[PATCH 0/7] qemu: Fix broken qemu caps cache invalidation

[Jiri Denemark]

On Mon, Apr 25, 2022 at 15:28:24 +0200, Peter Krempa wrote:
> Bugs in the code meant to invalidate the qemu capabilities cache
> resulted in us always re-probing capabilities on startup of
> libvirtd/virtqemud. This got extremely annoying with the modern
> deployments using --timeout.
> 
> Apart from issues in inserting the detected features, it also turns out
> that AMD boxes report data which changes based on which CPU the
> instruction happened to execute, so we need to mask that out.
> 
> Peter Krempa (7):
>   virCPUx86DataIsIdentical: Add debug output
>   virCPUx86DataGetHost: Fix construction of the returned data
>   virHostCPUGetCPUID: Add comment on how KVM_GET_SUPPORTED_CPUID works
>   util: virhostcpu: Extract filtering of the returned data from
>     virHostCPUGetCPUID
>   virHostCPUGetCPUID: Fix possible allocation of huge amount of memory
>   virHostCPUGetCPUID: Limit the buffer size ranges
>   virHostCPUGetCPUIDFilterVolatile: Filter out topology data on AMD
> 
>  src/cpu/cpu_x86.c     |  31 ++++++++++---
>  src/util/virhostcpu.c | 104 ++++++++++++++++++++++++++++++++++++------
>  2 files changed, 116 insertions(+), 19 deletions(-)

Wow, KVM_GET_SUPPORTED_CPUID has a very unfriendly semantics.

Reviewed-by: Jiri Denemark <jdenemar at redhat.com>