linux-kernel - Re: [PATCH v4 19/29] drm/i915/gvt: switch from ->track_flush_slot() to ->track_remove

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Date:   Tue, 1 Aug 2023 14:39:33 +0300
From:   "Wang, Zhi A" <zhi.a.wang@...el.com>
To:     Sean Christopherson <seanjc@...gle.com>,
        Paolo Bonzini <pbonzini@...hat.com>,
        Zhenyu Wang <zhenyuw@...ux.intel.com>
CC:     <kvm@...r.kernel.org>, <intel-gvt-dev@...ts.freedesktop.org>,
        <intel-gfx@...ts.freedesktop.org>, <linux-kernel@...r.kernel.org>,
        Yan Zhao <yan.y.zhao@...el.com>,
        Yongwei Ma <yongwei.ma@...el.com>,
        Ben Gardon <bgardon@...gle.com>
Subject: Re: [PATCH v4 19/29] drm/i915/gvt: switch from ->track_flush_slot()
 to ->track_remove_region()

On 7/29/2023 4:35 AM, Sean Christopherson wrote:
> From: Yan Zhao <yan.y.zhao@...el.com>
> 
> Switch from the poorly named and flawed ->track_flush_slot() to the newly
> introduced ->track_remove_region().  From KVMGT's perspective, the two
> hooks are functionally equivalent, the only difference being that
> ->track_remove_region() is called only when KVM is 100% certain the
> memory region will be removed, i.e. is invoked slightly later in KVM's
> memslot modification flow.
> 
> Cc: Zhenyu Wang <zhenyuw@...ux.intel.com>
> Suggested-by: Sean Christopherson <seanjc@...gle.com>
> Signed-off-by: Yan Zhao <yan.y.zhao@...el.com>
> [sean: handle name change, massage changelog, rebase]
> Tested-by: Yan Zhao <yan.y.zhao@...el.com>
> Tested-by: Yongwei Ma <yongwei.ma@...el.com>
> Signed-off-by: Sean Christopherson <seanjc@...gle.com>
> ---
>   drivers/gpu/drm/i915/gvt/kvmgt.c | 21 +++++++++------------
>   1 file changed, 9 insertions(+), 12 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/gvt/kvmgt.c b/drivers/gpu/drm/i915/gvt/kvmgt.c
> index 3ea3cb9eb599..3f2327455d85 100644
> --- a/drivers/gpu/drm/i915/gvt/kvmgt.c
> +++ b/drivers/gpu/drm/i915/gvt/kvmgt.c
> @@ -108,9 +108,8 @@ struct gvt_dma {
>   
>   static void kvmgt_page_track_write(gpa_t gpa, const u8 *val, int len,
>   				   struct kvm_page_track_notifier_node *node);
> -static void kvmgt_page_track_flush_slot(struct kvm *kvm,
> -		struct kvm_memory_slot *slot,
> -		struct kvm_page_track_notifier_node *node);
> +static void kvmgt_page_track_remove_region(gfn_t gfn, unsigned long nr_pages,
> +					   struct kvm_page_track_notifier_node *node);
>   
>   static ssize_t intel_vgpu_show_description(struct mdev_type *mtype, char *buf)
>   {
> @@ -666,7 +665,7 @@ static int intel_vgpu_open_device(struct vfio_device *vfio_dev)
>   		return -EEXIST;
>   
>   	vgpu->track_node.track_write = kvmgt_page_track_write;
> -	vgpu->track_node.track_flush_slot = kvmgt_page_track_flush_slot;
> +	vgpu->track_node.track_remove_region = kvmgt_page_track_remove_region;
>   	kvm_get_kvm(vgpu->vfio_device.kvm);
>   	kvm_page_track_register_notifier(vgpu->vfio_device.kvm,
>   					 &vgpu->track_node);
> @@ -1617,22 +1616,20 @@ static void kvmgt_page_track_write(gpa_t gpa, const u8 *val, int len,
>   	mutex_unlock(&info->vgpu_lock);
>   }
>   
> -static void kvmgt_page_track_flush_slot(struct kvm *kvm,
> -		struct kvm_memory_slot *slot,
> -		struct kvm_page_track_notifier_node *node)
> +static void kvmgt_page_track_remove_region(gfn_t gfn, unsigned long nr_pages,
> +					   struct kvm_page_track_notifier_node *node)
>   {
>   	unsigned long i;
> -	gfn_t gfn;
>   	struct intel_vgpu *info =
>   		container_of(node, struct intel_vgpu, track_node);
>   
>   	mutex_lock(&info->vgpu_lock);
>   
> -	for (i = 0; i < slot->npages; i++) {
> -		gfn = slot->base_gfn + i;
> -		if (kvmgt_gfn_is_write_protected(info, gfn))
> -			kvmgt_protect_table_del(info, gfn);
> +	for (i = 0; i < nr_pages; i++) {
> +		if (kvmgt_gfn_is_write_protected(info, gfn + i))
> +			kvmgt_protect_table_del(info, gfn + i);
>   	}
> +
>   	mutex_unlock(&info->vgpu_lock);
>   }
>   
Reviewed-by: Zhi Wang <zhi.a.wang@...el.com>