From: "guanghuifeng@linux•alibaba.com" <guanghuifeng@linux•alibaba.com>
To: Jason Gunthorpe <jgg@ziepe•ca>
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,
alikernel-developer <alikernel-developer@linux•alibaba.com>
Subject: Re: [PATCH 1/9] iommu: introduce iova_to_phys_length in iommu_domain_ops
Date: Mon, 1 Jun 2026 16:41:48 +0800 [thread overview]
Message-ID: <a0875d9f-4aed-4164-861c-6fbbdfe04080@linux.alibaba.com> (raw)
In-Reply-To: <20260531235148.GV2487554@ziepe.ca>
在 2026/6/1 7:51, Jason Gunthorpe 写道:
> 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
Implementations such as arm_smmu_iova_to_phys/DOMAIN_NS(iova_to_phys)
all use a return value of 0 as an invalid state, so 0 is used as the
representation
of an invalid state to maintain compatibility.
>
>> +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
In accordance with the implementation of iommu_iova_to_phys, it returns
a phy value of 0 in invalid states.
>
>>
>> - 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.
Does this mean retaining the iommu_iova_to_phys implementation but
implementing it through domain->ops->iova_to_phys_length (mapped_length
is NULL)?
>
> Jason
next prev parent reply other threads:[~2026-06-01 8:42 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
2026-06-01 8:41 ` guanghuifeng [this message]
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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