuobj = object_new(possible_cpus->cpus[n].type);
-
cs = CPU(cpuobj);
- cs->cpu_index = n;
aarch64 &= object_property_get_bool(cpuobj, "aarch64", NULL);
object_property_set_int(cpuobj, "socket-id",
@@ -2402,11 +2396,53 @@ static void machvirt_init(MachineState *machine)
object_property_set_int(cpuobj, "thread-id",
virt_get_thread_id(machine, n), NULL);
- cpu_slot = virt_find_cpu_slot(machine, cs->cpu_index);
- virt_cpu_set_properties(cpuobj, cpu_slot, &error_fatal);
+ if (n < smp_cpus) {
+ qdev_realize(DEVICE(cpuobj), NULL, &error_fatal);
+ object_unref(cpuobj);
+ } else {
+ /* handling for vcpus which are yet to be hot-plugged */
+ cs->cpu_index = n;
+ cpu_slot = virt_find_cpu_slot(machine, cs->cpu_index);
- qdev_realize(DEVICE(cpuobj), NULL, &error_fatal);
- object_unref(cpuobj);
+ /*
+ * ARM host vCPU features need to be fixed at the boot time. But as
+ * per current approach this CPU object will be destroyed during
+ * cpu_post_init(). During hotplug of vCPUs these properties are
+ * initialized again.
+ */
+ virt_cpu_set_properties(cpuobj, cpu_slot, &error_fatal);
+
+ /*
+ * For KVM, we shall be pre-creating the now disabled/un-plugged
+ * possbile host vcpus and park them till the time they are
+ * actually hot plugged. This is required to pre-size the host
+ * GICC and GICR with the all possible vcpus for this VM.
+ */
+ if (kvm_enabled()) {
+ kvm_arm_create_host_vcpu(ARM_CPU(cs));
+ }
+ /*
+ * Add disabled vCPU to CPU slot during the init phase of the virt
+ * machine
+ * 1. We need this ARMCPU object during the GIC init. This object
+ * will facilitate in pre-realizing the GIC. Any info like
+ * mp-affinity(required to derive gicr_type) etc. could still be
+ * fetched while preserving QOM abstraction akin to realized
+ * vCPUs.
+ * 2. Now, after initialization of the virt machine is complete we
+ * could use two approaches to deal with this ARMCPU object:
+ * (i) re-use this ARMCPU object during hotplug of this vCPU.
+ * OR
+ * (ii) defer release this ARMCPU object after gic has been
+ * initialized or during pre-plug phase when a vCPU is
+ * hotplugged.
+ *
+ * We will use the (ii) approach and release the ARMCPU objects
+ * after GIC and machine has been fully initialized during
+ * machine_init_done() phase.
+ */
+ cpu_slot->cpu = cs;
+ }
}
/* Now we've created the CPUs we can see if they have the hypvirt timer */
diff --git a/include/hw/core/cpu.h b/include/hw/core/cpu.h
index 60b4778da9..62e68611c0 100644
--- a/include/hw/core/cpu.h
+++ b/include/hw/core/cpu.h
@@ -520,6 +520,7 @@ struct CPUState {
uint64_t dirty_pages;
int kvm_vcpu_stats_fd;
bool vcpu_dirty;
+ VMChangeStateEntry *vmcse;
/* Use by accel-block: CPU is executing an ioctl() */
QemuLockCnt in_ioctl_lock;
diff --git a/target/arm/cpu64.c b/target/arm/cpu64.c
index d6b48b3424..9b7e8b032c 100644
--- a/target/arm/cpu64.c
+++ b/target/arm/cpu64.c
@@ -789,6 +789,7 @@ static void aarch64_cpu_initfn(Object *obj)
* enabled explicitly
*/
cs->disabled = true;
+ cs->thread_id = 0;
}
static void aarch64_cpu_finalizefn(Object *obj)
diff --git a/target/arm/kvm.c b/target/arm/kvm.c
index 7cf5cf31de..01c83c1994 100644
--- a/target/arm/kvm.c
+++ b/target/arm/kvm.c
@@ -1003,6 +1003,38 @@ void kvm_arm_reset_vcpu(ARMCPU *cpu)
write_list_to_cpustate(cpu);
}
+void kvm_arm_create_host_vcpu(ARMCPU *cpu)
+{
+ CPUState *cs = CPU(cpu);
+ unsigned long vcpu_id = cs->cpu_index;
+ int ret;
+
+ ret = kvm_create_vcpu(cs);
+ if (ret < 0) {
+ error_report("Failed to create host vcpu %ld", vcpu_id);
+ abort();
+ }
+
+ /*
+ * Initialize the vCPU in the host. This will reset the sys regs
+ * for this vCPU and related registers like MPIDR_EL1 etc. also
+ * gets programmed during this call to host. These are referred
+ * later while setting device attributes of the GICR during GICv3
+ * reset
+ */
+ ret = kvm_arch_init_vcpu(cs);
+ if (ret < 0) {
+ error_report("Failed to initialize host vcpu %ld", vcpu_id);
+ abort();
+ }
+
+ /*
+ * park the created vCPU. shall be used during kvm_get_vcpu() when
+ * threads are created during realization of ARM vCPUs.
+ */
+ kvm_park_vcpu(cs);
+}
+
/*
* Update KVM's MP_STATE based on what QEMU thinks it is
*/
@@ -1874,7 +1906,14 @@ int kvm_arch_init_vcpu(CPUState *cs)
return -EINVAL;
}
- qemu_add_vm_change_state_handler(kvm_arm_vm_state_change, cpu);
+ /*
+ * Install VM change handler only when vCPU thread has been spawned
+ * i.e. vCPU is being realized
+ */
+ if (cs->thread_id) {
+ cs->vmcse = qemu_add_vm_change_state_handler(kvm_arm_vm_state_change,
+ cpu);
+ }
/* Determine init features for this CPU */
memset(cpu->kvm_init_features, 0, sizeof(cpu->kvm_init_features));
diff --git a/target/arm/kvm_arm.h b/target/arm/kvm_arm.h
index cfaa0d9bc7..0be7e896d2 100644
--- a/target/arm/kvm_arm.h
+++ b/target/arm/kvm_arm.h
@@ -96,6 +96,17 @@ void kvm_arm_cpu_post_load(ARMCPU *cpu);
*/
void kvm_arm_reset_vcpu(ARMCPU *cpu);
+/**
+ * kvm_arm_create_host_vcpu:
+ * @cpu: ARMCPU
+ *
+ * Called at to pre create all possible kvm vCPUs within the the host at the
+ * virt machine init time. This will also init this pre-created vCPU and
+ * hence result in vCPU reset at host. These pre created and inited vCPUs
+ * shall be parked for use when ARM vCPUs are actually realized.
+ */
+void kvm_arm_create_host_vcpu(ARMCPU *cpu);
+
#ifdef CONFIG_KVM
/**
* kvm_arm_create_scratch_host_vcpu:
--
2.34.1On 6/14/24 9:36 AM, Salil Mehta wrote:
> In the ARMv8 architecture, the GIC must know all the CPUs it is connected to
> during its initialization, and this cannot change afterward. This must be
> ensured during the initialization of the VGIC as well in KVM, which requires all
> vCPUs to be created and present during its initialization. This is necessary
> because:
>
> 1. The association between GICC and MPIDR must be fixed at VM initialization
> time. This is represented by the register `GIC_TYPER(mp_affinity, proc_num)`.
> 2. GICC (CPU interfaces), GICR (redistributors), etc., must all be initialized
> at boot time.
> 3. Memory regions associated with GICR, etc., cannot be changed (added, deleted,
> or modified) after the VM has been initialized.
>
> This patch adds support to pre-create all possible vCPUs within the host using
> the KVM interface as part of the virtual machine initialization. These vCPUs can
> later be attached to QOM/ACPI when they are actually hot-plugged and made
> present.
>
> Co-developed-by: Keqian Zhu <zhukeqian1@huawei.com>
> Signed-off-by: Keqian Zhu <zhukeqian1@huawei.com>
> Signed-off-by: Salil Mehta <salil.mehta@huawei.com>
> Reported-by: Vishnu Pajjuri <vishnu@os.amperecomputing.com>
> [VP: Identified CPU stall issue & suggested probable fix]
> ---
> hw/arm/virt.c | 56 +++++++++++++++++++++++++++++++++++--------
> include/hw/core/cpu.h | 1 +
> target/arm/cpu64.c | 1 +
> target/arm/kvm.c | 41 ++++++++++++++++++++++++++++++-
> target/arm/kvm_arm.h | 11 +++++++++
> 5 files changed, 99 insertions(+), 11 deletions(-)
>
The vCPU file descriptor is associated with a feature bitmap when the file descriptor
is initialized by ioctl(vm_fd, KVM_ARM_VCPU_INIT, &init). The feature bitmap is sorted
out based on the vCPU properties. The vCPU properties can be different when the vCPU
file descriptor is initialized for the first time when the vCPU is instantiated, and
re-initialized when the vCPU is hot added.
It can lead to system crash as below. We probably need a mechanism to disallow passing
extra properties when vCPU is hot added to avoid the conflicts to the global properties
from the command line "-cpu host,pmu=on". Some of the properties like "id", "socket-id"
are still needed.
/home/gavin/sandbox/qemu.main/build/qemu-system-aarch64 \
-accel kvm -machine virt,gic-version=host,nvdimm=on \
-cpu host -smp maxcpus=2,cpus=1,sockets=2,clusters=1,cores=1,threads=1 \
-m 4096M,slots=16,maxmem=128G \
-object memory-backend-ram,id=mem0,size=2048M \
-object memory-backend-ram,id=mem1,size=2048M \
-numa node,nodeid=0,memdev=mem0,cpus=0-0 \
-numa node,nodeid=1,memdev=mem1,cpus=1-1 \
-L /home/gavin/sandbox/qemu.main/build/pc-bios \
-monitor none -serial mon:stdio -nographic \
-gdb tcp::6666 -qmp tcp:localhost:5555,server,wait=off \
-bios /home/gavin/sandbox/qemu.main/build/pc-bios/edk2-aarch64-code.fd \
-kernel /home/gavin/sandbox/linux.guest/arch/arm64/boot/Image \
-initrd /home/gavin/sandbox/images/rootfs.cpio.xz \
-append memhp_default_state=online_movable \
:
(qemu) device_add host-arm-cpu,id=cpu1,socket-id=1,pmu=off
kvm_arch_init_vcpu: Error -22 from kvm_arm_vcpu_init()
qemu-system-aarch64: kvm_init_vcpu: kvm_arch_init_vcpu failed (1): Invalid argument
Thanks,
Gavin
Hi Gavin, > From: Gavin Shan <gshan@redhat.com> > Sent: Monday, August 19, 2024 6:32 AM > To: Salil Mehta <salil.mehta@huawei.com>; qemu-devel@nongnu.org; > qemu-arm@nongnu.org; mst@redhat.com > > On 6/14/24 9:36 AM, Salil Mehta wrote: > > In the ARMv8 architecture, the GIC must know all the CPUs it is > > connected to during its initialization, and this cannot change > > afterward. This must be ensured during the initialization of the VGIC > > as well in KVM, which requires all vCPUs to be created and present > > during its initialization. This is necessary > > because: > > > > 1. The association between GICC and MPIDR must be fixed at VM > initialization > > time. This is represented by the register `GIC_TYPER(mp_affinity, > proc_num)`. > > 2. GICC (CPU interfaces), GICR (redistributors), etc., must all be initialized > > at boot time. > > 3. Memory regions associated with GICR, etc., cannot be changed (added, deleted, > > or modified) after the VM has been initialized. > > > > This patch adds support to pre-create all possible vCPUs within the > > host using the KVM interface as part of the virtual machine > > initialization. These vCPUs can later be attached to QOM/ACPI when > > they are actually hot-plugged and made present. > > > > Co-developed-by: Keqian Zhu <zhukeqian1@huawei.com> > > Signed-off-by: Keqian Zhu <zhukeqian1@huawei.com> > > Signed-off-by: Salil Mehta <salil.mehta@huawei.com> > > Reported-by: Vishnu Pajjuri <vishnu@os.amperecomputing.com> > > [VP: Identified CPU stall issue & suggested probable fix] > > --- > > hw/arm/virt.c | 56 +++++++++++++++++++++++++++++++++++----- > --- > > include/hw/core/cpu.h | 1 + > > target/arm/cpu64.c | 1 + > > target/arm/kvm.c | 41 ++++++++++++++++++++++++++++++- > > target/arm/kvm_arm.h | 11 +++++++++ > > 5 files changed, 99 insertions(+), 11 deletions(-) > > > > The vCPU file descriptor is associated with a feature bitmap when the file > descriptor is initialized by ioctl(vm_fd, KVM_ARM_VCPU_INIT, &init). The > feature bitmap is sorted out based on the vCPU properties. The vCPU > properties can be different when the vCPU file descriptor is initialized for > the first time when the vCPU is instantiated, and re-initialized when the > vCPU is hot added. > It can lead to system crash as below. We probably need a mechanism to > disallow passing extra properties when vCPU is hot added to avoid the > conflicts to the global properties from the command line "-cpu > host,pmu=on". Some of the properties like "id", "socket-id" > are still needed. Yes, Good catch. I knew that but It almost went under my hood. Thanks for pointing and reminding it. We need a check there. Will fix it. > > /home/gavin/sandbox/qemu.main/build/qemu-system-aarch64 \ > -accel kvm -machine virt,gic-version=host,nvdimm=on \ > -cpu host -smp maxcpus=2,cpus=1,sockets=2,clusters=1,cores=1,threads=1 > \ > -m 4096M,slots=16,maxmem=128G \ > -object memory-backend-ram,id=mem0,size=2048M \ > -object memory-backend-ram,id=mem1,size=2048M \ > -numa node,nodeid=0,memdev=mem0,cpus=0-0 \ > -numa node,nodeid=1,memdev=mem1,cpus=1-1 \ > -L /home/gavin/sandbox/qemu.main/build/pc-bios \ > -monitor none -serial mon:stdio -nographic \ > -gdb tcp::6666 -qmp tcp:localhost:5555,server,wait=off \ > -bios /home/gavin/sandbox/qemu.main/build/pc-bios/edk2-aarch64- > code.fd \ > -kernel /home/gavin/sandbox/linux.guest/arch/arm64/boot/Image \ > -initrd /home/gavin/sandbox/images/rootfs.cpio.xz \ > -append memhp_default_state=online_movable \ > : > (qemu) device_add host-arm-cpu,id=cpu1,socket-id=1,pmu=off > kvm_arch_init_vcpu: Error -22 from kvm_arm_vcpu_init() > qemu-system-aarch64: kvm_init_vcpu: kvm_arch_init_vcpu failed (1): > Invalid argument Yes. thanks. > > Thanks, > Gavin >
On 6/14/24 9:36 AM, Salil Mehta wrote:
> In the ARMv8 architecture, the GIC must know all the CPUs it is connected to
> during its initialization, and this cannot change afterward. This must be
> ensured during the initialization of the VGIC as well in KVM, which requires all
> vCPUs to be created and present during its initialization. This is necessary
> because:
>
> 1. The association between GICC and MPIDR must be fixed at VM initialization
> time. This is represented by the register `GIC_TYPER(mp_affinity, proc_num)`.
> 2. GICC (CPU interfaces), GICR (redistributors), etc., must all be initialized
> at boot time.
> 3. Memory regions associated with GICR, etc., cannot be changed (added, deleted,
> or modified) after the VM has been initialized.
>
> This patch adds support to pre-create all possible vCPUs within the host using
> the KVM interface as part of the virtual machine initialization. These vCPUs can
> later be attached to QOM/ACPI when they are actually hot-plugged and made
> present.
>
> Co-developed-by: Keqian Zhu <zhukeqian1@huawei.com>
> Signed-off-by: Keqian Zhu <zhukeqian1@huawei.com>
> Signed-off-by: Salil Mehta <salil.mehta@huawei.com>
> Reported-by: Vishnu Pajjuri <vishnu@os.amperecomputing.com>
> [VP: Identified CPU stall issue & suggested probable fix]
> ---
> hw/arm/virt.c | 56 +++++++++++++++++++++++++++++++++++--------
> include/hw/core/cpu.h | 1 +
> target/arm/cpu64.c | 1 +
> target/arm/kvm.c | 41 ++++++++++++++++++++++++++++++-
> target/arm/kvm_arm.h | 11 +++++++++
> 5 files changed, 99 insertions(+), 11 deletions(-)
>
> diff --git a/hw/arm/virt.c b/hw/arm/virt.c
> index a285139165..81e7a27786 100644
> --- a/hw/arm/virt.c
> +++ b/hw/arm/virt.c
> @@ -2383,14 +2383,8 @@ static void machvirt_init(MachineState *machine)
> Object *cpuobj;
> CPUState *cs;
>
> - if (n >= smp_cpus) {
> - break;
> - }
> -
> cpuobj = object_new(possible_cpus->cpus[n].type);
> -
> cs = CPU(cpuobj);
> - cs->cpu_index = n;
>
Fixed @cpu_index assignment is removed here...
> aarch64 &= object_property_get_bool(cpuobj, "aarch64", NULL);
> object_property_set_int(cpuobj, "socket-id",
> @@ -2402,11 +2396,53 @@ static void machvirt_init(MachineState *machine)
> object_property_set_int(cpuobj, "thread-id",
> virt_get_thread_id(machine, n), NULL);
>
> - cpu_slot = virt_find_cpu_slot(machine, cs->cpu_index);
> - virt_cpu_set_properties(cpuobj, cpu_slot, &error_fatal);
> + if (n < smp_cpus) {
> + qdev_realize(DEVICE(cpuobj), NULL, &error_fatal);
> + object_unref(cpuobj);
> + } else {
> + /* handling for vcpus which are yet to be hot-plugged */
> + cs->cpu_index = n;
> + cpu_slot = virt_find_cpu_slot(machine, cs->cpu_index);
>
For hotpluggable vCPUs, we have the fixed @cpu_index assignment here and virt_cpu_pre_plug().
However, @cpu_index for non-hotpluggable vCPUs will be automatically assigned in the following
path. It causes inconsistent behaviour to hotpluggable and non-hotpluggable vCPUs. We need to
fix @cpu_index for non-hotpluggable vCPUs as well.
qdev_realize
arm_cpu_realizefn
cpu_exec_realizefn
cpu_list_add
> - qdev_realize(DEVICE(cpuobj), NULL, &error_fatal);
> - object_unref(cpuobj);
> + /*
> + * ARM host vCPU features need to be fixed at the boot time. But as
> + * per current approach this CPU object will be destroyed during
> + * cpu_post_init(). During hotplug of vCPUs these properties are
> + * initialized again.
> + */
> + virt_cpu_set_properties(cpuobj, cpu_slot, &error_fatal);
> +
> + /*
> + * For KVM, we shall be pre-creating the now disabled/un-plugged
> + * possbile host vcpus and park them till the time they are
> + * actually hot plugged. This is required to pre-size the host
> + * GICC and GICR with the all possible vcpus for this VM.
> + */
> + if (kvm_enabled()) {
> + kvm_arm_create_host_vcpu(ARM_CPU(cs));
> + }
> + /*
> + * Add disabled vCPU to CPU slot during the init phase of the virt
> + * machine
> + * 1. We need this ARMCPU object during the GIC init. This object
> + * will facilitate in pre-realizing the GIC. Any info like
> + * mp-affinity(required to derive gicr_type) etc. could still be
> + * fetched while preserving QOM abstraction akin to realized
> + * vCPUs.
> + * 2. Now, after initialization of the virt machine is complete we
> + * could use two approaches to deal with this ARMCPU object:
> + * (i) re-use this ARMCPU object during hotplug of this vCPU.
> + * OR
> + * (ii) defer release this ARMCPU object after gic has been
> + * initialized or during pre-plug phase when a vCPU is
> + * hotplugged.
> + *
> + * We will use the (ii) approach and release the ARMCPU objects
> + * after GIC and machine has been fully initialized during
> + * machine_init_done() phase.
> + */
For those hotpluggable vCPUs, ARMCPU objects are instanciated, providing information
for GIC's initialization and then destroyed. ARMCPU objects are a bit heavy for that.
The question is if ms->possible_cpus->cpus[] can be reused to provide information for
GIC's initialization? If it can be used for that, the left question is how to avoid
instanciating ARMCPU objects when vCPU fds are created and parked.
> + cpu_slot->cpu = cs;
> + }
> }
>
> /* Now we've created the CPUs we can see if they have the hypvirt timer */
> diff --git a/include/hw/core/cpu.h b/include/hw/core/cpu.h
> index 60b4778da9..62e68611c0 100644
> --- a/include/hw/core/cpu.h
> +++ b/include/hw/core/cpu.h
> @@ -520,6 +520,7 @@ struct CPUState {
> uint64_t dirty_pages;
> int kvm_vcpu_stats_fd;
> bool vcpu_dirty;
> + VMChangeStateEntry *vmcse;
>
> /* Use by accel-block: CPU is executing an ioctl() */
> QemuLockCnt in_ioctl_lock;
> diff --git a/target/arm/cpu64.c b/target/arm/cpu64.c
> index d6b48b3424..9b7e8b032c 100644
> --- a/target/arm/cpu64.c
> +++ b/target/arm/cpu64.c
> @@ -789,6 +789,7 @@ static void aarch64_cpu_initfn(Object *obj)
> * enabled explicitly
> */
> cs->disabled = true;
> + cs->thread_id = 0;
> }
>
> static void aarch64_cpu_finalizefn(Object *obj)
> diff --git a/target/arm/kvm.c b/target/arm/kvm.c
> index 7cf5cf31de..01c83c1994 100644
> --- a/target/arm/kvm.c
> +++ b/target/arm/kvm.c
> @@ -1003,6 +1003,38 @@ void kvm_arm_reset_vcpu(ARMCPU *cpu)
> write_list_to_cpustate(cpu);
> }
>
> +void kvm_arm_create_host_vcpu(ARMCPU *cpu)
> +{
> + CPUState *cs = CPU(cpu);
> + unsigned long vcpu_id = cs->cpu_index;
> + int ret;
> +
> + ret = kvm_create_vcpu(cs);
> + if (ret < 0) {
> + error_report("Failed to create host vcpu %ld", vcpu_id);
> + abort();
> + }
> +
> + /*
> + * Initialize the vCPU in the host. This will reset the sys regs
> + * for this vCPU and related registers like MPIDR_EL1 etc. also
> + * gets programmed during this call to host. These are referred
> + * later while setting device attributes of the GICR during GICv3
> + * reset
> + */
> + ret = kvm_arch_init_vcpu(cs);
> + if (ret < 0) {
> + error_report("Failed to initialize host vcpu %ld", vcpu_id);
> + abort();
> + }
> +
> + /*
> + * park the created vCPU. shall be used during kvm_get_vcpu() when
> + * threads are created during realization of ARM vCPUs.
> + */
> + kvm_park_vcpu(cs);
> +}
> +
> /*
> * Update KVM's MP_STATE based on what QEMU thinks it is
> */
> @@ -1874,7 +1906,14 @@ int kvm_arch_init_vcpu(CPUState *cs)
> return -EINVAL;
> }
>
> - qemu_add_vm_change_state_handler(kvm_arm_vm_state_change, cpu);
> + /*
> + * Install VM change handler only when vCPU thread has been spawned
> + * i.e. vCPU is being realized
> + */
> + if (cs->thread_id) {
> + cs->vmcse = qemu_add_vm_change_state_handler(kvm_arm_vm_state_change,
> + cpu);
> + }
>
> /* Determine init features for this CPU */
> memset(cpu->kvm_init_features, 0, sizeof(cpu->kvm_init_features));
> diff --git a/target/arm/kvm_arm.h b/target/arm/kvm_arm.h
> index cfaa0d9bc7..0be7e896d2 100644
> --- a/target/arm/kvm_arm.h
> +++ b/target/arm/kvm_arm.h
> @@ -96,6 +96,17 @@ void kvm_arm_cpu_post_load(ARMCPU *cpu);
> */
> void kvm_arm_reset_vcpu(ARMCPU *cpu);
>
> +/**
> + * kvm_arm_create_host_vcpu:
> + * @cpu: ARMCPU
> + *
> + * Called at to pre create all possible kvm vCPUs within the the host at the
> + * virt machine init time. This will also init this pre-created vCPU and
> + * hence result in vCPU reset at host. These pre created and inited vCPUs
> + * shall be parked for use when ARM vCPUs are actually realized.
> + */
> +void kvm_arm_create_host_vcpu(ARMCPU *cpu);
> +
> #ifdef CONFIG_KVM
> /**
> * kvm_arm_create_scratch_host_vcpu:
Thanks,
Gavin
© 2016 - 2024 Red Hat, Inc.