Re: [PATCH v2 25/25] iommu: Convert remaining simple drivers to domain_alloc_paging()

[Robin Murphy]

On 2023-05-16 01:00, Jason Gunthorpe wrote:
These drivers don't support IOMMU_DOMAIN_DMA, so this commit effectively
allows them to support that mode.
The prior work to require default_domains makes this safe because every
one of these drivers is either compilation incompatible with dma-iommu.c,
or already establishing a default_domain. In both cases alloc_domain()
will never be called with IOMMU_DOMAIN_DMA for these drivers so it is safe
to drop the test.

Removing these tests clarifies that the domain allocation path is only
about the functionality of a paging domain and has nothing to do with
policy of how the paging domain is used for UNMANAGED/DMA/DMA_FQ.

Tested-by: Niklas Schnelle <schne...@linux.ibm.com>
Signed-off-by: Jason Gunthorpe <j...@nvidia.com>
---
  drivers/iommu/fsl_pamu_domain.c | 7 ++-----
  drivers/iommu/msm_iommu.c       | 7 ++-----
  drivers/iommu/mtk_iommu_v1.c    | 7 ++-----
  drivers/iommu/omap-iommu.c      | 7 ++-----
  drivers/iommu/s390-iommu.c      | 7 ++-----
  5 files changed, 10 insertions(+), 25 deletions(-)

diff --git a/drivers/iommu/fsl_pamu_domain.c b/drivers/iommu/fsl_pamu_domain.c
index ca4f5ebf028783..8d5d6a3acf9dfd 100644
--- a/drivers/iommu/fsl_pamu_domain.c
+++ b/drivers/iommu/fsl_pamu_domain.c
@@ -192,13 +192,10 @@ static void fsl_pamu_domain_free(struct iommu_domain 
*domain)
        kmem_cache_free(fsl_pamu_domain_cache, dma_domain);
  }
  
-static struct iommu_domain *fsl_pamu_domain_alloc(unsigned type)
+static struct iommu_domain *fsl_pamu_domain_alloc_paging(struct device *dev)

This isn't a paging domain - it doesn't support map/unmap, and AFAICT 
all it has ever been intended to do is "isolate" accesses to within an 
aperture which is never set to anything less than the entire physical 
address space :/

I hate to imagine what the VFIO userspace applications looked like...

Thanks,
Robin.

  {
        struct fsl_dma_domain *dma_domain;
  
-	if (type != IOMMU_DOMAIN_UNMANAGED)
-               return NULL;
-
        dma_domain = kmem_cache_zalloc(fsl_pamu_domain_cache, GFP_KERNEL);
        if (!dma_domain)
                return NULL;
@@ -476,7 +473,7 @@ static const struct iommu_ops fsl_pamu_ops = {
        .identity_domain = &fsl_pamu_identity_domain,
        .def_domain_type = &fsl_pamu_def_domain_type,
        .capable        = fsl_pamu_capable,
-       .domain_alloc   = fsl_pamu_domain_alloc,
+       .domain_alloc_paging = fsl_pamu_domain_alloc_paging,
        .probe_device   = fsl_pamu_probe_device,
        .device_group   = fsl_pamu_device_group,
        .default_domain_ops = &(const struct iommu_domain_ops) {
diff --git a/drivers/iommu/msm_iommu.c b/drivers/iommu/msm_iommu.c
index 26ed81cfeee897..a163cee0b7242d 100644
--- a/drivers/iommu/msm_iommu.c
+++ b/drivers/iommu/msm_iommu.c
@@ -302,13 +302,10 @@ static void __program_context(void __iomem *base, int ctx,
        SET_M(base, ctx, 1);
  }
  
-static struct iommu_domain *msm_iommu_domain_alloc(unsigned type)
+static struct iommu_domain *msm_iommu_domain_alloc_paging(struct device *dev)
  {
        struct msm_priv *priv;
  
-	if (type != IOMMU_DOMAIN_UNMANAGED)
-               return NULL;
-
        priv = kzalloc(sizeof(*priv), GFP_KERNEL);
        if (!priv)
                goto fail_nomem;
@@ -691,7 +688,7 @@ irqreturn_t msm_iommu_fault_handler(int irq, void *dev_id)
  
  static struct iommu_ops msm_iommu_ops = {
        .identity_domain = &msm_iommu_identity_domain,
-       .domain_alloc = msm_iommu_domain_alloc,
+       .domain_alloc_paging = msm_iommu_domain_alloc_paging,
        .probe_device = msm_iommu_probe_device,
        .device_group = generic_device_group,
        .pgsize_bitmap = MSM_IOMMU_PGSIZES,
diff --git a/drivers/iommu/mtk_iommu_v1.c b/drivers/iommu/mtk_iommu_v1.c
index 7c0c1d50df5f75..67e044c1a7d93b 100644
--- a/drivers/iommu/mtk_iommu_v1.c
+++ b/drivers/iommu/mtk_iommu_v1.c
@@ -270,13 +270,10 @@ static int mtk_iommu_v1_domain_finalise(struct 
mtk_iommu_v1_data *data)
        return 0;
  }
  
-static struct iommu_domain *mtk_iommu_v1_domain_alloc(unsigned type)
+static struct iommu_domain *mtk_iommu_v1_domain_alloc_paging(struct device 
*dev)
  {
        struct mtk_iommu_v1_domain *dom;
  
-	if (type != IOMMU_DOMAIN_UNMANAGED)
-               return NULL;
-
        dom = kzalloc(sizeof(*dom), GFP_KERNEL);
        if (!dom)
                return NULL;
@@ -585,7 +582,7 @@ static int mtk_iommu_v1_hw_init(const struct 
mtk_iommu_v1_data *data)
  
  static const struct iommu_ops mtk_iommu_v1_ops = {
        .identity_domain = &mtk_iommu_v1_identity_domain,
-       .domain_alloc   = mtk_iommu_v1_domain_alloc,
+       .domain_alloc_paging = mtk_iommu_v1_domain_alloc_paging,
        .probe_device   = mtk_iommu_v1_probe_device,
        .probe_finalize = mtk_iommu_v1_probe_finalize,
        .release_device = mtk_iommu_v1_release_device,
diff --git a/drivers/iommu/omap-iommu.c b/drivers/iommu/omap-iommu.c
index 34340ef15241bc..fcf99bd195b32e 100644
--- a/drivers/iommu/omap-iommu.c
+++ b/drivers/iommu/omap-iommu.c
@@ -1580,13 +1580,10 @@ static struct iommu_domain omap_iommu_identity_domain = 
{
        .ops = &omap_iommu_identity_ops,
  };
  
-static struct iommu_domain *omap_iommu_domain_alloc(unsigned type)
+static struct iommu_domain *omap_iommu_domain_alloc_paging(struct device *dev)
  {
        struct omap_iommu_domain *omap_domain;
  
-	if (type != IOMMU_DOMAIN_UNMANAGED)
-               return NULL;
-
        omap_domain = kzalloc(sizeof(*omap_domain), GFP_KERNEL);
        if (!omap_domain)
                return NULL;
@@ -1748,7 +1745,7 @@ static struct iommu_group *omap_iommu_device_group(struct 
device *dev)
  
  static const struct iommu_ops omap_iommu_ops = {
        .identity_domain = &omap_iommu_identity_domain,
-       .domain_alloc   = omap_iommu_domain_alloc,
+       .domain_alloc_paging = omap_iommu_domain_alloc_paging,
        .probe_device   = omap_iommu_probe_device,
        .release_device = omap_iommu_release_device,
        .device_group   = omap_iommu_device_group,
diff --git a/drivers/iommu/s390-iommu.c b/drivers/iommu/s390-iommu.c
index f0c867c57a5b9b..5695ad71d60e24 100644
--- a/drivers/iommu/s390-iommu.c
+++ b/drivers/iommu/s390-iommu.c
@@ -39,13 +39,10 @@ static bool s390_iommu_capable(struct device *dev, enum 
iommu_cap cap)
        }
  }
  
-static struct iommu_domain *s390_domain_alloc(unsigned domain_type)
+static struct iommu_domain *s390_domain_alloc_paging(struct device *dev)
  {
        struct s390_domain *s390_domain;
  
-	if (domain_type != IOMMU_DOMAIN_UNMANAGED)
-               return NULL;
-
        s390_domain = kzalloc(sizeof(*s390_domain), GFP_KERNEL);
        if (!s390_domain)
                return NULL;
@@ -447,7 +444,7 @@ void zpci_destroy_iommu(struct zpci_dev *zdev)
  static const struct iommu_ops s390_iommu_ops = {
        .default_domain = &s390_iommu_platform_domain,
        .capable = s390_iommu_capable,
-       .domain_alloc = s390_domain_alloc,
+       .domain_alloc_paging = s390_domain_alloc_paging,
        .probe_device = s390_iommu_probe_device,
        .release_device = s390_iommu_release_device,
        .device_group = generic_device_group,