]> www.infradead.org Git - users/dwmw2/qemu.git/commit
hw/xen: do not repeatedly try to create a failing backend device
authorDavid Woodhouse <dwmw@amazon.co.uk>
Mon, 16 Oct 2023 09:28:17 +0000 (10:28 +0100)
committerDavid Woodhouse <dwmw@amazon.co.uk>
Wed, 25 Oct 2023 11:45:22 +0000 (12:45 +0100)
commite003ae6f47bcc4052052f02f1807802c3b4a706d
tree9e9f1611f0e63ef4e767041d168b622b5c9973f8
parentfc67b4ca33ab2e13f209f161b2e3ceab6f804ebc
hw/xen: do not repeatedly try to create a failing backend device

If xen_backend_device_create() fails to instantiate a device, the XenBus
code will just keep trying over and over again each time the bus is
re-enumerated, as long as the backend appears online and in
XenbusStateInitialising.

The only thing which prevents the XenBus code from recreating duplicates
of devices which already exist, is the fact that xen_device_realize()
sets the backend state to XenbusStateInitWait. If the attempt to create
the device doesn't get *that* far, that's when it will keep getting
retried.

My first thought was to handle errors by setting the backend state to
XenbusStateClosed, but that doesn't work for XenConsole which wants to
*ignore* any device of type != "ioemu" completely.

So, make xen_backend_device_create() *keep* the XenBackendInstance for a
failed device, and provide a new xen_backend_exists() function to allow
xen_bus_type_enumerate() to check whether one already exists before
creating a new one.

Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Reviewed-by: Paul Durrant <paul@xen.org>
hw/xen/xen-backend.c
hw/xen/xen-bus.c
include/hw/xen/xen-backend.h