target/i386: Clear RF on SYSCALL instruction

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>
Message-Id: <20181019122449.26387-1-rka@sysgo.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/target/i386/seg_helper.c b/target/i386/seg_helper.c
index 33714bc6e131262940a1bc51b4db3299cb119517..63e265cb38e0e5adc92ce08c3d78414491a5714a 100644 (file)
--- 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,