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arm/kvm: Enable support for KVM_CAP_ARM_EAGER_SPLIT_CHUNK_SIZE

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Now that we have Eager Page Split support added for ARM in the kernel,
enable it in Qemu. This adds,
 -eager-split-size to -accel sub-options to set the eager page split chunk size.
 -enable KVM_CAP_ARM_EAGER_SPLIT_CHUNK_SIZE.

The chunk size specifies how many pages to break at a time, using a
single allocation. Bigger the chunk size, more pages need to be
allocated ahead of time.

Reviewed-by: Gavin Shan <gshan@redhat.com>
Signed-off-by: Shameer Kolothum <shameerali.kolothum.thodi@huawei.com>
Message-id: 20230905091246.1931-1-shameerali.kolothum.thodi@huawei.com
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
This commit is contained in:
Shameer Kolothum 2023-09-05 10:12:46 +01:00 • committed by Peter Maydell
parent d03396a8bb
commit c8f2eb5d41
4 changed files with 78 additions and 0 deletions
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61
target/arm/kvm.c
View file

@ -30,6 +30,7 @@
#include "exec/address-spaces.h"
#include "hw/boards.h"
#include "hw/irq.h"
#include "qapi/visitor.h"
#include "qemu/log.h"
const KVMCapabilityInfo kvm_arch_required_capabilities[] = {
@ -287,6 +288,26 @@ int kvm_arch_init(MachineState *ms, KVMState *s)
}
}
if (s->kvm_eager_split_size) {
uint32_t sizes;
sizes = kvm_vm_check_extension(s, KVM_CAP_ARM_SUPPORTED_BLOCK_SIZES);
if (!sizes) {
s->kvm_eager_split_size = 0;
warn_report("Eager Page Split support not available");
} else if (!(s->kvm_eager_split_size & sizes)) {
error_report("Eager Page Split requested chunk size not valid");
ret = -EINVAL;
} else {
ret = kvm_vm_enable_cap(s, KVM_CAP_ARM_EAGER_SPLIT_CHUNK_SIZE, 0,
s->kvm_eager_split_size);
if (ret < 0) {
error_report("Enabling of Eager Page Split failed: %s",
strerror(-ret));
}
}
}
kvm_arm_init_debug(s);
return ret;
@ -1069,6 +1090,46 @@ bool kvm_arch_cpu_check_are_resettable(void)
return true;
}
static void kvm_arch_get_eager_split_size(Object *obj, Visitor *v,
const char *name, void *opaque,
Error **errp)
{
KVMState *s = KVM_STATE(obj);
uint64_t value = s->kvm_eager_split_size;
visit_type_size(v, name, &value, errp);
}
static void kvm_arch_set_eager_split_size(Object *obj, Visitor *v,
const char *name, void *opaque,
Error **errp)
{
KVMState *s = KVM_STATE(obj);
uint64_t value;
if (s->fd != -1) {
error_setg(errp, "Unable to set early-split-size after KVM has been initialized");
return;
}
if (!visit_type_size(v, name, &value, errp)) {
return;
}
if (value && !is_power_of_2(value)) {
error_setg(errp, "early-split-size must be a power of two");
return;
}
s->kvm_eager_split_size = value;
}
void kvm_arch_accel_class_init(ObjectClass *oc)
{
object_class_property_add(oc, "eager-split-size", "size",
kvm_arch_get_eager_split_size,
kvm_arch_set_eager_split_size, NULL, NULL);
object_class_property_set_description(oc, "eager-split-size",
"Eager Page Split chunk size for hugepages. (default: 0, disabled)");
}