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Re: [Qemu-devel] [PATCH] Clear RF on SYSCALL instruction
From: |
Paolo Bonzini |
Subject: |
Re: [Qemu-devel] [PATCH] Clear RF on SYSCALL instruction |
Date: |
Fri, 19 Oct 2018 14:27:07 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.0 |
On 19/10/2018 14:24, Roman Kapl wrote:
> From: Rudolf Marek <address@hidden>
>
> 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 <address@hidden>
> Signed-off-by: Rudolf Marek <address@hidden>
> ---
> 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