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From: Jason Gunthorpe <jgg@nvidia.com>
To: Joao Martins <joao.m.martins@oracle.com>
Cc: Arnd Bergmann <arnd@arndb.de>,
	iommu@lists.linux.dev, Kevin Tian <kevin.tian@intel.com>,
	Shameerali Kolothum Thodi <shameerali.kolothum.thodi@huawei.com>,
	Baolu Lu <baolu.lu@linux.intel.com>, Yi Liu <yi.l.liu@intel.com>,
	Yi Y Sun <yi.y.sun@intel.com>, Nicolin Chen <nicolinc@nvidia.com>,
	Joerg Roedel <joro@8bytes.org>,
	Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>,
	Will Deacon <will@kernel.org>,
	Robin Murphy <robin.murphy@arm.com>,
	Zhenzhong Duan <zhenzhong.duan@intel.com>,
	Alex Williamson <alex.williamson@redhat.com>,
	kvm@vger.kernel.org
Subject: Re: [PATCH v5 07/18] iommufd: Add IOMMU_HWPT_GET_DIRTY_BITMAP
Date: Mon, 23 Oct 2023 15:08:21 -0300	[thread overview]
Message-ID: <20231023180821.GF3952@nvidia.com> (raw)
In-Reply-To: <5069116b-11c4-40ea-bfa2-91313ee4fbe2@oracle.com>

On Mon, Oct 23, 2023 at 06:55:56PM +0100, Joao Martins wrote:
> On 23/10/2023 17:34, Jason Gunthorpe wrote:
> > On Mon, Oct 23, 2023 at 05:31:22PM +0100, Joao Martins wrote:
> >>> Write it like this:
> >>>
> >>> int iommufd_check_iova_range(struct iommufd_ioas *ioas,
> >>> 			     struct iommu_hwpt_get_dirty_bitmap *bitmap)
> >>> {
> >>> 	size_t iommu_pgsize = ioas->iopt.iova_alignment;
> >>> 	u64 last_iova;
> >>>
> >>> 	if (check_add_overflow(bitmap->iova, bitmap->length - 1, &last_iova))
> >>> 		return -EOVERFLOW;
> >>>
> >>> 	if (bitmap->iova > ULONG_MAX || last_iova > ULONG_MAX)
> >>> 		return -EOVERFLOW;
> >>>
> >>> 	if ((bitmap->iova & (iommu_pgsize - 1)) ||
> >>> 	    ((last_iova + 1) & (iommu_pgsize - 1)))
> >>> 		return -EINVAL;
> >>> 	return 0;
> >>> }
> >>>
> >>> And if 0 should really be rejected then check iova == last_iova
> >>
> >> It should; Perhaps extending the above and replicate that second the ::page_size
> >> alignment check is important as it's what's used by the bitmap e.g.
> > 
> > That makes sense, much clearer what it is trying to do that way
> 
> In regards to clearity, I am still checking if bitmap::page_size being 0 or not,
> to avoid being so implicitly in the last check i.e. (bitmap->iova &
> (bitmap->page_size - 1)) being an and to 0xfffffffff.

I think you have to check explicitly, iova/last_iova could also be
zero..

Jason


  reply	other threads:[~2023-10-23 18:08 UTC|newest]

Thread overview: 50+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-10-20 22:27 [PATCH v5 00/18] IOMMUFD Dirty Tracking Joao Martins
2023-10-20 22:27 ` [PATCH v5 01/18] vfio/iova_bitmap: Export more API symbols Joao Martins
2023-10-20 22:27 ` [PATCH v5 02/18] vfio: Move iova_bitmap into iommufd Joao Martins
2023-10-20 22:27 ` [PATCH v5 03/18] iommufd/iova_bitmap: Move symbols to IOMMUFD namespace Joao Martins
2023-10-20 22:27 ` [PATCH v5 04/18] iommu: Add iommu_domain ops for dirty tracking Joao Martins
2023-10-20 22:27 ` [PATCH v5 05/18] iommufd: Add a flag to enforce dirty tracking on attach Joao Martins
2023-10-20 22:27 ` [PATCH v5 06/18] iommufd: Add IOMMU_HWPT_SET_DIRTY_TRACKING Joao Martins
2023-10-20 22:27 ` [PATCH v5 07/18] iommufd: Add IOMMU_HWPT_GET_DIRTY_BITMAP Joao Martins
2023-10-23  9:09   ` Arnd Bergmann
2023-10-23  9:28     ` Joao Martins
2023-10-23 12:10       ` Jason Gunthorpe
2023-10-23 12:41         ` Arnd Bergmann
2023-10-23 15:56           ` Joao Martins
2023-10-23 16:16             ` Jason Gunthorpe
2023-10-23 16:31               ` Joao Martins
2023-10-23 16:34                 ` Jason Gunthorpe
2023-10-23 17:55                   ` Joao Martins
2023-10-23 18:08                     ` Jason Gunthorpe [this message]
2023-10-20 22:27 ` [PATCH v5 08/18] iommufd: Add capabilities to IOMMU_GET_HW_INFO Joao Martins
2023-10-20 22:27 ` [PATCH v5 09/18] iommufd: Add a flag to skip clearing of IOPTE dirty Joao Martins
2023-10-20 22:27 ` [PATCH v5 10/18] iommu/amd: Add domain_alloc_user based domain allocation Joao Martins
2023-10-20 22:27 ` [PATCH v5 11/18] iommu/amd: Access/Dirty bit support in IOPTEs Joao Martins
2023-10-20 22:27 ` [PATCH v5 12/18] iommu/intel: Access/Dirty bit support for SL domains Joao Martins
2023-10-24 12:34   ` Yi Liu
2023-10-24 12:42     ` Joao Martins
2023-10-24 12:52       ` Joao Martins
2023-10-24 13:51         ` Yi Liu
2023-10-20 22:27 ` [PATCH v5 13/18] iommufd/selftest: Expand mock_domain with dev_flags Joao Martins
2023-10-20 22:28 ` [PATCH v5 14/18] iommufd/selftest: Test IOMMU_HWPT_ALLOC_DIRTY_TRACKING Joao Martins
2023-10-20 22:28 ` [PATCH v5 15/18] iommufd/selftest: Test IOMMU_HWPT_SET_DIRTY_TRACKING Joao Martins
2023-10-20 22:28 ` [PATCH v5 16/18] iommufd/selftest: Test IOMMU_HWPT_GET_DIRTY_BITMAP Joao Martins
2023-10-23 20:08   ` Nicolin Chen
2023-10-23 20:15     ` Joao Martins
2023-10-23 20:37       ` Nicolin Chen
2023-10-23 20:50         ` Joao Martins
2023-10-23 21:46           ` Joao Martins
2023-10-23 21:56             ` Nicolin Chen
2023-10-20 22:28 ` [PATCH v5 17/18] iommufd/selftest: Test out_capabilities in IOMMU_GET_HW_INFO Joao Martins
2023-10-20 22:28 ` [PATCH v5 18/18] iommufd/selftest: Test IOMMU_HWPT_GET_DIRTY_BITMAP_NO_CLEAR flag Joao Martins
2023-10-21 16:23 ` [PATCH v5 00/18] IOMMUFD Dirty Tracking Jason Gunthorpe
2023-10-23  1:36   ` Nicolin Chen
2023-10-23  9:15     ` Joao Martins
2023-10-23 11:49       ` Joao Martins
2023-10-23 13:24         ` Jason Gunthorpe
2023-10-23 18:12         ` Nicolin Chen
2023-10-23 18:21           ` Joao Martins
2023-10-23 18:32             ` Nicolin Chen
2023-10-23 18:52               ` Joao Martins
2023-10-23 18:10       ` Nicolin Chen
2023-10-23 18:20         ` Joao Martins

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