similar to: [PATCH net] vhost: flush dcache page when logging dirty pages

On Tue, Apr 09, 2019 at 12:16:47PM +0800, Jason Wang wrote: > We set dirty bit through setting up kmaps and access them through > kernel virtual address, this may result alias in virtually tagged > caches that require a dcache flush afterwards. > > Cc: Christoph Hellwig <hch at infradead.org> > Cc: James Bottomley <James.Bottomley at HansenPartnership.com> > Cc:

On Tue, Mar 12, 2019 at 10:59:09AM +0800, Jason Wang wrote: > > On 2019/3/12 ??2:14, David Miller wrote: > > From: "Michael S. Tsirkin" <mst at redhat.com> > > Date: Mon, 11 Mar 2019 09:59:28 -0400 > > > > > On Mon, Mar 11, 2019 at 03:13:17PM +0800, Jason Wang wrote: > > > > On 2019/3/8 ??10:12, Christoph Hellwig wrote: > > >

On Tue, Mar 12, 2019 at 10:59:09AM +0800, Jason Wang wrote: > > On 2019/3/12 ??2:14, David Miller wrote: > > From: "Michael S. Tsirkin" <mst at redhat.com> > > Date: Mon, 11 Mar 2019 09:59:28 -0400 > > > > > On Mon, Mar 11, 2019 at 03:13:17PM +0800, Jason Wang wrote: > > > > On 2019/3/8 ??10:12, Christoph Hellwig wrote: > > >

From: "Michael S. Tsirkin" <mst at redhat.com> Date: Mon, 11 Mar 2019 09:59:28 -0400 > On Mon, Mar 11, 2019 at 03:13:17PM +0800, Jason Wang wrote: >> >> On 2019/3/8 ??10:12, Christoph Hellwig wrote: >> > On Wed, Mar 06, 2019 at 02:18:07AM -0500, Jason Wang wrote: >> > > This series tries to access virtqueue metadata through kernel virtual

From: "Michael S. Tsirkin" <mst at redhat.com> Date: Mon, 11 Mar 2019 09:59:28 -0400 > On Mon, Mar 11, 2019 at 03:13:17PM +0800, Jason Wang wrote: >> >> On 2019/3/8 ??10:12, Christoph Hellwig wrote: >> > On Wed, Mar 06, 2019 at 02:18:07AM -0500, Jason Wang wrote: >> > > This series tries to access virtqueue metadata through kernel virtual

Vhost log dirty pages directly to a userspace bitmap through GUP and kmap_atomic() since kernel doesn't have a set_bit_to_user() helper. This will cause issues for the arch that has virtually tagged caches. The way to fix is to keep using userspace virtual address. Fortunately, futex has arch_futex_atomic_op_inuser() which could be used for setting a bit to user. Note there're several

Vhost log dirty pages directly to a userspace bitmap through GUP and kmap_atomic() since kernel doesn't have a set_bit_to_user() helper. This will cause issues for the arch that has virtually tagged caches. The way to fix is to keep using userspace virtual address. Fortunately, futex has arch_futex_atomic_op_inuser() which could be used for setting a bit to user. Note there're several

Vhost log dirty pages directly to a userspace bitmap through GUP and kmap_atomic() since kernel doesn't have a set_bit_to_user() helper. This will cause issues for the arch that has virtually tagged caches. The way to fix is to keep using userspace virtual address. Fortunately, futex has a cmpxchg to userspace memory helper futex_atomic_cmpxchg_inatomic(). So switch to use it to exchange the

Vhost log dirty pages directly to a userspace bitmap through GUP and kmap_atomic() since kernel doesn't have a set_bit_to_user() helper. This will cause issues for the arch that has virtually tagged caches. The way to fix is to keep using userspace virtual address. Fortunately, futex has a cmpxchg to userspace memory helper futex_atomic_cmpxchg_inatomic(). So switch to use it to exchange the

Vhost log dirty pages directly to a userspace bitmap through GUP and kmap_atomic() since kernel doesn't have a set_bit_to_user() helper. This will cause issues for the arch that has virtually tagged caches. The way to fix is to keep using userspace virtual address. Fortunately, futex has arch_futex_atomic_op_inuser() which could be used for setting a bit to user. Note: - There're archs

Vhost log dirty pages directly to a userspace bitmap through GUP and kmap_atomic() since kernel doesn't have a set_bit_to_user() helper. This will cause issues for the arch that has virtually tagged caches. The way to fix is to keep using userspace virtual address. Fortunately, futex has arch_futex_atomic_op_inuser() which could be used for setting a bit to user. Note: - There're archs

On Mon, May 06, 2019 at 10:23:29PM -0400, Jason Wang wrote: > Vhost log dirty pages directly to a userspace bitmap through GUP and > kmap_atomic() since kernel doesn't have a set_bit_to_user() > helper. This will cause issues for the arch that has virtually tagged > caches. The way to fix is to keep using userspace virtual address. > > Fortunately, futex has a cmpxchg to

On Mon, May 13, 2019 at 01:27:45AM -0400, Jason Wang wrote: > Vhost log dirty pages directly to a userspace bitmap through GUP and > kmap_atomic() since kernel doesn't have a set_bit_to_user() > helper. This will cause issues for the arch that has virtually tagged > caches. The way to fix is to keep using userspace virtual > address. Fortunately, futex has

On Thu, May 09, 2019 at 08:58:00AM -0400, Jason Wang wrote: > Vhost log dirty pages directly to a userspace bitmap through GUP and > kmap_atomic() since kernel doesn't have a set_bit_to_user() > helper. This will cause issues for the arch that has virtually tagged > caches. The way to fix is to keep using userspace virtual > address. Fortunately, futex has

On 2019/5/9 ??9:18, Michael S. Tsirkin wrote: > On Thu, May 09, 2019 at 08:58:00AM -0400, Jason Wang wrote: >> Vhost log dirty pages directly to a userspace bitmap through GUP and >> kmap_atomic() since kernel doesn't have a set_bit_to_user() >> helper. This will cause issues for the arch that has virtually tagged >> caches. The way to fix is to keep using userspace

On 2019/5/9 ??9:18, Michael S. Tsirkin wrote: > On Thu, May 09, 2019 at 08:58:00AM -0400, Jason Wang wrote: >> Vhost log dirty pages directly to a userspace bitmap through GUP and >> kmap_atomic() since kernel doesn't have a set_bit_to_user() >> helper. This will cause issues for the arch that has virtually tagged >> caches. The way to fix is to keep using userspace

From: Jason Wang <jasowang at redhat.com> Date: Mon, 13 May 2019 01:27:45 -0400 > Vhost log dirty pages directly to a userspace bitmap through GUP and > kmap_atomic() since kernel doesn't have a set_bit_to_user() > helper. This will cause issues for the arch that has virtually tagged > caches. The way to fix is to keep using userspace virtual > address. Fortunately, futex

Hi, It recently became clear to me that there are some get_user_pages*() callers that don't fit neatly into any of the four cases that are so far listed in pin_user_pages.rst. vhost.c is one of those. Add a Case 5 to the documentation, and refer to that when converting vhost.c. Thanks to Jan Kara for helping me (again) in understanding the interaction between get_user_pages() and page

This problem is found in meego testing: http://bugs.meego.com/show_bug.cgi?id=6672 A file in btrfs is mmaped and the mmaped buffer is passed to pwrite to write to the same page of the same file. In btrfs_file_aio_write(), the pages is locked by prepare_pages(). So when btrfs_copy_from_user() is called, page fault happens and the same page needs to be locked again in filemap_fault(). The fix is to

On 2019/3/12 ??1:14, James Bottomley wrote: > On Tue, 2019-03-12 at 10:59 +0800, Jason Wang wrote: >> On 2019/3/12 ??2:14, David Miller wrote: >>> From: "Michael S. Tsirkin" <mst at redhat.com> >>> Date: Mon, 11 Mar 2019 09:59:28 -0400 >>> >>>> On Mon, Mar 11, 2019 at 03:13:17PM +0800, Jason Wang wrote: >>>>> On