diff options
| -rw-r--r-- | accel/kvm/kvm-all.c | 46 | ||||
| -rw-r--r-- | qemu-options.hx | 12 |
2 files changed, 58 insertions, 0 deletions
diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c index df9fbf59a6..5afe15ae66 100644 --- a/accel/kvm/kvm-all.c +++ b/accel/kvm/kvm-all.c @@ -126,6 +126,8 @@ struct KVMState KVMMemoryListener *ml; AddressSpace *as; } *as; + uint64_t kvm_dirty_ring_bytes; /* Size of the per-vcpu dirty ring */ + uint32_t kvm_dirty_ring_size; /* Number of dirty GFNs per ring */ }; KVMState *kvm_state; @@ -3182,6 +3184,42 @@ bool kvm_kernel_irqchip_split(void) return kvm_state->kernel_irqchip_split == ON_OFF_AUTO_ON; } +static void kvm_get_dirty_ring_size(Object *obj, Visitor *v, + const char *name, void *opaque, + Error **errp) +{ + KVMState *s = KVM_STATE(obj); + uint32_t value = s->kvm_dirty_ring_size; + + visit_type_uint32(v, name, &value, errp); +} + +static void kvm_set_dirty_ring_size(Object *obj, Visitor *v, + const char *name, void *opaque, + Error **errp) +{ + KVMState *s = KVM_STATE(obj); + Error *error = NULL; + uint32_t value; + + if (s->fd != -1) { + error_setg(errp, "Cannot set properties after the accelerator has been initialized"); + return; + } + + visit_type_uint32(v, name, &value, &error); + if (error) { + error_propagate(errp, error); + return; + } + if (value & (value - 1)) { + error_setg(errp, "dirty-ring-size must be a power of two."); + return; + } + + s->kvm_dirty_ring_size = value; +} + static void kvm_accel_instance_init(Object *obj) { KVMState *s = KVM_STATE(obj); @@ -3191,6 +3229,8 @@ static void kvm_accel_instance_init(Object *obj) s->kvm_shadow_mem = -1; s->kernel_irqchip_allowed = true; s->kernel_irqchip_split = ON_OFF_AUTO_AUTO; + /* KVM dirty ring is by default off */ + s->kvm_dirty_ring_size = 0; } static void kvm_accel_class_init(ObjectClass *oc, void *data) @@ -3212,6 +3252,12 @@ static void kvm_accel_class_init(ObjectClass *oc, void *data) NULL, NULL); object_class_property_set_description(oc, "kvm-shadow-mem", "KVM shadow MMU size"); + + object_class_property_add(oc, "dirty-ring-size", "uint32", + kvm_get_dirty_ring_size, kvm_set_dirty_ring_size, + NULL, NULL); + object_class_property_set_description(oc, "dirty-ring-size", + "Size of KVM dirty page ring buffer (default: 0, i.e. use bitmap)"); } static const TypeInfo kvm_accel_type = { diff --git a/qemu-options.hx b/qemu-options.hx index e22fb94d99..ecdb064409 100644 --- a/qemu-options.hx +++ b/qemu-options.hx @@ -141,6 +141,7 @@ DEF("accel", HAS_ARG, QEMU_OPTION_accel, " kvm-shadow-mem=size of KVM shadow MMU in bytes\n" " split-wx=on|off (enable TCG split w^x mapping)\n" " tb-size=n (TCG translation block cache size)\n" + " dirty-ring-size=n (KVM dirty ring GFN count, default 0)\n" " thread=single|multi (enable multi-threaded TCG)\n", QEMU_ARCH_ALL) SRST ``-accel name[,prop=value[,...]]`` @@ -181,6 +182,17 @@ SRST where both the back-end and front-ends support it and no incompatible TCG features have been enabled (e.g. icount/replay). + + ``dirty-ring-size=n`` + When the KVM accelerator is used, it controls the size of the per-vCPU + dirty page ring buffer (number of entries for each vCPU). It should + be a value that is power of two, and it should be 1024 or bigger (but + still less than the maximum value that the kernel supports). 4096 + could be a good initial value if you have no idea which is the best. + Set this value to 0 to disable the feature. By default, this feature + is disabled (dirty-ring-size=0). When enabled, KVM will instead + record dirty pages in a bitmap. + ERST DEF("smp", HAS_ARG, QEMU_OPTION_smp, |