Subject: Re: linux-next: manual merge of the iommufd tree with the iommu tree

From: Stephen Rothwell <[email-masked]>
Date: Tue, 31 Oct 2023 16:12:14 +1100

Hi all,

On Mon, 30 Oct 2023 15:26:21 -0300 Jason Gunthorpe <[email-masked]> wrote:
>
> On Fri, Oct 27, 2023 at 05:15:22PM +1100, Stephen Rothwell wrote:
> > 
> > On Fri, 27 Oct 2023 15:55:22 +1100 Stephen Rothwell <[email-masked]> wrote:  
> > >
> > > Today's linux-next merge of the iommufd tree got a conflict in:
> > > 
> > >   drivers/iommu/iommufd/selftest.c
> > > 
> > > between commits:
> > > 
> > >   1c68cbc64fe6 ("iommu: Add IOMMU_DOMAIN_PLATFORM")
> > >   13fbceb1b8e9 ("iommufd: Convert to alloc_domain_paging()")
> > > 
> > > from the iommu tree and commits:
> > > 
> > >   408663619fcf ("iommufd/selftest: Add domain_alloc_user() support in iommu mock")
> > >   266ce58989ba ("iommufd/selftest: Test IOMMU_HWPT_ALLOC_DIRTY_TRACKING")
> > >   7adf267d66d1 ("iommufd/selftest: Test IOMMU_HWPT_SET_DIRTY_TRACKING")
> > >   a9af47e382a4 ("iommufd/selftest: Test IOMMU_HWPT_GET_DIRTY_BITMAP")
> > >   0795b305da89 ("iommufd/selftest: Test IOMMU_HWPT_GET_DIRTY_BITMAP_NO_CLEAR flag")
> > >   65fe32f7a447 ("iommufd/selftest: Add nested domain allocation for mock domain")
> > > 
> > > from the iommufd tree.
> > > 
> > > I fixed it up (see below) and can carry the fix as necessary. This
> > > is now fixed as far as linux-next is concerned, but any non trivial
> > > conflicts should be mentioned to your upstream maintainer when your tree
> > > is submitted for merging.  You may also want to consider cooperating
> > > with the maintainer of the conflicting tree to minimise any particularly
> > > complex conflicts.  
> > 
> > The resolution should have been as below (I think).  
> 
> This was too horrible, I pushed a patch to reorganize the new iommufd side
> code to more closely match how the domain_alloc_paging stuff is
> supposed to work

I have used the conflict resolution below now.

-- 
Cheers,
Stephen Rothwell

diff --cc drivers/iommu/iommufd/selftest.c
index ee6079847091,d43a87737c1e..5d93434003d8
--- a/drivers/iommu/iommufd/selftest.c
+++ b/drivers/iommu/iommufd/selftest.c
@@@ -155,6 -240,81 +235,72 @@@ static struct iommu_domain *mock_domain
  	return &mock->domain;
  }
  
+ static struct iommu_domain *
+ __mock_domain_alloc_nested(struct mock_iommu_domain *mock_parent,
+ 			   const struct iommu_hwpt_selftest *user_cfg)
+ {
+ 	struct mock_iommu_domain_nested *mock_nested;
+ 	int i;
+ 
+ 	mock_nested = kzalloc(sizeof(*mock_nested), GFP_KERNEL);
+ 	if (!mock_nested)
+ 		return ERR_PTR(-ENOMEM);
+ 	mock_nested->parent = mock_parent;
+ 	mock_nested->domain.ops = &domain_nested_ops;
+ 	mock_nested->domain.type = IOMMU_DOMAIN_NESTED;
+ 	for (i = 0; i < MOCK_NESTED_DOMAIN_IOTLB_NUM; i++)
+ 		mock_nested->iotlb[i] = user_cfg->iotlb;
+ 	return &mock_nested->domain;
+ }
+ 
 -static struct iommu_domain *mock_domain_alloc(unsigned int iommu_domain_type)
 -{
 -	if (iommu_domain_type == IOMMU_DOMAIN_BLOCKED)
 -		return &mock_blocking_domain;
 -	if (iommu_domain_type == IOMMU_DOMAIN_UNMANAGED)
 -		return mock_domain_alloc_paging(NULL);
 -	return NULL;
 -}
 -
+ static struct iommu_domain *
+ mock_domain_alloc_user(struct device *dev, u32 flags,
+ 		       struct iommu_domain *parent,
+ 		       const struct iommu_user_data *user_data)
+ {
+ 	struct mock_iommu_domain *mock_parent;
+ 	struct iommu_hwpt_selftest user_cfg;
+ 	int rc;
+ 
+ 	/* must be mock_domain */
+ 	if (!parent) {
+ 		struct mock_dev *mdev = container_of(dev, struct mock_dev, dev);
+ 		bool has_dirty_flag = flags & IOMMU_HWPT_ALLOC_DIRTY_TRACKING;
+ 		bool no_dirty_ops = mdev->flags & MOCK_FLAGS_DEVICE_NO_DIRTY;
+ 		struct iommu_domain *domain;
+ 
+ 		if (flags & (~(IOMMU_HWPT_ALLOC_NEST_PARENT |
+ 			       IOMMU_HWPT_ALLOC_DIRTY_TRACKING)))
+ 			return ERR_PTR(-EOPNOTSUPP);
+ 		if (user_data || (has_dirty_flag && no_dirty_ops))
+ 			return ERR_PTR(-EOPNOTSUPP);
+ 		domain = mock_domain_alloc_paging(NULL);
+ 		if (!domain)
+ 			return ERR_PTR(-ENOMEM);
+ 		if (has_dirty_flag)
+ 			container_of(domain, struct mock_iommu_domain, domain)
+ 				->domain.dirty_ops = &dirty_ops;
+ 		return domain;
+ 	}
+ 
+ 	/* must be mock_domain_nested */
+ 	if (user_data->type != IOMMU_HWPT_DATA_SELFTEST || flags)
+ 		return ERR_PTR(-EOPNOTSUPP);
+ 	if (!parent || parent->ops != mock_ops.default_domain_ops)
+ 		return ERR_PTR(-EINVAL);
+ 
+ 	mock_parent = container_of(parent, struct mock_iommu_domain, domain);
+ 	if (!mock_parent)
+ 		return ERR_PTR(-EINVAL);
+ 
+ 	rc = iommu_copy_struct_from_user(&user_cfg, user_data,
+ 					 IOMMU_HWPT_DATA_SELFTEST, iotlb);
+ 	if (rc)
+ 		return ERR_PTR(rc);
+ 
+ 	return __mock_domain_alloc_nested(mock_parent, &user_cfg);
+ }
+ 
  static void mock_domain_free(struct iommu_domain *domain)
  {
  	struct mock_iommu_domain *mock =
@@@ -272,9 -432,28 +418,20 @@@ static phys_addr_t mock_domain_iova_to_
  
  static bool mock_domain_capable(struct device *dev, enum iommu_cap cap)
  {
- 	return cap == IOMMU_CAP_CACHE_COHERENCY;
+ 	struct mock_dev *mdev = container_of(dev, struct mock_dev, dev);
+ 
+ 	switch (cap) {
+ 	case IOMMU_CAP_CACHE_COHERENCY:
+ 		return true;
+ 	case IOMMU_CAP_DIRTY_TRACKING:
+ 		return !(mdev->flags & MOCK_FLAGS_DEVICE_NO_DIRTY);
+ 	default:
+ 		break;
+ 	}
+ 
+ 	return false;
  }
  
 -static void mock_domain_set_plaform_dma_ops(struct device *dev)
 -{
 -	/*
 -	 * mock doesn't setup default domains because we can't hook into the
 -	 * normal probe path
 -	 */
 -}
 -
  static struct iommu_device mock_iommu_device = {
  };
  
@@@ -293,8 -466,10 +450,9 @@@ static const struct iommu_ops mock_ops 
  	.owner = THIS_MODULE,
  	.pgsize_bitmap = MOCK_IO_PAGE_SIZE,
  	.hw_info = mock_domain_hw_info,
 -	.domain_alloc = mock_domain_alloc,
 +	.domain_alloc_paging = mock_domain_alloc_paging,
+ 	.domain_alloc_user = mock_domain_alloc_user,
  	.capable = mock_domain_capable,
 -	.set_platform_dma_ops = mock_domain_set_plaform_dma_ops,
  	.device_group = generic_device_group,
  	.probe_device = mock_probe_device,
  	.default_domain_ops =