2021-09-21 16:02:41

by Jean-Philippe Brucker

[permalink] [raw]
Subject: Re: [PATCH RFC v1 02/11] iommu/virtio: Maintain a list of endpoints served by viommu_dev

On Fri, Apr 23, 2021 at 03:21:38PM +0530, Vivek Gautam wrote:
> Keeping a record of list of endpoints that are served by the virtio-iommu
> device would help in redirecting the requests of page faults to the
> correct endpoint device to handle such requests.
>
> Signed-off-by: Vivek Gautam <[email protected]>
> ---
> drivers/iommu/virtio-iommu.c | 21 +++++++++++++++++++++
> 1 file changed, 21 insertions(+)
>
> diff --git a/drivers/iommu/virtio-iommu.c b/drivers/iommu/virtio-iommu.c
> index 50039070e2aa..c970f386f031 100644
> --- a/drivers/iommu/virtio-iommu.c
> +++ b/drivers/iommu/virtio-iommu.c
> @@ -48,6 +48,7 @@ struct viommu_dev {
> spinlock_t request_lock;
> struct list_head requests;
> void *evts;
> + struct list_head endpoints;

As we're going to search by ID, an xarray or rb_tree would be more
appropriate than a list

>
> /* Device configuration */
> struct iommu_domain_geometry geometry;
> @@ -115,6 +116,12 @@ struct viommu_endpoint {
> void *pgtf;
> };
>
> +struct viommu_ep_entry {
> + u32 eid;
> + struct viommu_endpoint *vdev;
> + struct list_head list;
> +};

No need for a separate struct, I think you can just add the list head and
id into viommu_endpoint.

> +
> struct viommu_request {
> struct list_head list;
> void *writeback;
> @@ -573,6 +580,7 @@ static int viommu_probe_endpoint(struct viommu_dev *viommu, struct device *dev)
> size_t probe_len;
> struct virtio_iommu_req_probe *probe;
> struct virtio_iommu_probe_property *prop;
> + struct viommu_ep_entry *ep;
> struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev);
> struct viommu_endpoint *vdev = dev_iommu_priv_get(dev);
>
> @@ -640,6 +648,18 @@ static int viommu_probe_endpoint(struct viommu_dev *viommu, struct device *dev)
> prop = (void *)probe->properties + cur;
> type = le16_to_cpu(prop->type) & VIRTIO_IOMMU_PROBE_T_MASK;
> }
> + if (ret)
> + goto out_free;
> +
> + ep = kzalloc(sizeof(*ep), GFP_KERNEL);
> + if (!ep) {
> + ret = -ENOMEM;
> + goto out_free;
> + }
> + ep->eid = probe->endpoint;
> + ep->vdev = vdev;
> +
> + list_add(&ep->list, &viommu->endpoints);

This should be in viommu_probe_device() (viommu_probe_endpoint() is only
called if F_PROBE is negotiated). I think we need a lock for this
list/xarray

Thanks,
Jean

>
> out_free:
> kfree(probe);
> @@ -1649,6 +1669,7 @@ static int viommu_probe(struct virtio_device *vdev)
> viommu->dev = dev;
> viommu->vdev = vdev;
> INIT_LIST_HEAD(&viommu->requests);
> + INIT_LIST_HEAD(&viommu->endpoints);
>
> ret = viommu_init_vqs(viommu);
> if (ret)
> --
> 2.17.1
>


2021-09-30 09:24:05

by Vivek Kumar Gautam

[permalink] [raw]
Subject: Re: [PATCH RFC v1 02/11] iommu/virtio: Maintain a list of endpoints served by viommu_dev



On 9/21/21 9:29 PM, Jean-Philippe Brucker wrote:
> On Fri, Apr 23, 2021 at 03:21:38PM +0530, Vivek Gautam wrote:
>> Keeping a record of list of endpoints that are served by the virtio-iommu
>> device would help in redirecting the requests of page faults to the
>> correct endpoint device to handle such requests.
>>
>> Signed-off-by: Vivek Gautam <[email protected]>
>> ---
>> drivers/iommu/virtio-iommu.c | 21 +++++++++++++++++++++
>> 1 file changed, 21 insertions(+)
>>
>> diff --git a/drivers/iommu/virtio-iommu.c b/drivers/iommu/virtio-iommu.c
>> index 50039070e2aa..c970f386f031 100644
>> --- a/drivers/iommu/virtio-iommu.c
>> +++ b/drivers/iommu/virtio-iommu.c
>> @@ -48,6 +48,7 @@ struct viommu_dev {
>> spinlock_t request_lock;
>> struct list_head requests;
>> void *evts;
>> + struct list_head endpoints;
>
> As we're going to search by ID, an xarray or rb_tree would be more
> appropriate than a list

Sure, I will update this with a rb_tree.

>
>>
>> /* Device configuration */
>> struct iommu_domain_geometry geometry;
>> @@ -115,6 +116,12 @@ struct viommu_endpoint {
>> void *pgtf;
>> };
>>
>> +struct viommu_ep_entry {
>> + u32 eid;
>> + struct viommu_endpoint *vdev;
>> + struct list_head list;
>> +};
>
> No need for a separate struct, I think you can just add the list head and
> id into viommu_endpoint.

Yea right. I will update it.

>
>> +
>> struct viommu_request {
>> struct list_head list;
>> void *writeback;
>> @@ -573,6 +580,7 @@ static int viommu_probe_endpoint(struct viommu_dev *viommu, struct device *dev)
>> size_t probe_len;
>> struct virtio_iommu_req_probe *probe;
>> struct virtio_iommu_probe_property *prop;
>> + struct viommu_ep_entry *ep;
>> struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev);
>> struct viommu_endpoint *vdev = dev_iommu_priv_get(dev);
>>
>> @@ -640,6 +648,18 @@ static int viommu_probe_endpoint(struct viommu_dev *viommu, struct device *dev)
>> prop = (void *)probe->properties + cur;
>> type = le16_to_cpu(prop->type) & VIRTIO_IOMMU_PROBE_T_MASK;
>> }
>> + if (ret)
>> + goto out_free;
>> +
>> + ep = kzalloc(sizeof(*ep), GFP_KERNEL);
>> + if (!ep) {
>> + ret = -ENOMEM;
>> + goto out_free;
>> + }
>> + ep->eid = probe->endpoint;
>> + ep->vdev = vdev;
>> +
>> + list_add(&ep->list, &viommu->endpoints);
>
> This should be in viommu_probe_device() (viommu_probe_endpoint() is only
> called if F_PROBE is negotiated). I think we need a lock for this
> list/xarray

Sure, will fix this, and add the needed locking around.

Thanks & regards
Vivek

>
> Thanks,
> Jean
>
>>
>> out_free:
>> kfree(probe);
>> @@ -1649,6 +1669,7 @@ static int viommu_probe(struct virtio_device *vdev)
>> viommu->dev = dev;
>> viommu->vdev = vdev;
>> INIT_LIST_HEAD(&viommu->requests);
>> + INIT_LIST_HEAD(&viommu->endpoints);
>>
>> ret = viommu_init_vqs(viommu);
>> if (ret)
>> --
>> 2.17.1
>>