From: Bjorn Helgaas <helgaas@kernel.org>
To: Vidya Sagar <vidyas@nvidia.com>
Cc: bhelgaas@google.com, lorenzo.pieralisi@arm.com,
thierry.reding@gmail.com, jonathanh@nvidia.com,
linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org,
kthota@nvidia.com, mmaddireddy@nvidia.com, sagar.tv@gmail.com
Subject: Re: [PATCH] PCI/MSI: Set device flag indicating only 32-bit MSI support
Date: Fri, 20 Nov 2020 15:30:36 -0600 [thread overview]
Message-ID: <20201120213036.GA278887@bjorn-Precision-5520> (raw)
In-Reply-To: <20201117145728.4516-1-vidyas@nvidia.com>
On Tue, Nov 17, 2020 at 08:27:28PM +0530, Vidya Sagar wrote:
> There are devices (Ex:- Marvell SATA controller) that don't support
> 64-bit MSIs and the same is advertised through their MSI capability
> register.
I *think* you're saying these devices behave correctly per spec: they
don't support 64-bit MSI, and they don't advertise support for 64-bit
MSI. Right?
> Set no_64bit_msi flag explicitly for such devices in the
> MSI setup code so that the msi_verify_entries() API would catch
> if the MSI arch code tries to use 64-bit MSI.
And you want msi_verify_entries() to catch attempts by the arch code
to assign a 64-bit MSI address?
That sounds OK, but the error message ("Device has broken 64-bit MSI")
is not appropriate if the device is actually *not* broken.
> Signed-off-by: Vidya Sagar <vidyas@nvidia.com>
> ---
> drivers/pci/msi.c | 6 ++++--
> 1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/pci/msi.c b/drivers/pci/msi.c
> index d52d118979a6..af49da28854e 100644
> --- a/drivers/pci/msi.c
> +++ b/drivers/pci/msi.c
> @@ -581,10 +581,12 @@ msi_setup_entry(struct pci_dev *dev, int nvec, struct irq_affinity *affd)
> entry->msi_attrib.multi_cap = (control & PCI_MSI_FLAGS_QMASK) >> 1;
> entry->msi_attrib.multiple = ilog2(__roundup_pow_of_two(nvec));
>
> - if (control & PCI_MSI_FLAGS_64BIT)
> + if (control & PCI_MSI_FLAGS_64BIT) {
> entry->mask_pos = dev->msi_cap + PCI_MSI_MASK_64;
> - else
> + } else {
> entry->mask_pos = dev->msi_cap + PCI_MSI_MASK_32;
> + dev->no_64bit_msi = 1;
> + }
>
> /* Save the initial mask status */
> if (entry->msi_attrib.maskbit)
> --
> 2.17.1
>
next prev parent reply other threads:[~2020-11-20 21:30 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-17 14:57 [PATCH] PCI/MSI: Set device flag indicating only 32-bit MSI support Vidya Sagar
2020-11-20 21:30 ` Bjorn Helgaas [this message]
2020-11-24 3:57 ` Vidya Sagar
2020-11-24 10:50 ` [PATCH V2] " Vidya Sagar
2020-12-03 5:00 ` Vidya Sagar
2020-12-03 18:24 ` Bjorn Helgaas
2020-12-03 19:03 ` Vidya Sagar
2020-12-03 19:54 ` Bjorn Helgaas
2020-12-04 2:28 ` Vidya Sagar
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