From: Jason Gunthorpe <jgg@mellanox.com>
To: Christoph Hellwig <hch@lst.de>
Cc: Jerome Glisse <jglisse@redhat.com>,
Ralph Campbell <rcampbell@nvidia.com>,
Felix.Kuehling@amd.com, linux-mm@kvack.org,
John Hubbard <jhubbard@nvidia.com>,
dri-devel@lists.freedesktop.org, amd-gfx@lists.freedesktop.org,
Philip Yang <Philip.Yang@amd.com>
Subject: Re: [PATCH hmm 8/8] mm/hmm: add missing call to hmm_pte_need_fault in HMM_PFN_SPECIAL handling
Date: Mon, 16 Mar 2020 09:10:53 -0300 [thread overview]
Message-ID: <20200316121053.GP13183@mellanox.com> (raw)
In-Reply-To: <20200316091347.GH12439@lst.de>
On Mon, Mar 16, 2020 at 10:13:47AM +0100, Christoph Hellwig wrote:
> On Wed, Mar 11, 2020 at 03:35:06PM -0300, Jason Gunthorpe wrote:
> > From: Jason Gunthorpe <jgg@mellanox.com>
> >
> > Currently if a special PTE is encountered hmm_range_fault() immediately
> > returns EFAULT and sets the HMM_PFN_SPECIAL error output (which nothing
> > uses).
> >
> > EFAULT should only be returned after testing with hmm_pte_need_fault().
> >
> > Also pte_devmap() and pte_special() are exclusive, and there is no need to
> > check IS_ENABLED, pte_special() is stubbed out to return false on
> > unsupported architectures.
>
> I think the right fix is to just kill HMM_PFN_SPECIAL and treat any
> fault on special ptes that aren't the zero page as an error.
I have another series that is doing that - this change is to make the
next series make sense and not introduce new control logic too.
Even when this is switched to ERROR it still needs to have the
hmm_range_fault() logic this patch introduces.
Thanks,
Jason
next prev parent reply other threads:[~2020-03-16 12:11 UTC|newest]
Thread overview: 56+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-11 18:34 [PATCH hmm 0/8] Various error case bug fixes for hmm_range_fault() Jason Gunthorpe
2020-03-11 18:34 ` [PATCH hmm 1/8] mm/hmm: add missing unmaps of the ptep during hmm_vma_handle_pte() Jason Gunthorpe
2020-03-12 1:28 ` Ralph Campbell
2020-03-12 14:24 ` Jason Gunthorpe
2020-03-16 8:58 ` Christoph Hellwig
2020-03-11 18:35 ` [PATCH hmm 2/8] mm/hmm: don't free the cached pgmap while scanning Jason Gunthorpe
2020-03-12 1:29 ` Ralph Campbell
2020-03-16 9:02 ` Christoph Hellwig
2020-03-16 18:07 ` Jason Gunthorpe
2020-03-16 18:13 ` Christoph Hellwig
2020-03-16 19:23 ` Jason Gunthorpe
2020-03-11 18:35 ` [PATCH hmm 3/8] mm/hmm: do not call hmm_vma_walk_hole() while holding a spinlock Jason Gunthorpe
2020-03-12 1:31 ` Ralph Campbell
2020-03-12 8:54 ` Steven Price
2020-03-12 10:28 ` [PATCH] mm/hmm: Simplify hmm_vma_walk_pud slightly Steven Price
2020-03-12 14:27 ` Jason Gunthorpe
2020-03-12 14:40 ` Steven Price
2020-03-12 15:11 ` Jason Gunthorpe
2020-03-12 16:16 ` Steven Price
2020-03-12 16:37 ` Jason Gunthorpe
2020-03-12 17:02 ` Steven Price
2020-03-12 17:17 ` Jason Gunthorpe
2020-03-13 19:55 ` Jason Gunthorpe
2020-03-13 21:04 ` Matthew Wilcox
2020-03-13 22:51 ` Jason Gunthorpe
2020-03-16 9:05 ` [PATCH hmm 3/8] mm/hmm: do not call hmm_vma_walk_hole() while holding a spinlock Christoph Hellwig
2020-03-16 12:56 ` Jason Gunthorpe
2020-03-11 18:35 ` [PATCH hmm 4/8] mm/hmm: add missing pfns set to hmm_vma_walk_pmd() Jason Gunthorpe
2020-03-12 1:33 ` Ralph Campbell
2020-03-16 9:06 ` Christoph Hellwig
2020-03-11 18:35 ` [PATCH hmm 5/8] mm/hmm: add missing call to hmm_range_need_fault() before returning EFAULT Jason Gunthorpe
2020-03-12 1:34 ` Ralph Campbell
2020-03-16 9:07 ` Christoph Hellwig
2020-03-11 18:35 ` [PATCH hmm 6/8] mm/hmm: reorganize how !pte_present is handled in hmm_vma_handle_pte() Jason Gunthorpe
2020-03-12 1:36 ` Ralph Campbell
2020-03-16 9:11 ` Christoph Hellwig
2020-03-11 18:35 ` [PATCH hmm 7/8] mm/hmm: return -EFAULT when setting HMM_PFN_ERROR on requested valid pages Jason Gunthorpe
2020-03-12 1:36 ` Ralph Campbell
2020-03-12 14:35 ` Jason Gunthorpe
2020-03-16 9:12 ` Christoph Hellwig
2020-03-11 18:35 ` [PATCH hmm 8/8] mm/hmm: add missing call to hmm_pte_need_fault in HMM_PFN_SPECIAL handling Jason Gunthorpe
2020-03-12 1:38 ` Ralph Campbell
2020-03-16 9:13 ` Christoph Hellwig
2020-03-16 12:10 ` Jason Gunthorpe [this message]
2020-03-16 12:49 ` Christoph Hellwig
2020-03-16 13:04 ` Jason Gunthorpe
2020-03-16 13:12 ` Christoph Hellwig
2020-03-17 12:32 ` Christoph Hellwig
2020-03-17 12:53 ` Jason Gunthorpe
2020-03-17 13:06 ` Christoph Hellwig
2020-03-17 13:25 ` Jason Gunthorpe
2020-03-16 12:51 ` Christoph Hellwig
2020-03-12 19:33 ` [PATCH hmm 9/8] mm/hmm: do not check pmd_protnone twice in hmm_vma_handle_pmd() Jason Gunthorpe
2020-03-12 23:50 ` Ralph Campbell
2020-03-16 9:14 ` Christoph Hellwig
2020-03-16 18:25 ` [PATCH hmm 0/8] Various error case bug fixes for hmm_range_fault() Jason Gunthorpe
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