On 03.05.2025 01:49, victorm.l...@amd.com wrote:
> From: Nicola Vetrini <nicola.vetr...@bugseng.com>
>
> Rule 19.1 states: "An object shall not be assigned or copied
> to an overlapping object". In the function like macro "get_rep_prefix",
> one member of a union is assigned the value of another member. Reading from
> one
> member and writing to the other violates the rule, while not causing Undefined
> Behavior due to their relative sizes. Instead, use casts combined with exactly
> overlapping accesses to address violations.
>
> No functional change.
>
> Signed-off-by: Nicola Vetrini <nicola.vetr...@bugseng.com>
> Signed-off-by: Federico Serafini <federico.seraf...@bugseng.com>
> Signed-off-by: Victor Lira <victorm.l...@amd.com>
Reviewed-by: Jan Beulich <jbeul...@suse.com>
albeit strictly speaking the description covers only ...
> --- a/xen/arch/x86/x86_emulate/x86_emulate.c
> +++ b/xen/arch/x86/x86_emulate/x86_emulate.c
> @@ -527,8 +527,8 @@ static inline void put_loop_count(
> if ( !amd_like(ctxt) && mode_64bit() && ad_bytes == 4 ) \
> { \
> _regs.r(cx) = 0; \
> - if ( extend_si ) _regs.r(si) = _regs.esi; \
> - if ( extend_di ) _regs.r(di) = _regs.edi; \
> + if ( extend_si ) _regs.r(si) = (uint32_t)_regs.r(si); \
> + if ( extend_di ) _regs.r(di) = (uint32_t)_regs.r(di); \
> } \
> goto complete_insn; \
> } \
... this hunk, but not ...
> @@ -2029,7 +2029,7 @@ x86_emulate(
> switch ( op_bytes )
> {
> case 2: _regs.ax = (int8_t)_regs.ax; break; /* cbw */
> - case 4: _regs.r(ax) = (uint32_t)(int16_t)_regs.ax; break; /* cwde */
> + case 4: _regs.r(ax) = (uint32_t)(int16_t)_regs.r(ax); break; /* cwde
> */
> case 8: _regs.r(ax) = (int32_t)_regs.r(ax); break; /* cdqe */
> }
> break;
... this one.
Also the padding of the backslashes ought to be adjusted, which I guess I'll
do while committing.
Jan
