From: Jason Gunthorpe <jgg@ziepe•ca>
To: Guanghui Feng <guanghuifeng@linux•alibaba.com>
Cc: boris.brezillon@collabora•com, robh@kernel•org,
steven.price@arm•com, adrian.larumbe@collabora•com,
maarten.lankhorst@linux•intel.com, mripard@kernel•org,
tzimmermann@suse•de, airlied@gmail•com, liviu.dudau@arm•com,
joro@8bytes•org, will@kernel•org, robin.murphy@arm•com,
alex@shazbot•org, dri-devel@lists•freedesktop.org,
linux-kernel@vger•kernel.org, iommu@lists•linux.dev,
kvm@vger•kernel.org, linux-arm-kernel@lists•infradead.org,
kevin.tian@intel•com, baolu.lu@linux•intel.com,
suravee.suthikulpanit@amd•com, dwmw2@infradead•org,
xlpang@linux•alibaba.com, oliver.yang@linux•alibaba.com,
shiyu.zsq@linux•alibaba.com, wei.guo.simon@linux•alibaba.com
Subject: Re: [PATCH 1/9] iommu: introduce iova_to_phys_length in iommu_domain_ops
Date: Sun, 31 May 2026 20:51:48 -0300 [thread overview]
Message-ID: <20260531235148.GV2487554@ziepe.ca> (raw)
In-Reply-To: <20260531093637.3893199-2-guanghuifeng@linux.alibaba.com>
On Sun, May 31, 2026 at 05:36:29PM +0800, Guanghui Feng wrote:
> Add iova_to_phys_length callback to struct iommu_domain_ops alongside
> the existing iova_to_phys. The new callback returns both the physical
> address and the PTE mapping page size in a single page table walk.
>
> Add iommu_iova_to_phys_length() core function that:
> - Checks ops->iova_to_phys_length first (preferred path)
> - Falls back to ops->iova_to_phys for unmigrated drivers
>
> This enables callers like VFIO to efficiently traverse IOVA space
> by actual mapping granularity instead of fixed PAGE_SIZE steps.
>
> Signed-off-by: Guanghui Feng <guanghuifeng@linux•alibaba.com>
> Acked-by: Shiqiang Zhang <shiyu.zsq@linux•alibaba.com>
> Acked-by: Simon Guo <wei.guo.simon@linux•alibaba.com>
> ---
> drivers/iommu/iommu.c | 34 ++++++++++++++++++++++++++++++++--
> include/linux/iommu.h | 9 +++++++++
> 2 files changed, 41 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
> index d1a9e713d3a0..43323229a1df 100644
> --- a/drivers/iommu/iommu.c
> +++ b/drivers/iommu/iommu.c
> @@ -2545,15 +2545,45 @@ void iommu_detach_group(struct iommu_domain *domain, struct iommu_group *group)
> }
> EXPORT_SYMBOL_GPL(iommu_detach_group);
>
> -phys_addr_t iommu_iova_to_phys(struct iommu_domain *domain, dma_addr_t iova)
> +/**
> + * iommu_iova_to_phys_length - Translate IOVA and return mapping page size
> + * @domain: IOMMU domain to query
> + * @iova: IO virtual address to translate
> + * @mapped_length: Output parameter for the PTE page size (e.g. 4KB/2MB/1GB)
> + *
> + * Like iommu_iova_to_phys() but additionally returns the page size of the
> + * PTE mapping at @iova through @mapped_length.
> + *
> + * Return: The physical address for the given IOVA, or 0 if no translation.
> + */
When introducing the new function I would like to fix this 0 error as
well, it should return PHYS_MAX for error
> +phys_addr_t iommu_iova_to_phys_length(struct iommu_domain *domain,
> + dma_addr_t iova,
> + size_t *mapped_length)
> {
> + if (mapped_length)
> + *mapped_length = 0;
> +
> if (domain->type == IOMMU_DOMAIN_IDENTITY)
> return iova;
>
> if (domain->type == IOMMU_DOMAIN_BLOCKED)
> return 0;
Any domain that doesn't have an op should fail, blocked is one example
>
> - return domain->ops->iova_to_phys(domain, iova);
> + if (domain->ops->iova_to_phys_length)
> + return domain->ops->iova_to_phys_length(domain, iova,
> + mapped_length);
> +
> + /* Fallback to legacy iova_to_phys without length info */
> + if (domain->ops->iova_to_phys)
> + return domain->ops->iova_to_phys(domain, iova);
If it falls back it should return something sensible for the length.
I suggest you approach the patch plan a little differently, the first
patches should implement the new function and an iommput
implementation
Arrange things so the normal iova_to_phys calls the new function if it
is available and discards the length.
Then convert callers that can take advantage of it. Have the fallback
path also compute the length by iterating internally.
Finally one patch per driver implementing the new op, this could even
be a second series.
Don't remove iova_to_phys(), it is fine for things that don't need the
length.
Jason
next prev parent reply other threads:[~2026-05-31 23:52 UTC|newest]
Thread overview: 95+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20260529115116.GR2487554@ziepe.ca>
2026-05-31 9:36 ` [PATCH 0/9] iommu: introduce iova_to_phys_length for efficient IOVA-to-physical translation Guanghui Feng
2026-05-31 9:36 ` [PATCH 1/9] iommu: introduce iova_to_phys_length in iommu_domain_ops Guanghui Feng
2026-05-31 23:51 ` Jason Gunthorpe [this message]
2026-06-01 8:41 ` guanghuifeng
2026-06-01 13:43 ` Jason Gunthorpe
2026-06-01 14:14 ` guanghuifeng
2026-06-01 14:31 ` Jason Gunthorpe
2026-05-31 9:36 ` [PATCH 2/9] iommu/io-pgtable: introduce iova_to_phys_length in io_pgtable_ops Guanghui Feng
2026-05-31 9:36 ` [PATCH 3/9] iommu/generic_pt: implement iova_to_phys_length Guanghui Feng
2026-05-31 23:54 ` Jason Gunthorpe
2026-06-01 9:23 ` guanghuifeng
[not found] ` <fa924b86-1ca9-4819-8330-0d5f6ede8923@linux.alibaba.com>
2026-06-01 14:32 ` Jason Gunthorpe
2026-06-02 7:20 ` guanghuifeng
2026-06-02 12:32 ` Jason Gunthorpe
2026-05-31 9:36 ` [PATCH 4/9] iommu/arm-smmu: " Guanghui Feng
2026-05-31 9:36 ` [PATCH 5/9] iommu: apple-dart/ipmmu/mtk_iommu " Guanghui Feng
2026-05-31 9:36 ` [PATCH 6/9] iommu: direct page-table drivers " Guanghui Feng
2026-05-31 9:36 ` [PATCH 7/9] vfio/iommufd: use iova_to_phys_length for efficient unmap Guanghui Feng
2026-05-31 23:58 ` Jason Gunthorpe
2026-05-31 9:36 ` [PATCH 8/9] drm/gpu, iommu/io-pgtable: switch to iova_to_phys_length Guanghui Feng
2026-05-31 9:36 ` [PATCH 9/9] iommu: remove deprecated iova_to_phys from domain_ops and io_pgtable_ops Guanghui Feng
2026-06-02 10:46 ` [PATCH v2 00/30] iommu: introduce iova_to_phys_length for efficient IOVA-to-physical translation Guanghui Feng
2026-06-02 10:46 ` [PATCH v2 01/30] iommu: introduce iova_to_phys_length in iommu_domain_ops Guanghui Feng
2026-06-03 1:08 ` Jason Gunthorpe
2026-06-02 10:46 ` [PATCH v2 02/30] iommu/io-pgtable-arm: introduce iova_to_phys_length in io_pgtable_ops Guanghui Feng
2026-06-02 10:46 ` [PATCH v2 03/30] iommu/io-pgtable-arm-v7s: " Guanghui Feng
2026-06-02 10:46 ` [PATCH v2 04/30] iommu/io-pgtable-dart: " Guanghui Feng
2026-06-02 10:46 ` [PATCH v2 05/30] iommu/generic_pt: implement iova_to_phys_length Guanghui Feng
2026-06-03 1:11 ` Jason Gunthorpe
2026-06-02 10:46 ` [PATCH v2 06/30] iommu/arm-smmu-v3: " Guanghui Feng
2026-06-02 10:46 ` [PATCH v2 07/30] iommu/arm-smmu: " Guanghui Feng
2026-06-02 10:46 ` [PATCH v2 08/30] iommu/qcom_iommu: " Guanghui Feng
2026-06-02 10:46 ` [PATCH v2 09/30] iommu/apple-dart: " Guanghui Feng
2026-06-02 10:46 ` [PATCH v2 10/30] iommu/ipmmu-vmsa: " Guanghui Feng
2026-06-03 1:13 ` Jason Gunthorpe
2026-06-02 10:46 ` [PATCH v2 11/30] iommu/mtk_iommu: " Guanghui Feng
2026-06-03 1:17 ` Jason Gunthorpe
2026-06-02 10:46 ` [PATCH v2 12/30] iommu/exynos: " Guanghui Feng
2026-06-02 10:46 ` [PATCH v2 13/30] iommu/fsl_pamu: " Guanghui Feng
2026-06-02 10:46 ` [PATCH v2 14/30] iommu/msm: " Guanghui Feng
2026-06-02 10:46 ` [PATCH v2 15/30] iommu/mtk_v1: " Guanghui Feng
2026-06-02 10:46 ` [PATCH v2 16/30] iommu/omap: " Guanghui Feng
2026-06-02 10:46 ` [PATCH v2 17/30] iommu/rockchip: " Guanghui Feng
2026-06-02 10:46 ` [PATCH v2 18/30] iommu/s390: " Guanghui Feng
2026-06-02 10:46 ` [PATCH v2 19/30] iommu/sprd: " Guanghui Feng
2026-06-02 10:46 ` [PATCH v2 20/30] iommu/sun50i: " Guanghui Feng
2026-06-02 10:46 ` [PATCH v2 21/30] iommu/tegra-smmu: " Guanghui Feng
2026-06-02 10:46 ` [PATCH v2 22/30] iommu/virtio: " Guanghui Feng
2026-06-02 10:46 ` [PATCH v2 23/30] vfio/iommufd: use iova_to_phys_length for efficient unmap Guanghui Feng
2026-06-02 10:46 ` [PATCH v2 24/30] drm/panfrost: switch to iova_to_phys_length Guanghui Feng
2026-06-02 10:46 ` [PATCH v2 25/30] drm/panthor: " Guanghui Feng
2026-06-02 10:46 ` [PATCH v2 26/30] iommu/io-pgtable: selftests " Guanghui Feng
2026-06-02 10:46 ` [PATCH v2 27/30] iommu/io-pgtable-arm: remove deprecated iova_to_phys wrapper Guanghui Feng
2026-06-02 10:46 ` [PATCH v2 28/30] iommu/io-pgtable-arm-v7s: " Guanghui Feng
2026-06-02 10:46 ` [PATCH v2 29/30] iommu/io-pgtable-dart: " Guanghui Feng
2026-06-02 10:46 ` [PATCH v2 30/30] iommu: remove iova_to_phys from domain_ops and io_pgtable_ops Guanghui Feng
2026-06-03 15:17 ` [PATCH v3 00/32] iommu: introduce iova_to_phys_length and remove iova_to_phys Guanghui Feng
2026-06-03 15:17 ` [PATCH v3 01/32] iommu: introduce iova_to_phys_length in iommu_domain_ops Guanghui Feng
2026-06-04 2:44 ` Baolu Lu
2026-06-04 14:16 ` Jason Gunthorpe
2026-06-03 15:17 ` [PATCH v3 02/32] iommu/io-pgtable-arm: introduce iova_to_phys_length in io_pgtable_ops Guanghui Feng
2026-06-03 15:17 ` [PATCH v3 03/32] iommu/io-pgtable-arm-v7s: " Guanghui Feng
2026-06-03 15:17 ` [PATCH v3 04/32] iommu/io-pgtable-dart: " Guanghui Feng
2026-06-03 15:17 ` [PATCH v3 05/32] iommu/generic_pt: implement iova_to_phys_length Guanghui Feng
2026-06-04 3:30 ` Baolu Lu
2026-06-04 14:12 ` Jason Gunthorpe
2026-06-03 15:17 ` [PATCH v3 06/32] iommu/arm-smmu-v3: " Guanghui Feng
2026-06-03 15:17 ` [PATCH v3 07/32] iommu/arm-smmu: " Guanghui Feng
2026-06-03 15:17 ` [PATCH v3 08/32] iommu/qcom_iommu: " Guanghui Feng
2026-06-03 15:17 ` [PATCH v3 09/32] iommu/apple-dart: " Guanghui Feng
2026-06-03 15:17 ` [PATCH v3 10/32] iommu/ipmmu-vmsa: " Guanghui Feng
2026-06-03 15:17 ` [PATCH v3 11/32] iommu/mtk_iommu: " Guanghui Feng
2026-06-03 15:17 ` [PATCH v3 12/32] iommu/exynos: " Guanghui Feng
2026-06-03 15:17 ` [PATCH v3 13/32] iommu/fsl_pamu: " Guanghui Feng
2026-06-03 15:17 ` [PATCH v3 14/32] iommu/msm: " Guanghui Feng
2026-06-03 15:17 ` [PATCH v3 15/32] iommu/mtk_v1: " Guanghui Feng
2026-06-03 15:17 ` [PATCH v3 16/32] iommu/omap: " Guanghui Feng
2026-06-03 15:17 ` [PATCH v3 17/32] iommu/rockchip: " Guanghui Feng
2026-06-03 15:17 ` [PATCH v3 18/32] iommu/s390: " Guanghui Feng
2026-06-03 15:17 ` [PATCH v3 19/32] iommu/sprd: " Guanghui Feng
2026-06-03 15:17 ` [PATCH v3 20/32] iommu/sun50i: " Guanghui Feng
2026-06-03 15:17 ` [PATCH v3 21/32] iommu/tegra-smmu: " Guanghui Feng
2026-06-03 15:17 ` [PATCH v3 22/32] iommu/virtio: " Guanghui Feng
2026-06-03 15:17 ` [PATCH v3 23/32] vfio: use iova_to_phys_length for efficient unmap Guanghui Feng
2026-06-04 14:27 ` Jason Gunthorpe
2026-06-03 15:17 ` [PATCH v3 24/32] iommufd: " Guanghui Feng
2026-06-04 14:26 ` Jason Gunthorpe
2026-06-03 15:17 ` [PATCH v3 25/32] iommufd/selftest: switch to iommu_iova_to_phys_length Guanghui Feng
2026-06-03 15:17 ` [PATCH v3 26/32] drm/panfrost: switch to iova_to_phys_length Guanghui Feng
2026-06-03 15:17 ` [PATCH v3 27/32] drm/panthor: " Guanghui Feng
2026-06-03 15:18 ` [PATCH v3 28/32] iommu/io-pgtable: selftests " Guanghui Feng
2026-06-03 15:18 ` [PATCH v3 29/32] iommu/io-pgtable-arm: remove deprecated iova_to_phys wrapper Guanghui Feng
2026-06-03 15:18 ` [PATCH v3 30/32] iommu/io-pgtable-arm-v7s: " Guanghui Feng
2026-06-03 15:18 ` [PATCH v3 31/32] iommu/io-pgtable-dart: " Guanghui Feng
2026-06-03 15:18 ` [PATCH v3 32/32] iommu: remove iova_to_phys from domain_ops and io_pgtable_ops Guanghui Feng
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