On Thu, Aug 20, 2026 at 8:52 PM Philippe Mathieu-Daudé <[email protected]> wrote: > > On 2026-08-20 18:24, Philippe Mathieu-Daudé wrote: > > On 2026-08-20 17:21, Richard Henderson wrote: > >> On 8/20/26 03:47, Philippe Mathieu-Daudé wrote: > >>> Introduce const-qualified variants of cpu_env() and > >>> env_archcpu(), to safely access CPU architecture > >>> state when it should not be modified. > >>> > >>> Signed-off-by: Philippe Mathieu-Daudé <[email protected]> > >>> --- > >>> include/exec/cpu-common.h | 11 +++++++++++ > >>> include/hw/core/cpu.h | 6 ++++++ > >>> 2 files changed, 17 insertions(+) > >>> > >>> diff --git a/include/exec/cpu-common.h b/include/exec/cpu-common.h > >>> index 6594f7fa1be..f3a3799f451 100644 > >>> --- a/include/exec/cpu-common.h > >>> +++ b/include/exec/cpu-common.h > >>> @@ -79,6 +79,17 @@ static inline bool cpu_loop_exit_requested(const > >>> CPUState *cpu) > >>> } > >>> #endif /* CONFIG_TCG */ > >>> +/** > >>> + * env_archcpu_const(env) > >>> + * @env: The architecture environment (const). > >>> + * > >>> + * Return the const ArchCPU associated with the environment. > >>> + */ > >>> +static inline const ArchCPU *env_archcpu_const(const CPUArchState *env) > >>> +{ > >>> + return (const void *)env - sizeof(CPUState); > >>> +} > >>> + > >>> /** > >>> * env_archcpu(env) > >>> * @env: The architecture environment > >>> diff --git a/include/hw/core/cpu.h b/include/hw/core/cpu.h > >>> index 81af7b9ee1a..59f777f3f15 100644 > >>> --- a/include/hw/core/cpu.h > >>> +++ b/include/hw/core/cpu.h > >>> @@ -594,6 +594,12 @@ struct CPUState { > >>> QEMU_BUILD_BUG_ON(offsetof(CPUState, neg) != > >>> sizeof(CPUState) - sizeof(CPUNegativeOffsetState)); > >>> +static inline const CPUArchState *cpu_env_const(const CPUState *cpu) > >>> +{ > >>> + /* We validate that CPUArchState follows CPUState in cpu- > >>> target.c */ > >>> + return (const CPUArchState *)(cpu + 1); > >>> +} > >>> + > >>> static inline CPUArchState *cpu_env(CPUState *cpu) > >>> { > >>> /* We validate that CPUArchState follows CPUState in cpu- > >>> target.c */ > >> > >> I wonder if we can use _Generic to make this automatic, rather than > >> have to choose between two different function names. > > Eh clever :) This seems to work: > > > > #define env_archcpu_(p) _Generic(*(p), \ > > CPUArchState: (void *)p, \ > > const CPUArchState: (const void *)p) > > Actually simpler and even well readable: > > -- >8 -- > diff --git a/include/exec/cpu-common.h b/include/exec/cpu-common.h > index 6594f7fa1b..d67d008236 100644 > --- a/include/exec/cpu-common.h > +++ b/include/exec/cpu-common.h > @@ -85,21 +85,11 @@ static inline bool cpu_loop_exit_requested(const > CPUState *cpu) > * > * Return the ArchCPU associated with the environment. > */ > -static inline ArchCPU *env_archcpu(CPUArchState *env) > -{ > - return (void *)env - sizeof(CPUState); > -} > - > -/** > - * env_cpu_const(env) > - * @env: The architecture environment > - * > - * Return the CPUState associated with the environment. > - */ > -static inline const CPUState *env_cpu_const(const CPUArchState *env) > -{ > - return (void *)env - sizeof(CPUState); > -} > +#define env_archcpu(env) _Generic(*(env), \ > + CPUArchState: \ > + (ArchCPU *)((void *)env - sizeof(CPUState)), \ > + const CPUArchState: \ > + (const ArchCPU *)((const void *)env - sizeof(CPUState))) > > /** > * env_cpu(env) > @@ -107,9 +97,10 @@ static inline const CPUState *env_cpu_const(const > CPUArchState *env) > * > * Return the CPUState associated with the environment. > */ > -static inline CPUState *env_cpu(CPUArchState *env) > -{ > - return (CPUState *)env_cpu_const(env); > -} > +#define env_cpu(env) _Generic(*(env), \ > + CPUArchState: \ > + (CPUState *)((void *)env - sizeof(CPUState)), \ > + const CPUArchState: \ > + (const CPUState *)((const void *)env - sizeof(CPUState))) > > #endif /* CPU_COMMON_H */ > --- >
lgtm too Reviewed-by: Marc-André Lureau <[email protected]> -- Marc-André Lureau
