From: Stefan Hajnoczi <stefanha@redhat.com>
To: "Dr. David Alan Gilbert (git)" <dgilbert@redhat.com>
Cc: virtio-fs@redhat.com, qemu-devel@nongnu.org, vgoyal@redhat.com,
groug@kaod.org
Subject: Re: [PATCH v3 20/26] DAX/unmap virtiofsd: Parse unmappable elements
Date: Thu, 6 May 2021 16:23:49 +0100 [thread overview]
Message-ID: <YJQKBfZ+++VUiSOO@stefanha-x1.localdomain> (raw)
In-Reply-To: <20210428110100.27757-21-dgilbert@redhat.com>
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On Wed, Apr 28, 2021 at 12:00:54PM +0100, Dr. David Alan Gilbert (git) wrote:
> From: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
>
> For some read/writes the virtio queue elements are unmappable by
> the daemon; these are cases where the data is to be read/written
> from non-RAM. In viritofs's case this is typically a direct read/write
s/viritofs/virtiofs/
> into an mmap'd DAX file also on virtiofs (possibly on another instance).
>
> When we receive a virtio queue element, check that we have enough
> mappable data to handle the headers. Make a note of the number of
> unmappable 'in' entries (ie. for read data back to the VMM),
> and flag the fuse_bufvec for 'out' entries with a new flag
> FUSE_BUF_PHYS_ADDR.
>
> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
> with fix by:
> Signed-off-by: Liu Bo <bo.liu@linux.alibaba.com>
> ---
> tools/virtiofsd/buffer.c | 4 +-
> tools/virtiofsd/fuse_common.h | 7 ++
> tools/virtiofsd/fuse_virtio.c | 230 ++++++++++++++++++++++++----------
> 3 files changed, 173 insertions(+), 68 deletions(-)
>
> diff --git a/tools/virtiofsd/buffer.c b/tools/virtiofsd/buffer.c
> index 874f01c488..1a050aa441 100644
> --- a/tools/virtiofsd/buffer.c
> +++ b/tools/virtiofsd/buffer.c
> @@ -77,6 +77,7 @@ static ssize_t fuse_buf_write(const struct fuse_buf *dst, size_t dst_off,
> ssize_t res = 0;
> size_t copied = 0;
>
> + assert(!(src->flags & FUSE_BUF_PHYS_ADDR));
> while (len) {
> if (dst->flags & FUSE_BUF_FD_SEEK) {
> res = pwrite(dst->fd, (char *)src->mem + src_off, len,
> @@ -272,7 +273,8 @@ ssize_t fuse_buf_copy(struct fuse_bufvec *dstv, struct fuse_bufvec *srcv)
> * process
> */
> for (i = 0; i < srcv->count; i++) {
> - if (srcv->buf[i].flags & FUSE_BUF_IS_FD) {
> + if ((srcv->buf[i].flags & FUSE_BUF_PHYS_ADDR) ||
> + (srcv->buf[i].flags & FUSE_BUF_IS_FD)) {
> break;
> }
> }
> diff --git a/tools/virtiofsd/fuse_common.h b/tools/virtiofsd/fuse_common.h
> index fa9671872e..af43cf19f9 100644
> --- a/tools/virtiofsd/fuse_common.h
> +++ b/tools/virtiofsd/fuse_common.h
> @@ -626,6 +626,13 @@ enum fuse_buf_flags {
> * detected.
> */
> FUSE_BUF_FD_RETRY = (1 << 3),
> +
> + /**
> + * The addresses in the iovec represent guest physical addresses
> + * that can't be mapped by the daemon process.
> + * IO must be bounced back to the VMM to do it.
> + */
> + FUSE_BUF_PHYS_ADDR = (1 << 4),
Based on the previous patch this is not a gpa, it's an IOVA. Depending
on the virtiofs device's DMA address space in QEMU this might be the
same as guest physical addresses but there could also be vIOMMU
translation (see the address_space_translate() call in the patch that
implemented the IO slave command).
Maybe virtiofs + vIOMMU has never been tested though... I'm not sure it
works today.
If you want to leave it as is, feel free:
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
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next prev parent reply other threads:[~2021-05-06 15:26 UTC|newest]
Thread overview: 66+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-28 11:00 [PATCH v3 00/26] virtiofs dax patches Dr. David Alan Gilbert (git)
2021-04-28 11:00 ` [PATCH v3 01/26] virtiofs: Fixup printf args Dr. David Alan Gilbert (git)
2021-05-04 14:54 ` Stefan Hajnoczi
2021-05-05 11:06 ` Dr. David Alan Gilbert
2021-05-06 15:56 ` Dr. David Alan Gilbert
2021-04-28 11:00 ` [PATCH v3 02/26] virtiofsd: Don't assume header layout Dr. David Alan Gilbert (git)
2021-05-04 15:12 ` Stefan Hajnoczi
2021-05-06 15:56 ` Dr. David Alan Gilbert
2021-04-28 11:00 ` [PATCH v3 03/26] DAX: vhost-user: Rework slave return values Dr. David Alan Gilbert (git)
2021-05-04 15:23 ` Stefan Hajnoczi
2021-05-27 15:59 ` Dr. David Alan Gilbert
2021-04-28 11:00 ` [PATCH v3 04/26] DAX: libvhost-user: Route slave message payload Dr. David Alan Gilbert (git)
2021-05-04 15:26 ` Stefan Hajnoczi
2021-04-28 11:00 ` [PATCH v3 05/26] DAX: libvhost-user: Allow popping a queue element with bad pointers Dr. David Alan Gilbert (git)
2021-04-28 11:00 ` [PATCH v3 06/26] DAX subprojects/libvhost-user: Add virtio-fs slave types Dr. David Alan Gilbert (git)
2021-04-29 15:48 ` Dr. David Alan Gilbert
2021-04-28 11:00 ` [PATCH v3 07/26] DAX: virtio: Add shared memory capability Dr. David Alan Gilbert (git)
2021-04-28 11:00 ` [PATCH v3 08/26] DAX: virtio-fs: Add cache BAR Dr. David Alan Gilbert (git)
2021-05-05 12:12 ` Stefan Hajnoczi
2021-05-05 18:59 ` Dr. David Alan Gilbert
2021-04-28 11:00 ` [PATCH v3 09/26] DAX: virtio-fs: Add vhost-user slave commands for mapping Dr. David Alan Gilbert (git)
2021-05-05 14:15 ` Stefan Hajnoczi
2021-05-27 16:57 ` Dr. David Alan Gilbert
2021-04-28 11:00 ` [PATCH v3 10/26] DAX: virtio-fs: Fill in " Dr. David Alan Gilbert (git)
2021-05-05 16:43 ` Stefan Hajnoczi
2021-04-28 11:00 ` [PATCH v3 11/26] DAX: virtiofsd Add cache accessor functions Dr. David Alan Gilbert (git)
2021-04-28 11:00 ` [PATCH v3 12/26] DAX: virtiofsd: Add setup/remove mappings fuse commands Dr. David Alan Gilbert (git)
2021-05-06 15:02 ` Stefan Hajnoczi
2021-04-28 11:00 ` [PATCH v3 13/26] DAX: virtiofsd: Add setup/remove mapping handlers to passthrough_ll Dr. David Alan Gilbert (git)
2021-04-28 11:00 ` [PATCH v3 14/26] DAX: virtiofsd: Wire up passthrough_ll's lo_setupmapping Dr. David Alan Gilbert (git)
2021-04-28 11:00 ` [PATCH v3 15/26] DAX: virtiofsd: Make lo_removemapping() work Dr. David Alan Gilbert (git)
2021-04-28 11:00 ` [PATCH v3 16/26] DAX: virtiofsd: route se down to destroy method Dr. David Alan Gilbert (git)
2021-04-28 11:00 ` [PATCH v3 17/26] DAX: virtiofsd: Perform an unmap on destroy Dr. David Alan Gilbert (git)
2021-04-28 11:00 ` [PATCH v3 18/26] DAX/unmap: virtiofsd: Add VHOST_USER_SLAVE_FS_IO Dr. David Alan Gilbert (git)
2021-05-06 15:12 ` Stefan Hajnoczi
2021-05-27 17:44 ` Dr. David Alan Gilbert
2021-05-06 15:16 ` Stefan Hajnoczi
2021-05-27 17:31 ` Dr. David Alan Gilbert
2021-04-28 11:00 ` [PATCH v3 19/26] DAX/unmap virtiofsd: Add wrappers for VHOST_USER_SLAVE_FS_IO Dr. David Alan Gilbert (git)
2021-04-28 12:53 ` Dr. David Alan Gilbert
2021-04-28 11:00 ` [PATCH v3 20/26] DAX/unmap virtiofsd: Parse unmappable elements Dr. David Alan Gilbert (git)
2021-05-06 15:23 ` Stefan Hajnoczi [this message]
2021-05-27 17:56 ` Dr. David Alan Gilbert
2021-04-28 11:00 ` [PATCH v3 21/26] DAX/unmap virtiofsd: Route unmappable reads Dr. David Alan Gilbert (git)
2021-05-06 15:27 ` Stefan Hajnoczi
2021-04-28 11:00 ` [PATCH v3 22/26] DAX/unmap virtiofsd: route unmappable write to slave command Dr. David Alan Gilbert (git)
2021-05-06 15:28 ` Stefan Hajnoczi
2021-04-28 11:00 ` [PATCH v3 23/26] DAX:virtiofsd: implement FUSE_INIT map_alignment field Dr. David Alan Gilbert (git)
2021-04-28 11:00 ` [PATCH v3 24/26] vhost-user-fs: Extend VhostUserFSSlaveMsg to pass additional info Dr. David Alan Gilbert (git)
2021-05-06 15:31 ` Stefan Hajnoczi
2021-05-06 15:32 ` Stefan Hajnoczi
2021-04-28 11:00 ` [PATCH v3 25/26] vhost-user-fs: Implement drop CAP_FSETID functionality Dr. David Alan Gilbert (git)
2021-04-28 11:01 ` [PATCH v3 26/26] virtiofsd: Ask qemu to drop CAP_FSETID if client asked for it Dr. David Alan Gilbert (git)
2021-05-06 15:37 ` Stefan Hajnoczi
2021-05-06 16:02 ` Vivek Goyal
2021-05-10 9:05 ` Stefan Hajnoczi
2021-05-10 15:23 ` Vivek Goyal
2021-05-10 15:32 ` Stefan Hajnoczi
2021-05-27 19:09 ` Dr. David Alan Gilbert
2021-06-10 15:29 ` Dr. David Alan Gilbert
2021-06-10 16:23 ` Stefan Hajnoczi
2021-06-16 12:36 ` Dr. David Alan Gilbert
2021-06-16 15:29 ` Stefan Hajnoczi
2021-06-16 18:35 ` Dr. David Alan Gilbert
2021-04-28 11:27 ` [PATCH v3 00/26] virtiofs dax patches no-reply
2021-05-06 15:37 ` Stefan Hajnoczi
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