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From: Alex Williamson <alex.williamson@redhat.com>
Date: Thu, 24 Dec 2015 11:20:26 -0700
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References: <cover.1447748073.git.chen.fan.fnst@cn.fujitsu.com>
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	<20151224163132-mutt-send-email-mst@redhat.com>
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	<20151224200603-mutt-send-email-mst@redhat.com>
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Subject: Re: [Qemu-devel] [PATCH v14 Resend 08/13] vfio: add check host bus
 reset is support or not
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To: "Michael S. Tsirkin" <mst@redhat.com>
Cc: chen.fan.fnst@cn.fujitsu.com, Cao jin <caoj.fnst@cn.fujitsu.com>, qemu-devel@nongnu.org

On Thu, 2015-12-24 at 20:06 +0200, Michael S. Tsirkin wrote:
> On Thu, Dec 24, 2015 at 10:47:06AM -0700, Alex Williamson wrote:
> > On Thu, 2015-12-24 at 16:32 +0200, Michael S. Tsirkin wrote:
> > > On Thu, Dec 17, 2015 at 09:41:49AM +0800, Cao jin wrote:
> > > > From: Chen Fan <chen.fan.fnst@cn.fujitsu.com>
> > > >=20
> > > > when init vfio devices done, we should test all the devices
> > > > supported
> > > > aer whether conflict with others. For each one, get the hot
> > > > reset
> > > > info for the affected device list.=C2=A0=C2=A0For each affected d=
evice,
> > > > all
> > > > should attach to the VM and on/below the same bus. also, we
> > > > should
> > > > test
> > > > all of the non-AER supporting vfio-pci devices on or below the
> > > > target
> > > > bus to verify they have a reset mechanism.
> > > >=20
> > > > Signed-off-by: Chen Fan <chen.fan.fnst@cn.fujitsu.com>
> > > > ---
> > > > =C2=A0hw/vfio/pci.c | 236
> > > > ++++++++++++++++++++++++++++++++++++++++++++++++++++++++--
> > > > =C2=A0hw/vfio/pci.h |=C2=A0=C2=A0=C2=A01 +
> > > > =C2=A02 files changed, 230 insertions(+), 7 deletions(-)
> > > >=20
> > > > diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c
> > > > index d00b0e4..6926dcc 100644
> > > > --- a/hw/vfio/pci.c
> > > > +++ b/hw/vfio/pci.c
> > > > @@ -1806,6 +1806,216 @@ static int
> > > > vfio_add_std_cap(VFIOPCIDevice
> > > > *vdev, uint8_t pos)
> > > > =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0return 0;
> > > > =C2=A0}
> > > > =C2=A0
> > > > +static bool vfio_pci_host_slot_match(PCIHostDeviceAddress
> > > > *host1,
> > > > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=
=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=
=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=
=C2=A0PCIHostDeviceAddress
> > > > *host2)
> > > > +{
> > > > +=C2=A0=C2=A0=C2=A0=C2=A0return (host1->domain =3D=3D host2->doma=
in && host1->bus =3D=3D
> > > > host2-
> > > > > bus &&
> > > > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=
=C2=A0host1->slot =3D=3D host2->slot);
> > > > +}
> > > > +
> > > > +static bool vfio_pci_host_match(PCIHostDeviceAddress *host1,
> > > > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=
=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=
=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0PCIHostDeviceAddress *=
host2)
> > > > +{
> > > > +=C2=A0=C2=A0=C2=A0=C2=A0return (vfio_pci_host_slot_match(host1, =
host2) &&
> > > > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=
=C2=A0host1->function =3D=3D host2->function);
> > > > +}
> > > > +
> > > > +struct VFIODeviceFind {
> > > > +=C2=A0=C2=A0=C2=A0=C2=A0PCIDevice *pdev;
> > > > +=C2=A0=C2=A0=C2=A0=C2=A0bool found;
> > > > +};
> > > > +
> > > > +static void vfio_check_device_noreset(PCIBus *bus, PCIDevice
> > > > *pdev,
> > > > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=
=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=
=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=
=C2=A0=C2=A0void *opaque)
> > > > +{
> > > > +=C2=A0=C2=A0=C2=A0=C2=A0DeviceState *dev =3D DEVICE(pdev);
> > > > +=C2=A0=C2=A0=C2=A0=C2=A0DeviceClass *dc =3D DEVICE_GET_CLASS(dev=
);
> > > > +=C2=A0=C2=A0=C2=A0=C2=A0VFIOPCIDevice *vdev;
> > > > +=C2=A0=C2=A0=C2=A0=C2=A0struct VFIODeviceFind *find =3D opaque;
> > > > +
> > > > +=C2=A0=C2=A0=C2=A0=C2=A0if (find->found) {
> > > > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0return;
> > > > +=C2=A0=C2=A0=C2=A0=C2=A0}
> > > > +
> > > > +=C2=A0=C2=A0=C2=A0=C2=A0if (!object_dynamic_cast(OBJECT(dev), "v=
fio-pci")) {
> > > > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0if (!dc->reset) =
{
> > > > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=
=C2=A0goto found;
> > > > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0}
> > > > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0return;
> > > > +=C2=A0=C2=A0=C2=A0=C2=A0}
> > > > +=C2=A0=C2=A0=C2=A0=C2=A0vdev =3D DO_UPCAST(VFIOPCIDevice, pdev, =
pdev);
> > > > +=C2=A0=C2=A0=C2=A0=C2=A0if (!(vdev->features & VFIO_FEATURE_ENAB=
LE_AER) &&
> > > > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0!vdev->vbasedev.=
reset_works) {
> > > > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0goto found;
> > > > +=C2=A0=C2=A0=C2=A0=C2=A0}
> > > > +
> > > > +=C2=A0=C2=A0=C2=A0=C2=A0return;
> > > > +found:
> > > > +=C2=A0=C2=A0=C2=A0=C2=A0find->pdev =3D pdev;
> > > > +=C2=A0=C2=A0=C2=A0=C2=A0find->found =3D true;
> > > > +}
> > > > +
> > > > +static void device_find(PCIBus *bus, PCIDevice *pdev, void
> > > > *opaque)
> > > > +{
> > > > +=C2=A0=C2=A0=C2=A0=C2=A0struct VFIODeviceFind *find =3D opaque;
> > > > +
> > > > +=C2=A0=C2=A0=C2=A0=C2=A0if (find->found) {
> > > > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0return;
> > > > +=C2=A0=C2=A0=C2=A0=C2=A0}
> > > > +
> > > > +=C2=A0=C2=A0=C2=A0=C2=A0if (pdev =3D=3D find->pdev) {
> > > > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0find->found =3D =
true;
> > > > +=C2=A0=C2=A0=C2=A0=C2=A0}
> > > > +}
> > > > +
> > > > +static int vfio_check_host_bus_reset(VFIOPCIDevice *vdev)
> > > > +{
> > > > +=C2=A0=C2=A0=C2=A0=C2=A0PCIBus *bus =3D vdev->pdev.bus;
> > > > +=C2=A0=C2=A0=C2=A0=C2=A0struct vfio_pci_hot_reset_info *info =3D=
 NULL;
> > > > +=C2=A0=C2=A0=C2=A0=C2=A0struct vfio_pci_dependent_device *device=
s;
> > > > +=C2=A0=C2=A0=C2=A0=C2=A0VFIOGroup *group;
> > > > +=C2=A0=C2=A0=C2=A0=C2=A0struct VFIODeviceFind find;
> > > > +=C2=A0=C2=A0=C2=A0=C2=A0int ret, i;
> > > > +
> > > > +=C2=A0=C2=A0=C2=A0=C2=A0ret =3D vfio_get_hot_reset_info(vdev, &i=
nfo);
> > > > +=C2=A0=C2=A0=C2=A0=C2=A0if (ret) {
> > > > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0error_report("vf=
io: Cannot enable AER for device %s,"
> > > > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=
=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0" device does=
 not support hot reset.",
> > > > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=
=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0vdev->vbasede=
v.name);
> > > > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0goto out;
> > > > +=C2=A0=C2=A0=C2=A0=C2=A0}
> > > > +
> > > > +=C2=A0=C2=A0=C2=A0=C2=A0/* List all affected devices by bus rese=
t */
> > > > +=C2=A0=C2=A0=C2=A0=C2=A0devices =3D &info->devices[0];
> > > > +
> > > > +=C2=A0=C2=A0=C2=A0=C2=A0/* Verify that we have all the groups re=
quired */
> > > > +=C2=A0=C2=A0=C2=A0=C2=A0for (i =3D 0; i < info->count; i++) {
> > > > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0PCIHostDeviceAdd=
ress host;
> > > > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0VFIOPCIDevice *t=
mp;
> > > > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0VFIODevice *vbas=
edev_iter;
> > > > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0bool found =3D f=
alse;
> > > > +
> > > > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0host.domain =3D =
devices[i].segment;
> > > > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0host.bus =3D dev=
ices[i].bus;
> > > > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0host.slot =3D PC=
I_SLOT(devices[i].devfn);
> > > > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0host.function =3D=
 PCI_FUNC(devices[i].devfn);
> > > > +
> > > > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0/* Skip the curr=
ent device */
> > > > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0if (vfio_pci_hos=
t_match(&host, &vdev->host)) {
> > > > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=
=C2=A0continue;
> > > > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0}
> > > > +
> > > > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0/* Ensure we own=
 the group of the affected device */
> > > > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0QLIST_FOREACH(gr=
oup, &vfio_group_list, next) {
> > > > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=
=C2=A0if (group->groupid =3D=3D devices[i].group_id) {
> > > > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=
=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0break;
> > > > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=
=C2=A0}
> > > > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0}
> > > > +
> > > > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0if (!group) {
> > > > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=
=C2=A0error_report("vfio: Cannot enable AER for device
> > > > %s, "
> > > > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=
=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=
=A0=C2=A0"depends on group %d which is not
> > > > owned.",
> > > > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=
=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=
=A0=C2=A0vdev->vbasedev.name,
> > > > devices[i].group_id);
> > > > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=
=C2=A0ret =3D -1;
> > > > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=
=C2=A0goto out;
> > > > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0}
> > > > +
> > > > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0/* Ensure affect=
ed devices for reset on/blow the bus
> > > > */
> > > > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0QLIST_FOREACH(vb=
asedev_iter, &group->device_list,
> > > > next) {
> > > > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=
=C2=A0if (vbasedev_iter->type !=3D VFIO_DEVICE_TYPE_PCI) {
> > > > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=
=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0continue;
> > > > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=
=C2=A0}
> > > > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=
=C2=A0tmp =3D container_of(vbasedev_iter, VFIOPCIDevice,
> > > > vbasedev);
> > > > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=
=C2=A0if (vfio_pci_host_match(&host, &tmp->host)) {
> > > > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=
=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0PCIDevice *pci =3D PCI_DEVICE(tmp);
> > > > +
> > > > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=
=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0/*
> > > > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=
=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0* For multifunction device, due to vf=
io
> > > > driver
> > > > signal all
> > > > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=
=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0* functions under the upstream link o=
f the
> > > > end
> > > > point. here
> > > > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=
=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0* we validate all functions whether e=
nable
> > > > AER.
> > > > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=
=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0*/
> > > > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=
=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0if (vfio_pci_host_slot_match(&vdev->host,
> > > > &tmp-
> > > > > host) &&
> > > > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=
=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0!(tmp->features &
> > > > VFIO_FEATURE_ENABLE_AER)) {
> > > > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=
=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0error_report("vfio:=
 Cannot enable AER for
> > > > device %s, on same slot"
> > > > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=
=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=
=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0" the dependent =
device %s
> > > > which
> > > > does not enable AER.",
> > > > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=
=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=
=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0vdev->vbasedev.n=
ame, tmp-
> > > > > vbasedev.name);
> > > > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=
=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0ret =3D -1;
> > > > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=
=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0goto out;
> > > > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=
=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0}
> > > > +
> > > > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=
=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0find.pdev =3D pci;
> > > > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=
=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0find.found =3D false;
> > > > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=
=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0pci_for_each_device(bus, pci_bus_num(bus),
> > > > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=
=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=
=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=
device_find, &find);
> > > > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=
=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0if (!find.found) {
> > > > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=
=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0error_report("vfio:=
 Cannot enable AER for
> > > > device %s, "
> > > > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=
=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=
=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0"the dependent d=
evice %s is
> > > > not
> > > > under the same bus",
> > > > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=
=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=
=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0vdev->vbasedev.n=
ame, tmp-
> > > > > vbasedev.name);
> > > > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=
=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0ret =3D -1;
> > > > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=
=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0goto out;
> > > > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=
=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0}
> > > > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=
=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0found =3D true;
> > > > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=
=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0break;
> > > > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=
=C2=A0}
> > > > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0}
> > > > +
> > > > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0/* Ensure all af=
fected devices assigned to VM */
> > >=20
> > > I am puzzled.
> > > Does not kernel enforce this already?
> > > If not it's a security problem.
> > > If yes why does userspace need to check this?
> >=20
> > DMA isolation and bus level isolation are separate concepts. =C2=A0Ea=
ch
> > function of a multi-function device can have DMA isolation, but a
> > user
> > needs to own all of the functions affected by a bus reset in order
> > to
> > perform one. =C2=A0An AER configuration can only be created if the us=
er
> > can
> > translate a guest bus reset into a host bus reset and therefore
> > needs
> > to test whether it has the permissions to do so. =C2=A0I believe over
> > the
> > course of reviews we've also added some simplifying constraints
> > around
> > this to reduce the problem set, things like all the groups being
> > assigned rather than just owned by the user. =C2=A0However, I believe
> > the
> > kernel is sound in how it provides security for bus resets.
> > =C2=A0Thanks,
> >=20
> > Alex
>=20
> Yes, sounds good.
>=20
> So how about just trying to do bus reset at setup time?
> If kernel allows this, we know it is safe ...

The host may support hotplug, what's possible at setup time may not be
possible when an error occurs. =C2=A0It's unlikely, but worth considering=
 I
think. =C2=A0Thanks,

Alex