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[34.38.181.8]) by smtp.gmail.com with ESMTPSA id 6a1803df08f44-8b53d450dcbsm376655416d6.45.2026.05.13.08.11.50 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 13 May 2026 08:11:52 -0700 (PDT) Date: Wed, 13 May 2026 15:11:44 +0000 From: Mostafa Saleh To: Jason Gunthorpe Cc: iommu@lists.linux.dev, Joerg Roedel , Robin Murphy , Will Deacon , Alejandro Jimenez , Lu Baolu , Joerg Roedel , Josua Mayer , Kevin Tian , Pasha Tatashin , patches@lists.linux.dev, Pranjal Shrivastava , Samiullah Khawaja , stable@vger.kernel.org Subject: Re: [PATCH rc 2/5] iommu: Fix up map/unmap debugging for iommupt domains Message-ID: References: <0-v1-44b2fef88b25+d3-iommupt_map_rc_jgg@nvidia.com> <2-v1-44b2fef88b25+d3-iommupt_map_rc_jgg@nvidia.com> Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <2-v1-44b2fef88b25+d3-iommupt_map_rc_jgg@nvidia.com> On Tue, May 12, 2026 at 01:46:14PM -0300, Jason Gunthorpe wrote: > Sashiko noticed a few issues in this path, and a few more were > found on review. Tidy them up further. These are intertwined > because the debug code depends on some of the WARN_ONs to function > right: > > Lift into iommu_map_nosync(): > - The might_sleep_if() > - 0 pgsize_bitmap WARN_ON > - Promote the illegal domain->type to a WARN_ON > - WARN_ON for illegal gfp flags > > Then remove the return 0 since it is now safe to call > iommu_debug_map(). > > Lift into __iommu_unmap(): > - 0 pgsize_bitmap WARN_ON > - Promote the illegal domain->type to a WARN_ON > - iommu_debug_unmap_begin() > > This now pairs with the unconditional iommu_debug_map() on the > mapping side. Thus iommu debugging now works for iommupt along > with some of the other debugging features. > > Fixes: 99fb8afa16ad ("iommupt: Directly call iommupt's unmap_range()") > Fixes: d6c65b0fd621 ("iommupt: Avoid rewalking during map") > Signed-off-by: Jason Gunthorpe Reviewed-by: Mostafa Saleh Thanks, Mostafa > --- > drivers/iommu/iommu.c | 43 ++++++++++++++++++++++--------------------- > 1 file changed, 22 insertions(+), 21 deletions(-) > > diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c > index 6e53cfad5dc001..e334588a2476b4 100644 > --- a/drivers/iommu/iommu.c > +++ b/drivers/iommu/iommu.c > @@ -2583,19 +2583,9 @@ static int __iommu_map_domain_pgtbl(struct iommu_domain *domain, > size_t orig_size = size; > int ret = 0; > > - might_sleep_if(gfpflags_allow_blocking(gfp)); > - > - if (unlikely(!(domain->type & __IOMMU_DOMAIN_PAGING))) > - return -EINVAL; > - > - if (WARN_ON(!ops->map_pages || domain->pgsize_bitmap == 0UL)) > + if (WARN_ON(!ops->map_pages)) > return -ENODEV; > > - /* Discourage passing strange GFP flags */ > - if (WARN_ON_ONCE(gfp & (__GFP_COMP | __GFP_DMA | __GFP_DMA32 | > - __GFP_HIGHMEM))) > - return -EINVAL; > - > /* find out the minimum page size supported */ > min_pagesz = 1 << __ffs(domain->pgsize_bitmap); > > @@ -2657,6 +2647,15 @@ int iommu_map_nosync(struct iommu_domain *domain, unsigned long iova, > struct pt_iommu *pt = iommupt_from_domain(domain); > int ret; > > + might_sleep_if(gfpflags_allow_blocking(gfp)); > + > + /* Discourage passing strange GFP flags or illegal domains */ > + if (WARN_ON_ONCE(!(domain->type & __IOMMU_DOMAIN_PAGING) || > + !domain->pgsize_bitmap || > + (gfp & (__GFP_COMP | __GFP_DMA | __GFP_DMA32 | > + __GFP_HIGHMEM)))) > + return -EINVAL; > + > if (pt) { > size_t mapped = 0; > > @@ -2666,11 +2665,12 @@ int iommu_map_nosync(struct iommu_domain *domain, unsigned long iova, > iommu_unmap(domain, iova, mapped); > return ret; > } > - return 0; > + } else { > + ret = __iommu_map_domain_pgtbl(domain, iova, paddr, size, prot, > + gfp); > + if (ret) > + return ret; > } > - ret = __iommu_map_domain_pgtbl(domain, iova, paddr, size, prot, gfp); > - if (ret) > - return ret; > > trace_map(iova, paddr, size); > iommu_debug_map(domain, paddr, size); > @@ -2702,10 +2702,7 @@ __iommu_unmap_domain_pgtbl(struct iommu_domain *domain, unsigned long iova, > size_t unmapped_page, unmapped = 0; > unsigned int min_pagesz; > > - if (unlikely(!(domain->type & __IOMMU_DOMAIN_PAGING))) > - return 0; > - > - if (WARN_ON(!ops->unmap_pages || domain->pgsize_bitmap == 0UL)) > + if (WARN_ON(!ops->unmap_pages)) > return 0; > > /* find out the minimum page size supported */ > @@ -2724,8 +2721,6 @@ __iommu_unmap_domain_pgtbl(struct iommu_domain *domain, unsigned long iova, > > pr_debug("unmap this: iova 0x%lx size 0x%zx\n", iova, size); > > - iommu_debug_unmap_begin(domain, iova, size); > - > /* > * Keep iterating until we either unmap 'size' bytes (or more) > * or we hit an area that isn't mapped. > @@ -2761,6 +2756,12 @@ static size_t __iommu_unmap(struct iommu_domain *domain, unsigned long iova, > struct pt_iommu *pt = iommupt_from_domain(domain); > size_t unmapped; > > + if (WARN_ON_ONCE(!(domain->type & __IOMMU_DOMAIN_PAGING) || > + !domain->pgsize_bitmap)) > + return 0; > + > + iommu_debug_unmap_begin(domain, iova, size); > + > if (pt) > unmapped = pt->ops->unmap_range(pt, iova, size, iotlb_gather); > else > -- > 2.43.0 >