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From: Alex Williamson <alex.williamson@redhat.com>
Date: Thu, 24 Dec 2015 11:41:15 -0700
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References: <cover.1447748073.git.chen.fan.fnst@cn.fujitsu.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 20:23 +0200, Michael S. Tsirkin wrote:
> On Thu, Dec 24, 2015 at 11:20:26AM -0700, Alex Williamson wrote:
> > 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 affect=
ed
> > > > > > device,
> > > > > > 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->=
domain && 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=A0PCIHostDeviceAdd=
ress
> > > > > > *host2)
> > > > > > +{
> > > > > > +=C2=A0=C2=A0=C2=A0=C2=A0return (vfio_pci_host_slot_match(hos=
t1, 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 opaq=
ue;
> > > > > > +
> > > > > > +=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)=
, "vfio-pci")) {
> > > > > > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0if (!dc->res=
et) {
> > > > > > +=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, pd=
ev, pdev);
> > > > > > +=C2=A0=C2=A0=C2=A0=C2=A0if (!(vdev->features & VFIO_FEATURE_=
ENABLE_AER) &&
> > > > > > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0!vdev->vbase=
dev.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 opaq=
ue;
> > > > > > +
> > > > > > +=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 *de=
vices;
> > > > > > +=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=
, &info);
> > > > > > +=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=
("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" devic=
e 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->v=
basedev.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 =
reset */
> > > > > > +=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 group=
s required */
> > > > > > +=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=A0PCIHostDevic=
eAddress host;
> > > > > > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0VFIOPCIDevic=
e *tmp;
> > > > > > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0VFIODevice *=
vbasedev_iter;
> > > > > > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0bool found =3D=
 false;
> > > > > > +
> > > > > > +=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=
 devices[i].bus;
> > > > > > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0host.slot =3D=
 PCI_SLOT(devices[i].devfn);
> > > > > > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0host.functio=
n =3D PCI_FUNC(devices[i].devfn);
> > > > > > +
> > > > > > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0/* Skip the =
current device */
> > > > > > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0if (vfio_pci=
_host_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_FOREAC=
H(group, &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 af=
fected devices for reset on/blow the
> > > > > > bus
> > > > > > */
> > > > > > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0QLIST_FOREAC=
H(vbasedev_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 vfio
> > > > > > 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 of
> > > > > > 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 whe=
ther
> > > > > > 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=A0if (vfio_pci_host_slot_match(&vdev->h=
ost,
> > > > > > &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->featur=
es &
> > > > > > 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 depe=
ndent 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->vbas=
edev.name, 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=A0device_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 depen=
dent device %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->vbas=
edev.name, 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 al=
l affected 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=A0Each
> > > > 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 th=
e
> > > > user
> > > > 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 ...
> >=20
> > The host may support hotplug, what's possible at setup time may not
> > be
> > possible when an error occurs.
>=20
> How does this patch help solve this problem?

I believe there's a patch in this series that re-tests on the
occurrence of an error, before injecting the AER into the guest.

> > It's unlikely, but worth considering I
> > think.
>=20
> I suspect vfio will have to solve this in kernel
> (e.g. automatically add all new devices in the same group
> wrt reset).

Nope, the user simply loses their ability to reset the bus if they
don't own all the groups at the time they attempt to do a bus reset.
=C2=A0Mixing bus isolation and DMA isolation would cause a mess of groups=
.