| Submitter | Michael S. Tsirkin |
|---|---|
| Date | 2009-10-29 15:24:59 |
| Message ID | <20091029152459.GA5480@redhat.com> |
| Download | mbox | patch |
| Permalink | /patch/56477/ |
| State | Accepted |
| Headers | show |
Comments
On Thu, 29 Oct 2009 17:24:59 +0200 "Michael S. Tsirkin" <mst@redhat.com> wrote: > When probing for ROM BAR size, we should not > change bits 1:10 in this BAR, because these > bits are marked as "reserved for future use" in PCI spec, > so changing them might have side effects. > > No such issue for I/O or memory, as there is > an implementation note in PCI spec which explicitly allows > writing 0xfffffffff there. > > Signed-off-by: Michael S. Tsirkin <mst@redhat.com> > --- > drivers/pci/probe.c | 4 ++-- > 1 files changed, 2 insertions(+), 2 deletions(-) > > diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c > index 8105e32..d65aae4 100644 > --- a/drivers/pci/probe.c > +++ b/drivers/pci/probe.c > @@ -163,12 +163,12 @@ int __pci_read_base(struct pci_dev *dev, enum > pci_bar_type type, { > u32 l, sz, mask; > > - mask = type ? ~PCI_ROM_ADDRESS_ENABLE : ~0; > + mask = type ? PCI_ROM_ADDRESS_MASK : ~0; > > res->name = pci_name(dev); > > pci_read_config_dword(dev, pos, &l); > - pci_write_config_dword(dev, pos, mask); > + pci_write_config_dword(dev, pos, l | mask); > pci_read_config_dword(dev, pos, &sz); > pci_write_config_dword(dev, pos, l); Applied to linux-next, thanks. Another possible enhancement here would be to make the mask into a switch based on the type, since mem32 and mem64 "BARs" (added by willy for doing BAR-like stuff) could probably use ~0 as well. Jesse -- 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 Wed, Nov 04, 2009 at 09:04:09AM -0800, Jesse Barnes wrote: > On Thu, 29 Oct 2009 17:24:59 +0200 > "Michael S. Tsirkin" <mst@redhat.com> wrote: > > > When probing for ROM BAR size, we should not > > change bits 1:10 in this BAR, because these > > bits are marked as "reserved for future use" in PCI spec, > > so changing them might have side effects. > > > > No such issue for I/O or memory, as there is > > an implementation note in PCI spec which explicitly allows > > writing 0xfffffffff there. > > > > Signed-off-by: Michael S. Tsirkin <mst@redhat.com> > > --- > > drivers/pci/probe.c | 4 ++-- > > 1 files changed, 2 insertions(+), 2 deletions(-) > > > > diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c > > index 8105e32..d65aae4 100644 > > --- a/drivers/pci/probe.c > > +++ b/drivers/pci/probe.c > > @@ -163,12 +163,12 @@ int __pci_read_base(struct pci_dev *dev, enum > > pci_bar_type type, { > > u32 l, sz, mask; > > > > - mask = type ? ~PCI_ROM_ADDRESS_ENABLE : ~0; > > + mask = type ? PCI_ROM_ADDRESS_MASK : ~0; > > > > res->name = pci_name(dev); > > > > pci_read_config_dword(dev, pos, &l); > > - pci_write_config_dword(dev, pos, mask); > > + pci_write_config_dword(dev, pos, l | mask); > > pci_read_config_dword(dev, pos, &sz); > > pci_write_config_dword(dev, pos, l); > > Applied to linux-next, thanks. Another possible enhancement here would > be to make the mask into a switch based on the type, since mem32 and > mem64 "BARs" (added by willy for doing BAR-like stuff) could probably > use ~0 as well. > > Jesse Where can I find the patch by willy that adds these?
On Wed, 4 Nov 2009 19:06:19 +0200 "Michael S. Tsirkin" <mst@redhat.com> wrote: > On Wed, Nov 04, 2009 at 09:04:09AM -0800, Jesse Barnes wrote: > > On Thu, 29 Oct 2009 17:24:59 +0200 > > "Michael S. Tsirkin" <mst@redhat.com> wrote: > > > > > When probing for ROM BAR size, we should not > > > change bits 1:10 in this BAR, because these > > > bits are marked as "reserved for future use" in PCI spec, > > > so changing them might have side effects. > > > > > > No such issue for I/O or memory, as there is > > > an implementation note in PCI spec which explicitly allows > > > writing 0xfffffffff there. > > > > > > Signed-off-by: Michael S. Tsirkin <mst@redhat.com> > > > --- > > > drivers/pci/probe.c | 4 ++-- > > > 1 files changed, 2 insertions(+), 2 deletions(-) > > > > > > diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c > > > index 8105e32..d65aae4 100644 > > > --- a/drivers/pci/probe.c > > > +++ b/drivers/pci/probe.c > > > @@ -163,12 +163,12 @@ int __pci_read_base(struct pci_dev *dev, > > > enum pci_bar_type type, { > > > u32 l, sz, mask; > > > > > > - mask = type ? ~PCI_ROM_ADDRESS_ENABLE : ~0; > > > + mask = type ? PCI_ROM_ADDRESS_MASK : ~0; > > > > > > res->name = pci_name(dev); > > > > > > pci_read_config_dword(dev, pos, &l); > > > - pci_write_config_dword(dev, pos, mask); > > > + pci_write_config_dword(dev, pos, l | mask); > > > pci_read_config_dword(dev, pos, &sz); > > > pci_write_config_dword(dev, pos, l); > > > > Applied to linux-next, thanks. Another possible enhancement here > > would be to make the mask into a switch based on the type, since > > mem32 and mem64 "BARs" (added by willy for doing BAR-like stuff) > > could probably use ~0 as well. > > > > Jesse > > Where can I find the patch by willy that adds these? commit 6ac665c63dcac8fcec534a1d224ecbb8b867ad59 Author: Matthew Wilcox <matthew@wil.cx> Date: Mon Jul 28 13:38:59 2008 -0400 PCI: rewrite PCI BAR reading code
Patch
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c index 8105e32..d65aae4 100644 --- a/drivers/pci/probe.c +++ b/drivers/pci/probe.c @@ -163,12 +163,12 @@ int __pci_read_base(struct pci_dev *dev, enum pci_bar_type type, { u32 l, sz, mask; - mask = type ? ~PCI_ROM_ADDRESS_ENABLE : ~0; + mask = type ? PCI_ROM_ADDRESS_MASK : ~0; res->name = pci_name(dev); pci_read_config_dword(dev, pos, &l); - pci_write_config_dword(dev, pos, mask); + pci_write_config_dword(dev, pos, l | mask); pci_read_config_dword(dev, pos, &sz); pci_write_config_dword(dev, pos, l);
When probing for ROM BAR size, we should not change bits 1:10 in this BAR, because these bits are marked as "reserved for future use" in PCI spec, so changing them might have side effects. No such issue for I/O or memory, as there is an implementation note in PCI spec which explicitly allows writing 0xfffffffff there. Signed-off-by: Michael S. Tsirkin <mst@redhat.com> --- drivers/pci/probe.c | 4 ++-- 1 files changed, 2 insertions(+), 2 deletions(-)