| Message ID | 20120511225555.30496.80525.stgit@bling.home |
|---|---|
| State | Superseded |
| Headers | show |
On Fri, May 11, 2012 at 04:55:55PM -0600, Alex Williamson wrote: > Integrating IOMMU groups more closely into the driver core allows > us to more easily work around DMA quirks. The Ricoh multifunction > controller is a favorite example of devices that are currently > incompatible with IOMMU isolation as all the functions use the > requestor ID of function 0 for DMA. Passing this device into > pci_dma_quirk returns the PCI device to use for DMA. The IOMMU > driver can then construct an IOMMU group including both devices. > > Signed-off-by: Alex Williamson <alex.williamson@redhat.com> > --- > > drivers/pci/quirks.c | 22 ++++++++++++++++++++++ > include/linux/pci.h | 2 ++ > 2 files changed, 24 insertions(+), 0 deletions(-) > > diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c > index 4bf7102..6f9f7f9 100644 > --- a/drivers/pci/quirks.c > +++ b/drivers/pci/quirks.c > @@ -3109,3 +3109,25 @@ int pci_dev_specific_reset(struct pci_dev *dev, int probe) > > return -ENOTTY; > } > + > +struct pci_dev *pci_dma_quirk(struct pci_dev *dev) > +{ > + struct pci_dev *dma_dev = dev; > + > + /* > + * https://bugzilla.redhat.com/show_bug.cgi?id=605888 > + * > + * Some Ricoh devices use the function 0 source ID for DMA on > + * other functions of a multifunction device. The DMA devices > + * is therefore function 0, which will have implications of the > + * iommu grouping of these devices. > + */ > + if (dev->vendor == PCI_VENDOR_ID_RICOH && > + (dev->device == 0xe822 || dev->device == 0xe230 || > + dev->device == 0xe832 || dev->device == 0xe476)) { > + dma_dev = pci_get_slot(dev->bus, > + PCI_DEVFN(PCI_SLOT(dev->devfn), 0)); > + } Hrm. This seems like a very generic name for a function performing a very specific test. We could well have devices with the same problem in future, so shouldn't this be set up so the same quirk can be easily added to new device ids without changing the function code itself.
On Thu, 2012-05-17 at 13:39 +1000, David Gibson wrote: > On Fri, May 11, 2012 at 04:55:55PM -0600, Alex Williamson wrote: > > Integrating IOMMU groups more closely into the driver core allows > > us to more easily work around DMA quirks. The Ricoh multifunction > > controller is a favorite example of devices that are currently > > incompatible with IOMMU isolation as all the functions use the > > requestor ID of function 0 for DMA. Passing this device into > > pci_dma_quirk returns the PCI device to use for DMA. The IOMMU > > driver can then construct an IOMMU group including both devices. > > > > Signed-off-by: Alex Williamson <alex.williamson@redhat.com> > > --- > > > > drivers/pci/quirks.c | 22 ++++++++++++++++++++++ > > include/linux/pci.h | 2 ++ > > 2 files changed, 24 insertions(+), 0 deletions(-) > > > > diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c > > index 4bf7102..6f9f7f9 100644 > > --- a/drivers/pci/quirks.c > > +++ b/drivers/pci/quirks.c > > @@ -3109,3 +3109,25 @@ int pci_dev_specific_reset(struct pci_dev *dev, int probe) > > > > return -ENOTTY; > > } > > + > > +struct pci_dev *pci_dma_quirk(struct pci_dev *dev) > > +{ > > + struct pci_dev *dma_dev = dev; > > + > > + /* > > + * https://bugzilla.redhat.com/show_bug.cgi?id=605888 > > + * > > + * Some Ricoh devices use the function 0 source ID for DMA on > > + * other functions of a multifunction device. The DMA devices > > + * is therefore function 0, which will have implications of the > > + * iommu grouping of these devices. > > + */ > > + if (dev->vendor == PCI_VENDOR_ID_RICOH && > > + (dev->device == 0xe822 || dev->device == 0xe230 || > > + dev->device == 0xe832 || dev->device == 0xe476)) { > > + dma_dev = pci_get_slot(dev->bus, > > + PCI_DEVFN(PCI_SLOT(dev->devfn), 0)); > > + } > > Hrm. This seems like a very generic name for a function performing a > very specific test. We could well have devices with the same problem > in future, so shouldn't this be set up so the same quirk can be easily > added to new device ids without changing the function code itself. I've since added a USB quirk here to group all the USB functions in a slot. I'll take a closer look at the quirk helpers to see if anything makes this easier, but I didn't see much point in spending a lot of time over-optimizing this for 1 or 2 quirks that we can just step through in a monolithic function. Thanks, Alex -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Alex, On Sat, May 12, 2012 at 6:55 AM, Alex Williamson <alex.williamson@redhat.com> wrote: > Integrating IOMMU groups more closely into the driver core allows > us to more easily work around DMA quirks. The Ricoh multifunction > controller is a favorite example of devices that are currently > incompatible with IOMMU isolation as all the functions use the > requestor ID of function 0 for DMA. Passing this device into > pci_dma_quirk returns the PCI device to use for DMA. The IOMMU > driver can then construct an IOMMU group including both devices. > Please give some thought to the Marvell SATA controller quirk as well. Instead of multiple visible functions using the same requester ID of function 0, the Marvell device only makes function 0 visible, but uses the requestor ID of function 1 as well during DMA. See https://bugzilla.redhat.com/show_bug.cgi?id=757166 -- A. -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Thu, 2012-05-17 at 15:19 +0800, Anonymous wrote: > Alex, > > On Sat, May 12, 2012 at 6:55 AM, Alex Williamson > <alex.williamson@redhat.com> wrote: > > Integrating IOMMU groups more closely into the driver core allows > > us to more easily work around DMA quirks. The Ricoh multifunction > > controller is a favorite example of devices that are currently > > incompatible with IOMMU isolation as all the functions use the > > requestor ID of function 0 for DMA. Passing this device into > > pci_dma_quirk returns the PCI device to use for DMA. The IOMMU > > driver can then construct an IOMMU group including both devices. > > > > Please give some thought to the Marvell SATA controller quirk as well. > > Instead of multiple visible functions using the same requester ID of > function 0, the Marvell device only makes function 0 visible, but uses > the requestor ID of function 1 as well during DMA. > > See https://bugzilla.redhat.com/show_bug.cgi?id=757166 Wow. That one isn't quite as easy to deal with since there's no existing device in the kernel to point to. This comment might be on the right track: https://bugzilla.kernel.org/show_bug.cgi?id=42679#c11 Perhaps David Woodhouse can comment on support for phantom functions. If we had infrastructure for that it might be easy for the quirk to update the pci_dev struct, inserting a new phantom function. Otherwise we'd need to create a new device in the kernel for it. Thanks, Alex -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c index 4bf7102..6f9f7f9 100644 --- a/drivers/pci/quirks.c +++ b/drivers/pci/quirks.c @@ -3109,3 +3109,25 @@ int pci_dev_specific_reset(struct pci_dev *dev, int probe) return -ENOTTY; } + +struct pci_dev *pci_dma_quirk(struct pci_dev *dev) +{ + struct pci_dev *dma_dev = dev; + + /* + * https://bugzilla.redhat.com/show_bug.cgi?id=605888 + * + * Some Ricoh devices use the function 0 source ID for DMA on + * other functions of a multifunction device. The DMA devices + * is therefore function 0, which will have implications of the + * iommu grouping of these devices. + */ + if (dev->vendor == PCI_VENDOR_ID_RICOH && + (dev->device == 0xe822 || dev->device == 0xe230 || + dev->device == 0xe832 || dev->device == 0xe476)) { + dma_dev = pci_get_slot(dev->bus, + PCI_DEVFN(PCI_SLOT(dev->devfn), 0)); + } + + return dma_dev; +} diff --git a/include/linux/pci.h b/include/linux/pci.h index e444f5b..9910b5c 100644 --- a/include/linux/pci.h +++ b/include/linux/pci.h @@ -1479,9 +1479,11 @@ enum pci_fixup_pass { #ifdef CONFIG_PCI_QUIRKS void pci_fixup_device(enum pci_fixup_pass pass, struct pci_dev *dev); +struct pci_dev *pci_dma_quirk(struct pci_dev *dev); #else static inline void pci_fixup_device(enum pci_fixup_pass pass, struct pci_dev *dev) {} +struct pci_dev *pci_dma_quirk(struct pci_dev *dev) { return dev } #endif void __iomem *pcim_iomap(struct pci_dev *pdev, int bar, unsigned long maxlen);
Integrating IOMMU groups more closely into the driver core allows us to more easily work around DMA quirks. The Ricoh multifunction controller is a favorite example of devices that are currently incompatible with IOMMU isolation as all the functions use the requestor ID of function 0 for DMA. Passing this device into pci_dma_quirk returns the PCI device to use for DMA. The IOMMU driver can then construct an IOMMU group including both devices. Signed-off-by: Alex Williamson <alex.williamson@redhat.com> --- drivers/pci/quirks.c | 22 ++++++++++++++++++++++ include/linux/pci.h | 2 ++ 2 files changed, 24 insertions(+), 0 deletions(-) -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html