[Spice-devel] [spice-server] cursor: Delay release of QXL guest cursor resources
Frediano Ziglio
fziglio at redhat.com
Tue Apr 10 11:44:23 UTC 2018
>
> Ping? I would like to move forward with having this fix temporarily in
> spice-server even if in the long run, we'll be fixing QEMU too.
> This would ease the upgrade path, as having this patch means we don't
> tie upgrades to spice-server 0.14 with QEMU upgrades, it does not matter
> if you upgrade both at once or not, spice-server will have the same
> behaviour as in the 0.12 branch.
>
> Christophe
>
When do you plan to remove this patch from spice-server?
> On Thu, Apr 05, 2018 at 10:36:27AM +0200, Christophe Fergeau wrote:
> > There's an implicit API/ABI contract between QEMU and SPICE that SPICE
> > will keep the guest QXL resources alive as long as QEMU can hold a
> > pointer to them. This implicit contract was broken in 1c6e7cf7 "Release
> > cursor as soon as possible", causing crashes at migration time.
> > While the proper fix would be in QEMU so that spice-server does not need
> > to have that kind of knowledge regarding QEMU internal implementation,
> > this commit reverts to the pre-1c6e7cf7 behaviour to avoid a regression
> > while QEMU is being fixed.
> >
> > https://bugzilla.redhat.com/show_bug.cgi?id=1540919
> >
> > Signed-off-by: Christophe Fergeau <cfergeau at redhat.com>
Would not be better to add a qxl field in RedCursorCmd and free the resource
in red_put_cursor_cmd?
This patch looks pretty invasive.
Frediano
> > ---
> > server/cursor-channel.c | 16 +++++++++++++---
> > server/cursor-channel.h | 5 ++++-
> > server/red-stream-device.c | 4 ++--
> > server/red-worker.c | 10 ++++++++--
> > 4 files changed, 27 insertions(+), 8 deletions(-)
> >
> > diff --git a/server/cursor-channel.c b/server/cursor-channel.c
> > index 522261e3f..a7bee9815 100644
> > --- a/server/cursor-channel.c
> > +++ b/server/cursor-channel.c
> > @@ -31,6 +31,8 @@
> > typedef struct RedCursorPipeItem {
> > RedPipeItem base;
> > RedCursorCmd *red_cursor;
> > + ReleaseCommandCb release_command_cb;
> > + gpointer user_data;
> > } RedCursorPipeItem;
> >
> > struct CursorChannel
> > @@ -54,7 +56,9 @@ G_DEFINE_TYPE(CursorChannel, cursor_channel,
> > TYPE_COMMON_GRAPHICS_CHANNEL)
> >
> > static void cursor_pipe_item_free(RedPipeItem *pipe_item);
> >
> > -static RedCursorPipeItem *cursor_pipe_item_new(RedCursorCmd *cmd)
> > +static RedCursorPipeItem *cursor_pipe_item_new(RedCursorCmd *cmd,
> > + ReleaseCommandCb
> > release_command_cb,
> > + gpointer user_data)
> > {
> > RedCursorPipeItem *item = g_new0(RedCursorPipeItem, 1);
> >
> > @@ -63,6 +67,8 @@ static RedCursorPipeItem
> > *cursor_pipe_item_new(RedCursorCmd *cmd)
> > red_pipe_item_init_full(&item->base, RED_PIPE_ITEM_TYPE_CURSOR,
> > cursor_pipe_item_free);
> > item->red_cursor = cmd;
> > + item->release_command_cb = release_command_cb;
> > + item->user_data = user_data;
> >
> > return item;
> > }
> > @@ -73,6 +79,9 @@ static void cursor_pipe_item_free(RedPipeItem *base)
> > RedCursorPipeItem *pipe_item = SPICE_UPCAST(RedCursorPipeItem, base);
> >
> > cursor_cmd = pipe_item->red_cursor;
> > + if (pipe_item->release_command_cb) {
> > + pipe_item->release_command_cb(cursor_cmd, pipe_item->user_data);
> > + }
> > red_put_cursor_cmd(cursor_cmd);
> > g_free(cursor_cmd);
> >
> > @@ -246,7 +255,8 @@ CursorChannel* cursor_channel_new(RedsState *server,
> > int id,
> > NULL);
> > }
> >
> > -void cursor_channel_process_cmd(CursorChannel *cursor, RedCursorCmd
> > *cursor_cmd)
> > +void cursor_channel_process_cmd(CursorChannel *cursor, RedCursorCmd
> > *cursor_cmd,
> > + ReleaseCommandCb release_command_cb,
> > gpointer user_data)
> > {
> > RedCursorPipeItem *cursor_pipe_item;
> > bool cursor_show = false;
> > @@ -254,7 +264,7 @@ void cursor_channel_process_cmd(CursorChannel *cursor,
> > RedCursorCmd *cursor_cmd)
> > spice_return_if_fail(cursor);
> > spice_return_if_fail(cursor_cmd);
> >
> > - cursor_pipe_item = cursor_pipe_item_new(cursor_cmd);
> > + cursor_pipe_item = cursor_pipe_item_new(cursor_cmd,
> > release_command_cb, user_data);
> >
> > switch (cursor_cmd->type) {
> > case QXL_CURSOR_SET:
> > diff --git a/server/cursor-channel.h b/server/cursor-channel.h
> > index 603c2c0ac..e41e52438 100644
> > --- a/server/cursor-channel.h
> > +++ b/server/cursor-channel.h
> > @@ -44,6 +44,8 @@ typedef struct CursorChannelClass CursorChannelClass;
> >
> > GType cursor_channel_get_type(void) G_GNUC_CONST;
> >
> > +typedef void (*ReleaseCommandCb)(RedCursorCmd *command, gpointer
> > user_data);
> > +
> > /**
> > * Create CursorChannel.
> > * Since CursorChannel is intended to be run in a separate thread,
> > @@ -61,7 +63,8 @@ CursorChannel* cursor_channel_new(RedsState *server, int
> > id,
> >
> > void cursor_channel_reset (CursorChannel *cursor);
> > void cursor_channel_do_init (CursorChannel *cursor);
> > -void cursor_channel_process_cmd (CursorChannel *cursor,
> > RedCursorCmd *cursor_cmd);
> > +void cursor_channel_process_cmd(CursorChannel *cursor,
> > RedCursorCmd *cursor_cmd,
> > + ReleaseCommandCb
> > release_command_cb, gpointer user_data);
> > void cursor_channel_set_mouse_mode(CursorChannel *cursor,
> > uint32_t mode);
> >
> > /**
> > diff --git a/server/red-stream-device.c b/server/red-stream-device.c
> > index e151de367..36f8b4b61 100644
> > --- a/server/red-stream-device.c
> > +++ b/server/red-stream-device.c
> > @@ -386,7 +386,7 @@ handle_msg_cursor_set(StreamDevice *dev,
> > SpiceCharDeviceInstance *sin)
> > if (!cmd) {
> > return handle_msg_invalid(dev, sin, NULL);
> > }
> > - cursor_channel_process_cmd(dev->cursor_channel, cmd);
> > + cursor_channel_process_cmd(dev->cursor_channel, cmd, NULL, NULL);
> >
> > return true;
> > }
> > @@ -413,7 +413,7 @@ handle_msg_cursor_move(StreamDevice *dev,
> > SpiceCharDeviceInstance *sin)
> > cmd->u.position.x = move->x;
> > cmd->u.position.y = move->y;
> >
> > - cursor_channel_process_cmd(dev->cursor_channel, cmd);
> > + cursor_channel_process_cmd(dev->cursor_channel, cmd, NULL, NULL);
> >
> > return true;
> > }
> > diff --git a/server/red-worker.c b/server/red-worker.c
> > index 387f500e8..a549becf0 100644
> > --- a/server/red-worker.c
> > +++ b/server/red-worker.c
> > @@ -109,6 +109,13 @@ void red_drawable_unref(RedDrawable *red_drawable)
> > g_free(red_drawable);
> > }
> >
> > +static void release_cursor_cmd_cb(RedCursorCmd *cursor_cmd, gpointer
> > user_data)
> > +{
> > + QXLInstance *qxl = user_data;
> > +
> > + red_qxl_release_resource(qxl, cursor_cmd->release_info_ext);
> > +}
> > +
> > static gboolean red_process_cursor_cmd(RedWorker *worker, const
> > QXLCommandExt *ext)
> > {
> > RedCursorCmd *cursor_cmd;
> > @@ -118,8 +125,7 @@ static gboolean red_process_cursor_cmd(RedWorker
> > *worker, const QXLCommandExt *e
> > g_free(cursor_cmd);
> > return FALSE;
> > }
> > - red_qxl_release_resource(worker->qxl, cursor_cmd->release_info_ext);
> > - cursor_channel_process_cmd(worker->cursor_channel, cursor_cmd);
> > + cursor_channel_process_cmd(worker->cursor_channel, cursor_cmd,
> > release_cursor_cmd_cb, worker->qxl);
> > return TRUE;
> > }
> >
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