From: Harsh Prateek Bora <hars...@linux.ibm.com>
Sent: Thursday, May 16, 2024 6:32 AM
From: Salil Mehta <salil.me...@huawei.com>
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 instead of DPRINTF. No functional change is
intended here.
Signed-off-by: Salil Mehta <salil.me...@huawei.com>
Reviewed-by: Gavin Shan <gs...@redhat.com>
Tested-by: Vishnu Pajjuri <vis...@os.amperecomputing.com>
Reviewed-by: Jonathan Cameron <jonathan.came...@huawei.com>
Tested-by: Xianglai Li <lixiang...@loongson.cn>
Tested-by: Miguel Luis <miguel.l...@oracle.com>
Reviewed-by: Shaoqin Huang <shahu...@redhat.com>
[harshpb: fixed rebase failures in include/sysemu/kvm.h]
Signed-off-by: Harsh Prateek Bora <hars...@linux.ibm.com>
---
include/sysemu/kvm.h | 15 ++++++++++
accel/kvm/kvm-all.c | 64 ++++++++++++++++++++++++++++++++--------
--
accel/kvm/trace-events | 5 +++-
3 files changed, 68 insertions(+), 16 deletions(-)
diff --git a/include/sysemu/kvm.h b/include/sysemu/kvm.h index
eaf801bc93..fa3ec74442 100644
--- a/include/sysemu/kvm.h
+++ b/include/sysemu/kvm.h
@@ -434,6 +434,21 @@ 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
fetched/created.
+ *
+ * @returns: 0 when success, errno (<0) when failed.
+ */
+int kvm_create_vcpu(CPUState *cpu);
+
+/**
+ * kvm_park_vcpu - Park QEMU KVM vCPU context
+ * @cpu: QOM CPUState object for which QEMU KVM vCPU context has to
be parked.
+ *
+ * @returns: none
+ */
+void kvm_park_vcpu(CPUState *cpu);
#endif /* COMPILING_PER_TARGET */
diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c index
d7281b93f3..30d42847de 100644
--- a/accel/kvm/kvm-all.c
+++ b/accel/kvm/kvm-all.c
@@ -128,6 +128,7 @@ 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) { @@ -340,14 +341,53
@@ 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_create_vcpu(CPUState *cpu)
+{
+ unsigned long vcpu_id = kvm_arch_vcpu_id(cpu);
+ KVMState *s = kvm_state;
+ int kvm_fd;
+
+ trace_kvm_create_vcpu(cpu->cpu_index, kvm_arch_vcpu_id(cpu));
+
+ /* 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 %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;
+
+ 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 +413,7 @@ 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;
}
@@ -397,6 +434,8 @@ static int kvm_get_vcpu(KVMState *s, unsigned long
vcpu_id)
if (cpu->vcpu_id == vcpu_id) {
int kvm_fd;
+ trace_kvm_get_vcpu(vcpu_id);
+
QLIST_REMOVE(cpu, node);
kvm_fd = cpu->kvm_fd;
g_free(cpu);
@@ -404,7 +443,7 @@ static int kvm_get_vcpu(KVMState *s, unsigned long
vcpu_id)
}
}
- return kvm_vm_ioctl(s, KVM_CREATE_VCPU, (void *)vcpu_id);
+ return -ENOENT;
}
int kvm_init_vcpu(CPUState *cpu, Error **errp) @@ -415,19 +454,14 @@
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/accel/kvm/trace-events b/accel/kvm/trace-events index
681ccb667d..75c1724e78 100644
--- a/accel/kvm/trace-events
+++ b/accel/kvm/trace-events
@@ -9,6 +9,10 @@ kvm_device_ioctl(int fd, int type, void *arg) "dev fd %d,
type 0x%x, arg %p"
kvm_failed_reg_get(uint64_t id, const char *msg) "Warning: Unable to
retrieve ONEREG %" PRIu64 " from KVM: %s"
kvm_failed_reg_set(uint64_t id, const char *msg) "Warning: Unable to set
ONEREG %" PRIu64 " to KVM: %s"
kvm_init_vcpu(int cpu_index, unsigned long arch_cpu_id) "index: %d id:
%lu"
+kvm_create_vcpu(int cpu_index, unsigned long arch_cpu_id) "index: %d
id: %lu"
+kvm_get_vcpu(unsigned long arch_cpu_id) "id: %lu"
+kvm_destroy_vcpu(int cpu_index, unsigned long arch_cpu_id) "index: %d
id: %lu"
+kvm_park_vcpu(int cpu_index, unsigned long arch_cpu_id) "index: %d id:
%lu"
kvm_irqchip_commit_routes(void) ""
kvm_irqchip_add_msi_route(char *name, int vector, int virq) "dev %s
vector %d virq %d"
kvm_irqchip_update_msi_route(int virq) "Updating MSI route virq=%d"
@@ -25,7 +29,6 @@ kvm_dirty_ring_reaper(const char *s) "%s"
kvm_dirty_ring_reap(uint64_t count, int64_t t) "reaped %"PRIu64" pages
(took %"PRIi64" us)"
kvm_dirty_ring_reaper_kick(const char *reason) "%s"
kvm_dirty_ring_flush(int finished) "%d"
-kvm_destroy_vcpu(void) ""
kvm_failed_get_vcpu_mmap_size(void) ""
kvm_cpu_exec(void) ""
kvm_interrupt_exit_request(void) ""
--
2.39.3
