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Andrew Cooper
2eed83a9aa
x86_cpuid_copy_to_buffer() currently serialises the full content of the
various subleaf unions. While leaves 4, 0xb and 0xd don't have a concrete
max_subleaf field, they do have well defined upper bounds.
Diffing the results of `xen-cpuid -p` shows the resulting saving:
@@ -1,5 +1,5 @@
Xen reports there are maximum 114 leaves and 1 MSRs
-Raw policy: 93 leaves, 1 MSRs
+Raw policy: 38 leaves, 1 MSRs
CPUID:
leaf subleaf -> eax ebx ecx edx
00000000:ffffffff -> 00000016:756e6547:6c65746e:49656e69
@@ -32,7 +32,7 @@ Raw policy: 93 leaves, 1 MSRs
MSRs:
index -> value
000000ce -> 0000000080000000
-Host policy: 93 leaves, 1 MSRs
+Host policy: 33 leaves, 1 MSRs
CPUID:
leaf subleaf -> eax ebx ecx edx
00000000:ffffffff -> 0000000d:756e6547:6c65746e:49656e69
which is mostly due to no longer writing out 64 leaves for xstate when (on
this CoffeeLake system) 8 will do.
Extend the unit tests to cover empty and partially filled subleaf unions.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>