Please cherry-pick this commit to v5.15.y, 5.10.y and 5.4.y: 23e118a48acf ("PCI: hv: Do not set PCI_COMMAND_MEMORY to reduce VM boot time")

Please cherry-pick this commit to v5.15.y, 5.10.y and 5.4.y: 23e118a48acf ("PCI: hv: Do not set PCI_COMMAND_MEMORY to reduce VM boot time")

[Dexuan Cui]

Hi, 
The commit has been in v6.1.y for 3+ years (but not in the 5.x stable branches):
        23e118a48acf ("PCI: hv: Do not set PCI_COMMAND_MEMORY to reduce VM boot time")

The commit can be cherry-picked cleanly to the latest 5.x stable branches, i.e. 5.15.185, 5.10.238 and 5.4.294.

Some Linux distro kernels are still based on the 5.x stable branches, and they have been carrying the commit explicitly. It would be great to have the commit in the upstream 5.x branches, so they don't have to carry the commit explicitly.

There is a Debian 10.3 user who wants the commit, but the commit is absent from Debian 10.3's kernel, whose full version string is:
	Linux version 5.10.0-0.deb10.30-amd64 (debian-kernel@lists.debian.org) (gcc-8 (Debian 8.3.0-6) 8.3.0, GNU ld (GNU Binutils for Debian) 2.31.1) #1 SMP Debian 5.10.218-1~deb10u1 (2024-06-12)

If the commit is cherry-picked into the upstream 5.10.y, the next Debian 10.3 kernel update would have the commit automatically.

Thanks!
-- Dexuan

Re: Please cherry-pick this commit to v5.15.y, 5.10.y and 5.4.y: 23e118a48acf ("PCI: hv: Do not set PCI_COMMAND_MEMORY to reduce VM boot time")

[Greg KH]

On Wed, Jun 25, 2025 at 06:05:26AM +0000, Dexuan Cui wrote:
> Hi, 
> The commit has been in v6.1.y for 3+ years (but not in the 5.x stable branches):
>         23e118a48acf ("PCI: hv: Do not set PCI_COMMAND_MEMORY to reduce VM boot time")
> 
> The commit can be cherry-picked cleanly to the latest 5.x stable branches, i.e. 5.15.185, 5.10.238 and 5.4.294.

It adds a new build warning on 5.4.y, so I will not apply it there,
sorry.  Will go apply it to 5.10.y and 5.15.y for now.

thanks,

greg k-h

RE: [EXTERNAL] Re: Please cherry-pick this commit to v5.15.y, 5.10.y and 5.4.y: 23e118a48acf ("PCI: hv: Do not set PCI_COMMAND_MEMORY to reduce VM boot time")

[Dexuan Cui]

> From: Greg KH <gregkh@linuxfoundation.org>
> Sent: Wednesday, July 2, 2025 1:08 AM
> To: Dexuan Cui <decui@microsoft.com>
> Cc: Stable <stable@vger.kernel.org>; Long Li <longli@microsoft.com>
> Subject: [EXTERNAL] Re: Please cherry-pick this commit to v5.15.y, 5.10.y and
> 5.4.y: 23e118a48acf ("PCI: hv: Do not set PCI_COMMAND_MEMORY to
> reduce VM boot time")
> 
> On Wed, Jun 25, 2025 at 06:05:26AM +0000, Dexuan Cui wrote:
> > Hi,
> > The commit has been in v6.1.y for 3+ years (but not in the 5.x stable
> > branches):
> >         23e118a48acf ("PCI: hv: Do not set PCI_COMMAND_MEMORY to
> > reduce VM boot time")
> >
> > The commit can be cherry-picked cleanly to the latest 5.x stable branches,
> > i.e. 5.15.185, 5.10.238 and 5.4.294.
> 
> It adds a new build warning on 5.4.y, so I will not apply it there,
> sorry.  Will go apply it to 5.10.y and 5.15.y for now.

Out of curiosity, I built 5.4.y plus the commit and got this warning:

drivers/pci/controller//pci-hyperv.c: In function 'prepopulate_bars':
drivers/pci/controller//pci-hyperv.c:1731:13: warning: unused variable 'command' [-Wunused-variable]

I think 5.4.y lacks another commit made in 2019:
ac82fc832708 ("PCI: hv: Add hibernation support")
but definitely we don't want to pull this commit into 5.4.y.

> thanks,
> 
> greg k-h

I guess this requested commit doesn't really need to go into 5.4.y,
which I suppose isn't used widely any more. I listed it just for
completeness :-)

Thank you Greg for applying the commit into 5.10.y and 5.15.y!

Thanks,
Dexuan

Re: [EXTERNAL] Re: Please cherry-pick this commit to v5.15.y, 5.10.y and 5.4.y: 23e118a48acf ("PCI: hv: Do not set PCI_COMMAND_MEMORY to reduce VM boot time")

[Greg KH]

On Thu, Jul 03, 2025 at 01:15:47AM +0000, Dexuan Cui wrote:
> 
> > From: Greg KH <gregkh@linuxfoundation.org>
> > Sent: Wednesday, July 2, 2025 1:08 AM
> > To: Dexuan Cui <decui@microsoft.com>
> > Cc: Stable <stable@vger.kernel.org>; Long Li <longli@microsoft.com>
> > Subject: [EXTERNAL] Re: Please cherry-pick this commit to v5.15.y, 5.10.y and
> > 5.4.y: 23e118a48acf ("PCI: hv: Do not set PCI_COMMAND_MEMORY to
> > reduce VM boot time")
> > 
> > On Wed, Jun 25, 2025 at 06:05:26AM +0000, Dexuan Cui wrote:
> > > Hi,
> > > The commit has been in v6.1.y for 3+ years (but not in the 5.x stable
> > > branches):
> > >         23e118a48acf ("PCI: hv: Do not set PCI_COMMAND_MEMORY to
> > > reduce VM boot time")
> > >
> > > The commit can be cherry-picked cleanly to the latest 5.x stable branches,
> > > i.e. 5.15.185, 5.10.238 and 5.4.294.
> > 
> > It adds a new build warning on 5.4.y, so I will not apply it there,
> > sorry.  Will go apply it to 5.10.y and 5.15.y for now.
> 
> Out of curiosity, I built 5.4.y plus the commit and got this warning:
> 
> drivers/pci/controller//pci-hyperv.c: In function 'prepopulate_bars':
> drivers/pci/controller//pci-hyperv.c:1731:13: warning: unused variable 'command' [-Wunused-variable]
> 
> I think 5.4.y lacks another commit made in 2019:
> ac82fc832708 ("PCI: hv: Add hibernation support")
> but definitely we don't want to pull this commit into 5.4.y.
> 
> > thanks,
> > 
> > greg k-h
> 
> I guess this requested commit doesn't really need to go into 5.4.y,
> which I suppose isn't used widely any more. I listed it just for
> completeness :-)

If you really want it in 5.4.y, please provide a version that doesn't
add the warning :)

RE: [EXTERNAL] Re: Please cherry-pick this commit to v5.15.y, 5.10.y and 5.4.y: 23e118a48acf ("PCI: hv: Do not set PCI_COMMAND_MEMORY to reduce VM boot time")

[Dexuan Cui]

> From: Greg KH <gregkh@linuxfoundation.org>
> Sent: Wednesday, July 2, 2025 10:14 PM
> > ...
> > I guess this requested commit doesn't really need to go into 5.4.y,
> > which I suppose isn't used widely any more. I listed it just for
> > completeness :-)
> 
> If you really want it in 5.4.y, please provide a version that doesn't
> add the warning :)

I don't really want it in 5.4.y. It's good enough to me for the commit
to be in 5.15 and 5.10.

Thanks,
Dexuan