On 14/12/24 06:29, Richard Henderson wrote:
On 12/13/24 21:44, Pierrick Bouvier wrote:
Hi Richard,
On 12/13/24 13:47, Richard Henderson wrote:
Hi,
Several of the recent contrib/plugins/ patches do not build on e.g.
arm32.
All of the issues are related to casting between pointers and
uint64_t; there is a Werror
generated for casting between pointers and integers of different sizes.
I suspect all of the instances will need to use separate structures
to store uint64_t
within the hash tables. The hash values themselves can use
uintptr_t, as "hash" by
definition loses data.
The following is *not* a suggested patch, just touches every place
with an error to
highlight all of the places.
This is something I already tried to fix this way, but alas, casting
values is not enough, we might lose information (in the case where
guest is 64 bits). Some plugins need a refactoring to allocate data
dynamically, instead of hiding it under a pointer.
See this previous series:
https://patchew.org/QEMU/20240814233645.944327-1-
pierrick.bouv...@linaro.org/
Finally, we discussed it was not worth the effort, and Alex simply
deactivated plugins by default for 32 bits platform, so it should not
be built for arm 32 bits. If we really have someone that needs this
usecase, we might make the effort, but for now, it does not seem worth
the hassle.
This is:
commit cf2a78cbbb463d5716da9805c8fc5758937924d8
Author: Alex Bennée <alex.ben...@linaro.org>
Date: Mon Sep 16 09:53:43 2024 +0100
deprecation: don't enable TCG plugins by default on 32 bit hosts
The existing plugins already liberally use host pointer stuffing for
passing user data which will fail when doing 64 bit guests on 32 bit
hosts. We should discourage this by officially deprecating support and
adding another nail to the 32 bit host coffin.
...
+TCG Plugin support not enabled by default on 32-bit hosts (since 9.2)
+'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
...
-if test "$plugins" != "no"; then
+if test "$plugins" != "no" && test $host_bits -eq 64; then
plugins=yes
Hmm. I didn't delete my 32-bit build tree, but it certainly re-
configured. If plugins are supposed to be disabled, something may be
wrong there...
r~
