From: Ralph Campbell <rcampbell@nvidia.com>
To: Alistair Popple <apopple@nvidia.com>,
"linux-mm@kvack.org" <linux-mm@kvack.org>,
"nouveau@lists.freedesktop.org" <nouveau@lists.freedesktop.org>,
"bskeggs@redhat.com" <bskeggs@redhat.com>,
"akpm@linux-foundation.org" <akpm@linux-foundation.org>
Cc: "linux-doc@vger.kernel.org" <linux-doc@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"dri-devel@lists.freedesktop.org"
<dri-devel@lists.freedesktop.org>,
"John Hubbard" <jhubbard@nvidia.com>,
"jglisse@redhat.com" <jglisse@redhat.com>,
Jason Gunthorpe <jgg@nvidia.com>,
"hch@infradead.org" <hch@infradead.org>,
"daniel@ffwll.ch" <daniel@ffwll.ch>
Subject: RE: [PATCH v3 5/8] mm: Device exclusive memory access
Date: Mon, 1 Mar 2021 22:55:48 +0000 [thread overview]
Message-ID: <MN2PR12MB43449C6419A839E4F5605B6EC29A9@MN2PR12MB4344.namprd12.prod.outlook.com> (raw)
In-Reply-To: <20210226071832.31547-6-apopple@nvidia.com>
> From: Alistair Popple <apopple@nvidia.com>
> Sent: Thursday, February 25, 2021 11:18 PM
> To: linux-mm@kvack.org; nouveau@lists.freedesktop.org;
> bskeggs@redhat.com; akpm@linux-foundation.org
> Cc: linux-doc@vger.kernel.org; linux-kernel@vger.kernel.org; dri-
> devel@lists.freedesktop.org; John Hubbard <jhubbard@nvidia.com>; Ralph
> Campbell <rcampbell@nvidia.com>; jglisse@redhat.com; Jason Gunthorpe
> <jgg@nvidia.com>; hch@infradead.org; daniel@ffwll.ch; Alistair Popple
> <apopple@nvidia.com>
> Subject: [PATCH v3 5/8] mm: Device exclusive memory access
>
> Some devices require exclusive write access to shared virtual memory (SVM)
> ranges to perform atomic operations on that memory. This requires CPU page
> tables to be updated to deny access whilst atomic operations are occurring.
>
> In order to do this introduce a new swap entry type (SWP_DEVICE_EXCLUSIVE).
> When a SVM range needs to be marked for exclusive access by a device all page
> table mappings for the particular range are replaced with device exclusive swap
> entries. This causes any CPU access to the page to result in a fault.
>
> Faults are resovled by replacing the faulting entry with the original mapping. This
> results in MMU notifiers being called which a driver uses to update access
> permissions such as revoking atomic access. After notifiers have been called the
> device will no longer have exclusive access to the region.
>
> Signed-off-by: Alistair Popple <apopple@nvidia.com>
> ---
> Documentation/vm/hmm.rst | 15 ++++
> include/linux/rmap.h | 3 +
> include/linux/swap.h | 4 +-
> include/linux/swapops.h | 44 ++++++++++-
> mm/hmm.c | 5 ++
> mm/memory.c | 108 +++++++++++++++++++++++++-
> mm/mprotect.c | 8 ++
> mm/page_vma_mapped.c | 9 ++-
> mm/rmap.c | 163 +++++++++++++++++++++++++++++++++++++++
> 9 files changed, 352 insertions(+), 7 deletions(-)
...
> +int make_device_exclusive_range(struct mm_struct *mm, unsigned long start,
> + unsigned long end, struct page **pages) {
> + long npages = (end - start) >> PAGE_SHIFT;
> + long i;
Nit: you should use unsigned long for 'i' and 'npages' to match start/end.
next prev parent reply other threads:[~2021-03-02 7:32 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-26 7:18 [PATCH v3 0/8] Add support for SVM atomics in Nouveau Alistair Popple
2021-02-26 7:18 ` [PATCH v3 1/8] mm: Remove special swap entry functions Alistair Popple
2021-02-26 15:59 ` Christoph Hellwig
2021-03-02 8:52 ` Alistair Popple
2021-03-02 12:02 ` Alistair Popple
2021-03-01 17:46 ` Jason Gunthorpe
2021-03-02 0:21 ` Alistair Popple
2021-02-26 7:18 ` [PATCH v3 2/8] mm/swapops: Rework swap entry manipulation code Alistair Popple
2021-02-26 16:00 ` Christoph Hellwig
2021-03-01 17:47 ` Jason Gunthorpe
2021-02-26 7:18 ` [PATCH v3 3/8] mm/rmap: Split try_to_munlock from try_to_unmap Alistair Popple
2021-02-26 16:01 ` Christoph Hellwig
2021-03-01 16:10 ` Jason Gunthorpe
2021-03-04 4:27 ` Alistair Popple
2021-02-26 7:18 ` [PATCH v3 4/8] mm/rmap: Split migration into its own function Alistair Popple
2021-02-26 16:03 ` Christoph Hellwig
2021-03-02 22:08 ` Zi Yan
2021-03-04 23:54 ` Alistair Popple
2021-02-26 7:18 ` [PATCH v3 5/8] mm: Device exclusive memory access Alistair Popple
2021-03-01 17:54 ` Jason Gunthorpe
2021-03-01 22:55 ` Ralph Campbell [this message]
2021-03-02 0:05 ` Jason Gunthorpe
2021-03-02 8:57 ` Alistair Popple
2021-03-02 12:41 ` Jason Gunthorpe
2021-03-04 5:20 ` Alistair Popple
2021-02-26 7:18 ` [PATCH v3 6/8] mm: Selftests for exclusive device memory Alistair Popple
2021-03-01 17:55 ` Jason Gunthorpe
2021-03-01 18:07 ` Ralph Campbell
2021-03-01 23:14 ` Ralph Campbell
2021-03-02 9:12 ` Alistair Popple
2021-02-26 7:18 ` [PATCH v3 7/8] nouveau/svm: Refactor nouveau_range_fault Alistair Popple
2021-02-26 7:18 ` [PATCH v3 8/8] nouveau/svm: Implement atomic SVM access Alistair Popple
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