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From: Jason Gunthorpe <jgg@ziepe•ca>
To: Guanghui Feng <guanghuifeng@linux•alibaba.com>
Cc: adrian.larumbe@collabora•com, airlied@gmail•com,
	alex@shazbot•org, alikernel-developer@linux•alibaba.com,
	baolu.lu@linux•intel.com, boris.brezillon@collabora•com,
	dri-devel@lists•freedesktop.org, dwmw2@infradead•org,
	iommu@lists•linux.dev, joro@8bytes•org, kevin.tian@intel•com,
	kvm@vger•kernel.org, linux-arm-kernel@lists•infradead.org,
	linux-kernel@vger•kernel.org, liviu.dudau@arm•com,
	maarten.lankhorst@linux•intel.com, mripard@kernel•org,
	oliver.yang@linux•alibaba.com, robh@kernel•org,
	robin.murphy@arm•com, shiyu.zsq@linux•alibaba.com,
	steven.price@arm•com, suravee.suthikulpanit@amd•com,
	tzimmermann@suse•de, wei.guo.simon@linux•alibaba.com,
	will@kernel•org, xlpang@linux•alibaba.com
Subject: Re: [PATCH v3 23/32] vfio: use iova_to_phys_length for efficient unmap
Date: Thu, 4 Jun 2026 11:27:06 -0300	[thread overview]
Message-ID: <20260604142706.GZ2487554@ziepe.ca> (raw)
In-Reply-To: <20260603151804.1963871-24-guanghuifeng@linux.alibaba.com>

On Wed, Jun 03, 2026 at 11:17:55PM +0800, Guanghui Feng wrote:
> Use iommu_iova_to_phys_length() to get PTE page size, allowing
> traversal by actual mapping granularity instead of 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/vfio/vfio_iommu_type1.c | 27 ++++++++++++++++++++++-----
>  1 file changed, 22 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
> index c8151ba54de3..115d88d7003e 100644
> --- a/drivers/vfio/vfio_iommu_type1.c
> +++ b/drivers/vfio/vfio_iommu_type1.c
> @@ -1177,25 +1177,42 @@ static long vfio_unmap_unpin(struct vfio_iommu *iommu, struct vfio_dma *dma,
>  
>  	iommu_iotlb_gather_init(&iotlb_gather);
>  	while (pos < dma->size) {
> -		size_t unmapped, len;
> +		size_t unmapped, len, pgsize;
>  		phys_addr_t phys, next;
>  		dma_addr_t iova = dma->iova + pos;
>  
> -		phys = iommu_iova_to_phys(domain->domain, iova);
> -		if (WARN_ON(!phys)) {
> +		/* Single page table walk returns both phys and PTE size */
> +		phys = iommu_iova_to_phys_length(domain->domain, iova,
> +						  &pgsize);
> +		if (WARN_ON(phys == PHYS_ADDR_MAX)) {
>  			pos += PAGE_SIZE;
>  			continue;
>  		}
> +		if (WARN_ON(!pgsize || pgsize < PAGE_SIZE))
> +			pgsize = PAGE_SIZE;
>  
>  		/*
>  		 * To optimize for fewer iommu_unmap() calls, each of which
>  		 * may require hardware cache flushing, try to find the
>  		 * largest contiguous physical memory chunk to unmap.
> +		 *
> +		 * mapped_length already accounts for contiguous entries
> +		 * from iova, then try to join following physically
> +		 * contiguous PTEs.
>  		 */
> -		for (len = PAGE_SIZE; pos + len < dma->size; len += PAGE_SIZE) {
> -			next = iommu_iova_to_phys(domain->domain, iova + len);
> +		len = min_t(size_t, pgsize, dma->size - pos);
> +		for (; pos + len < dma->size; ) {
> +			size_t next_pgsize;
> +
> +			next = iommu_iova_to_phys_length(domain->domain,
> +							  iova + len,
> +							  &next_pgsize);

vfio should not be calling it twice, the core code needs to give the
best length as efficiently as it can. not open coding this in callers.

I think I've said this three times now

Jason


  reply	other threads:[~2026-06-04 14:27 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
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 [this message]
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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