Re: preparations for 4.17.4

[Andrew Cooper <andrew.cooper3@xxxxxxxxxx>]

On 27/03/2024 12:33 pm, Andrew Cooper wrote:
> On 27/03/2024 12:23 pm, Jan Beulich wrote:
>> All,
>>
>> the release is due in two to three weeks. Please point out backports you find
>> missing from the respective staging branch, but which you consider relevant.
>>
>> Note that this is going to be the last Xen Project coordinated ordinary 
>> stable
>> release from this branch; the branch will move into security-only support 
>> mode
>> afterwards.
> 1) livepatching of .rodata:
>
> 989556c6f8ca - xen/virtual-region: Rename the start/end fields
> ef969144a425 - xen/virtual-region: Include rodata pointers
> b083b1c393dc - x86/livepatch: Relax permissions on rodata too
>
> And technically "x86/mm: fix detection of last L1 entry in
> modify_xen_mappings_lite()" too but you've already backported this one.
>
> Patching .rodata worked before Xen 4.17, and was broken (left as a TODO)
> when I adjusted Xen to stop using CR0.WP=0 for patching.
>
>
> 2) Policy fixes:
>
> e2d8a6522516 - x86/cpu-policy: Fix visibility of HTT/CMP_LEGACY in max
> policies
>
> This is a real bugfix for a real regression we found updating from Xen
> 4.13 -> 4.17.  It has a dependency on
>
> 5420aa165dfa - x86/cpu-policy: Hide x2APIC from PV guests
>
> which I know you had more concern with.  FWIW, I'm certain its a good
> fix, and should be backported.
>
>
> 3) Test fixes:
>
> 0263dc9069dd - tests/resource: Fix HVM guest in !SHADOW builds
>
> It's minor, but does make a difference for those of us who run these
> tests regularly.
>
>
> 4) Watchdog fixes:
>
> 9e18f339830c - x86/boot: Improve the boot watchdog determination of
> stuck cpus
> 131892e0dcc1 - x86/boot: Support the watchdog on newer AMD systems
>
> You took "x86/boot: Fix setup_apic_nmi_watchdog() to fail more cleanly"
> and the first of the two patches is in the same category IMO.  The
> second I also feel ok to take for the in-support releases, particularly
> as all it is doing is dropping a family list.
>
>
> 5) Ucode scan stability  (For 4.18 only)
>
> Xen 4.18 had "x86/ucode: Refresh raw CPU policy after microcode load" in
> it's .0 release, so should also gain:
>
> cf7fe8b72dea - x86/ucode: Fix stability of the raw CPU Policy rescan
>
> I've only noticed because I've got them both backported to 4.17 in
> XenServer, but I don't think upstream wants to take that route.

It occurs to me that these want considering:

b6cf604207fd - tools/oxenstored: Use Map instead of Hashtbl for quotas
098d868e52ac - tools/oxenstored: Make Quota.t pure

while 4.17 is still in general support.  These came from a performance
regression we investigated.

I've done the backport to 4.17 and they're not entirely trivial (owing
to the major source reformat in 4.18) so can commit them if you'd prefer.

~Andrew