Re: [Qemu-devel] [PATCH] Clear RF on SYSCALL instruction

[Paolo Bonzini <pbonzini@redhat.com>]

On 19/10/2018 14:24, Roman Kapl wrote:
> From: Rudolf Marek <rudolf.marek@sysgo.com>
> 
> Fix the SYSCALL instruction in 64-bit (long mode). The RF flag
> should be cleared in R11 as well as in the RFLAGS. Intel
> and AMD CPUs behave same. AMD has this documented in the
> APM vol 3.
> 
> Signed-off-by: Roman Kapl <rka@sysgo.com>
> Signed-off-by: Rudolf Marek <rudolf.marek@sysgo.com>
> ---
>  target/i386/seg_helper.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/target/i386/seg_helper.c b/target/i386/seg_helper.c
> index 33714bc6e1..63e265cb38 100644
> --- a/target/i386/seg_helper.c
> +++ b/target/i386/seg_helper.c
> @@ -991,11 +991,11 @@ void helper_syscall(CPUX86State *env, int next_eip_addend)
>          int code64;
>  
>          env->regs[R_ECX] = env->eip + next_eip_addend;
> -        env->regs[11] = cpu_compute_eflags(env);
> +        env->regs[11] = cpu_compute_eflags(env) & ~RF_MASK;
>  
>          code64 = env->hflags & HF_CS64_MASK;
>  
> -        env->eflags &= ~env->fmask;
> +        env->eflags &= ~(env->fmask | RF_MASK);
>          cpu_load_eflags(env, env->eflags, 0);
>          cpu_x86_load_seg_cache(env, R_CS, selector & 0xfffc,
>                             0, 0xffffffff,
> 

Queued, thanks.

Paolo