From nobody Mon Feb 9 05:41:15 2026 Delivered-To: importer@patchew.org Received-SPF: pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) client-ip=208.118.235.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Authentication-Results: mx.zohomail.com; spf=pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=fail(p=none dis=none) header.from=redhat.com Return-Path: Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) by mx.zohomail.com with SMTPS id 1527727516894535.9701176365197; Wed, 30 May 2018 17:45:16 -0700 (PDT) Received: from localhost ([::1]:41354 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fOBiJ-0006KH-KD for importer@patchew.org; Wed, 30 May 2018 20:45:11 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:59174) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fOBgf-0005H0-IE for qemu-devel@nongnu.org; Wed, 30 May 2018 20:43:30 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1fOBge-0006uP-Sa for qemu-devel@nongnu.org; Wed, 30 May 2018 20:43:29 -0400 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:33876 helo=mx1.redhat.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1fOBga-0006rr-UR; Wed, 30 May 2018 20:43:25 -0400 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.rdu2.redhat.com [10.11.54.4]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 6D37440137F6; Thu, 31 May 2018 00:43:24 +0000 (UTC) Received: from probe.bos.redhat.com (dhcp-17-177.bos.redhat.com [10.18.17.177]) by smtp.corp.redhat.com (Postfix) with ESMTP id 2FB9E2023583; Thu, 31 May 2018 00:43:24 +0000 (UTC) From: John Snow To: qemu-devel@nongnu.org, qemu-block@nongnu.org Date: Wed, 30 May 2018 20:43:22 -0400 Message-Id: <20180531004323.4611-3-jsnow@redhat.com> In-Reply-To: <20180531004323.4611-1-jsnow@redhat.com> References: <20180531004323.4611-1-jsnow@redhat.com> X-Scanned-By: MIMEDefang 2.78 on 10.11.54.4 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.6]); Thu, 31 May 2018 00:43:24 +0000 (UTC) X-Greylist: inspected by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.6]); Thu, 31 May 2018 00:43:24 +0000 (UTC) for IP:'10.11.54.4' DOMAIN:'int-mx04.intmail.prod.int.rdu2.redhat.com' HELO:'smtp.corp.redhat.com' FROM:'jsnow@redhat.com' RCPT:'' X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 66.187.233.73 Subject: [Qemu-devel] [PATCH 2/3] ahci: fix PxCI register race X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: John Snow Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail: RSF_0 Z_629925259 SPT_0 Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" AHCI presently signals completion prior to the PxCI register being cleared to indicate completion. If a guest driver attempts to issue a new command in its IRQ handler, it might be surprised to learn there is still a command pending. In the case of Windows 10's boot driver, it will actually poll the IRQ register hoping to find out when the command is done running -- which will never happen, as there isn't a command running. Fix this: clear PxCI in ahci_cmd_done and not in the asynchronous BH. Because it now runs synchronously, we don't need to check if the command is actually done by spying on the ATA registers. We know it's done. Signed-off-by: John Snow Reported-by: Fran=C3=A7ois Guerraz Reviewed-by: Jeff Cody Tested-by: Bruce Rogers --- hw/ide/ahci.c | 13 ++++++------- 1 file changed, 6 insertions(+), 7 deletions(-) diff --git a/hw/ide/ahci.c b/hw/ide/ahci.c index b7a6f68790..a9558e45e7 100644 --- a/hw/ide/ahci.c +++ b/hw/ide/ahci.c @@ -532,13 +532,6 @@ static void ahci_check_cmd_bh(void *opaque) qemu_bh_delete(ad->check_bh); ad->check_bh =3D NULL; =20 - if ((ad->busy_slot !=3D -1) && - !(ad->port.ifs[0].status & (BUSY_STAT|DRQ_STAT))) { - /* no longer busy */ - ad->port_regs.cmd_issue &=3D ~(1 << ad->busy_slot); - ad->busy_slot =3D -1; - } - check_cmd(ad->hba, ad->port_no); } =20 @@ -1425,6 +1418,12 @@ static void ahci_cmd_done(IDEDMA *dma) =20 trace_ahci_cmd_done(ad->hba, ad->port_no); =20 + /* no longer busy */ + if (ad->busy_slot !=3D -1) { + ad->port_regs.cmd_issue &=3D ~(1 << ad->busy_slot); + ad->busy_slot =3D -1; + } + /* update d2h status */ ahci_write_fis_d2h(ad); =20 --=20 2.14.3