From nobody Tue Nov 18 17:37:52 2025 Delivered-To: importer@patchew.org Authentication-Results: mx.zohomail.com; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org Return-Path: Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) by mx.zohomail.com with SMTPS id 1716798578845812.1970190950133; Mon, 27 May 2024 01:29:38 -0700 (PDT) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1sBVeN-0003ul-Cc; Mon, 27 May 2024 04:24:11 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1sBVdG-0001LL-0d; Mon, 27 May 2024 04:23:03 -0400 Received: from isrv.corpit.ru ([86.62.121.231]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1sBVdE-0000sV-9N; Mon, 27 May 2024 04:23:01 -0400 Received: from tsrv.corpit.ru (tsrv.tls.msk.ru [192.168.177.2]) by isrv.corpit.ru (Postfix) with ESMTP id C64476A56F; Mon, 27 May 2024 11:22:13 +0300 (MSK) Received: from tls.msk.ru (mjt.wg.tls.msk.ru [192.168.177.130]) by tsrv.corpit.ru (Postfix) with SMTP id F170CD850C; Mon, 27 May 2024 11:21:39 +0300 (MSK) Received: (nullmailer pid 66406 invoked by uid 1000); Mon, 27 May 2024 08:21:38 -0000 From: Michael Tokarev To: qemu-devel@nongnu.org Cc: qemu-stable@nongnu.org, Ruihan Li , Richard Henderson , Paolo Bonzini , Michael Tokarev Subject: [Stable-9.0.1 18/44] target/i386: Give IRQs a chance when resetting HF_INHIBIT_IRQ_MASK Date: Mon, 27 May 2024 11:21:09 +0300 Message-Id: <20240527082138.66217-18-mjt@tls.msk.ru> X-Mailer: git-send-email 2.39.2 In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Received-SPF: pass client-ip=86.62.121.231; envelope-from=mjt@tls.msk.ru; helo=isrv.corpit.ru X-Spam_score_int: -68 X-Spam_score: -6.9 X-Spam_bar: ------ X-Spam_report: (-6.9 / 5.0 requ) BAYES_00=-1.9, RCVD_IN_DNSWL_HI=-5, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: qemu-devel-bounces+importer=patchew.org@nongnu.org X-ZM-MESSAGEID: 1716798581108100003 Content-Type: text/plain; charset="utf-8" From: Ruihan Li When emulated with QEMU, interrupts will never come in the following loop. However, if the NOP instruction is uncommented, interrupts will fire as normal. loop: cli call do_sti jmp loop do_sti: sti # nop ret This behavior is different from that of a real processor. For example, if KVM is enabled, interrupts will always fire regardless of whether the NOP instruction is commented or not. Also, the Intel Software Developer Manual states that after the STI instruction is executed, the interrupt inhibit should end as soon as the next instruction (e.g., the RET instruction if the NOP instruction is commented) is executed. This problem is caused because the previous code may choose not to end the TB even if the HF_INHIBIT_IRQ_MASK has just been reset (e.g., in the case where the STI instruction is immediately followed by the RET instruction), so that IRQs may not have a change to trigger. This commit fixes the problem by always terminating the current TB to give IRQs a chance to trigger when HF_INHIBIT_IRQ_MASK is reset. Reviewed-by: Richard Henderson Signed-off-by: Ruihan Li Message-ID: <20240415064518.4951-4-lrh2000@pku.edu.cn> Signed-off-by: Paolo Bonzini (cherry picked from commit 6a5a63f74ba5c5355b7a8468d3d814bfffe928fb) Signed-off-by: Michael Tokarev diff --git a/target/i386/tcg/translate.c b/target/i386/tcg/translate.c index 76a42c679c..c84196c00b 100644 --- a/target/i386/tcg/translate.c +++ b/target/i386/tcg/translate.c @@ -2798,13 +2798,17 @@ static void gen_bnd_jmp(DisasContext *s) static void do_gen_eob_worker(DisasContext *s, bool inhibit, bool recheck_tf, bool jr) { + bool inhibit_reset; + gen_update_cc_op(s); =20 /* If several instructions disable interrupts, only the first does it.= */ - if (inhibit && !(s->flags & HF_INHIBIT_IRQ_MASK)) { - gen_set_hflag(s, HF_INHIBIT_IRQ_MASK); - } else { + inhibit_reset =3D false; + if (s->flags & HF_INHIBIT_IRQ_MASK) { gen_reset_hflag(s, HF_INHIBIT_IRQ_MASK); + inhibit_reset =3D true; + } else if (inhibit) { + gen_set_hflag(s, HF_INHIBIT_IRQ_MASK); } =20 if (s->base.tb->flags & HF_RF_MASK) { @@ -2815,7 +2819,9 @@ do_gen_eob_worker(DisasContext *s, bool inhibit, bool= recheck_tf, bool jr) tcg_gen_exit_tb(NULL, 0); } else if (s->flags & HF_TF_MASK) { gen_helper_single_step(tcg_env); - } else if (jr) { + } else if (jr && + /* give irqs a chance to happen */ + !inhibit_reset) { tcg_gen_lookup_and_goto_ptr(); } else { tcg_gen_exit_tb(NULL, 0); --=20 2.39.2