Be more explicit that the loop must roll at least once. Avoids the
following warning:
FAILED: libqemu-x86_64-softmmu.fa.p/hw_i386_amd_iommu.c.o
In function 'pte_get_page_mask',
inlined from 'amdvi_page_walk' at hw/i386/amd_iommu.c:945:25,
inlined from 'amdvi_do_translate' at hw/i386/amd_iommu.c:989:5,
inlined from 'amdvi_translate' at hw/i386/amd_iommu.c:1038:5:
hw/i386/amd_iommu.c:877:38: error: 'oldlevel' may be used uninitialized [-Werror=maybe-uninitialized]
877 | return ~((1UL << ((oldlevel * 9) + 3)) - 1);
| ~~~~~~~~~~~~~~~~^~~~
hw/i386/amd_iommu.c: In function 'amdvi_translate':
hw/i386/amd_iommu.c:906:41: note: 'oldlevel' was declared here
906 | unsigned level, present, pte_perms, oldlevel;
| ^~~~~~~~
cc1: all warnings being treated as errors
Having:
$ gcc --version
gcc (Debian 12-20220313-1) 12.0.1 20220314 (experimental)
Reported-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
17e6ffa6a5