[PATCH rc] drm/tegra: Do not assume that a NULL domain means no DMA IOMMU

[PATCH rc] drm/tegra: Do not assume that a NULL domain means no DMA IOMMU

[Jason Gunthorpe]

Previously with tegra-smmu, even with CONFIG_IOMMU_DMA, the default domain
could have been left as NULL. The NULL domain is specially recognized by
host1x_client_iommu_attach() as meaning it is not the DMA domain and
should be replaced with the special shared domain.

This happened prior to the below commit because tegra-smmu was using the
NULL domain to mean IDENTITY.

Now that the domain is properly labled the test in DRM doesn't see NULL.
Check for IDENTITY as well to enable the special domains.

Fixes: c8cc2655cc6c ("iommu/tegra-smmu: Implement an IDENTITY domain")
Reported-by: diogo.ivo@tecnico.ulisboa.pt
Closes: https://lore.kernel.org/all/bbmhcoghrprmbdibnjum6lefix2eoquxrde7wyqeulm4xabmlm@b6jy32saugqh/
Tested-by: diogo.ivo@tecnico.ulisboa.pt
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
---
 drivers/gpu/drm/tegra/drm.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/tegra/drm.c b/drivers/gpu/drm/tegra/drm.c
index ff36171c8fb700..a73cff7a307082 100644
--- a/drivers/gpu/drm/tegra/drm.c
+++ b/drivers/gpu/drm/tegra/drm.c
@@ -960,7 +960,8 @@ int host1x_client_iommu_attach(struct host1x_client *client)
 	 * not the shared IOMMU domain, don't try to attach it to a different
 	 * domain. This allows using the IOMMU-backed DMA API.
 	 */
-	if (domain && domain != tegra->domain)
+	if (domain && domain->type != IOMMU_DOMAIN_IDENTITY &&
+	    domain != tegra->domain)
 		return 0;
 
 	if (tegra->domain) {

base-commit: 755bd21c4a64124e9c85a77e742df3073eac9a41
-- 
2.43.0

[PATCH rc] drm/tegra: Do not assume that a NULL domain means no DMA IOMMU

[Jason Gunthorpe]

Previously with tegra-smmu, even with CONFIG_IOMMU_DMA, the default domain
could have been left as NULL. The NULL domain is specially recognized by
host1x_client_iommu_attach() as meaning it is not the DMA domain and
should be replaced with the special shared domain.

This happened prior to the below commit because tegra-smmu was using the
NULL domain to mean IDENTITY.

Now that the domain is properly labled the test in DRM doesn't see NULL.
Check for IDENTITY as well to enable the special domains.

Fixes: c8cc2655cc6c ("iommu/tegra-smmu: Implement an IDENTITY domain")
Reported-by: diogo.ivo@tecnico.ulisboa.pt
Closes: https://lore.kernel.org/all/bbmhcoghrprmbdibnjum6lefix2eoquxrde7wyqeulm4xabmlm@b6jy32saugqh/
Tested-by: diogo.ivo@tecnico.ulisboa.pt
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
---
 drivers/gpu/drm/tegra/drm.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/tegra/drm.c b/drivers/gpu/drm/tegra/drm.c
index ff36171c8fb700..a73cff7a307082 100644
--- a/drivers/gpu/drm/tegra/drm.c
+++ b/drivers/gpu/drm/tegra/drm.c
@@ -960,7 +960,8 @@ int host1x_client_iommu_attach(struct host1x_client *client)
 	 * not the shared IOMMU domain, don't try to attach it to a different
 	 * domain. This allows using the IOMMU-backed DMA API.
 	 */
-	if (domain && domain != tegra->domain)
+	if (domain && domain->type != IOMMU_DOMAIN_IDENTITY &&
+	    domain != tegra->domain)
 		return 0;
 
 	if (tegra->domain) {

base-commit: 755bd21c4a64124e9c85a77e742df3073eac9a41
-- 
2.43.0

Re: [PATCH rc] drm/tegra: Do not assume that a NULL domain means no DMA IOMMU

[Joerg Roedel]

On Tue, Jan 30, 2024 at 12:14:54PM -0400, Jason Gunthorpe wrote:
> Previously with tegra-smmu, even with CONFIG_IOMMU_DMA, the default domain
> could have been left as NULL. The NULL domain is specially recognized by
> host1x_client_iommu_attach() as meaning it is not the DMA domain and
> should be replaced with the special shared domain.
> 
> This happened prior to the below commit because tegra-smmu was using the
> NULL domain to mean IDENTITY.
> 
> Now that the domain is properly labled the test in DRM doesn't see NULL.
> Check for IDENTITY as well to enable the special domains.
> 
> Fixes: c8cc2655cc6c ("iommu/tegra-smmu: Implement an IDENTITY domain")
> Reported-by: diogo.ivo@tecnico.ulisboa.pt
> Closes: https://lore.kernel.org/all/bbmhcoghrprmbdibnjum6lefix2eoquxrde7wyqeulm4xabmlm@b6jy32saugqh/
> Tested-by: diogo.ivo@tecnico.ulisboa.pt
> Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
> ---
>  drivers/gpu/drm/tegra/drm.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)

Applied, thanks.

-- 
Jörg Rödel
jroedel@suse.de

SUSE Software Solutions Germany GmbH
Frankenstraße 146
90461 Nürnberg
Germany
https://www.suse.com/

Geschäftsführer: Ivo Totev, Andrew McDonald, Werner Knoblich
(HRB 36809, AG Nürnberg)