Re: [PATCH v2 0/2] Emulated AMD IOMMU cleanup and fixes

[Vasant Hegde <vasant.hegde@amd.com>]

Hi,


On 2/26/2025 8:52 PM, Michael Tokarev wrote:
> 26.02.2025 15:53, Vasant Hegde wrote:
>> Hi Michael,
> 
> Hi!
> 
>> On 2/25/2025 2:17 PM, Michael Tokarev wrote:
> ...>> Is this qemu-stable material (current series: 7.2, 8.2, 9.2)?
>>
>> Linux kernel doesn't use these changes. So its fine. But I believe we care for
>> other OS as well? if yes then better to backport.
> 
> Yes, we definitely care about other OSes.  There are numerous possible
> other questions though.  For example, how relevant these changes are
> for older 7.2.x series, where AMD IOMMU is in less current state (missing
> all further development) so might not be as relevant anymore.
> 
>>> 3684717b74 "amd_iommu: Use correct bitmask to set capability BAR" does
>>> not apply to 7.2, since v8.0.0-10-g6291a28645 "hw/i386/amd_iommu: Explicit
>>> use of AMDVI_BASE_ADDR in amdvi_init" in not in 7.2, but the change can be
>>> adjusted for 7.2 easily, or 6291a28645 can be picked up too.
>>
>> How is this works? You will pick it up -OR- you want us to backport and send it
>> to stable mailing list?
> 
> This is just a data point, nothing more.  Indicating that for 7.2, it needs some
> more work.  I picked it up for 7.2 already: https://gitlab.com/mjt0k/qemu/-/
> tree/staging-7.2

Thanks. Looks good.

> But this is more mechanical way, maybe you, who know this area much better than
> me, prefer other way, like picking up already mentioned commit 6291a28645.
> Or maybe it isn't worth the effort for 7.2 anyway, provided the issue isn't
> that important and it needs any additional work to back-port.
> 
> If you especially care about some older stable releases and think one or
> another change really needs to be there *and* needs some backporting work,
> you might do a backport yourself or give some notes for me to do that.
> 
> It's always a trade-off between "importance" of the change, age of the
> stable series, the amount of work needed for backporting, and possibility
> of breakage.  For less-important or less-used stuff, even thinking about
> this tradeoff is already too much work ;)

:-)

Thanks for detailed explanation. Next time, if its not applying cleanly we can
backport it and give it to you.

-Vasant