[PATCH 02/15] iommu: Introduce iommu domain types
From: Will Deacon <hidden>
Date: 2015-01-28 20:18:12
Also in:
linux-iommu, linux-samsung-soc, linux-tegra, lkml
Hi Joerg, Thanks for posting this! On Mon, Jan 26, 2015 at 11:51:32PM +0000, Joerg Roedel wrote:
quoted hunk ↗ jump to hunk
From: Joerg Roedel <redacted> This allows to handle domains differently based on their type in the future. An IOMMU driver can implement certain optimizations for DMA-API domains for example. Signed-off-by: Joerg Roedel <redacted> --- drivers/iommu/iommu.c | 5 +++-- include/linux/iommu.h | 11 ++++++++++- 2 files changed, 13 insertions(+), 3 deletions(-)diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c index 684efc0..ab24d77 100644 --- a/drivers/iommu/iommu.c +++ b/drivers/iommu/iommu.c@@ -909,14 +909,15 @@ struct iommu_domain *iommu_domain_alloc(struct bus_type *bus) ops = bus->iommu_ops; if (ops->domain_alloc) - domain = ops->domain_alloc(); + domain = ops->domain_alloc(IOMMU_DOMAIN_UNMANAGED); else domain = kzalloc(sizeof(*domain), GFP_KERNEL); if (!domain) return NULL; - domain->ops = bus->iommu_ops; + domain->ops = bus->iommu_ops; + domain->type = IOMMU_DOMAIN_UNMANAGED; if (ops->domain_init && domain->ops->domain_init(domain)) goto out_free;diff --git a/include/linux/iommu.h b/include/linux/iommu.h index 69d1d12..0b67f65 100644 --- a/include/linux/iommu.h +++ b/include/linux/iommu.h@@ -51,7 +51,16 @@ struct iommu_domain_geometry { bool force_aperture; /* DMA only allowed in mappable range? */ }; +/* This are the possible domain-types */ +enum iommu_domain_type { + IOMMU_DOMAIN_DMA, /* Domain used for DMA-API */ + IOMMU_DOMAIN_IDENTITY, /* Identity mapped domain */
What happens if somebody calls map or unmap on an identity-mapping domain? Can we catch that in the IOMMU core before calling the IOMMU driver? That also implies we need something extra to parameterise the attributes for the mapping (e.g. cacheable, read-only) and also potentially the address range.
+ IOMMU_DOMAIN_UNMANAGED, /* Domain mappings are managed by a third party + user (like KVM or VFIO) */
We already have the domain attributes (iommu_attr) to describe features of a domain. Is there really a need for this extra type, or can we extend the attribute set and allow for domain allocation with attributes? Will