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SubjectRe: [PATCH v7 07/15] iommu: Hook up '->unmap_pages' driver callback
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On 6/16/21 9:38 PM, Georgi Djakov wrote:
> From: Will Deacon <will@kernel.org>
>
> Extend iommu_pgsize() to populate an optional 'count' parameter so that
> we can direct unmapping operation to the ->unmap_pages callback if it
> has been provided by the driver.
>
> Signed-off-by: Will Deacon <will@kernel.org>
> Signed-off-by: Isaac J. Manjarres <isaacm@codeaurora.org>
> Signed-off-by: Georgi Djakov <quic_c_gdjako@quicinc.com>
> ---
> drivers/iommu/iommu.c | 59 +++++++++++++++++++++++++++++++++++++++++++--------
> 1 file changed, 50 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
> index 80e14c139d40..725622c7e603 100644
> --- a/drivers/iommu/iommu.c
> +++ b/drivers/iommu/iommu.c
> @@ -2376,11 +2376,11 @@ 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 iova,
> - phys_addr_t paddr, size_t size)
> + phys_addr_t paddr, size_t size, size_t *count)
> {
> - unsigned int pgsize_idx;
> + unsigned int pgsize_idx, pgsize_idx_next;
> unsigned long pgsizes;
> - size_t pgsize;
> + size_t offset, pgsize, pgsize_next;
> unsigned long addr_merge = paddr | iova;
>
> /* Page sizes supported by the hardware and small enough for @size */
> @@ -2396,7 +2396,36 @@ static size_t iommu_pgsize(struct iommu_domain *domain, unsigned long iova,
> /* Pick the biggest page size remaining */
> pgsize_idx = __fls(pgsizes);
> pgsize = BIT(pgsize_idx);
> + if (!count)
> + return pgsize;
>
> + /* Find the next biggest support page size, if it exists */
> + pgsizes = domain->pgsize_bitmap & ~GENMASK(pgsize_idx, 0);
> + if (!pgsizes)
> + goto out_set_count;
> +
> + pgsize_idx_next = __ffs(pgsizes);
> + pgsize_next = BIT(pgsize_idx_next);
> +
> + /*
> + * There's no point trying a bigger page size unless the virtual
> + * and physical addresses are similarly offset within the larger page.
> + */
> + if ((iova ^ paddr) & (pgsize_next - 1))
> + goto out_set_count;
> +
> + /* Calculate the offset to the next page size alignment boundary */
> + offset = pgsize_next - (addr_merge & (pgsize_next - 1));
> +
> + /*
> + * If size is big enough to accommodate the larger page, reduce
> + * the number of smaller pages.
> + */
> + if (offset + pgsize_next <= size)
> + size = offset;
> +
> +out_set_count:
> + *count = size >> pgsize_idx;
> return pgsize;
> }
>
> @@ -2434,7 +2463,7 @@ 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, NULL);
>
> pr_debug("mapping: iova 0x%lx pa %pa pgsize 0x%zx\n",
> iova, &paddr, pgsize);
> @@ -2485,6 +2514,19 @@ int iommu_map_atomic(struct iommu_domain *domain, unsigned long iova,
> }
> EXPORT_SYMBOL_GPL(iommu_map_atomic);
>
> +static size_t __iommu_unmap_pages(struct iommu_domain *domain,
> + unsigned long iova, size_t size,
> + struct iommu_iotlb_gather *iotlb_gather)
> +{
> + const struct iommu_ops *ops = domain->ops;
> + size_t pgsize, count;
> +
> + pgsize = iommu_pgsize(domain, iova, iova, size, &count);
> + return ops->unmap_pages ?
> + ops->unmap_pages(domain, iova, pgsize, count, iotlb_gather) :
> + ops->unmap(domain, iova, pgsize, iotlb_gather);
> +}
> +
> static size_t __iommu_unmap(struct iommu_domain *domain,
> unsigned long iova, size_t size,
> struct iommu_iotlb_gather *iotlb_gather)
> @@ -2494,7 +2536,7 @@ static size_t __iommu_unmap(struct iommu_domain *domain,
> unsigned long orig_iova = iova;
> unsigned int min_pagesz;
>
> - if (unlikely(ops->unmap == NULL ||
> + if (unlikely(!(ops->unmap || ops->unmap_pages) ||
> domain->pgsize_bitmap == 0UL))
> return 0;
>
> @@ -2522,10 +2564,9 @@ static size_t __iommu_unmap(struct iommu_domain *domain,
> * or we hit an area that isn't mapped.
> */
> while (unmapped < size) {
> - size_t pgsize;
> -
> - pgsize = iommu_pgsize(domain, iova, iova, size - unmapped);
> - unmapped_page = ops->unmap(domain, iova, pgsize, iotlb_gather);
> + unmapped_page = __iommu_unmap_pages(domain, iova,
> + size - unmapped,
> + iotlb_gather);
> if (!unmapped_page)
> break;
>
>

Reviewed-by: Lu Baolu <baolu.lu@linux.intel.com>

Best regards,
baolu

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