From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:46272) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dSeWX-0004Ml-OE for qemu-devel@nongnu.org; Wed, 05 Jul 2017 03:14:59 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1dSeWW-0007RR-Cw for qemu-devel@nongnu.org; Wed, 05 Jul 2017 03:14:57 -0400 Received: from mail-wm0-x241.google.com ([2a00:1450:400c:c09::241]:33116) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1dSeWW-0007QX-6Y for qemu-devel@nongnu.org; Wed, 05 Jul 2017 03:14:56 -0400 Received: by mail-wm0-x241.google.com with SMTP id j85so30446722wmj.0 for ; Wed, 05 Jul 2017 00:14:56 -0700 (PDT) Received: from 640k.lan (94-39-191-51.adsl-ull.clienti.tiscali.it. [94.39.191.51]) by smtp.gmail.com with ESMTPSA id y35sm22202793wrc.51.2017.07.05.00.14.54 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 05 Jul 2017 00:14:54 -0700 (PDT) Sender: Paolo Bonzini From: Paolo Bonzini Date: Wed, 5 Jul 2017 09:14:08 +0200 Message-Id: <1499238885-26161-6-git-send-email-pbonzini@redhat.com> In-Reply-To: <1499238885-26161-1-git-send-email-pbonzini@redhat.com> References: <1499238885-26161-1-git-send-email-pbonzini@redhat.com> Subject: [Qemu-devel] [PULL 05/42] target/i386: simplify handling of conforming code segments on interrupt List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Move the handling of conforming code segments before the handling of stack switch. Because dpl == cpl after the new "if", it's now unnecessary to check the C bit when testing dpl < cpl. Furthermore, dpl > cpl is checked slightly above the modified code, so the final "else" is unreachable and we can remove it. Signed-off-by: Paolo Bonzini --- target/i386/seg_helper.c | 28 ++++++++++------------------ 1 file changed, 10 insertions(+), 18 deletions(-) diff --git a/target/i386/seg_helper.c b/target/i386/seg_helper.c index 9af69c2..600a4d7 100644 --- a/target/i386/seg_helper.c +++ b/target/i386/seg_helper.c @@ -692,7 +692,10 @@ static void do_interrupt_protected(CPUX86State *env, int intno, int is_int, if (!(e2 & DESC_P_MASK)) { raise_exception_err(env, EXCP0B_NOSEG, selector & 0xfffc); } - if (!(e2 & DESC_C_MASK) && dpl < cpl) { + if (e2 & DESC_C_MASK) { + dpl = cpl; + } + if (dpl < cpl) { /* to inner privilege */ get_ss_esp_from_tss(env, &ss, &esp, dpl, 0); if ((ss & 0xfffc) == 0) { @@ -719,7 +722,7 @@ static void do_interrupt_protected(CPUX86State *env, int intno, int is_int, new_stack = 1; sp_mask = get_sp_mask(ss_e2); ssp = get_seg_base(ss_e1, ss_e2); - } else if ((e2 & DESC_C_MASK) || dpl == cpl) { + } else { /* to same privilege */ if (vm86) { raise_exception_err(env, EXCP0D_GPF, selector & 0xfffc); @@ -728,13 +731,6 @@ static void do_interrupt_protected(CPUX86State *env, int intno, int is_int, sp_mask = get_sp_mask(env->segs[R_SS].flags); ssp = env->segs[R_SS].base; esp = env->regs[R_ESP]; - dpl = cpl; - } else { - raise_exception_err(env, EXCP0D_GPF, selector & 0xfffc); - new_stack = 0; /* avoid warning */ - sp_mask = 0; /* avoid warning */ - ssp = 0; /* avoid warning */ - esp = 0; /* avoid warning */ } shift = type >> 3; @@ -919,25 +915,21 @@ static void do_interrupt64(CPUX86State *env, int intno, int is_int, if (!(e2 & DESC_L_MASK) || (e2 & DESC_B_MASK)) { raise_exception_err(env, EXCP0D_GPF, selector & 0xfffc); } - if ((!(e2 & DESC_C_MASK) && dpl < cpl) || ist != 0) { + if (e2 & DESC_C_MASK) { + dpl = cpl; + } + if (dpl < cpl || ist != 0) { /* to inner privilege */ new_stack = 1; esp = get_rsp_from_tss(env, ist != 0 ? ist + 3 : dpl); ss = 0; - } else if ((e2 & DESC_C_MASK) || dpl == cpl) { + } else { /* to same privilege */ if (env->eflags & VM_MASK) { raise_exception_err(env, EXCP0D_GPF, selector & 0xfffc); } new_stack = 0; esp = env->regs[R_ESP]; - } else { - raise_exception_err(env, EXCP0D_GPF, selector & 0xfffc); - new_stack = 0; /* avoid warning */ - esp = 0; /* avoid warning */ - } - if (e2 & DESC_C_MASK) { - dpl = cpl; } esp &= ~0xfLL; /* align stack */ -- 1.8.3.1