RE: Patch "PCI: hv: Fix multi-MSI to allow more than one MSI vector" has been added to the 5.18-stable tree

RE: Patch "PCI: hv: Fix multi-MSI to allow more than one MSI vector" has been added to the 5.18-stable tree

[Dexuan Cui]

> From: Sasha Levin <sashal@kernel.org>
> Sent: Monday, June 6, 2022 4:08 AM
> To: stable-commits@vger.kernel.org; quic_jhugo@quicinc.com
> Cc: KY Srinivasan <kys@microsoft.com>; Haiyang Zhang
> <haiyangz@microsoft.com>; Stephen Hemminger <sthemmin@microsoft.com>;
> Wei Liu <wei.liu@kernel.org>; Dexuan Cui <decui@microsoft.com>; Lorenzo
> Pieralisi <lorenzo.pieralisi@arm.com>; Rob Herring <robh@kernel.org>;
> Krzysztof Wilczyński <kw@linux.com>; Bjorn Helgaas <bhelgaas@google.com>
> Subject: Patch "PCI: hv: Fix multi-MSI to allow more than one MSI vector" has
> been added to the 5.18-stable tree
> 
> This is a note to let you know that I've just added the patch titled
> 
>     PCI: hv: Fix multi-MSI to allow more than one MSI vector

(+ stable@vger.kernel.org)

Hi Sasha and stable kernel maintainers,
If we want to support multi-MSI in the pci-hyperv driver, we need all of the
4 patches:

08e61e861a0e ("PCI: hv: Fix multi-MSI to allow more than one MSI vector")
455880dfe292 ("PCI: hv: Fix hv_arch_irq_unmask() for multi-MSI")
b4b77778ecc5 ("PCI: hv: Reuse existing IRTE allocation in compose_msi_msg()")
a2bad844a67b ("PCI: hv: Fix interrupt mapping for multi-MSI")

Multi-MSI can't work properly if we only pick up the first patch.

We need to either pick up all the 4 patches to 5.18/5.17/etc. or pick up nothing.
I suggest we pick up all the 4 patches. 
The patch author Jeffrey may want to chime in.

Thanks,
-- Dexuan

Re: Patch "PCI: hv: Fix multi-MSI to allow more than one MSI vector" has been added to the 5.18-stable tree

[Sasha Levin]

On Mon, Jun 06, 2022 at 05:02:41PM +0000, Dexuan Cui wrote:
>> From: Sasha Levin <sashal@kernel.org>
>> Sent: Monday, June 6, 2022 4:08 AM
>> To: stable-commits@vger.kernel.org; quic_jhugo@quicinc.com
>> Cc: KY Srinivasan <kys@microsoft.com>; Haiyang Zhang
>> <haiyangz@microsoft.com>; Stephen Hemminger <sthemmin@microsoft.com>;
>> Wei Liu <wei.liu@kernel.org>; Dexuan Cui <decui@microsoft.com>; Lorenzo
>> Pieralisi <lorenzo.pieralisi@arm.com>; Rob Herring <robh@kernel.org>;
>> Krzysztof Wilczyński <kw@linux.com>; Bjorn Helgaas <bhelgaas@google.com>
>> Subject: Patch "PCI: hv: Fix multi-MSI to allow more than one MSI vector" has
>> been added to the 5.18-stable tree
>>
>> This is a note to let you know that I've just added the patch titled
>>
>>     PCI: hv: Fix multi-MSI to allow more than one MSI vector
>
>(+ stable@vger.kernel.org)
>
>Hi Sasha and stable kernel maintainers,
>If we want to support multi-MSI in the pci-hyperv driver, we need all of the
>4 patches:
>
>08e61e861a0e ("PCI: hv: Fix multi-MSI to allow more than one MSI vector")
>455880dfe292 ("PCI: hv: Fix hv_arch_irq_unmask() for multi-MSI")
>b4b77778ecc5 ("PCI: hv: Reuse existing IRTE allocation in compose_msi_msg()")
>a2bad844a67b ("PCI: hv: Fix interrupt mapping for multi-MSI")
>
>Multi-MSI can't work properly if we only pick up the first patch.
>
>We need to either pick up all the 4 patches to 5.18/5.17/etc. or pick up nothing.
>I suggest we pick up all the 4 patches.
>The patch author Jeffrey may want to chime in.

Hey Dexuan,

I wasn't trying to enable multi-MSI, I was just picking something that
looked like a fix. I'll go ahead and drop it, thanks!

-- 
Thanks,
Sasha

Re: Patch "PCI: hv: Fix multi-MSI to allow more than one MSI vector" has been added to the 5.18-stable tree

[Jeffrey Hugo]

On 6/7/2022 5:05 AM, Sasha Levin wrote:
> On Mon, Jun 06, 2022 at 05:02:41PM +0000, Dexuan Cui wrote:
>>> From: Sasha Levin <sashal@kernel.org>
>>> Sent: Monday, June 6, 2022 4:08 AM
>>> To: stable-commits@vger.kernel.org; quic_jhugo@quicinc.com
>>> Cc: KY Srinivasan <kys@microsoft.com>; Haiyang Zhang
>>> <haiyangz@microsoft.com>; Stephen Hemminger <sthemmin@microsoft.com>;
>>> Wei Liu <wei.liu@kernel.org>; Dexuan Cui <decui@microsoft.com>; Lorenzo
>>> Pieralisi <lorenzo.pieralisi@arm.com>; Rob Herring <robh@kernel.org>;
>>> Krzysztof Wilczyński <kw@linux.com>; Bjorn Helgaas <bhelgaas@google.com>
>>> Subject: Patch "PCI: hv: Fix multi-MSI to allow more than one MSI 
>>> vector" has
>>> been added to the 5.18-stable tree
>>>
>>> This is a note to let you know that I've just added the patch titled
>>>
>>>     PCI: hv: Fix multi-MSI to allow more than one MSI vector
>>
>> (+ stable@vger.kernel.org)
>>
>> Hi Sasha and stable kernel maintainers,
>> If we want to support multi-MSI in the pci-hyperv driver, we need all 
>> of the
>> 4 patches:
>>
>> 08e61e861a0e ("PCI: hv: Fix multi-MSI to allow more than one MSI vector")
>> 455880dfe292 ("PCI: hv: Fix hv_arch_irq_unmask() for multi-MSI")
>> b4b77778ecc5 ("PCI: hv: Reuse existing IRTE allocation in 
>> compose_msi_msg()")
>> a2bad844a67b ("PCI: hv: Fix interrupt mapping for multi-MSI")
>>
>> Multi-MSI can't work properly if we only pick up the first patch.
>>
>> We need to either pick up all the 4 patches to 5.18/5.17/etc. or pick 
>> up nothing.
>> I suggest we pick up all the 4 patches.
>> The patch author Jeffrey may want to chime in.
> 
> Hey Dexuan,
> 
> I wasn't trying to enable multi-MSI, I was just picking something that
> looked like a fix. I'll go ahead and drop it, thanks!
> 

IMO it is a fix to an existing feature - not adding a new one.  The 
driver enables Multi-MSI, advertises the support, but it doesn't work. 
The changes fix the driver so it actually works.

It would be my preference for these to be backported.  Ideally the 
distros would then pick them up, and it would make support easier.