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Re: [PATCH] x86/shadow: Fix PV32 shadowing in !HVM builds
The OSSTest bisector identified an issue with c/s 1894049fa283 ("x86/shadow:
L2H shadow type is PV32-only") in !HVM builds.
The bug is ultimately caused by sh_type_to_size[] not actually being specific
to HVM guests, and it's position in shadow/hvm.c mislead the reasoning.
To fix the issue that OSSTest identified, SH_type_l2h_64_shadow must still
have the value 1 in any CONFIG_PV32 build. But simply adjusting this leaves
us with misleading logic, and a reasonable chance of making a related error
again in the future.
In hindsight, moving sh_type_to_size[] out of common.c in the first place a
mistake. Therefore, move sh_type_to_size[] back to living in common.c,
leaving a comment explaining why it happens to be inside an HVM conditional.
This effectively reverts the second half of 4fec945409fc ("x86/shadow: adjust
and move sh_type_to_size[]") while retaining the other improvements from the
same changeset.
While making this change, also adjust the sh_type_to_size[] declaration to
match its definition.
Fixes: 4fec945409fc ("x86/shadow: adjust and move sh_type_to_size[]")
Fixes: 1894049fa283 ("x86/shadow: L2H shadow type is PV32-only")
Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
I don't have super-strong opinions here; I'd be OK with any of the patches. But I tend to sympathize with Andrew's arguments re communicating what's going on.
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