| Message ID | 20240812130606.90410-8-edgar.iglesias@gmail.com |
|---|---|
| State | New |
| Headers | show |
| Series | xen: pvh: Partial QOM:fication with new x86 PVH machine | expand |
On Mon, 12 Aug 2024, Edgar E. Iglesias wrote: > From: "Edgar E. Iglesias" <edgar.iglesias@amd.com> > > We've been creating the virtio-mmio devices in forwards order > but since the qbus lists prepend (rather than append) entries, > the virtio busses end up with decreasing base address order. > > Xen enables virtio-mmio nodes in forwards order so there's been > a missmatch. So far, we've been working around this with an > out-of-tree patch to Xen. > > This reverses the order making sure the virtio busses end up > ordered with increasing base addresses avoiding the need to > patch Xen. > > Signed-off-by: Edgar E. Iglesias <edgar.iglesias@amd.com> Acked-by: Stefano Stabellini <sstabellini@kernel.org> > --- > hw/xen/xen-pvh-common.c | 13 ++++++++++++- > 1 file changed, 12 insertions(+), 1 deletion(-) > > diff --git a/hw/xen/xen-pvh-common.c b/hw/xen/xen-pvh-common.c > index 0d368398d0..69a2dbdb6d 100644 > --- a/hw/xen/xen-pvh-common.c > +++ b/hw/xen/xen-pvh-common.c > @@ -73,7 +73,18 @@ static void xen_create_virtio_mmio_devices(XenPVHCommonState *s) > { > int i; > > - for (i = 0; i < s->cfg.virtio_mmio_num; i++) { > + /* > + * We create the transports in reverse order. Since qbus_realize() > + * prepends (not appends) new child buses, the decrementing loop below will > + * create a list of virtio-mmio buses with increasing base addresses. > + * > + * When a -device option is processed from the command line, > + * qbus_find_recursive() picks the next free virtio-mmio bus in forwards > + * order. > + * > + * This is what the Xen tools expect. > + */ > + for (i = s->cfg.virtio_mmio_num - 1; i >= 0; i--) { > hwaddr base = s->cfg.virtio_mmio.base + i * s->cfg.virtio_mmio.size; > qemu_irq irq = qemu_allocate_irq(xen_set_irq, NULL, > s->cfg.virtio_mmio_irq_base + i); > -- > 2.43.0 >
diff --git a/hw/xen/xen-pvh-common.c b/hw/xen/xen-pvh-common.c index 0d368398d0..69a2dbdb6d 100644 --- a/hw/xen/xen-pvh-common.c +++ b/hw/xen/xen-pvh-common.c @@ -73,7 +73,18 @@ static void xen_create_virtio_mmio_devices(XenPVHCommonState *s) { int i; - for (i = 0; i < s->cfg.virtio_mmio_num; i++) { + /* + * We create the transports in reverse order. Since qbus_realize() + * prepends (not appends) new child buses, the decrementing loop below will + * create a list of virtio-mmio buses with increasing base addresses. + * + * When a -device option is processed from the command line, + * qbus_find_recursive() picks the next free virtio-mmio bus in forwards + * order. + * + * This is what the Xen tools expect. + */ + for (i = s->cfg.virtio_mmio_num - 1; i >= 0; i--) { hwaddr base = s->cfg.virtio_mmio.base + i * s->cfg.virtio_mmio.size; qemu_irq irq = qemu_allocate_irq(xen_set_irq, NULL, s->cfg.virtio_mmio_irq_base + i);