On Mon, Jan 07, 2019 at 07:43:26PM +0100, Cédric Le Goater wrote:
> When the VM is stopped in a migration sequence, the sources are masked
> and the XIVE IC is synced to stabilize the EQs. When done, the KVM
> ioctl KVM_DEV_XIVE_SAVE_EQ_PAGES is called to mark dirty the EQ pages.
>
> The migration can then transfer the remaining dirty pages to the
> destination and start collecting the state of the devices.
Is there a reason to make this a separate step from the SYNC
operation?
>
> Signed-off-by: Cédric Le Goater <clg@xxxxxxxx>
> ---
> arch/powerpc/include/uapi/asm/kvm.h | 1 +
> arch/powerpc/kvm/book3s_xive_native.c | 40 +++++++++++++++++++++++++++
> 2 files changed, 41 insertions(+)
>
> diff --git a/arch/powerpc/include/uapi/asm/kvm.h b/arch/powerpc/include/uapi/asm/kvm.h
> index f3b859223b80..1a8740629acf 100644
> --- a/arch/powerpc/include/uapi/asm/kvm.h
> +++ b/arch/powerpc/include/uapi/asm/kvm.h
> @@ -680,6 +680,7 @@ struct kvm_ppc_cpu_char {
> #define KVM_DEV_XIVE_GET_ESB_FD 1
> #define KVM_DEV_XIVE_GET_TIMA_FD 2
> #define KVM_DEV_XIVE_VC_BASE 3
> +#define KVM_DEV_XIVE_SAVE_EQ_PAGES 4
> #define KVM_DEV_XIVE_GRP_SOURCES 2 /* 64-bit source attributes */
> #define KVM_DEV_XIVE_GRP_SYNC 3 /* 64-bit source attributes */
>
> diff --git a/arch/powerpc/kvm/book3s_xive_native.c b/arch/powerpc/kvm/book3s_xive_native.c
> index a8052867afc1..f2de1bcf3b35 100644
> --- a/arch/powerpc/kvm/book3s_xive_native.c
> +++ b/arch/powerpc/kvm/book3s_xive_native.c
> @@ -373,6 +373,43 @@ static int kvmppc_xive_native_get_tima_fd(struct kvmppc_xive *xive, u64 addr)
> return put_user(ret, ubufp);
> }
>
> +static int kvmppc_xive_native_vcpu_save_eq_pages(struct kvm_vcpu *vcpu)
> +{
> + struct kvmppc_xive_vcpu *xc = vcpu->arch.xive_vcpu;
> + unsigned int prio;
> +
> + if (!xc)
> + return -ENOENT;
> +
> + for (prio = 0; prio < KVMPPC_XIVE_Q_COUNT; prio++) {
> + struct xive_q *q = &xc->queues[prio];
> +
> + if (!q->qpage)
> + continue;
> +
> + /* Mark EQ page dirty for migration */
> + mark_page_dirty(vcpu->kvm, gpa_to_gfn(q->guest_qpage));
> + }
> + return 0;
> +}
> +
> +static int kvmppc_xive_native_save_eq_pages(struct kvmppc_xive *xive)
> +{
> + struct kvm *kvm = xive->kvm;
> + struct kvm_vcpu *vcpu;
> + unsigned int i;
> +
> + pr_devel("%s\n", __func__);
> +
> + mutex_lock(&kvm->lock);
> + kvm_for_each_vcpu(i, vcpu, kvm) {
> + kvmppc_xive_native_vcpu_save_eq_pages(vcpu);
> + }
> + mutex_unlock(&kvm->lock);
> +
> + return 0;
> +}
> +
> static int xive_native_validate_queue_size(u32 qsize)
> {
> switch (qsize) {
> @@ -498,6 +535,8 @@ static int kvmppc_xive_native_set_attr(struct kvm_device *dev,
> switch (attr->attr) {
> case KVM_DEV_XIVE_VC_BASE:
> return kvmppc_xive_native_set_vc_base(xive, attr->addr);
> + case KVM_DEV_XIVE_SAVE_EQ_PAGES:
> + return kvmppc_xive_native_save_eq_pages(xive);
> }
> break;
> case KVM_DEV_XIVE_GRP_SOURCES:
> @@ -538,6 +577,7 @@ static int kvmppc_xive_native_has_attr(struct kvm_device *dev,
> case KVM_DEV_XIVE_GET_ESB_FD:
> case KVM_DEV_XIVE_GET_TIMA_FD:
> case KVM_DEV_XIVE_VC_BASE:
> + case KVM_DEV_XIVE_SAVE_EQ_PAGES:
> return 0;
> }
> break;
--
David Gibson | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_
| _way_ _around_!
http://www.ozlabs.org/~dgibson
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