On Tue, 22 Mar 2016 18:14:45 +0800
Chen Fan <chen.fan.f...@cn.fujitsu.com> wrote:
> On 03/22/2016 05:40 AM, Alex Williamson wrote:
> > On Mon, 21 Mar 2016 18:08:44 +0800
> > Cao jin <caoj.f...@cn.fujitsu.com> wrote:
> >
> >> From: Chen Fan <chen.fan.f...@cn.fujitsu.com>
> >>
> >> Due to all devices assigned to VM on the same way as host if enable
> >> aer, so we can easily do the hot reset by selecting the function #0
> >> to do the hot reset.
> >>
> >> Signed-off-by: Chen Fan <chen.fan.f...@cn.fujitsu.com>
> >> ---
> >> hw/vfio/pci.c | 50 ++++++++++++++++++++++++++++++++++++++++++++++++++
> >> hw/vfio/pci.h | 2 ++
> >> 2 files changed, 52 insertions(+)
> >>
> >> diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c
> >> index 9902c87..718cde7 100644
> >> --- a/hw/vfio/pci.c
> >> +++ b/hw/vfio/pci.c
> >> @@ -1900,6 +1900,8 @@ static void vfio_check_hot_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;
> >> @@ -2608,11 +2610,36 @@ static void vfio_put_device(VFIOPCIDevice *vdev)
> >> static void vfio_err_notifier_handler(void *opaque)
> >> {
> >> VFIOPCIDevice *vdev = opaque;
> >> + PCIDevice *pdev = &vdev->pdev;
> >>
> >> if (!event_notifier_test_and_clear(&vdev->err_notifier)) {
> >> return;
> >> }
> >>
> >> + if (vdev->features & VFIO_FEATURE_ENABLE_AER) {
> >> + VFIOPCIDevice *tmp;
> >> + PCIDevice *dev;
> >> + int devfn;
> >> +
> >> + /*
> >> + * If one device has aer capability on a bus, when aer occurred,
> >> + * we should notify all devices on the bus there was an aer
> >> arrived,
> >> + * then we are able to vote the device #0 to do host bus reset.
> >> + */
> >> + for (devfn = 0; devfn < 8; devfn++) {
> > ARI?
> >
> >> + dev = pci_find_device(pdev->bus, pci_bus_num(pdev->bus),
> >> + PCI_DEVFN(PCI_SLOT(pdev->devfn), devfn));
> >> + if (!dev) {
> >> + continue;
> >> + }
> >> + if (!object_dynamic_cast(OBJECT(dev), "vfio-pci")) {
> >> + continue;
> >> + }
> >> + tmp = DO_UPCAST(VFIOPCIDevice, pdev, dev);
> >> + tmp->aer_occurred = true;
> >> + }
> >> + }
> >> +
> >> /*
> >> * TBD. Retrieve the error details and decide what action
> >> * needs to be taken. One of the actions could be to pass
> >> @@ -3075,6 +3102,29 @@ static void vfio_pci_reset(DeviceState *dev)
> >>
> >> trace_vfio_pci_reset(vdev->vbasedev.name);
> >>
> >> + if (vdev->aer_occurred) {
> >> + PCIDevice *br = pci_bridge_get_device(pdev->bus);
> >> +
> >> + if (br &&
> >> + (pci_get_word(br->config + PCI_BRIDGE_CONTROL) &
> >> + PCI_BRIDGE_CTL_BUS_RESET)) {
> >> + /* simply voting the function 0 to do hot bus reset */
> >> + if (pci_get_function_0(pdev) == pdev) {
> >> + if (vdev->features & VFIO_FEATURE_ENABLE_AER) {
> >> + vfio_pci_hot_reset(vdev, vdev->single_depend_dev);
> >> + } else {
> >> + /* if this device has not AER capability, code
> >> + * coming here indicates there is another function
> >> + * on the bus has AER capability.
> >> + * */
> > This shouldn't be possible, right?
> >
> >> + vfio_pci_hot_reset(vdev, false);
> >> + }
> >> + }
> >> + vdev->aer_occurred = false;
> >> + return;
> >> + }
> >> + }
> > Why do we care than an AER occurred now? Can't we simply test:
> >
> > if (vdev->features & VFIO_FEATURE_ENABLE_AER &&
> > pci_get_function_0(pdev) == pdev) {
> > PCIDevice *br = pci_bridge_get_device(pdev->bus);
> >
> > if (pci_get_word(br->config + PCI_BRIDGE_CONTROL) &
> > PCI_BRIDGE_CTL_BUS_RESET)) {
> >
> > vfio_pci_hot_reset(vdev, vdev->single_depend_dev);
> > return;
> > }
> > }
>
> do we have the case that only one/few of the devices affected
> by a bus reset assigned to VM enabled AER, then when bus
> reset, we let the function 0 do hot reset, which may not enable AER,
> but we should tell other devices on the bus that they don't need
> to do bus reset. so I just mark all devices on the bus when needing a
> hot reset.
I thought we were requiring all the bus reset affected devices to
enable AER, so that example should not be possible. I think it matches
our target use case to make this a requirement. Thanks,
Alex
