by Lu Baolu

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Subject: Re: [PATCH v7 9/9] vfio/type1: Handle different mdev isolation type

Hi Neo,

On 3/9/19 2:03 AM, Neo Jia wrote:
> On Thu, Mar 07, 2019 at 04:56:23PM -0700, Alex Williamson wrote:
>> On Thu, 7 Mar 2019 00:44:54 -0800
>> Neo Jia <[email protected]> wrote:
>>
>>> On Fri, Feb 22, 2019 at 10:19:27AM +0800, Lu Baolu wrote:
>>>> This adds the support to determine the isolation type
>>>> of a mediated device group by checking whether it has
>>>> an iommu device. If an iommu device exists, an iommu
>>>> domain will be allocated and then attached to the iommu
>>>> device. Otherwise, keep the same behavior as it is.
>>>>
>>>> Cc: Ashok Raj <[email protected]>
>>>> Cc: Jacob Pan <[email protected]>
>>>> Cc: Kevin Tian <[email protected]>
>>>> Signed-off-by: Sanjay Kumar <[email protected]>
>>>> Signed-off-by: Liu Yi L <[email protected]>
>>>> Signed-off-by: Lu Baolu <[email protected]>
>>>> Reviewed-by: Jean-Philippe Brucker <[email protected]>
>>>> ---
>>>> drivers/vfio/vfio_iommu_type1.c | 48 ++++++++++++++++++++++++++++-----
>>>> 1 file changed, 41 insertions(+), 7 deletions(-)
>>>>
>>>> diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
>>>> index ccc4165474aa..f1392c582a3c 100644
>>>> --- a/drivers/vfio/vfio_iommu_type1.c
>>>> +++ b/drivers/vfio/vfio_iommu_type1.c
>>>> @@ -1368,13 +1368,40 @@ static void vfio_iommu_detach_group(struct vfio_domain *domain,
>>>> iommu_detach_group(domain->domain, group->iommu_group);
>>>> }
>>>>
>>>
>>> Hi Baolu,
>>>
>>> To allow IOMMU-awared mdev, I think you need to modify the
>>> vfio_iommu_type1_pin_pages and vfio_iommu_type1_unpin_pages to remove the
>>> iommu->external_domain check.
>>>
>>> Could you please include that in your patch? If not, I can send out a separate
>>> patch to address that issue.
>>
>> I figured it was intentional that an IOMMU backed mdev would not use
>> the pin/unpin interface and therefore the exiting -EINVAL returns would
>> be correct. Can you elaborate on the use case for still requiring the
>> mdev pin/unpin interface for these devices? Thanks,
>
> Sure. We are using this api to fetch a pfn of a guest physical address so we can
> access it for PV.

Okay, I will remove these two checks in the next version.

Best regards,
Lu Baolu

2019-03-26 09:35:31

by Kirti Wankhede

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Subject: Re: [PATCH v7 8/9] vfio/type1: Add domain at(de)taching group helpers

On 2/22/2019 7:49 AM, Lu Baolu wrote:
> This adds helpers to attach or detach a domain to a
> group. This will replace iommu_attach_group() which
> only works for non-mdev devices.
>
> If a domain is attaching to a group which includes the
> mediated devices, it should attach to the iommu device
> (a pci device which represents the mdev in iommu scope)
> instead. The added helper supports attaching domain to
> groups for both pci and mdev devices.
>
> Cc: Ashok Raj <[email protected]>
> Cc: Jacob Pan <[email protected]>
> Cc: Kevin Tian <[email protected]>
> Signed-off-by: Sanjay Kumar <[email protected]>
> Signed-off-by: Liu Yi L <[email protected]>
> Signed-off-by: Lu Baolu <[email protected]>
> Reviewed-by: Jean-Philippe Brucker <[email protected]>

Reviewed-by: Kirti Wankhede <[email protected]>

Thanks,
Kirti

> ---
> drivers/vfio/vfio_iommu_type1.c | 84 ++++++++++++++++++++++++++++++---
> 1 file changed, 77 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
> index 73652e21efec..ccc4165474aa 100644
> --- a/drivers/vfio/vfio_iommu_type1.c
> +++ b/drivers/vfio/vfio_iommu_type1.c
> @@ -91,6 +91,7 @@ struct vfio_dma {
> struct vfio_group {
> struct iommu_group *iommu_group;
> struct list_head next;
> + bool mdev_group; /* An mdev group */
> };
>
> /*
> @@ -1298,6 +1299,75 @@ static bool vfio_iommu_has_sw_msi(struct iommu_group *group, phys_addr_t *base)
> return ret;
> }
>
> +static struct device *vfio_mdev_get_iommu_device(struct device *dev)
> +{
> + struct device *(*fn)(struct device *dev);
> + struct device *iommu_device;
> +
> + fn = symbol_get(mdev_get_iommu_device);
> + if (fn) {
> + iommu_device = fn(dev);
> + symbol_put(mdev_get_iommu_device);
> +
> + return iommu_device;
> + }
> +
> + return NULL;
> +}
> +
> +static int vfio_mdev_attach_domain(struct device *dev, void *data)
> +{
> + struct iommu_domain *domain = data;
> + struct device *iommu_device;
> +
> + iommu_device = vfio_mdev_get_iommu_device(dev);
> + if (iommu_device) {
> + if (iommu_dev_feature_enabled(iommu_device, IOMMU_DEV_FEAT_AUX))
> + return iommu_aux_attach_device(domain, iommu_device);
> + else
> + return iommu_attach_device(domain, iommu_device);
> + }
> +
> + return -EINVAL;
> +}
> +
> +static int vfio_mdev_detach_domain(struct device *dev, void *data)
> +{
> + struct iommu_domain *domain = data;
> + struct device *iommu_device;
> +
> + iommu_device = vfio_mdev_get_iommu_device(dev);
> + if (iommu_device) {
> + if (iommu_dev_feature_enabled(iommu_device, IOMMU_DEV_FEAT_AUX))
> + iommu_aux_detach_device(domain, iommu_device);
> + else
> + iommu_detach_device(domain, iommu_device);
> + }
> +
> + return 0;
> +}
> +
> +static int vfio_iommu_attach_group(struct vfio_domain *domain,
> + struct vfio_group *group)
> +{
> + if (group->mdev_group)
> + return iommu_group_for_each_dev(group->iommu_group,
> + domain->domain,
> + vfio_mdev_attach_domain);
> + else
> + return iommu_attach_group(domain->domain, group->iommu_group);
> +}
> +
> +static void vfio_iommu_detach_group(struct vfio_domain *domain,
> + struct vfio_group *group)
> +{
> + if (group->mdev_group)
> + iommu_group_for_each_dev(group->iommu_group, domain->domain,
> + vfio_mdev_detach_domain);
> + else
> + iommu_detach_group(domain->domain, group->iommu_group);
> +}
> +
> static int vfio_iommu_type1_attach_group(void *iommu_data,
> struct iommu_group *iommu_group)
> {
> @@ -1373,7 +1443,7 @@ static int vfio_iommu_type1_attach_group(void *iommu_data,
> goto out_domain;
> }
>
> - ret = iommu_attach_group(domain->domain, iommu_group);
> + ret = vfio_iommu_attach_group(domain, group);
> if (ret)
> goto out_domain;
>
> @@ -1405,8 +1475,8 @@ static int vfio_iommu_type1_attach_group(void *iommu_data,
> list_for_each_entry(d, &iommu->domain_list, next) {
> if (d->domain->ops == domain->domain->ops &&
> d->prot == domain->prot) {
> - iommu_detach_group(domain->domain, iommu_group);
> - if (!iommu_attach_group(d->domain, iommu_group)) {
> + vfio_iommu_detach_group(domain, group);
> + if (!vfio_iommu_attach_group(d, group)) {
> list_add(&group->next, &d->group_list);
> iommu_domain_free(domain->domain);
> kfree(domain);
> @@ -1414,7 +1484,7 @@ static int vfio_iommu_type1_attach_group(void *iommu_data,
> return 0;
> }
>
> - ret = iommu_attach_group(domain->domain, iommu_group);
> + ret = vfio_iommu_attach_group(domain, group);
> if (ret)
> goto out_domain;
> }
> @@ -1440,7 +1510,7 @@ static int vfio_iommu_type1_attach_group(void *iommu_data,
> return 0;
>
> out_detach:
> - iommu_detach_group(domain->domain, iommu_group);
> + vfio_iommu_detach_group(domain, group);
> out_domain:
> iommu_domain_free(domain->domain);
> out_free:
> @@ -1531,7 +1601,7 @@ static void vfio_iommu_type1_detach_group(void *iommu_data,
> if (!group)
> continue;
>
> - iommu_detach_group(domain->domain, iommu_group);
> + vfio_iommu_detach_group(domain, group);
> list_del(&group->next);
> kfree(group);
> /*
> @@ -1596,7 +1666,7 @@ static void vfio_release_domain(struct vfio_domain *domain, bool external)
> list_for_each_entry_safe(group, group_tmp,
> &domain->group_list, next) {
> if (!external)
> - iommu_detach_group(domain->domain, group->iommu_group);
> + vfio_iommu_detach_group(domain, group);
> list_del(&group->next);
> kfree(group);
> }
>