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Re: [PATCH RFCv1 6/8] kvm: Add helper kvm_dirty_ring_init()
From: |
Juan Quintela |
Subject: |
Re: [PATCH RFCv1 6/8] kvm: Add helper kvm_dirty_ring_init() |
Date: |
Wed, 08 Feb 2023 23:11:53 +0100 |
User-agent: |
Gnus/5.13 (Gnus v5.13) Emacs/28.2 (gnu/linux) |
Gavin Shan <gshan@redhat.com> wrote:
> Due to multiple capabilities associated with the dirty ring for different
> architectures: KVM_CAP_DIRTY_{LOG_RING, LOG_RING_ACQ_REL} for x86 and
> arm64 separately. There will be more to be done in order to support the
> dirty ring for arm64.
>
> Lets add helper kvm_dirty_ring_init() to enable the dirty ring. With this,
> the code looks a bit clean.
>
> No functional change intended.
>
> Signed-off-by: Gavin Shan <gshan@redhat.com>
> ---
> accel/kvm/kvm-all.c | 73 ++++++++++++++++++++++++++++-----------------
> 1 file changed, 46 insertions(+), 27 deletions(-)
>
> diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c
> index 9ec117c441..399ef0f7e6 100644
> --- a/accel/kvm/kvm-all.c
> +++ b/accel/kvm/kvm-all.c
> @@ -1476,6 +1476,49 @@ static int kvm_dirty_ring_reaper_init(KVMState *s)
> return 0;
> }
>
> +static int kvm_dirty_ring_init(KVMState *s)
> +{
> + uint64_t ring_bytes;
> + int ret;
> +
> + /*
> + * Read the max supported pages. Fall back to dirty logging mode
> + * if the dirty ring isn't supported.
> + */
> + ret = kvm_vm_check_extension(s, KVM_CAP_DIRTY_LOG_RING);
> + if (ret <= 0) {
> + warn_report("KVM dirty ring not available, using bitmap method");
> + s->kvm_dirty_ring_size = 0;
> + return 0;
> + }
> +
> + ring_bytes = s->kvm_dirty_ring_size * sizeof(struct kvm_dirty_gfn);
> + if (ring_bytes > ret) {
> + error_report("KVM dirty ring size %" PRIu32 " too big "
> + "(maximum is %ld). Please use a smaller value.",
> + s->kvm_dirty_ring_size,
> + (long)ret / sizeof(struct kvm_dirty_gfn));
> + ret = -EINVAL;
> + goto out;
> + }
> +
> + ret = kvm_vm_enable_cap(s, KVM_CAP_DIRTY_LOG_RING, 0, ring_bytes);
> + if (ret) {
> + error_report("Enabling of KVM dirty ring failed: %s. "
> + "Suggested minimum value is 1024.", strerror(-ret));
> + ret = -EIO;
> + }
> +
> +out:
> + if (ret) {
> + s->kvm_dirty_ring_size = 0;
> + } else {
> + s->kvm_dirty_ring_bytes = ring_bytes;
> + }
> +
> + return ret;
> +}
If you split it, you don't need the goto.
static int kvm_dirty_ring_init(KVMState *s)
{
s->kvm_dirty_ring_size = 0;
/*
* Read the max supported pages. Fall back to dirty logging mode
* if the dirty ring isn't supported.
*/
int ret = kvm_vm_check_extension(s, KVM_CAP_DIRTY_LOG_RING);
if (ret <= 0) {
warn_report("KVM dirty ring not available, using bitmap method");
return 0;
}
uint64_t ring_bytes = s->kvm_dirty_ring_size * sizeof(struct kvm_dirty_gfn);
if (ring_bytes > ret) {
error_report("KVM dirty ring size %" PRIu32 " too big "
"(maximum is %ld). Please use a smaller value.",
s->kvm_dirty_ring_size,
(long)ret / sizeof(struct kvm_dirty_gfn));
return -EINVAL;
}
ret = kvm_vm_enable_cap(s, KVM_CAP_DIRTY_LOG_RING, 0, ring_bytes);
if (ret) {
error_report("Enabling of KVM dirty ring failed: %s. "
"Suggested minimum value is 1024.", strerror(-ret));
return -EIO;
}
s->kvm_dirty_ring_bytes = ring_bytes;
return ret;
}
> +
> static void kvm_region_add(MemoryListener *listener,
> MemoryRegionSection *section)
> {
> @@ -2545,33 +2588,9 @@ static int kvm_init(MachineState *ms)
> * dirty logging mode
> */
> if (s->kvm_dirty_ring_size > 0) {
> - uint64_t ring_bytes;
> -
> - ring_bytes = s->kvm_dirty_ring_size * sizeof(struct kvm_dirty_gfn);
> -
> - /* Read the max supported pages */
> - ret = kvm_vm_check_extension(s, KVM_CAP_DIRTY_LOG_RING);
> - if (ret > 0) {
> - if (ring_bytes > ret) {
> - error_report("KVM dirty ring size %" PRIu32 " too big "
> - "(maximum is %ld). Please use a smaller
> value.",
> - s->kvm_dirty_ring_size,
> - (long)ret / sizeof(struct kvm_dirty_gfn));
> - ret = -EINVAL;
> - goto err;
> - }
> -
> - ret = kvm_vm_enable_cap(s, KVM_CAP_DIRTY_LOG_RING, 0,
> ring_bytes);
> - if (ret) {
> - error_report("Enabling of KVM dirty ring failed: %s. "
> - "Suggested minimum value is 1024.",
> strerror(-ret));
> - goto err;
> - }
> -
> - s->kvm_dirty_ring_bytes = ring_bytes;
> - } else {
> - warn_report("KVM dirty ring not available, using bitmap
> method");
> - s->kvm_dirty_ring_size = 0;
> + ret = kvm_dirty_ring_init(s);
> + if (ret < 0) {
> + goto err;
> }
> }
- [PATCH RFCv1 2/8] memory: Add last stage indicator to global dirty log synchronization, (continued)
- [PATCH RFCv1 2/8] memory: Add last stage indicator to global dirty log synchronization, Gavin Shan, 2023/02/06
- [PATCH RFCv1 3/8] migration: Add last stage indicator to global dirty log synchronization, Gavin Shan, 2023/02/06
- [PATCH RFCv1 4/8] kvm: Introduce secondary dirty bitmap, Gavin Shan, 2023/02/06
- [PATCH RFCv1 8/8] kvm: Enable dirty ring for arm64, Gavin Shan, 2023/02/06
- [PATCH RFCv1 6/8] kvm: Add helper kvm_dirty_ring_init(), Gavin Shan, 2023/02/06
- Re: [PATCH RFCv1 6/8] kvm: Add helper kvm_dirty_ring_init(),
Juan Quintela <=
- [PATCH RFCv1 5/8] kvm: Synchronize secondary bitmap in last stage, Gavin Shan, 2023/02/06
- [PATCH RFCv1 7/8] hw/arm/virt: Enable backup bitmap for dirty ring, Gavin Shan, 2023/02/06