[RFC PATCH v3 06/12] iommu: Split 'addr_merge' argument to iommu_pgsize() into separate parts

[Isaac J. Manjarres]

From: Will Deacon 

The 'addr_merge' parameter to iommu_pgsize() is a fabricated address
intended to describe the alignment requirements to consider when
choosing an appropriate page size. On the iommu_map() path, this address
is the logical OR of the virtual and physical addresses.

Subsequent improvements to iommu_pgsize() will need to check the
alignment of the virtual and physical components of 'addr_merge'
independently, so pass them in as separate parameters and reconstruct
'addr_merge' locally.

No functional change.

Signed-off-by: Will Deacon 
Signed-off-by: Isaac J. Manjarres 
---
 drivers/iommu/iommu.c | 10 ++
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index 9006397b6604..a3bbf7e310b0 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -2357,12 +2357,13 @@ phys_addr_t iommu_iova_to_phys(struct iommu_domain 
*domain, dma_addr_t iova)
 }
 EXPORT_SYMBOL_GPL(iommu_iova_to_phys);
 
-static size_t iommu_pgsize(struct iommu_domain *domain,
-  unsigned long addr_merge, size_t size)
+static size_t iommu_pgsize(struct iommu_domain *domain, unsigned long iova,
+  phys_addr_t paddr, size_t size)
 {
unsigned int pgsize_idx;
unsigned long pgsizes;
size_t pgsize;
+   phys_addr_t addr_merge = paddr | iova;
 
/* Page sizes supported by the hardware and small enough for @size */
pgsizes = domain->pgsize_bitmap & GENMASK_ULL(__fls(size), 0);
@@ -2415,7 +2416,7 @@ static int __iommu_map(struct iommu_domain *domain, 
unsigned long iova,
pr_debug("map: iova 0x%lx pa %pa size 0x%zx\n", iova, &paddr, size);
 
while (size) {
-   size_t pgsize = iommu_pgsize(domain, iova | paddr, size);
+   size_t pgsize = iommu_pgsize(domain, iova, paddr, size);
 
pr_debug("mapping: iova 0x%lx pa %pa pgsize 0x%zx\n",
 iova, &paddr, pgsize);
@@ -2503,8 +2504,9 @@ static size_t __iommu_unmap(struct iommu_domain *domain,
 * or we hit an area that isn't mapped.
 */
while (unmapped < size) {
-   size_t pgsize = iommu_pgsize(domain, iova, size - unmapped);
+   size_t pgsize;
 
+   pgsize = iommu_pgsize(domain, iova, iova, size - unmapped);
unmapped_page = ops->unmap(domain, iova, pgsize, iotlb_gather);
if (!unmapped_page)
break;
-- 
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project

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Re: [RFC PATCH v3 06/12] iommu: Split 'addr_merge' argument to iommu_pgsize() into separate parts

[Will Deacon]

On Mon, Apr 05, 2021 at 12:11:06PM -0700, Isaac J. Manjarres wrote:
> From: Will Deacon 
> 
> The 'addr_merge' parameter to iommu_pgsize() is a fabricated address
> intended to describe the alignment requirements to consider when
> choosing an appropriate page size. On the iommu_map() path, this address
> is the logical OR of the virtual and physical addresses.
> 
> Subsequent improvements to iommu_pgsize() will need to check the
> alignment of the virtual and physical components of 'addr_merge'
> independently, so pass them in as separate parameters and reconstruct
> 'addr_merge' locally.
> 
> No functional change.
> 
> Signed-off-by: Will Deacon 
> Signed-off-by: Isaac J. Manjarres 
> ---
>  drivers/iommu/iommu.c | 10 ++
>  1 file changed, 6 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
> index 9006397b6604..a3bbf7e310b0 100644
> --- a/drivers/iommu/iommu.c
> +++ b/drivers/iommu/iommu.c
> @@ -2357,12 +2357,13 @@ phys_addr_t iommu_iova_to_phys(struct iommu_domain 
> *domain, dma_addr_t iova)
>  }
>  EXPORT_SYMBOL_GPL(iommu_iova_to_phys);
>  
> -static size_t iommu_pgsize(struct iommu_domain *domain,
> -unsigned long addr_merge, size_t size)
> +static size_t iommu_pgsize(struct iommu_domain *domain, unsigned long iova,
> +phys_addr_t paddr, size_t size)
>  {
>   unsigned int pgsize_idx;
>   unsigned long pgsizes;
>   size_t pgsize;
> + phys_addr_t addr_merge = paddr | iova;

Huh, so this was 'unsigned long' before and, given that the pgsize_bitmap
on the domain is also unsigned long, then I think that's fine. So using
that would mean you don't need GENMASK_ULL for this guy either.

Will
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Re: [RFC PATCH v3 06/12] iommu: Split 'addr_merge' argument to iommu_pgsize() into separate parts

[isaacm]

On 2021-04-06 04:53, Will Deacon wrote:

On Mon, Apr 05, 2021 at 12:11:06PM -0700, Isaac J. Manjarres wrote:

From: Will Deacon 

The 'addr_merge' parameter to iommu_pgsize() is a fabricated address
intended to describe the alignment requirements to consider when
choosing an appropriate page size. On the iommu_map() path, this 
address

is the logical OR of the virtual and physical addresses.

Subsequent improvements to iommu_pgsize() will need to check the
alignment of the virtual and physical components of 'addr_merge'
independently, so pass them in as separate parameters and reconstruct
'addr_merge' locally.

No functional change.

Signed-off-by: Will Deacon 
Signed-off-by: Isaac J. Manjarres 
---
 drivers/iommu/iommu.c | 10 ++
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index 9006397b6604..a3bbf7e310b0 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -2357,12 +2357,13 @@ phys_addr_t iommu_iova_to_phys(struct 
iommu_domain *domain, dma_addr_t iova)

 }
 EXPORT_SYMBOL_GPL(iommu_iova_to_phys);

-static size_t iommu_pgsize(struct iommu_domain *domain,
-  unsigned long addr_merge, size_t size)
+static size_t iommu_pgsize(struct iommu_domain *domain, unsigned long 
iova,

+  phys_addr_t paddr, size_t size)
 {
unsigned int pgsize_idx;
unsigned long pgsizes;
size_t pgsize;
+   phys_addr_t addr_merge = paddr | iova;


Huh, so this was 'unsigned long' before and, given that the 
pgsize_bitmap

on the domain is also unsigned long, then I think that's fine. So using
that would mean you don't need GENMASK_ULL for this guy either.

Will

Thanks, I will address this in version 4 of the series.

--Isaac
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