* [PATCH] pci: fix nit in ROM BAR size probing
@ 2009-10-29 15:24 Michael S. Tsirkin
2009-11-04 17:04 ` Jesse Barnes
0 siblings, 1 reply; 4+ messages in thread
From: Michael S. Tsirkin @ 2009-10-29 15:24 UTC (permalink / raw)
To: Jesse Barnes, Alex Chiang, Yu Zhao, Matthew Wilcox, linux-pci,
linux-kernel, gleb
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);
--
1.6.5.rc2
^ permalink raw reply related [flat|nested] 4+ messages in thread* Re: [PATCH] pci: fix nit in ROM BAR size probing
2009-10-29 15:24 [PATCH] pci: fix nit in ROM BAR size probing Michael S. Tsirkin
@ 2009-11-04 17:04 ` Jesse Barnes
2009-11-04 17:06 ` Michael S. Tsirkin
0 siblings, 1 reply; 4+ messages in thread
From: Jesse Barnes @ 2009-11-04 17:04 UTC (permalink / raw)
To: Michael S. Tsirkin
Cc: Alex Chiang, Yu Zhao, Matthew Wilcox, linux-pci, linux-kernel,
gleb
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
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH] pci: fix nit in ROM BAR size probing
2009-11-04 17:04 ` Jesse Barnes
@ 2009-11-04 17:06 ` Michael S. Tsirkin
2009-11-04 17:14 ` Jesse Barnes
0 siblings, 1 reply; 4+ messages in thread
From: Michael S. Tsirkin @ 2009-11-04 17:06 UTC (permalink / raw)
To: Jesse Barnes
Cc: Alex Chiang, Yu Zhao, Matthew Wilcox, linux-pci, linux-kernel,
gleb
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?
--
MST
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH] pci: fix nit in ROM BAR size probing
2009-11-04 17:06 ` Michael S. Tsirkin
@ 2009-11-04 17:14 ` Jesse Barnes
0 siblings, 0 replies; 4+ messages in thread
From: Jesse Barnes @ 2009-11-04 17:14 UTC (permalink / raw)
To: Michael S. Tsirkin
Cc: Alex Chiang, Yu Zhao, Matthew Wilcox, linux-pci, linux-kernel,
gleb
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
--
Jesse Barnes, Intel Open Source Technology Center
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2009-11-04 17:14 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2009-10-29 15:24 [PATCH] pci: fix nit in ROM BAR size probing Michael S. Tsirkin
2009-11-04 17:04 ` Jesse Barnes
2009-11-04 17:06 ` Michael S. Tsirkin
2009-11-04 17:14 ` Jesse Barnes
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox