[Bug] x86 EFLAGS refresh is not happening correctly

[Stevie Lavern]

Hello,

I'm posting this here instead of opening an issue as it is not clear to me if this is a bug or not.

The issue is located in function "cpu_compute_eflags" in target/i386/cpu.h

(https://gitlab.com/qemu-project/qemu/-/blob/master/target/i386/cpu.h#L2071)

This function is exectued in an out of cpu loop context.

It is used to synchronize TCG internal eflags registers (CC_OP, CC_SRC,  etc...) with the CPU eflags field upon loop exit.

It does:

    eflags |= cpu_cc_compute_all(env, CC_OP) | (env->df & DF_MASK);

Shouldn't it be:

     eflags = cpu_cc_compute_all(env, CC_OP) | (env->df & DF_MASK);

as eflags is entirely reevaluated by "cpu_cc_compute_all" ?

Thanks,

Kind regards,

Stevie