| Message ID | 20240812071034.9443-3-baolu.lu@linux.intel.com |
|---|---|
| State | New |
| Headers | show |
| Series | [1/3] drm/nouveau/tegra: Use iommu_paging_domain_alloc() | expand |
On 2024/8/28 23:27, Thierry Reding wrote: > On Mon, Aug 12, 2024 at 03:10:34PM GMT, Lu Baolu wrote: >> Commit <17de3f5fdd35> ("iommu: Retire bus ops") removes iommu ops from >> the bus structure. The iommu subsystem no longer relies on bus for >> operations. So iommu_domain_alloc() interface is no longer relevant. >> >> Normally, iommu_paging_domain_alloc() could be a replacement for >> iommu_domain_alloc() if the caller has the right device for IOMMU API >> use. Unfortunately, this is not the case for this driver. >> >> Iterate the devices on the platform bus and find a suitable device >> whose device DMA is translated by an IOMMU. Then use this device to >> allocate an iommu domain. The iommu subsystem prevents domains >> allocated by one iommu driver from being attached to devices managed >> by any different iommu driver. >> >> Signed-off-by: Lu Baolu<baolu.lu@linux.intel.com> >> Link:https://lore.kernel.org/r/20240610085555.88197-20-baolu.lu@linux.intel.com >> --- >> drivers/gpu/drm/tegra/drm.c | 34 +++++++++++++++++++++++++--------- >> 1 file changed, 25 insertions(+), 9 deletions(-) > Actually I think we can just do something like this: > > --- >8 --- > diff --git a/drivers/gpu/drm/tegra/drm.c b/drivers/gpu/drm/tegra/drm.c > index d9f0728c3afd..d35e411d536b 100644 > --- a/drivers/gpu/drm/tegra/drm.c > +++ b/drivers/gpu/drm/tegra/drm.c > @@ -1150,7 +1150,7 @@ static int host1x_drm_probe(struct host1x_device *dev) > } > > if (host1x_drm_wants_iommu(dev) && iommu_present(&platform_bus_type)) { > - tegra->domain = iommu_domain_alloc(&platform_bus_type); > + tegra->domain = iommu_paging_domain_alloc(dev->dev.parent); > if (!tegra->domain) { > err = -ENOMEM; > goto free; > --- >8 --- > > That refers to the physical device that the host1x_device virtual device > was instantiated from and is a common parent to all physical devices > that are part of the virtual device. Yes, this is really what we want. I will update the patch series later. Thanks, baolu
diff --git a/drivers/gpu/drm/tegra/drm.c b/drivers/gpu/drm/tegra/drm.c index 03d1c76aec2d..ee391f859992 100644 --- a/drivers/gpu/drm/tegra/drm.c +++ b/drivers/gpu/drm/tegra/drm.c @@ -1133,6 +1133,17 @@ static bool host1x_drm_wants_iommu(struct host1x_device *dev) return domain != NULL; } +static int iommu_mapped_device(struct device *dev, void *data) +{ + struct device **iommu_dev = data; + + if (!device_iommu_mapped(dev)) + return 0; + + *iommu_dev = dev; + return 1; +} + static int host1x_drm_probe(struct host1x_device *dev) { struct tegra_drm *tegra; @@ -1149,16 +1160,21 @@ static int host1x_drm_probe(struct host1x_device *dev) goto put; } - if (host1x_drm_wants_iommu(dev) && iommu_present(&platform_bus_type)) { - tegra->domain = iommu_domain_alloc(&platform_bus_type); - if (!tegra->domain) { - err = -ENOMEM; - goto free; + if (host1x_drm_wants_iommu(dev)) { + struct device *iommu_dev = NULL; + + bus_for_each_dev(&platform_bus_type, NULL, &iommu_dev, iommu_mapped_device); + if (iommu_dev) { + tegra->domain = iommu_paging_domain_alloc(iommu_dev); + if (IS_ERR(tegra->domain)) { + err = PTR_ERR(tegra->domain); + goto free; + } + + err = iova_cache_get(); + if (err < 0) + goto domain; } - - err = iova_cache_get(); - if (err < 0) - goto domain; } mutex_init(&tegra->clients_lock);
Commit <17de3f5fdd35> ("iommu: Retire bus ops") removes iommu ops from the bus structure. The iommu subsystem no longer relies on bus for operations. So iommu_domain_alloc() interface is no longer relevant. Normally, iommu_paging_domain_alloc() could be a replacement for iommu_domain_alloc() if the caller has the right device for IOMMU API use. Unfortunately, this is not the case for this driver. Iterate the devices on the platform bus and find a suitable device whose device DMA is translated by an IOMMU. Then use this device to allocate an iommu domain. The iommu subsystem prevents domains allocated by one iommu driver from being attached to devices managed by any different iommu driver. Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com> Link: https://lore.kernel.org/r/20240610085555.88197-20-baolu.lu@linux.intel.com --- drivers/gpu/drm/tegra/drm.c | 34 +++++++++++++++++++++++++--------- 1 file changed, 25 insertions(+), 9 deletions(-)