On 5/9/23 5:59 PM, Alex Williamson wrote: > From: Minwoo Im <minwoo...@samsung.com> > > VF token was introduced [1] to kernel vfio-pci along with SR-IOV > support [2]. This patch adds support VF token among PF and VF(s). To > passthu PCIe VF to a VM, kernel >= v5.7 needs this. > > It can be configured with UUID like: > > -device vfio-pci,host=DDDD:BB:DD:F,vf-token=<uuid>,... > > [1] > https://lore.kernel.org/linux-pci/158396393244.5601.10297430724964025753.st...@gimli.home/ > [2] > https://lore.kernel.org/linux-pci/158396044753.5601.14804870681174789709.st...@gimli.home/ > > Cc: Alex Williamson <alex.william...@redhat.com> > Signed-off-by: Minwoo Im <minwoo...@samsung.com> > Reviewed-by: Klaus Jensen <k.jen...@samsung.com> > Link: > https://lore.kernel.org/r/20230320073522epcms2p48f682ecdb73e0ae1a4850ad0712fd780@epcms2p4 > Signed-off-by: Alex Williamson <alex.william...@redhat.com>
Hi Minwoo, Alex, I'm seeing a regression in vfio-pci on s390 and bisect points to this commit. I don't believe it's specific to s390 though, but rather when not using this new vf-token, see below... > --- > hw/vfio/pci.c | 13 ++++++++++++- > hw/vfio/pci.h | 1 + > 2 files changed, 13 insertions(+), 1 deletion(-) > > diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c > index ec9a854361ac..cf27f28936cb 100644 > --- a/hw/vfio/pci.c > +++ b/hw/vfio/pci.c > @@ -2856,6 +2856,8 @@ static void vfio_realize(PCIDevice *pdev, Error **errp) > int groupid; > int i, ret; > bool is_mdev; > + char uuid[UUID_FMT_LEN]; > + char *name; > > if (!vbasedev->sysfsdev) { > if (!(~vdev->host.domain || ~vdev->host.bus || > @@ -2936,7 +2938,15 @@ static void vfio_realize(PCIDevice *pdev, Error **errp) > goto error; > } > > - ret = vfio_get_device(group, vbasedev->name, vbasedev, errp); > + if (!qemu_uuid_is_null(&vdev->vf_token)) { > + qemu_uuid_unparse(&vdev->vf_token, uuid); > + name = g_strdup_printf("%s vf_token=%s", vbasedev->name, uuid); > + } else { > + name = vbasedev->name; ^ here we copy the pointer when a vf-token was not specified. > + } > + > + ret = vfio_get_device(group, name, vbasedev, errp); > + g_free(name); ^ and then free it regardless. But I don't think we meant to free what vbasedev->name points to, this was meant to free a duplicate string. I'm subsequently seeing qemu crashes later on e.g. during device unplug. I think doing a strdup in either case would fix the issue OR skipping the g_free when qemu_uuid_is_null(&vdev->vf_token). FWIW, I tried the following and it resolved the issue for me: diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c index bf27a39905..73874a94de 100644 --- a/hw/vfio/pci.c +++ b/hw/vfio/pci.c @@ -2994,7 +2994,7 @@ static void vfio_realize(PCIDevice *pdev, Error **errp) qemu_uuid_unparse(&vdev->vf_token, uuid); name = g_strdup_printf("%s vf_token=%s", vbasedev->name, uuid); } else { - name = vbasedev->name; + name = g_strdup(vbasedev->name); } ret = vfio_get_device(group, name, vbasedev, errp);