| Message ID | 20150602170414.6252.48036.stgit@mdrustad-wks.jf.intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Delegated to: | Bjorn Helgaas |
| Headers | show |
On 06/02/2015 10:04 AM, Mark D Rustad wrote: > Add a dev_flags bit, PCI_DEV_FLAGS_VPD_REF_F0, to access VPD through > function 0 to provide VPD access on other functions. This solves > concurrent access problems on many devices without changing the > attributes exposed in sysfs. Never set this bit on funciton 0 or > there will be an infinite recursion. > > Signed-off-by: Mark Rustad <mark.d.rustad@intel.com> > --- > drivers/pci/access.c | 39 ++++++++++++++++++++++++++++++++++++++- > include/linux/pci.h | 2 ++ > 2 files changed, 40 insertions(+), 1 deletion(-) > > diff --git a/drivers/pci/access.c b/drivers/pci/access.c > index d9b64a175990..e435c087c354 100644 > --- a/drivers/pci/access.c > +++ b/drivers/pci/access.c > @@ -439,6 +439,40 @@ static const struct pci_vpd_ops pci_vpd_pci22_ops = { > .release = pci_vpd_pci22_release, > }; > > +static ssize_t pci_vpd_f0_read(struct pci_dev *dev, loff_t pos, size_t count, > + void *arg) > +{ > + struct pci_dev *tdev = pci_get_slot(dev->bus, PCI_SLOT(dev->devfn)); > + ssize_t ret; > + > + if (!tdev) > + return -ENODEV; > + > + ret = pci_read_vpd(tdev, pos, count, arg); > + pci_dev_put(tdev); > + return ret; > +} > + > +static ssize_t pci_vpd_f0_write(struct pci_dev *dev, loff_t pos, size_t count, > + const void *arg) > +{ > + struct pci_dev *tdev = pci_get_slot(dev->bus, PCI_SLOT(dev->devfn)); > + ssize_t ret; > + > + if (!tdev) > + return -ENODEV; > + > + ret = pci_write_vpd(tdev, pos, count, arg); > + pci_dev_put(tdev); > + return ret; > +} > + I'm pretty sure these could cause some serious errors if you direct assign the device into a VM since you then end up with multiple devices sharing a bus. Also it would likely have side-effects on a LOM (Lan On Motherboard) as it also shares the bus with multiple non-Ethernet devices. I believe you still need to add something like a check for !pci_is_root_bus(dev->bus) before you attempt to grab function 0. It probably also wouldn't hurt to check the dev->multifunction bit before running this code since it wouldn't make sense to go chasing down the VPD on another function if the device doesn't have one. You could probably do that either as a part of this code, or perhaps put it in the quirk. - Alex - 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
> On Jun 2, 2015, at 10:48 AM, Alexander Duyck <alexander.h.duyck@redhat.com> wrote: > > I'm pretty sure these could cause some serious errors if you direct assign the device into a VM since you then end up with multiple devices sharing a bus. Also it would likely have side-effects on a LOM (Lan On Motherboard) as it also shares the bus with multiple non-Ethernet devices. > > I believe you still need to add something like a check for !pci_is_root_bus(dev->bus) before you attempt to grab function 0. It probably also wouldn't hurt to check the dev->multifunction bit before running this code since it wouldn't make sense to go chasing down the VPD on another function if the device doesn't have one. You could probably do that either as a part of this code, or perhaps put it in the quirk. I'll look into those. I think you are right about more checks being needed. Thanks for the comments. -- Mark Rustad, Networking Division, Intel Corporation
diff --git a/drivers/pci/access.c b/drivers/pci/access.c index d9b64a175990..e435c087c354 100644 --- a/drivers/pci/access.c +++ b/drivers/pci/access.c @@ -439,6 +439,40 @@ static const struct pci_vpd_ops pci_vpd_pci22_ops = { .release = pci_vpd_pci22_release, }; +static ssize_t pci_vpd_f0_read(struct pci_dev *dev, loff_t pos, size_t count, + void *arg) +{ + struct pci_dev *tdev = pci_get_slot(dev->bus, PCI_SLOT(dev->devfn)); + ssize_t ret; + + if (!tdev) + return -ENODEV; + + ret = pci_read_vpd(tdev, pos, count, arg); + pci_dev_put(tdev); + return ret; +} + +static ssize_t pci_vpd_f0_write(struct pci_dev *dev, loff_t pos, size_t count, + const void *arg) +{ + struct pci_dev *tdev = pci_get_slot(dev->bus, PCI_SLOT(dev->devfn)); + ssize_t ret; + + if (!tdev) + return -ENODEV; + + ret = pci_write_vpd(tdev, pos, count, arg); + pci_dev_put(tdev); + return ret; +} + +static const struct pci_vpd_ops pci_vpd_f0_ops = { + .read = pci_vpd_f0_read, + .write = pci_vpd_f0_write, + .release = pci_vpd_pci22_release, +}; + int pci_vpd_pci22_init(struct pci_dev *dev) { struct pci_vpd_pci22 *vpd; @@ -452,7 +486,10 @@ int pci_vpd_pci22_init(struct pci_dev *dev) return -ENOMEM; vpd->base.len = PCI_VPD_PCI22_SIZE; - vpd->base.ops = &pci_vpd_pci22_ops; + if (dev->dev_flags & PCI_DEV_FLAGS_VPD_REF_F0) + vpd->base.ops = &pci_vpd_f0_ops; + else + vpd->base.ops = &pci_vpd_pci22_ops; mutex_init(&vpd->lock); vpd->cap = cap; vpd->busy = false; diff --git a/include/linux/pci.h b/include/linux/pci.h index 353db8dc4c6e..194df6d635e6 100644 --- a/include/linux/pci.h +++ b/include/linux/pci.h @@ -180,6 +180,8 @@ enum pci_dev_flags { PCI_DEV_FLAGS_NO_BUS_RESET = (__force pci_dev_flags_t) (1 << 6), /* Do not use PM reset even if device advertises NoSoftRst- */ PCI_DEV_FLAGS_NO_PM_RESET = (__force pci_dev_flags_t) (1 << 7), + /* Get VPD from function 0 VPD */ + PCI_DEV_FLAGS_VPD_REF_F0 = (__force pci_dev_flags_t) (1 << 8), }; enum pci_irq_reroute_variant {
Add a dev_flags bit, PCI_DEV_FLAGS_VPD_REF_F0, to access VPD through function 0 to provide VPD access on other functions. This solves concurrent access problems on many devices without changing the attributes exposed in sysfs. Never set this bit on funciton 0 or there will be an infinite recursion. Signed-off-by: Mark Rustad <mark.d.rustad@intel.com> --- drivers/pci/access.c | 39 ++++++++++++++++++++++++++++++++++++++- include/linux/pci.h | 2 ++ 2 files changed, 40 insertions(+), 1 deletion(-) -- 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