On Thu, Mar 4, 2021 at 7:48 AM Robin Murphy <robin.murphy@xxxxxxx> wrote:
>
> On 2021-03-01 08:42, Christoph Hellwig wrote:
> > Signed-off-by: Christoph Hellwig <hch@xxxxxx>
>
> Moreso than the previous patch, where the feature is at least relatively
> generic (note that there's a bunch of in-flight development around
> DOMAIN_ATTR_NESTING), I'm really not convinced that it's beneficial to
> bloat the generic iommu_ops structure with private driver-specific
> interfaces. The attribute interface is a great compromise for these
> kinds of things, and you can easily add type-checked wrappers around it
> for external callers (maybe even make the actual attributes internal
> between the IOMMU core and drivers) if that's your concern.
I suppose if this is *just* for the GPU we could move it into adreno_smmu_priv..
But one thing I'm not sure about is whether
IO_PGTABLE_QUIRK_ARM_OUTER_WBWA is something that other devices
*should* be using as well, but just haven't gotten around to yet.
BR,
-R
> Robin.
>
> > ---
> > drivers/gpu/drm/msm/adreno/adreno_gpu.c | 2 +-
> > drivers/iommu/arm/arm-smmu/arm-smmu.c | 40 +++++++------------------
> > drivers/iommu/iommu.c | 9 ++++++
> > include/linux/iommu.h | 9 +++++-
> > 4 files changed, 29 insertions(+), 31 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/msm/adreno/adreno_gpu.c b/drivers/gpu/drm/msm/adreno/adreno_gpu.c
> > index 0f184c3dd9d9ec..78d98ab2ee3a68 100644
> > --- a/drivers/gpu/drm/msm/adreno/adreno_gpu.c
> > +++ b/drivers/gpu/drm/msm/adreno/adreno_gpu.c
> > @@ -191,7 +191,7 @@ void adreno_set_llc_attributes(struct iommu_domain *iommu)
> > struct io_pgtable_domain_attr pgtbl_cfg;
> >
> > pgtbl_cfg.quirks = IO_PGTABLE_QUIRK_ARM_OUTER_WBWA;
> > - iommu_domain_set_attr(iommu, DOMAIN_ATTR_IO_PGTABLE_CFG, &pgtbl_cfg);
> > + iommu_domain_set_pgtable_attr(iommu, &pgtbl_cfg);
> > }
> >
> > struct msm_gem_address_space *
> > diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu.c b/drivers/iommu/arm/arm-smmu/arm-smmu.c
> > index 2e17d990d04481..2858999c86dfd1 100644
> > --- a/drivers/iommu/arm/arm-smmu/arm-smmu.c
> > +++ b/drivers/iommu/arm/arm-smmu/arm-smmu.c
> > @@ -1515,40 +1515,22 @@ static int arm_smmu_domain_enable_nesting(struct iommu_domain *domain)
> > return ret;
> > }
> >
> > -static int arm_smmu_domain_set_attr(struct iommu_domain *domain,
> > - enum iommu_attr attr, void *data)
> > +static int arm_smmu_domain_set_pgtable_attr(struct iommu_domain *domain,
> > + struct io_pgtable_domain_attr *pgtbl_cfg)
> > {
> > - int ret = 0;
> > struct arm_smmu_domain *smmu_domain = to_smmu_domain(domain);
> > + int ret = -EPERM;
> >
> > - mutex_lock(&smmu_domain->init_mutex);
> > -
> > - switch(domain->type) {
> > - case IOMMU_DOMAIN_UNMANAGED:
> > - switch (attr) {
> > - case DOMAIN_ATTR_IO_PGTABLE_CFG: {
> > - struct io_pgtable_domain_attr *pgtbl_cfg = data;
> > -
> > - if (smmu_domain->smmu) {
> > - ret = -EPERM;
> > - goto out_unlock;
> > - }
> > + if (domain->type != IOMMU_DOMAIN_UNMANAGED)
> > + return -EINVAL;
> >
> > - smmu_domain->pgtbl_cfg = *pgtbl_cfg;
> > - break;
> > - }
> > - default:
> > - ret = -ENODEV;
> > - }
> > - break;
> > - case IOMMU_DOMAIN_DMA:
> > - ret = -ENODEV;
> > - break;
> > - default:
> > - ret = -EINVAL;
> > + mutex_lock(&smmu_domain->init_mutex);
> > + if (!smmu_domain->smmu) {
> > + smmu_domain->pgtbl_cfg = *pgtbl_cfg;
> > + ret = 0;
> > }
> > -out_unlock:
> > mutex_unlock(&smmu_domain->init_mutex);
> > +
> > return ret;
> > }
> >
> > @@ -1609,7 +1591,7 @@ static struct iommu_ops arm_smmu_ops = {
> > .device_group = arm_smmu_device_group,
> > .dma_use_flush_queue = arm_smmu_dma_use_flush_queue,
> > .dma_enable_flush_queue = arm_smmu_dma_enable_flush_queue,
> > - .domain_set_attr = arm_smmu_domain_set_attr,
> > + .domain_set_pgtable_attr = arm_smmu_domain_set_pgtable_attr,
> > .domain_enable_nesting = arm_smmu_domain_enable_nesting,
> > .of_xlate = arm_smmu_of_xlate,
> > .get_resv_regions = arm_smmu_get_resv_regions,
> > diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
> > index 2e9e058501a953..8490aefd4b41f8 100644
> > --- a/drivers/iommu/iommu.c
> > +++ b/drivers/iommu/iommu.c
> > @@ -2693,6 +2693,15 @@ int iommu_domain_enable_nesting(struct iommu_domain *domain)
> > }
> > EXPORT_SYMBOL_GPL(iommu_domain_enable_nesting);
> >
> > +int iommu_domain_set_pgtable_attr(struct iommu_domain *domain,
> > + struct io_pgtable_domain_attr *pgtbl_cfg)
> > +{
> > + if (!domain->ops->domain_set_pgtable_attr)
> > + return -EINVAL;
> > + return domain->ops->domain_set_pgtable_attr(domain, pgtbl_cfg);
> > +}
> > +EXPORT_SYMBOL_GPL(iommu_domain_set_pgtable_attr);
> > +
> > void iommu_get_resv_regions(struct device *dev, struct list_head *list)
> > {
> > const struct iommu_ops *ops = dev->bus->iommu_ops;
> > diff --git a/include/linux/iommu.h b/include/linux/iommu.h
> > index aed88aa3bd3edf..39d3ed4d2700ac 100644
> > --- a/include/linux/iommu.h
> > +++ b/include/linux/iommu.h
> > @@ -40,6 +40,7 @@ struct iommu_domain;
> > struct notifier_block;
> > struct iommu_sva;
> > struct iommu_fault_event;
> > +struct io_pgtable_domain_attr;
> >
> > /* iommu fault flags */
> > #define IOMMU_FAULT_READ 0x0
> > @@ -107,7 +108,6 @@ enum iommu_cap {
> > */
> >
> > enum iommu_attr {
> > - DOMAIN_ATTR_IO_PGTABLE_CFG,
> > DOMAIN_ATTR_MAX,
> > };
> >
> > @@ -196,6 +196,7 @@ struct iommu_iotlb_gather {
> > * @dma_enable_flush_queue: Try to enable the DMA flush queue
> > * @domain_set_attr: Change domain attributes
> > * @domain_enable_nesting: Enable nesting
> > + * @domain_set_pgtable_attr: Set io page table attributes
> > * @get_resv_regions: Request list of reserved regions for a device
> > * @put_resv_regions: Free list of reserved regions for a device
> > * @apply_resv_region: Temporary helper call-back for iova reserved ranges
> > @@ -249,6 +250,8 @@ struct iommu_ops {
> > int (*domain_set_attr)(struct iommu_domain *domain,
> > enum iommu_attr attr, void *data);
> > int (*domain_enable_nesting)(struct iommu_domain *domain);
> > + int (*domain_set_pgtable_attr)(struct iommu_domain *domain,
> > + struct io_pgtable_domain_attr *pgtbl_cfg);
> >
> > /* Request/Free a list of reserved regions for a device */
> > void (*get_resv_regions)(struct device *dev, struct list_head *list);
> > @@ -493,9 +496,13 @@ extern int iommu_group_id(struct iommu_group *group);
> > extern struct iommu_domain *iommu_group_default_domain(struct iommu_group *);
> >
> > bool iommu_dma_use_flush_queue(struct iommu_domain *domain);
> > +int iommu_domain_set_pgtable_attr(struct iommu_domain *domain,
> > + struct io_pgtable_domain_attr *pgtbl_cfg);
> > extern int iommu_domain_set_attr(struct iommu_domain *domain, enum iommu_attr,
> > void *data);
> > int iommu_domain_enable_nesting(struct iommu_domain *domain);
> > +int iommu_domain_set_pgtable_attr(struct iommu_domain *domain,
> > + struct io_pgtable_domain_attr *pgtbl_cfg);
> >
> > extern int report_iommu_fault(struct iommu_domain *domain, struct device *dev,
> > unsigned long iova, int flags);
> >
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