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Re: [Qemu-devel] [PATCH v2 09/11] vfio: vote a device to do host bus res
From: |
Alex Williamson |
Subject: |
Re: [Qemu-devel] [PATCH v2 09/11] vfio: vote a device to do host bus reset |
Date: |
Wed, 9 Mar 2016 10:09:11 -0700 |
On Wed, 9 Mar 2016 18:39:51 +0200
"Michael S. Tsirkin" <address@hidden> wrote:
> On Mon, Mar 07, 2016 at 11:23:02AM +0800, Cao jin wrote:
> > From: Chen Fan <address@hidden>
> >
> > Signed-off-by: Chen Fan <address@hidden>
> > ---
> > hw/vfio/pci.c | 57
> > +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
> > hw/vfio/pci.h | 1 +
> > 2 files changed, 58 insertions(+)
> >
> > diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c
> > index 24848c9..8e902d2 100644
> > --- a/hw/vfio/pci.c
> > +++ b/hw/vfio/pci.c
> > @@ -1937,6 +1937,8 @@ static void vfio_check_host_bus_reset(VFIOPCIDevice
> > *vdev, Error **errp)
> > /* List all affected devices by bus reset */
> > devices = &info->devices[0];
> >
> > + vdev->single_depend_dev = (info->count == 1);
> > +
> > /* Verify that we have all the groups required */
> > for (i = 0; i < info->count; i++) {
> > PCIHostDeviceAddress host;
> > @@ -2998,6 +3000,49 @@ static void vfio_exitfn(PCIDevice *pdev)
> > vfio_unregister_bars(vdev);
> > }
> >
> > +static VFIOPCIDevice *vfio_pci_get_do_reset_device(VFIOPCIDevice *vdev)
> > +{
> > + struct vfio_pci_hot_reset_info *info = NULL;
> > + struct vfio_pci_dependent_device *devices;
> > + VFIOGroup *group;
> > + VFIODevice *vbasedev_iter;
> > + int ret;
> > +
> > + ret = vfio_get_hot_reset_info(vdev, &info);
> > + if (ret) {
> > + error_report("vfio: Cannot enable AER for device %s,"
> > + " device does not support hot reset.",
> > + vdev->vbasedev.name);
> > + return NULL;
> > + }
> > +
> > + devices = &info->devices[0];
> > +
> > + QLIST_FOREACH(group, &vfio_group_list, next) {
> > + if (group->groupid == devices[0].group_id) {
> > + break;
> > + }
> > + }
> > +
> > + if (!group) {
> > + error_report("vfio: Cannot enable AER for device %s, "
> > + "depends on group %d which is not owned.",
> > + vdev->vbasedev.name, devices[0].group_id);
> > + return NULL;
> > + }
> > +
> > + QLIST_FOREACH(vbasedev_iter, &group->device_list, next) {
> > + if (vbasedev_iter->type != VFIO_DEVICE_TYPE_PCI ||
> > + !(vdev->features & VFIO_FEATURE_ENABLE_AER)) {
> > + continue;
> > + }
> > +
> > + return container_of(vbasedev_iter, VFIOPCIDevice, vbasedev);
> > + }
> > +
> > + return NULL;
> > +}
> > +
> > static void vfio_pci_reset(DeviceState *dev)
> > {
> > PCIDevice *pdev = DO_UPCAST(PCIDevice, qdev, dev);
> > @@ -3005,6 +3050,18 @@ static void vfio_pci_reset(DeviceState *dev)
> >
> > trace_vfio_pci_reset(vdev->vbasedev.name);
> >
> > + if (pdev->bus->in_hot_reset) {
>
> After discussing this with Alex, I think what you
> really are looking for is
> if (dev->realized)
> in order to skip hot reset when device is plugged-in
> initially.
Seems fragile, device_reset() also gets called via pci_device_reset()
which would happen if we hooked up FLR to the device. That's clearly
intended to be a function local reset, as is I believe the dc->reset
itself, so assuming behavior based on states like dev->realized is
likely to break. Either we need some external hints, like what's added
here, or we need a separate callback for a bus reset. Thanks,
Alex
> > + VFIOPCIDevice *tmp;
> > +
> > + tmp = vfio_pci_get_do_reset_device(vdev);
> > + if (tmp) {
> > + if (tmp == vdev) {
> > + vfio_pci_hot_reset(vdev, vdev->single_depend_dev);
> > + }
> > + return;
> > + }
> > + }
> > +
> > vfio_pci_pre_reset(vdev);
> >
> > if (vdev->resetfn && !vdev->resetfn(vdev)) {
> > diff --git a/hw/vfio/pci.h b/hw/vfio/pci.h
> > index aff46c2..32bd31f 100644
> > --- a/hw/vfio/pci.h
> > +++ b/hw/vfio/pci.h
> > @@ -143,6 +143,7 @@ typedef struct VFIOPCIDevice {
> > bool no_kvm_intx;
> > bool no_kvm_msi;
> > bool no_kvm_msix;
> > + bool single_depend_dev;
> > } VFIOPCIDevice;
> >
> > uint32_t vfio_pci_read_config(PCIDevice *pdev, uint32_t addr, int len);
> > --
> > 1.9.3
> >
> >