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[0/3] target/i386/cpu: Misc Cleanup on host-cache-info

Message ID 20240619144215.3273989-1-zhao1.liu@intel.com (mailing list archive)
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Series target/i386/cpu: Misc Cleanup on host-cache-info | expand

Message

Zhao Liu June 19, 2024, 2:42 p.m. UTC 
Hi,

This series is mainly to addresss Igor's comment about if one check in
host-cache-info could be removed [1], i.e., whether Guest's cache
topology should be self-consistent (able to correspond to Guest's CPU
topology level, as we currently do with the Guest cache topo).

I originally thought (in the mail thread with Igor) that host-cache-info
should allow Guest and Host to have the same topology level information,
e.g. if Host shares cache on core level, then via host-cache-info, Guest
should also share on core level.

But in practice, I gave up on this idea, because in the cache info
passthrough case, it should be possible for Guest to get the original
Host cache info (including the original threads sharing cache) without
further modifying the info to Guest.

Therefore, I simply added the comment in PATCH 3 to hopefully illustrate
the need for such a check.

Hope my explanation is clear enough so that my poor English doesn't
bother you!

[1]: https://lore.kernel.org/qemu-devel/20240527170317.14520a2f@imammedo.users.ipa.redhat.com/

Thanks and Best Regards,
Zhao
---
Zhao Liu (3):
  target/i386/cpu: Use hex mask to check for valid cache CPUID leaf
  target/i386/cpu: Check guest_thread_ids_per_pkg for host-cache-info
    case
  target/i386/cpu: Add comment about adjusting the Guest cache topo for
    host-cache-info

 target/i386/cpu.c | 24 +++++++++++++++++++-----
 1 file changed, 19 insertions(+), 5 deletions(-)