Re: [RFC PATCH 7/7] iommu/amd: Add support for using AMD IOMMU v2 page table for DMA-API

[Joerg Roedel]

On Fri, Mar 12, 2021 at 03:04:11AM -0600, Suravee Suthikulpanit wrote:
> Introduce init function for setting up DMA domain for DMA-API with
> the IOMMU v2 page table.
> 
> Signed-off-by: Suravee Suthikulpanit 
> ---
>  drivers/iommu/amd/iommu.c | 21 +
>  1 file changed, 21 insertions(+)
> 
> diff --git a/drivers/iommu/amd/iommu.c b/drivers/iommu/amd/iommu.c
> index e29ece6e1e68..bd26de8764bd 100644
> --- a/drivers/iommu/amd/iommu.c
> +++ b/drivers/iommu/amd/iommu.c
> @@ -1937,6 +1937,24 @@ static int protection_domain_init_v1(struct 
> protection_domain *domain, int mode)
>   return 0;
>  }
>  
> +static int protection_domain_init_v2(struct protection_domain *domain)
> +{
> + spin_lock_init(>lock);
> + domain->id = domain_id_alloc();
> + if (!domain->id)
> + return -ENOMEM;
> + INIT_LIST_HEAD(>dev_list);
> +
> + domain->giov = true;
> +
> + if (amd_iommu_pgtable == AMD_IOMMU_V2 &&
> + domain_enable_v2(domain, 1, false)) {
> + return -ENOMEM;
> + }
> +
> + return 0;
> +}
> +

You also need to advertise a different aperture size and a different
pgsize-bitmap. The host page-table can only map a 48 bit address space,
not a 64 bit one like with v1 page-tables.

Regards,

Joerg

[RFC PATCH 7/7] iommu/amd: Add support for using AMD IOMMU v2 page table for DMA-API

[Suravee Suthikulpanit]

Introduce init function for setting up DMA domain for DMA-API with
the IOMMU v2 page table.

Signed-off-by: Suravee Suthikulpanit 
---
 drivers/iommu/amd/iommu.c | 21 +
 1 file changed, 21 insertions(+)

diff --git a/drivers/iommu/amd/iommu.c b/drivers/iommu/amd/iommu.c
index e29ece6e1e68..bd26de8764bd 100644
--- a/drivers/iommu/amd/iommu.c
+++ b/drivers/iommu/amd/iommu.c
@@ -1937,6 +1937,24 @@ static int protection_domain_init_v1(struct 
protection_domain *domain, int mode)
return 0;
 }
 
+static int protection_domain_init_v2(struct protection_domain *domain)
+{
+   spin_lock_init(>lock);
+   domain->id = domain_id_alloc();
+   if (!domain->id)
+   return -ENOMEM;
+   INIT_LIST_HEAD(>dev_list);
+
+   domain->giov = true;
+
+   if (amd_iommu_pgtable == AMD_IOMMU_V2 &&
+   domain_enable_v2(domain, 1, false)) {
+   return -ENOMEM;
+   }
+
+   return 0;
+}
+
 static struct protection_domain *protection_domain_alloc(unsigned int type)
 {
struct io_pgtable_ops *pgtbl_ops;
@@ -1964,6 +1982,9 @@ static struct protection_domain 
*protection_domain_alloc(unsigned int type)
case AMD_IOMMU_V1:
ret = protection_domain_init_v1(domain, mode);
break;
+   case AMD_IOMMU_V2:
+   ret = protection_domain_init_v2(domain);
+   break;
default:
ret = -EINVAL;
}
-- 
2.17.1