2009-01-04 22:08:38

by Rafael J. Wysocki

[permalink] [raw]
Subject: [PATCH] x86 PCI: Do not use interrupt links for devices using MSI-X

From: Rafael J. Wysocki <[email protected]>

pcibios_enable_device() and pcibios_disable_device() don't handle
IRQs for devices that have MSI enabled and it should tread the
devices with MSI-X enabled in the same way.

Signed-off-by: Rafael J. Wysocki <[email protected]>
---
arch/x86/pci/common.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

Index: linux-2.6/arch/x86/pci/common.c
===================================================================
--- linux-2.6.orig/arch/x86/pci/common.c
+++ linux-2.6/arch/x86/pci/common.c
@@ -551,14 +551,14 @@ int pcibios_enable_device(struct pci_dev
if ((err = pci_enable_resources(dev, mask)) < 0)
return err;

- if (!dev->msi_enabled)
+ if (!dev->msi_enabled && !dev->msix_enabled)
return pcibios_enable_irq(dev);
return 0;
}

void pcibios_disable_device (struct pci_dev *dev)
{
- if (!dev->msi_enabled && pcibios_disable_irq)
+ if (!dev->msi_enabled && !dev->msix_enabled && pcibios_disable_irq)
pcibios_disable_irq(dev);
}


2009-01-05 13:05:01

by Ingo Molnar

[permalink] [raw]
Subject: Re: [PATCH] x86 PCI: Do not use interrupt links for devices using MSI-X


* Rafael J. Wysocki <[email protected]> wrote:

> From: Rafael J. Wysocki <[email protected]>
>
> pcibios_enable_device() and pcibios_disable_device() don't handle
> IRQs for devices that have MSI enabled and it should tread the

s/tread/treat

> devices with MSI-X enabled in the same way.
>
> Signed-off-by: Rafael J. Wysocki <[email protected]>
> ---
> arch/x86/pci/common.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)

looks good - Jesse, what do you think?

Rafael, i'm curious is this in response to some regression/bug? Did some
box or driver get confused by us enabling/disabling the GSI? Some IRQ
flood perhaps?

btw., there's a small observation:

> + if (!dev->msi_enabled && !dev->msix_enabled)

maybe a "pci_has_gsi_irq()" wrapper would make these checks cleaner and
would make things more robust, should there be any new IRQ delivery method
be introduced in the future?

Ingo

2009-01-05 13:50:53

by Rafael J. Wysocki

[permalink] [raw]
Subject: Re: [PATCH] x86 PCI: Do not use interrupt links for devices using MSI-X

On Monday 05 January 2009, Ingo Molnar wrote:
>
> * Rafael J. Wysocki <[email protected]> wrote:
>
> > From: Rafael J. Wysocki <[email protected]>
> >
> > pcibios_enable_device() and pcibios_disable_device() don't handle
> > IRQs for devices that have MSI enabled and it should tread the
>
> s/tread/treat

Ah, thanks.

> > devices with MSI-X enabled in the same way.
> >
> > Signed-off-by: Rafael J. Wysocki <[email protected]>
> > ---
> > arch/x86/pci/common.c | 4 ++--
> > 1 file changed, 2 insertions(+), 2 deletions(-)
>
> looks good - Jesse, what do you think?
>
> Rafael, i'm curious is this in response to some regression/bug? Did some
> box or driver get confused by us enabling/disabling the GSI? Some IRQ
> flood perhaps?

Well, I don't have any MSI-X capable boxes around. :-)

I was just reviewing the code and spotted this.

> btw., there's a small observation:
>
> > + if (!dev->msi_enabled && !dev->msix_enabled)
>
> maybe a "pci_has_gsi_irq()" wrapper would make these checks cleaner and
> would make things more robust, should there be any new IRQ delivery method
> be introduced in the future?

Well, perhaps something like the patch below?

Thanks,
Rafael

---
Subject: x86 PCI: Do not use interrupt links for devices using MSI-X (rev. 2)
From: Rafael J. Wysocki <[email protected]>

pcibios_enable_device() and pcibios_disable_device() don't handle
IRQs for devices that have MSI enabled and it should treat the
devices with MSI-X enabled in the same way.

Signed-off-by: Rafael J. Wysocki <[email protected]>
---
arch/x86/pci/common.c | 4 ++--
include/linux/pci.h | 9 +++++++++
2 files changed, 11 insertions(+), 2 deletions(-)

Index: linux-2.6/arch/x86/pci/common.c
===================================================================
--- linux-2.6.orig/arch/x86/pci/common.c
+++ linux-2.6/arch/x86/pci/common.c
@@ -551,14 +551,14 @@ int pcibios_enable_device(struct pci_dev
if ((err = pci_enable_resources(dev, mask)) < 0)
return err;

- if (!dev->msi_enabled)
+ if (!pci_msi_enabled(dev))
return pcibios_enable_irq(dev);
return 0;
}

void pcibios_disable_device (struct pci_dev *dev)
{
- if (!dev->msi_enabled && pcibios_disable_irq)
+ if (!pci_msi_enabled(dev) && pcibios_disable_irq)
pcibios_disable_irq(dev);
}

Index: linux-2.6/include/linux/pci.h
===================================================================
--- linux-2.6.orig/include/linux/pci.h
+++ linux-2.6/include/linux/pci.h
@@ -274,6 +274,15 @@ static inline void pci_add_saved_cap(str
hlist_add_head(&new_cap->next, &pci_dev->saved_cap_space);
}

+#ifdef CONFIG_PCI_MSI
+static inline bool pci_msi_enabled(struct pci_dev *pci_dev)
+{
+ return dev->msi_enabled || dev->msix_enabled;
+}
+#else
+static inline bool pci_msi_enabled(struct pci_dev *pci_dev) { return false; }
+#endif
+
/*
* For PCI devices, the region numbers are assigned this way:
*

2009-01-05 19:53:24

by Jesse Barnes

[permalink] [raw]
Subject: Re: [PATCH] x86 PCI: Do not use interrupt links for devices using MSI-X

On Monday, January 5, 2009 5:04 am Ingo Molnar wrote:
> * Rafael J. Wysocki <[email protected]> wrote:
> > From: Rafael J. Wysocki <[email protected]>
> >
> > pcibios_enable_device() and pcibios_disable_device() don't handle
> > IRQs for devices that have MSI enabled and it should tread the
>
> s/tread/treat
>
> > devices with MSI-X enabled in the same way.
> >
> > Signed-off-by: Rafael J. Wysocki <[email protected]>
> > ---
> > arch/x86/pci/common.c | 4 ++--
> > 1 file changed, 2 insertions(+), 2 deletions(-)
>
> looks good - Jesse, what do you think?

Yeah, seems obviously correct, I'll queue it up.

> Rafael, i'm curious is this in response to some regression/bug? Did some
> box or driver get confused by us enabling/disabling the GSI? Some IRQ
> flood perhaps?
>
> btw., there's a small observation:
> > + if (!dev->msi_enabled && !dev->msix_enabled)
>
> maybe a "pci_has_gsi_irq()" wrapper would make these checks cleaner and
> would make things more robust, should there be any new IRQ delivery method
> be introduced in the future?

pci_has_msi_irq surely? Otherwise we'll catch pretty much everything? Or did
you mean !pci_has_gsi_irq() here instead?

Thanks,
--
Jesse Barnes, Intel Open Source Technology Center

2009-01-05 19:55:37

by Jesse Barnes

[permalink] [raw]
Subject: Re: [PATCH] x86 PCI: Do not use interrupt links for devices using MSI-X

On Monday, January 5, 2009 5:50 am Rafael J. Wysocki wrote:
> On Monday 05 January 2009, Ingo Molnar wrote:
> > * Rafael J. Wysocki <[email protected]> wrote:
> > > From: Rafael J. Wysocki <[email protected]>
> > >
> > > pcibios_enable_device() and pcibios_disable_device() don't handle
> > > IRQs for devices that have MSI enabled and it should tread the
> >
> > s/tread/treat
>
> Ah, thanks.
>
> > > devices with MSI-X enabled in the same way.
> > >
> > > Signed-off-by: Rafael J. Wysocki <[email protected]>
> > > ---
> > > arch/x86/pci/common.c | 4 ++--
> > > 1 file changed, 2 insertions(+), 2 deletions(-)
> >
> > looks good - Jesse, what do you think?
> >
> > Rafael, i'm curious is this in response to some regression/bug? Did some
> > box or driver get confused by us enabling/disabling the GSI? Some IRQ
> > flood perhaps?
>
> Well, I don't have any MSI-X capable boxes around. :-)
>
> I was just reviewing the code and spotted this.
>
> > btw., there's a small observation:
> > > + if (!dev->msi_enabled && !dev->msix_enabled)
> >
> > maybe a "pci_has_gsi_irq()" wrapper would make these checks cleaner and
> > would make things more robust, should there be any new IRQ delivery
> > method be introduced in the future?
>
> Well, perhaps something like the patch below?
>
> Thanks,
> Rafael
>
> ---
> Subject: x86 PCI: Do not use interrupt links for devices using MSI-X (rev.
> 2) From: Rafael J. Wysocki <[email protected]>
>
> pcibios_enable_device() and pcibios_disable_device() don't handle
> IRQs for devices that have MSI enabled and it should treat the
> devices with MSI-X enabled in the same way.
>
> Signed-off-by: Rafael J. Wysocki <[email protected]>

Looks good, applied this one.

Thanks,
--
Jesse Barnes, Intel Open Source Technology Center

2009-01-06 17:19:50

by Bjorn Helgaas

[permalink] [raw]
Subject: Re: [PATCH] x86 PCI: Do not use interrupt links for devices using MSI-X

On Sunday 04 January 2009 03:08:42 pm Rafael J. Wysocki wrote:
> pcibios_enable_device() and pcibios_disable_device() don't handle
> IRQs for devices that have MSI enabled and it should tread the
> devices with MSI-X enabled in the same way.

There are other places that need similar fixes, too, aren't there?
I see cris, frv, ia64, and a driver or two testing dev->msi_enabled.

> --- linux-2.6.orig/arch/x86/pci/common.c
> +++ linux-2.6/arch/x86/pci/common.c
> @@ -551,14 +551,14 @@ int pcibios_enable_device(struct pci_dev
> if ((err = pci_enable_resources(dev, mask)) < 0)
> return err;
>
> - if (!dev->msi_enabled)
> + if (!dev->msi_enabled && !dev->msix_enabled)
> return pcibios_enable_irq(dev);
> return 0;
> }
>
> void pcibios_disable_device (struct pci_dev *dev)
> {
> - if (!dev->msi_enabled && pcibios_disable_irq)
> + if (!dev->msi_enabled && !dev->msix_enabled && pcibios_disable_irq)
> pcibios_disable_irq(dev);
> }

2009-01-06 19:46:14

by Rafael J. Wysocki

[permalink] [raw]
Subject: Re: [PATCH] x86 PCI: Do not use interrupt links for devices using MSI-X

On Tuesday 06 January 2009, Bjorn Helgaas wrote:
> On Sunday 04 January 2009 03:08:42 pm Rafael J. Wysocki wrote:
> > pcibios_enable_device() and pcibios_disable_device() don't handle
> > IRQs for devices that have MSI enabled and it should tread the
> > devices with MSI-X enabled in the same way.
>
> There are other places that need similar fixes, too, aren't there?
> I see cris, frv, ia64, and a driver or two testing dev->msi_enabled.

Well, I didn't look at the other places, just found this one while reviewing
the code.

I'll check them later this week.

> > --- linux-2.6.orig/arch/x86/pci/common.c
> > +++ linux-2.6/arch/x86/pci/common.c
> > @@ -551,14 +551,14 @@ int pcibios_enable_device(struct pci_dev
> > if ((err = pci_enable_resources(dev, mask)) < 0)
> > return err;
> >
> > - if (!dev->msi_enabled)
> > + if (!dev->msi_enabled && !dev->msix_enabled)
> > return pcibios_enable_irq(dev);
> > return 0;
> > }
> >
> > void pcibios_disable_device (struct pci_dev *dev)
> > {
> > - if (!dev->msi_enabled && pcibios_disable_irq)
> > + if (!dev->msi_enabled && !dev->msix_enabled && pcibios_disable_irq)
> > pcibios_disable_irq(dev);
> > }

2009-01-07 13:14:17

by Ingo Molnar

[permalink] [raw]
Subject: Re: [PATCH] x86 PCI: Do not use interrupt links for devices using MSI-X


* Jesse Barnes <[email protected]> wrote:

> On Monday, January 5, 2009 5:04 am Ingo Molnar wrote:
> > * Rafael J. Wysocki <[email protected]> wrote:
> > > From: Rafael J. Wysocki <[email protected]>
> > >
> > > pcibios_enable_device() and pcibios_disable_device() don't handle
> > > IRQs for devices that have MSI enabled and it should tread the
> >
> > s/tread/treat
> >
> > > devices with MSI-X enabled in the same way.
> > >
> > > Signed-off-by: Rafael J. Wysocki <[email protected]>
> > > ---
> > > arch/x86/pci/common.c | 4 ++--
> > > 1 file changed, 2 insertions(+), 2 deletions(-)
> >
> > looks good - Jesse, what do you think?
>
> Yeah, seems obviously correct, I'll queue it up.
>
> > Rafael, i'm curious is this in response to some regression/bug? Did some
> > box or driver get confused by us enabling/disabling the GSI? Some IRQ
> > flood perhaps?
> >
> > btw., there's a small observation:
> > > + if (!dev->msi_enabled && !dev->msix_enabled)
> >
> > maybe a "pci_has_gsi_irq()" wrapper would make these checks cleaner and
> > would make things more robust, should there be any new IRQ delivery method
> > be introduced in the future?
>
> pci_has_msi_irq surely? Otherwise we'll catch pretty much everything? Or did
> you mean !pci_has_gsi_irq() here instead?

Well - here the check is: "if (not MSI or MSIX)" in essence. I thought
that it might be confusing to call it _msi() as well, so we could approach
it via the inverse space: general system interrupts (GSIs) - which are
device irqs that are neither MSI nor MSIX.

But if pci_has_msi_irq() can cleanly include the MSIX portion too, that's
fine too. (MSI-X is really MSI with wider eventing capabilities but
otherwise non-GSI just as much - and we dont want to enable (or even
touch) the legacy IRQ line registers for any of them, even if they happen
to be enumerated)

Right?

Ingo

2009-01-07 17:34:10

by Jesse Barnes

[permalink] [raw]
Subject: Re: [PATCH] x86 PCI: Do not use interrupt links for devices using MSI-X

On Wednesday, January 7, 2009 5:13 am Ingo Molnar wrote:
> * Jesse Barnes <[email protected]> wrote:
> > On Monday, January 5, 2009 5:04 am Ingo Molnar wrote:
> > > * Rafael J. Wysocki <[email protected]> wrote:
> > > > From: Rafael J. Wysocki <[email protected]>
> > > >
> > > > pcibios_enable_device() and pcibios_disable_device() don't handle
> > > > IRQs for devices that have MSI enabled and it should tread the
> > >
> > > s/tread/treat
> > >
> > > > devices with MSI-X enabled in the same way.
> > > >
> > > > Signed-off-by: Rafael J. Wysocki <[email protected]>
> > > > ---
> > > > arch/x86/pci/common.c | 4 ++--
> > > > 1 file changed, 2 insertions(+), 2 deletions(-)
> > >
> > > looks good - Jesse, what do you think?
> >
> > Yeah, seems obviously correct, I'll queue it up.
> >
> > > Rafael, i'm curious is this in response to some regression/bug? Did
> > > some box or driver get confused by us enabling/disabling the GSI? Some
> > > IRQ flood perhaps?
> > >
> > > btw., there's a small observation:
> > > > + if (!dev->msi_enabled && !dev->msix_enabled)
> > >
> > > maybe a "pci_has_gsi_irq()" wrapper would make these checks cleaner and
> > > would make things more robust, should there be any new IRQ delivery
> > > method be introduced in the future?
> >
> > pci_has_msi_irq surely? Otherwise we'll catch pretty much everything?
> > Or did you mean !pci_has_gsi_irq() here instead?
>
> Well - here the check is: "if (not MSI or MSIX)" in essence. I thought
> that it might be confusing to call it _msi() as well, so we could approach
> it via the inverse space: general system interrupts (GSIs) - which are
> device irqs that are neither MSI nor MSIX.
>
> But if pci_has_msi_irq() can cleanly include the MSIX portion too, that's
> fine too. (MSI-X is really MSI with wider eventing capabilities but
> otherwise non-GSI just as much - and we dont want to enable (or even
> touch) the legacy IRQ line registers for any of them, even if they happen
> to be enumerated)
>
> Right?

Right, I see where you're coming from. However, I've queued up Rafael's last
patch with some fixes for dev vs. pci_dev and a name collision
(pci_msi_enabled -> pci_dev_msi_enabled). Bjorn caught the fact that some
other arches may want similar treatment too, I think Rafael is checking that
out.

--
Jesse Barnes, Intel Open Source Technology Center

2009-01-07 17:45:53

by Ingo Molnar

[permalink] [raw]
Subject: Re: [PATCH] x86 PCI: Do not use interrupt links for devices using MSI-X


* Jesse Barnes <[email protected]> wrote:

> On Wednesday, January 7, 2009 5:13 am Ingo Molnar wrote:
> > * Jesse Barnes <[email protected]> wrote:
> > > On Monday, January 5, 2009 5:04 am Ingo Molnar wrote:
> > > > * Rafael J. Wysocki <[email protected]> wrote:
> > > > > From: Rafael J. Wysocki <[email protected]>
> > > > >
> > > > > pcibios_enable_device() and pcibios_disable_device() don't handle
> > > > > IRQs for devices that have MSI enabled and it should tread the
> > > >
> > > > s/tread/treat
> > > >
> > > > > devices with MSI-X enabled in the same way.
> > > > >
> > > > > Signed-off-by: Rafael J. Wysocki <[email protected]>
> > > > > ---
> > > > > arch/x86/pci/common.c | 4 ++--
> > > > > 1 file changed, 2 insertions(+), 2 deletions(-)
> > > >
> > > > looks good - Jesse, what do you think?
> > >
> > > Yeah, seems obviously correct, I'll queue it up.
> > >
> > > > Rafael, i'm curious is this in response to some regression/bug? Did
> > > > some box or driver get confused by us enabling/disabling the GSI? Some
> > > > IRQ flood perhaps?
> > > >
> > > > btw., there's a small observation:
> > > > > + if (!dev->msi_enabled && !dev->msix_enabled)
> > > >
> > > > maybe a "pci_has_gsi_irq()" wrapper would make these checks cleaner and
> > > > would make things more robust, should there be any new IRQ delivery
> > > > method be introduced in the future?
> > >
> > > pci_has_msi_irq surely? Otherwise we'll catch pretty much everything?
> > > Or did you mean !pci_has_gsi_irq() here instead?
> >
> > Well - here the check is: "if (not MSI or MSIX)" in essence. I thought
> > that it might be confusing to call it _msi() as well, so we could approach
> > it via the inverse space: general system interrupts (GSIs) - which are
> > device irqs that are neither MSI nor MSIX.
> >
> > But if pci_has_msi_irq() can cleanly include the MSIX portion too, that's
> > fine too. (MSI-X is really MSI with wider eventing capabilities but
> > otherwise non-GSI just as much - and we dont want to enable (or even
> > touch) the legacy IRQ line registers for any of them, even if they happen
> > to be enumerated)
> >
> > Right?
>
> Right, I see where you're coming from. However, I've queued up Rafael's
> last patch with some fixes for dev vs. pci_dev and a name collision
> (pci_msi_enabled -> pci_dev_msi_enabled). Bjorn caught the fact that
> some other arches may want similar treatment too, I think Rafael is
> checking that out.

Sure - that sounds good too!

Ingo

2009-01-07 18:13:27

by Rafael J. Wysocki

[permalink] [raw]
Subject: Re: [PATCH] x86 PCI: Do not use interrupt links for devices using MSI-X

On Wednesday 07 January 2009, Jesse Barnes wrote:
> On Wednesday, January 7, 2009 5:13 am Ingo Molnar wrote:
> > * Jesse Barnes <[email protected]> wrote:
> > > On Monday, January 5, 2009 5:04 am Ingo Molnar wrote:
> > > > * Rafael J. Wysocki <[email protected]> wrote:
> > > > > From: Rafael J. Wysocki <[email protected]>
> > > > >
> > > > > pcibios_enable_device() and pcibios_disable_device() don't handle
> > > > > IRQs for devices that have MSI enabled and it should tread the
> > > >
> > > > s/tread/treat
> > > >
> > > > > devices with MSI-X enabled in the same way.
> > > > >
> > > > > Signed-off-by: Rafael J. Wysocki <[email protected]>
> > > > > ---
> > > > > arch/x86/pci/common.c | 4 ++--
> > > > > 1 file changed, 2 insertions(+), 2 deletions(-)
> > > >
> > > > looks good - Jesse, what do you think?
> > >
> > > Yeah, seems obviously correct, I'll queue it up.
> > >
> > > > Rafael, i'm curious is this in response to some regression/bug? Did
> > > > some box or driver get confused by us enabling/disabling the GSI? Some
> > > > IRQ flood perhaps?
> > > >
> > > > btw., there's a small observation:
> > > > > + if (!dev->msi_enabled && !dev->msix_enabled)
> > > >
> > > > maybe a "pci_has_gsi_irq()" wrapper would make these checks cleaner and
> > > > would make things more robust, should there be any new IRQ delivery
> > > > method be introduced in the future?
> > >
> > > pci_has_msi_irq surely? Otherwise we'll catch pretty much everything?
> > > Or did you mean !pci_has_gsi_irq() here instead?
> >
> > Well - here the check is: "if (not MSI or MSIX)" in essence. I thought
> > that it might be confusing to call it _msi() as well, so we could approach
> > it via the inverse space: general system interrupts (GSIs) - which are
> > device irqs that are neither MSI nor MSIX.
> >
> > But if pci_has_msi_irq() can cleanly include the MSIX portion too, that's
> > fine too. (MSI-X is really MSI with wider eventing capabilities but
> > otherwise non-GSI just as much - and we dont want to enable (or even
> > touch) the legacy IRQ line registers for any of them, even if they happen
> > to be enumerated)
> >
> > Right?
>
> Right, I see where you're coming from. However, I've queued up Rafael's last
> patch with some fixes for dev vs. pci_dev and a name collision
> (pci_msi_enabled -> pci_dev_msi_enabled). Bjorn caught the fact that some
> other arches may want similar treatment too, I think Rafael is checking that
> out.

Yes, I am.

Thanks,
Rafael