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accel/kvm: Extract common KVM vCPU {creation,parking} code

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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. New APIs qemu_{create,park,unpark}_vcpu() can be externally
called. No functional change is intended here.

Signed-off-by: Salil Mehta <salil.mehta@huawei.com>
Reviewed-by: Gavin Shan <gshan@redhat.com>
Tested-by: Vishnu Pajjuri <vishnu@os.amperecomputing.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Tested-by: Xianglai Li <lixianglai@loongson.cn>
Tested-by: Miguel Luis <miguel.luis@oracle.com>
Reviewed-by: Shaoqin Huang <shahuang@redhat.com>
Reviewed-by: Vishnu Pajjuri <vishnu@os.amperecomputing.com>
Reviewed-by: Nicholas Piggin <npiggin@gmail.com>
Tested-by: Zhao Liu <zhao1.liu@intel.com>
Reviewed-by: Zhao Liu <zhao1.liu@intel.com>
Reviewed-by: Harsh Prateek Bora <harshpb@linux.ibm.com>
Reviewed-by: Igor Mammedov <imammedo@redhat.com>
Message-Id: <20240716111502.202344-2-salil.mehta@huawei.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
This commit is contained in:
Salil Mehta 2024-07-16 12:14:56 +01:00 • committed by Michael S. Tsirkin
parent 62f182c97b
commit 08c3286822
4 changed files with 92 additions and 34 deletions
Download patch file Download diff file Expand all files Collapse all files

95
accel/kvm/kvm-all.c
View file

@ -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" : "!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;
}
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;