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Re: [Qemu-devel] [PATCH V2 04/11] virtio-ccw: introduce ccw specific que
From: |
Cornelia Huck |
Subject: |
Re: [Qemu-devel] [PATCH V2 04/11] virtio-ccw: introduce ccw specific queue limit |
Date: |
Fri, 27 Feb 2015 10:41:53 +0100 |
On Fri, 27 Feb 2015 03:46:25 +0008
Jason Wang <address@hidden> wrote:
> On Thu, Feb 26, 2015 at 9:02 PM, Cornelia Huck
> <address@hidden> wrote:
> > On Thu, 26 Feb 2015 15:04:39 +0800
> > Jason Wang <address@hidden> wrote:
> >
> >> Instead of depending on marco, using a bus specific limit.
> >>
> >> Cc: Alexander Graf <address@hidden>
> >> Cc: Cornelia Huck <address@hidden>
> >> Cc: Christian Borntraeger <address@hidden>
> >> Cc: Richard Henderson <address@hidden>
> >> Signed-off-by: Jason Wang <address@hidden>
> >> ---
> >> hw/s390x/s390-virtio-ccw.c | 7 +++++--
> >> hw/s390x/virtio-ccw.c | 13 +++++++------
> >> include/hw/virtio/virtio.h | 1 +
> >> 3 files changed, 13 insertions(+), 8 deletions(-)
> >>
> >> diff --git a/hw/s390x/s390-virtio-ccw.c b/hw/s390x/s390-virtio-ccw.c
> >> index 71bafe0..6aeb815 100644
> >> --- a/hw/s390x/s390-virtio-ccw.c
> >> +++ b/hw/s390x/s390-virtio-ccw.c
> >> @@ -43,6 +43,7 @@ void io_subsystem_reset(void)
> >>
> >> static int virtio_ccw_hcall_notify(const uint64_t *args)
> >> {
> >> + VirtIODevice *vdev;
> >> uint64_t subch_id = args[0];
> >> uint64_t queue = args[1];
> >> SubchDev *sch;
> >> @@ -55,10 +56,12 @@ static int virtio_ccw_hcall_notify(const
> >> uint64_t *args)
> >> if (!sch || !css_subch_visible(sch)) {
> >> return -EINVAL;
> >> }
> >> - if (queue >= VIRTIO_PCI_QUEUE_MAX) {
> >> +
> >> + vdev = virtio_ccw_get_vdev(sch);
> >> + if (queue >= virtio_get_queue_max(vdev)) {
> >
> > But we already know we have a virtio_ccw device, right? So why not
> > just
> > check against VIRTIO_CCW_QUEUE_MAX?
>
> The problem is whether or not you want to increase the max queue for
> ccw. If yes, for migration compatibility, you could not just use a
> marco here since legacy machine type will also get increased.
Confused. With "legacy machine type", do you mean s390-virtio? It does
not register this hcall.
> Something
> dynamically like this is need so the machine initialization code can
> change this limit.
I fear I don't understand how the machine code comes into play here. Is
the virtio-ccw device code supposed to inherit the limit from the
machine?
Anyway, if we move the queue limit to the VirtIODevice, checking the
limit there instead of using a #define should work out fine.
- Re: [Qemu-devel] [PATCH V2 03/11] virito: introduce bus specific queue limit, (continued)
[Qemu-devel] [PATCH V2 05/11] virtio-serial-bus: switch to bus specific queue limit, Jason Wang, 2015/02/26
[Qemu-devel] [PATCH V2 04/11] virtio-ccw: introduce ccw specific queue limit, Jason Wang, 2015/02/26
[Qemu-devel] [PATCH V2 07/11] virtio-mmio: switch to bus specific queue limit, Jason Wang, 2015/02/26
[Qemu-devel] [PATCH V2 06/11] virtio-s390: switch to bus specific queue limit, Jason Wang, 2015/02/26
[Qemu-devel] [PATCH V2 09/11] virtio-pci: increase the maximum number of virtqueues to 513, Jason Wang, 2015/02/26
[Qemu-devel] [PATCH V2 08/11] virtio-pci: switch to use bus specific queue limit, Jason Wang, 2015/02/26