[PATCH 0/2] PCI: MSI: Deal with devices lying about their masking capability

[PATCH 0/2] PCI: MSI: Deal with devices lying about their masking capability

[Marc Zyngier]

Rui reported[1] that his Nvidia ION system stopped working with 5.15,
with the AHCI device failing to get any MSI. A rapid investigation
revealed that although the device doesn't advertise MSI masking, it
actually needs it. Quality hardware indeed.

Anyway, the couple of patches below are an attempt at dealing with the
issue in a more or less generic way.

[1] https://lore.kernel.org/r/CALjTZvbzYfBuLB+H=fj2J+9=DxjQ2Uqcy0if_PvmJ-nU-qEgkg@mail.gmail.com

Marc Zyngier (2):
  PCI: MSI: Deal with devices lying about their MSI mask capability
  PCI: Add MSI masking quirk for Nvidia ION AHCI

 drivers/pci/msi.c    | 3 +++
 drivers/pci/quirks.c | 6 ++++++
 include/linux/pci.h  | 2 ++
 3 files changed, 11 insertions(+)

-- 
2.30.2

[PATCH 1/2] PCI: MSI: Deal with devices lying about their MSI mask capability

[Marc Zyngier]

It appears that some devices are lying about their mask capability,
pretending that they don't have it, while they actually do.
The net result is that now that we don't enable MSIs on such
endpoint.

Add a new per-device flag to deal with this. Further patches will
make use of it, sadly.

Signed-off-by: Marc Zyngier <maz@kernel.org>
---
 drivers/pci/msi.c   | 3 +++
 include/linux/pci.h | 2 ++
 2 files changed, 5 insertions(+)

diff --git a/drivers/pci/msi.c b/drivers/pci/msi.c
index 0099a00af361..2f9ec7210991 100644
--- a/drivers/pci/msi.c
+++ b/drivers/pci/msi.c
@@ -479,6 +479,9 @@ msi_setup_entry(struct pci_dev *dev, int nvec, struct irq_affinity *affd)
 		goto out;
 
 	pci_read_config_word(dev, dev->msi_cap + PCI_MSI_FLAGS, &control);
+	/* Lies, damned lies, and MSIs */
+	if (dev->dev_flags & PCI_DEV_FLAGS_HAS_MSI_MASKING)
+		control |= PCI_MSI_FLAGS_MASKBIT;
 
 	entry->msi_attrib.is_msix	= 0;
 	entry->msi_attrib.is_64		= !!(control & PCI_MSI_FLAGS_64BIT);
diff --git a/include/linux/pci.h b/include/linux/pci.h
index cd8aa6fce204..152a4d74f87f 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -233,6 +233,8 @@ enum pci_dev_flags {
 	PCI_DEV_FLAGS_NO_FLR_RESET = (__force pci_dev_flags_t) (1 << 10),
 	/* Don't use Relaxed Ordering for TLPs directed at this device */
 	PCI_DEV_FLAGS_NO_RELAXED_ORDERING = (__force pci_dev_flags_t) (1 << 11),
+	/* Device does honor MSI masking despite saying otherwise */
+	PCI_DEV_FLAGS_HAS_MSI_MASKING = (__force pci_dev_flags_t) (1 << 12),
 };
 
 enum pci_irq_reroute_variant {
-- 
2.30.2

[PATCH 2/2] PCI: Add MSI masking quirk for Nvidia ION AHCI

[Marc Zyngier]

The ION AHCI device pretends that MSI masking isn't a thing,
while it actually implements it and needs MSIs to be unmasked
to work. Add a quirk to that effect.

Reported-by: Rui Salvaterra <rsalvaterra@gmail.com>
Tested-by: Rui Salvaterra <rsalvaterra@gmail.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/CALjTZvbzYfBuLB+H=fj2J+9=DxjQ2Uqcy0if_PvmJ-nU-qEgkg@mail.gmail.com
---
 drivers/pci/quirks.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
index 4537d1ea14fd..89c7c99cd1bb 100644
--- a/drivers/pci/quirks.c
+++ b/drivers/pci/quirks.c
@@ -5795,3 +5795,9 @@ static void apex_pci_fixup_class(struct pci_dev *pdev)
 }
 DECLARE_PCI_FIXUP_CLASS_HEADER(0x1ac1, 0x089a,
 			       PCI_CLASS_NOT_DEFINED, 8, apex_pci_fixup_class);
+
+static void nvidia_ion_ahci_fixup(struct pci_dev *pdev)
+{
+	pdev->dev_flags |= PCI_DEV_FLAGS_HAS_MSI_MASKING;
+}
+DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_NVIDIA, 0x0ab8, nvidia_ion_ahci_fixup);
-- 
2.30.2

Re: [PATCH 0/2] PCI: MSI: Deal with devices lying about their masking capability

[Thomas Gleixner]

On Thu, Nov 04 2021 at 18:01, Marc Zyngier wrote:
> Rui reported[1] that his Nvidia ION system stopped working with 5.15,
> with the AHCI device failing to get any MSI. A rapid investigation
> revealed that although the device doesn't advertise MSI masking, it
> actually needs it. Quality hardware indeed.
>
> Anyway, the couple of patches below are an attempt at dealing with the
> issue in a more or less generic way.
>
> [1] https://lore.kernel.org/r/CALjTZvbzYfBuLB+H=fj2J+9=DxjQ2Uqcy0if_PvmJ-nU-qEgkg@mail.gmail.com
>
> Marc Zyngier (2):
>   PCI: MSI: Deal with devices lying about their MSI mask capability
>   PCI: Add MSI masking quirk for Nvidia ION AHCI
>
>  drivers/pci/msi.c    | 3 +++
>  drivers/pci/quirks.c | 6 ++++++
>  include/linux/pci.h  | 2 ++
>  3 files changed, 11 insertions(+)

Groan.

Reviewed-by: Thomas Gleixner <tglx@linutronix.de>

Re: [PATCH 0/2] PCI: MSI: Deal with devices lying about their masking capability

[Rui Salvaterra]

Hi, Thomas,

On Fri, 5 Nov 2021 at 13:14, Thomas Gleixner <tglx@linutronix.de> wrote:
>
> On Thu, Nov 04 2021 at 18:01, Marc Zyngier wrote:
> > Rui reported[1] that his Nvidia ION system stopped working with 5.15,
> > with the AHCI device failing to get any MSI. A rapid investigation
> > revealed that although the device doesn't advertise MSI masking, it
> > actually needs it. Quality hardware indeed.
> >
> > Anyway, the couple of patches below are an attempt at dealing with the
> > issue in a more or less generic way.
> >
> > [1] https://lore.kernel.org/r/CALjTZvbzYfBuLB+H=fj2J+9=DxjQ2Uqcy0if_PvmJ-nU-qEgkg@mail.gmail.com
> >
> > Marc Zyngier (2):
> >   PCI: MSI: Deal with devices lying about their MSI mask capability
> >   PCI: Add MSI masking quirk for Nvidia ION AHCI
> >
> >  drivers/pci/msi.c    | 3 +++
> >  drivers/pci/quirks.c | 6 ++++++
> >  include/linux/pci.h  | 2 ++
> >  3 files changed, 11 insertions(+)
>
> Groan.
>
> Reviewed-by: Thomas Gleixner <tglx@linutronix.de>

Just a reminder, to make sure this doesn't fall through the cracks.
It's already in 5.16, but needs to be backported to 5.15. I'm not
seeing it in Greg's 5.15 stable queue yet.

Thanks,
Rui

Re: [PATCH 0/2] PCI: MSI: Deal with devices lying about their masking capability

[Greg KH]

On Tue, Nov 16, 2021 at 10:21:18AM +0000, Rui Salvaterra wrote:
> Hi, Thomas,
> 
> On Fri, 5 Nov 2021 at 13:14, Thomas Gleixner <tglx@linutronix.de> wrote:
> >
> > On Thu, Nov 04 2021 at 18:01, Marc Zyngier wrote:
> > > Rui reported[1] that his Nvidia ION system stopped working with 5.15,
> > > with the AHCI device failing to get any MSI. A rapid investigation
> > > revealed that although the device doesn't advertise MSI masking, it
> > > actually needs it. Quality hardware indeed.
> > >
> > > Anyway, the couple of patches below are an attempt at dealing with the
> > > issue in a more or less generic way.
> > >
> > > [1] https://lore.kernel.org/r/CALjTZvbzYfBuLB+H=fj2J+9=DxjQ2Uqcy0if_PvmJ-nU-qEgkg@mail.gmail.com
> > >
> > > Marc Zyngier (2):
> > >   PCI: MSI: Deal with devices lying about their MSI mask capability
> > >   PCI: Add MSI masking quirk for Nvidia ION AHCI
> > >
> > >  drivers/pci/msi.c    | 3 +++
> > >  drivers/pci/quirks.c | 6 ++++++
> > >  include/linux/pci.h  | 2 ++
> > >  3 files changed, 11 insertions(+)
> >
> > Groan.
> >
> > Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
> 
> Just a reminder, to make sure this doesn't fall through the cracks.
> It's already in 5.16, but needs to be backported to 5.15. I'm not
> seeing it in Greg's 5.15 stable queue yet.

What is the git commit ids of these changes in Linus's tree?

thanks,

greg k-h

Re: [PATCH 0/2] PCI: MSI: Deal with devices lying about their masking capability

[Rui Salvaterra]

Hi, Greg,

On Tue, 16 Nov 2021 at 10:39, Greg KH <gregkh@linuxfoundation.org> wrote:
>
> What is the git commit ids of these changes in Linus's tree?

2226667a145d ("PCI/MSI: Deal with devices lying about their MSI mask
capability")
f21082fb20db ("PCI: Add MSI masking quirk for Nvidia ION AHCI")

Thanks,
Rui

Re: [PATCH 0/2] PCI: MSI: Deal with devices lying about their masking capability

[Greg KH]

On Tue, Nov 16, 2021 at 10:47:23AM +0000, Rui Salvaterra wrote:
> Hi, Greg,
> 
> On Tue, 16 Nov 2021 at 10:39, Greg KH <gregkh@linuxfoundation.org> wrote:
> >
> > What is the git commit ids of these changes in Linus's tree?
> 
> 2226667a145d ("PCI/MSI: Deal with devices lying about their MSI mask
> capability")
> f21082fb20db ("PCI: Add MSI masking quirk for Nvidia ION AHCI")

Thanks, I'll queue them up in the next round of releases after the
current ones are out.

greg k-h

Re: [PATCH 0/2] PCI: MSI: Deal with devices lying about their masking capability

[Greg KH]

On Tue, Nov 16, 2021 at 11:56:32AM +0100, Greg KH wrote:
> On Tue, Nov 16, 2021 at 10:47:23AM +0000, Rui Salvaterra wrote:
> > Hi, Greg,
> > 
> > On Tue, 16 Nov 2021 at 10:39, Greg KH <gregkh@linuxfoundation.org> wrote:
> > >
> > > What is the git commit ids of these changes in Linus's tree?
> > 
> > 2226667a145d ("PCI/MSI: Deal with devices lying about their MSI mask
> > capability")
> > f21082fb20db ("PCI: Add MSI masking quirk for Nvidia ION AHCI")
> 
> Thanks, I'll queue them up in the next round of releases after the
> current ones are out.

Now queued up.

greg k-h