On Fri, Sep 08, 2023 at 10:59:48AM +0200, Kevin Wolf wrote: > Am 07.09.2023 um 20:40 hat Stefan Hajnoczi geschrieben: > > On Tue, Sep 05, 2023 at 04:50:02PM +0200, Kevin Wolf wrote: > > > virtio_load() as a whole should run in coroutine context because it > > > reads from the migration stream and we don't want this to block. > > > > Is that "should" a "must" or a "can"? > > > > If it's a "must" then virtio_load() needs assert(qemu_in_coroutine()). > > > > But the previous patch mentioned that loadvm for snapshots calls it > > outside coroutine context. So maybe it's a "can"? > > Where this makes a difference is when the function indirectly calls into > QIOChannel. When called from a coroutine, it yields while waiting for > I/O, and outside of a coroutine it blocks. Yielding is always > preferable, but in cases like HMP savevm/loadvm we also don't really > care because it's synchronous anyway. > > Whether that makes it a MAY or a SHOULD in the RFC sense, you decide. > If you wanted to make it a MUST, you'd need to check all callers first > and change some of them.
Thanks for clarifying. It is "can". Stefan
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