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Message-ID: <20240823161148.GB851@willie-the-truck>
Date: Fri, 23 Aug 2024 17:11:48 +0100
From: Will Deacon <will@...nel.org>
To: Rob Clark <robdclark@...il.com>
Cc: iommu@...ts.linux.dev, linux-arm-msm@...r.kernel.org,
freedreno@...ts.freedesktop.org,
Mostafa Saleh <smostafa@...gle.com>,
Rob Clark <robdclark@...omium.org>,
Robin Murphy <robin.murphy@....com>, Joerg Roedel <joro@...tes.org>,
"moderated list:ARM SMMU DRIVERS" <linux-arm-kernel@...ts.infradead.org>,
open list <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v7 2/4] iommu/io-pgtable-arm: Re-use the pgtable walk for
iova_to_phys
On Tue, Aug 20, 2024 at 10:16:45AM -0700, Rob Clark wrote:
> From: Rob Clark <robdclark@...omium.org>
>
> Re-use the generic pgtable walk path.
>
> Signed-off-by: Rob Clark <robdclark@...omium.org>
> ---
> drivers/iommu/io-pgtable-arm.c | 73 +++++++++++++++++-----------------
> 1 file changed, 36 insertions(+), 37 deletions(-)
>
> diff --git a/drivers/iommu/io-pgtable-arm.c b/drivers/iommu/io-pgtable-arm.c
> index b4bc358740e0..5fa1274a665a 100644
> --- a/drivers/iommu/io-pgtable-arm.c
> +++ b/drivers/iommu/io-pgtable-arm.c
> @@ -710,42 +710,6 @@ static size_t arm_lpae_unmap_pages(struct io_pgtable_ops *ops, unsigned long iov
> data->start_level, ptep);
> }
>
> -static phys_addr_t arm_lpae_iova_to_phys(struct io_pgtable_ops *ops,
> - unsigned long iova)
> -{
> - struct arm_lpae_io_pgtable *data = io_pgtable_ops_to_data(ops);
> - arm_lpae_iopte pte, *ptep = data->pgd;
> - int lvl = data->start_level;
> -
> - do {
> - /* Valid IOPTE pointer? */
> - if (!ptep)
> - return 0;
> -
> - /* Grab the IOPTE we're interested in */
> - ptep += ARM_LPAE_LVL_IDX(iova, lvl, data);
> - pte = READ_ONCE(*ptep);
> -
> - /* Valid entry? */
> - if (!pte)
> - return 0;
> -
> - /* Leaf entry? */
> - if (iopte_leaf(pte, lvl, data->iop.fmt))
> - goto found_translation;
> -
> - /* Take it to the next level */
> - ptep = iopte_deref(pte, data);
> - } while (++lvl < ARM_LPAE_MAX_LEVELS);
> -
> - /* Ran out of page tables to walk */
> - return 0;
> -
> -found_translation:
> - iova &= (ARM_LPAE_BLOCK_SIZE(lvl, data) - 1);
> - return iopte_to_paddr(pte, data) | iova;
> -}
> -
> struct io_pgtable_walk_data {
> void *data;
> int (*visit)(struct io_pgtable_walk_data *walk_data, int lvl,
> @@ -760,6 +724,41 @@ static int __arm_lpae_iopte_walk(struct arm_lpae_io_pgtable *data,
> arm_lpae_iopte *ptep,
> int lvl);
>
> +struct iova_to_phys_data {
> + arm_lpae_iopte pte;
> + int lvl;
> +};
> +
> +static int visit_iova_to_phys(struct io_pgtable_walk_data *walk_data, int lvl,
> + arm_lpae_iopte pte, size_t size)
> +{
> + struct iova_to_phys_data *data = walk_data->data;
> + data->pte = pte;
> + data->lvl = lvl;
> + return 0;
> +}
> +
> +static phys_addr_t arm_lpae_iova_to_phys(struct io_pgtable_ops *ops,
> + unsigned long iova)
> +{
> + struct arm_lpae_io_pgtable *data = io_pgtable_ops_to_data(ops);
> + struct iova_to_phys_data d;
> + struct io_pgtable_walk_data walk_data = {
> + .data = &d,
> + .visit = visit_iova_to_phys,
> + .addr = iova,
> + .end = iova + 1,
> + };
> + int ret;
> +
> + ret = __arm_lpae_iopte_walk(data, &walk_data, data->pgd, data->start_level);
> + if (ret)
> + return 0;
> +
> + iova &= (ARM_LPAE_BLOCK_SIZE(d.lvl, data) - 1);
> + return iopte_to_paddr(d.pte, data) | iova;
> +}
> +
> static int io_pgtable_visit(struct arm_lpae_io_pgtable *data,
> struct io_pgtable_walk_data *walk_data,
> arm_lpae_iopte *ptep, int lvl)
> @@ -776,7 +775,7 @@ static int io_pgtable_visit(struct arm_lpae_io_pgtable *data,
> return 0;
> }
>
> - if (WARN_ON(!iopte_table(pte, lvl)))
> + if (WARN_ON(!iopte_table(pte, lvl) && !selftest_running))
Why do you care about the selftest here?
Will
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