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Re: [Qemu-devel] [PATCH] Enable async page faults
From: |
Andreas Färber |
Subject: |
Re: [Qemu-devel] [PATCH] Enable async page faults |
Date: |
Wed, 10 Jul 2013 02:59:51 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130620 Thunderbird/17.0.7 |
Am 09.07.2013 17:47, schrieb Dominik Dingel:
> S390 can also use async page faults, to enhance guest scheduling.
> But in the case of live migration we want to disable the feature and know
> if there are still notifications in flight.
>
> Signed-off-by: Dominik Dingel <address@hidden>
> ---
> target-s390x/kvm.c | 42 ++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 42 insertions(+)
>
> diff --git a/target-s390x/kvm.c b/target-s390x/kvm.c
> index 42f758f..61df7d4 100644
> --- a/target-s390x/kvm.c
> +++ b/target-s390x/kvm.c
> @@ -36,6 +36,7 @@
> #include "sysemu/device_tree.h"
> #include "qapi/qmp/qjson.h"
> #include "monitor/monitor.h"
> +#include "migration/migration.h"
>
> /* #define DEBUG_KVM */
>
> @@ -92,9 +93,50 @@ const KVMCapabilityInfo kvm_arch_required_capabilities[] =
> {
>
> static int cap_sync_regs;
>
> +static int apf_disable(QEMUFile *f, void *opaque)
> +{
> + kvm_vm_ioctl(opaque, KVM_S390_APF_DISABLE);
Better don't pass opaques directly as a typed argument, especially in a
KVM file not widely tested; we just had such a runtime breakage.
KVMState *s = opaque; elegantly avoids it here and improves readability.
Regards,
Andreas
> + return 0;
> +}
> +
> +static void apf_enable(void *opaque)
> +{
> + kvm_vm_ioctl(opaque, KVM_S390_APF_ENABLE);
> +}
> +
> +static int apf_finish(QEMUFile *f, void *opaque, int version_id)
> +{
> + apf_enable(opaque);
> + return 0;
> +}
> +
> +static uint64_t apf_status(QEMUFile *f, void *opaque, uint64_t max_size)
> +{
> + uint64_t rc = 0;
> +
> + if (kvm_vm_ioctl(opaque, KVM_S390_APF_STATUS) !=
> + KVM_S390_APF_DISABLED_NON_PENDING) {
> + rc = 0xff0000;
> + }
> + return rc;
> +}
> +
> +SaveVMHandlers savevm_apf_handlers = {
> + .save_live_setup = apf_disable,
> + .save_live_iterate = NULL,
> + .save_live_complete = NULL,
> + .save_live_pending = apf_status,
> + .load_state = apf_finish,
> + .cancel = apf_enable,
> +};
> +
> int kvm_arch_init(KVMState *s)
> {
> cap_sync_regs = kvm_check_extension(s, KVM_CAP_SYNC_REGS);
> + if (kvm_check_extension(s, KVM_CAP_ASYNC_PF)) {
> + register_savevm_live(NULL, "apf", -1, 1, &savevm_apf_handlers, s);
> + kvm_vm_ioctl(s, KVM_S390_APF_ENABLE);
> + }
> return 0;
> }
>
>
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