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[PATCH 1/9] accel/kvm: Extract common KVM vCPU {creation, parking} code
From: |
Salil Mehta |
Subject: |
[PATCH 1/9] accel/kvm: Extract common KVM vCPU {creation, parking} code |
Date: |
Fri, 29 Sep 2023 13:42:56 +0100 |
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 <salil.mehta@huawei.com>
---
accel/kvm/kvm-all.c | 61 ++++++++++++++++++++++++++++++++++----------
include/sysemu/kvm.h | 2 ++
2 files changed, 49 insertions(+), 14 deletions(-)
diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c
index ff1578bb32..57889c5f6c 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->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;
+}
+
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 ee9025f8e9..17919567a8 100644
--- a/include/sysemu/kvm.h
+++ b/include/sysemu/kvm.h
@@ -464,6 +464,8 @@ 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 */
--
2.34.1
- [PATCH 0/9] Add architecture agnostic code to support vCPU Hotplug, Salil Mehta, 2023/09/29
- [PATCH 1/9] accel/kvm: Extract common KVM vCPU {creation, parking} code,
Salil Mehta <=
- [PATCH 2/9] hw/acpi: Move CPU ctrl-dev MMIO region len macro to common header file, Salil Mehta, 2023/09/29
- [PATCH 3/9] hw/acpi: Add ACPI CPU hotplug init stub, Salil Mehta, 2023/09/29
- [PATCH 4/9] hw/acpi: Init GED framework with cpu hotplug events, Salil Mehta, 2023/09/29