On Fri, 2013-01-11 at 08:45 +0000, Pandarathil, Vijaymohan R wrote: > > > -----Original Message----- > > From: Alex Williamson [mailto:alex.williamson@xxxxxxxxxx] > > Sent: Wednesday, January 09, 2013 11:05 AM > > To: Pandarathil, Vijaymohan R > > Cc: Bjorn Helgaas; Gleb Natapov; kvm@xxxxxxxxxxxxxxx; qemu- > > devel@xxxxxxxxxx; linux-pci@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx > > Subject: Re: [PATCH 1/2] VFIO-AER: Vfio-pci driver changes for supporting > > AER > > > > On Wed, 2013-01-09 at 10:52 -0700, Alex Williamson wrote: > > > On Wed, 2013-01-09 at 06:26 +0000, Pandarathil, Vijaymohan R wrote: > > > > - New ioctl which is used to pass the eventfd that is signaled when > > > > an error occurs in the vfio_pci_device > > > > > > > > - Register pci_error_handler for the vfio_pci driver > > > > > > > > - When the device encounters an error, the error handler registered > > by > > > > the vfio_pci driver gets invoked by the AER infrastructure > > > > > > > > - In the error handler, signal the eventfd registered for the device. > > > > > > > > - This results in the qemu eventfd handler getting invoked and > > > > appropriate action taken for the guest. > > > > > > > > Signed-off-by: Vijay Mohan Pandarathil <vijaymohan.pandarathil@xxxxxx> > > > > --- > > > > drivers/vfio/pci/vfio_pci.c | 29 +++++++++++++++++++++++++++++ > > > > drivers/vfio/pci/vfio_pci_private.h | 1 + > > > > drivers/vfio/vfio.c | 8 ++++++++ > > > > include/linux/vfio.h | 1 + > > > > include/uapi/linux/vfio.h | 9 +++++++++ > > > > 5 files changed, 48 insertions(+) > > > > > > > > diff --git a/drivers/vfio/pci/vfio_pci.c b/drivers/vfio/pci/vfio_pci.c > > > > index 6c11994..4ae9526 100644 > > > > --- a/drivers/vfio/pci/vfio_pci.c > > > > +++ b/drivers/vfio/pci/vfio_pci.c > > > > @@ -207,6 +207,8 @@ static long vfio_pci_ioctl(void *device_data, > > > > if (vdev->reset_works) > > > > info.flags |= VFIO_DEVICE_FLAGS_RESET; > > > > > > > > + info.flags |= VFIO_DEVICE_FLAGS_AER_NOTIFY; > > > > + > > > > > > This appears to be a PCI specific flag, so the name should include > > > _PCI_. We also support non-PCIe devices and it seems like it would be > > > possible to not have AER support available, so shouldn't this be > > > conditional? > > Will do that. > > > > > > > > info.num_regions = VFIO_PCI_NUM_REGIONS; > > > > info.num_irqs = VFIO_PCI_NUM_IRQS; > > > > > > > > @@ -348,6 +350,19 @@ static long vfio_pci_ioctl(void *device_data, > > > > > > > > return ret; > > > > > > > > + } else if (cmd == VFIO_DEVICE_SET_ERRFD) { > > > > + int32_t fd = (int32_t)arg; > > > > + > > > > + if (fd < 0) > > > > + return -EINVAL; > > > > + > > > > + vdev->err_trigger = eventfd_ctx_fdget(fd); > > > > + > > > > + if (IS_ERR(vdev->err_trigger)) > > > > + return PTR_ERR(vdev->err_trigger); > > > > + > > > > + return 0; > > > > + > > > > > > I'm not sure why we wouldn't describe this as just another interrupt > > > from the device and configure it via SET_IRQ. This ioctl has very > > > limited use and doesn't follow any of the conventions of all the other > > > vfio ioctls. > > I thought this was a fairly simple ioctl to implement this way. Moreover, > there is no device interrupt involved. Let me know if you really want to > model it as a SET_IRQ ioctl. I'd like to see something else for sure. We're trying to do AER piecemeal but this ioctl leaves no room for anything else. Seems like a soon to be wasted ioctl number. Note that there isn't even a de-assign interface, nor a flag to set to indicate de-assignment. The SET_IRQ ioctl already handles these in a very similar way to how we'd want to handle it for error signaling. It doesn't seem like that much of a stretch to me to include it there, but I'd also entertain other ideas. Thanks, Alex > > > > > > > } else if (cmd == VFIO_DEVICE_RESET) > > > > return vdev->reset_works ? > > > > pci_reset_function(vdev->pdev) : -EINVAL; > > > > @@ -527,11 +542,25 @@ static void vfio_pci_remove(struct pci_dev *pdev) > > > > kfree(vdev); > > > > } > > > > > > > > +static pci_ers_result_t vfio_err_detected(struct pci_dev *pdev, > > > > + pci_channel_state_t state) > > > > +{ > > > > + struct vfio_pci_device *vdev = vfio_get_vdev(&pdev->dev); > > > > + > > > > + eventfd_signal(vdev->err_trigger, 1); > > > > + return PCI_ERS_RESULT_CAN_RECOVER; > > > > +} > > > > > > What if err_trigger hasn't been set? > > Will fix that. > > > > > > > > + > > > > +static const struct pci_error_handlers vfio_err_handlers = { > > > > + .error_detected = vfio_err_detected, > > > > +}; > > > > + > > > > static struct pci_driver vfio_pci_driver = { > > > > .name = "vfio-pci", > > > > .id_table = NULL, /* only dynamic ids */ > > > > .probe = vfio_pci_probe, > > > > .remove = vfio_pci_remove, > > > > + .err_handler = &vfio_err_handlers, > > > > }; > > > > > > > > static void __exit vfio_pci_cleanup(void) > > > > diff --git a/drivers/vfio/pci/vfio_pci_private.h > > b/drivers/vfio/pci/vfio_pci_private.h > > > > index 611827c..daee62f 100644 > > > > --- a/drivers/vfio/pci/vfio_pci_private.h > > > > +++ b/drivers/vfio/pci/vfio_pci_private.h > > > > @@ -55,6 +55,7 @@ struct vfio_pci_device { > > > > bool bardirty; > > > > struct pci_saved_state *pci_saved_state; > > > > atomic_t refcnt; > > > > + struct eventfd_ctx *err_trigger; > > > > }; > > > > > > > > #define is_intx(vdev) (vdev->irq_type == VFIO_PCI_INTX_IRQ_INDEX) > > > > diff --git a/drivers/vfio/vfio.c b/drivers/vfio/vfio.c > > > > index 56097c6..5ed5a54 100644 > > > > --- a/drivers/vfio/vfio.c > > > > +++ b/drivers/vfio/vfio.c > > > > @@ -693,6 +693,14 @@ void *vfio_del_group_dev(struct device *dev) > > > > } > > > > EXPORT_SYMBOL_GPL(vfio_del_group_dev); > > > > > > > > +void *vfio_get_vdev(struct device *dev) > > > > +{ > > > > + struct vfio_device *device = dev_get_drvdata(dev); > > > > + > > > > + return device->device_data; > > > > +} > > > > +EXPORT_SYMBOL_GPL(vfio_get_vdev); > > > > + > > > > > > This is unsafe. How do we know dev is a vfio device? How do we keep > > > that drvdata valid while you're using it? I think you want to export > > > the existing vfio_group_get_device() and vfio_device_put(). Thanks, > > > > vfio_group_get_device() isn't quite what you want either since it > > assumes a reference count on the group. You'll want something like > > vfio_add_group_dev() or vfio_dev_present(), perhaps moving the > > iommu_group_get -> vfio_group_get_from_iommu -> vfio_group_get_device > > into a helper function. Thanks, > > Thanks for the pointers. Will make the change. > > Vijay > > > > > Alex > > > > > > /** > > > > * VFIO base fd, /dev/vfio/vfio > > > > */ > > > > diff --git a/include/linux/vfio.h b/include/linux/vfio.h > > > > index ab9e862..3c97b03 100644 > > > > --- a/include/linux/vfio.h > > > > +++ b/include/linux/vfio.h > > > > @@ -45,6 +45,7 @@ extern int vfio_add_group_dev(struct device *dev, > > > > void *device_data); > > > > > > > > extern void *vfio_del_group_dev(struct device *dev); > > > > +extern void *vfio_get_vdev(struct device *dev); > > > > > > > > /** > > > > * struct vfio_iommu_driver_ops - VFIO IOMMU driver callbacks > > > > diff --git a/include/uapi/linux/vfio.h b/include/uapi/linux/vfio.h > > > > index 4758d1b..fa67213 100644 > > > > --- a/include/uapi/linux/vfio.h > > > > +++ b/include/uapi/linux/vfio.h > > > > @@ -147,6 +147,7 @@ struct vfio_device_info { > > > > __u32 flags; > > > > #define VFIO_DEVICE_FLAGS_RESET (1 << 0) /* Device supports > > reset */ > > > > #define VFIO_DEVICE_FLAGS_PCI (1 << 1) /* vfio-pci device */ > > > > +#define VFIO_DEVICE_FLAGS_AER_NOTIFY (1 << 2) /* Supports aer > > notify */ > > > > __u32 num_regions; /* Max region index + 1 */ > > > > __u32 num_irqs; /* Max IRQ index + 1 */ > > > > }; > > > > @@ -288,6 +289,14 @@ struct vfio_irq_set { > > > > */ > > > > #define VFIO_DEVICE_RESET _IO(VFIO_TYPE, VFIO_BASE + 11) > > > > > > > > +/** > > > > + * VFIO_DEVICE_SET_ERRFD - _IO(VFIO_TYPE, VFIO_BASE + 12) > > > > + * > > > > + * Pass the eventfd to the vfio-pci driver for signalling any device > > > > + * error notifications > > > > + */ > > > > +#define VFIO_DEVICE_SET_ERRFD _IO(VFIO_TYPE, VFIO_BASE + 12) > > > > + > > > > /* > > > > * The VFIO-PCI bus driver makes use of the following fixed region and > > > > * IRQ index mapping. Unimplemented regions return a size of zero. > > > > > > > > > > > -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
