From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id E4A57C606B0 for ; Tue, 9 Jul 2019 10:32:19 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id BCA9A2082A for ; Tue, 9 Jul 2019 10:32:19 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org BCA9A2082A Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:48582 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hknQ3-0007Gs-2u for qemu-devel@archiver.kernel.org; Tue, 09 Jul 2019 06:32:19 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:59858) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hknOU-0006kR-P7 for qemu-devel@nongnu.org; Tue, 09 Jul 2019 06:30:45 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hknOS-0007lb-US for qemu-devel@nongnu.org; Tue, 09 Jul 2019 06:30:42 -0400 Received: from mx1.redhat.com ([209.132.183.28]:54110) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1hknOL-0007a9-4Z; Tue, 09 Jul 2019 06:30:35 -0400 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id B52D130BD1B3; Tue, 9 Jul 2019 10:30:30 +0000 (UTC) Received: from work-vm (ovpn-117-75.ams2.redhat.com [10.36.117.75]) by smtp.corp.redhat.com (Postfix) with ESMTPS id AA961608A4; Tue, 9 Jul 2019 10:30:24 +0000 (UTC) Date: Tue, 9 Jul 2019 11:30:22 +0100 From: "Dr. David Alan Gilbert" To: Philippe =?iso-8859-1?Q?Mathieu-Daud=E9?= Message-ID: <20190709103022.GA2766@work-vm> References: <20190705154639.16591-1-philmd@redhat.com> <20190705154639.16591-3-philmd@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline In-Reply-To: <20190705154639.16591-3-philmd@redhat.com> User-Agent: Mutt/1.12.0 (2019-05-25) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.49]); Tue, 09 Jul 2019 10:30:30 +0000 (UTC) Content-Transfer-Encoding: quoted-printable X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 209.132.183.28 Subject: Re: [Qemu-devel] [PATCH v3 2/9] hw/block/pflash_cfi01: Use the correct READ_ARRAY value X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Kevin Wolf , qemu-block@nongnu.org, John Snow , qemu-devel@nongnu.org, Max Reitz , Alistair Francis , Laszlo Ersek Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" * Philippe Mathieu-Daud=E9 (philmd@redhat.com) wrote: > In the "Read Array Flowchart" the command has a value of 0xFF. >=20 > In the document [*] the "Read Array Flowchart", the READ_ARRAY > command has a value of 0xff. >=20 > Use the correct value in the pflash model. >=20 > There is no change of behavior in the guest, because: > - when the guest were sending 0xFF, the reset_flash label > was setting the command value as 0x00 > - 0x00 was used internally for READ_ARRAY >=20 > To keep migration behaving correctly, we have to increase > the VMState version. When migrating from an older version, > we use the correct command value. The problem is that incrementing the version will break backwards compatibility; so you won't be able to migrate this back to an older QEMU version; so for example a q35/uefi with this won't be able to migrate backwards to a 4.0.0 or older qemu. So instead of bumping the version_id you probably need to wire the behaviour to a machine type and then on your new type wire a subsection containing a flag; the reception of that subsection tells you to use the new/correct semantics. Dave > [*] "Common Flash Interface (CFI) and Command Sets" > (Intel Application Note 646) > Appendix B "Basic Command Set" >=20 > Reviewed-by: John Snow > Reviewed-by: Alistair Francis > Regression-tested-by: Laszlo Ersek > Signed-off-by: Philippe Mathieu-Daud=E9 > --- > v3: Handle migrating the 'cmd' field. >=20 > Since Laszlo stated he did not test migration [*], I'm keeping his > test tag, because the change with v2 has no impact in the tests > he ran. >=20 > Likewise I'm keeping John and Alistair tags, but I'd like an extra > review for the migration change, thanks! >=20 > [*] https://lists.gnu.org/archive/html/qemu-devel/2019-07/msg00679.html > --- > hw/block/pflash_cfi01.c | 23 +++++++++++++---------- > 1 file changed, 13 insertions(+), 10 deletions(-) >=20 > diff --git a/hw/block/pflash_cfi01.c b/hw/block/pflash_cfi01.c > index 9e34fd4e82..58cbef0588 100644 > --- a/hw/block/pflash_cfi01.c > +++ b/hw/block/pflash_cfi01.c > @@ -100,7 +100,7 @@ static int pflash_post_load(void *opaque, int versi= on_id); > =20 > static const VMStateDescription vmstate_pflash =3D { > .name =3D "pflash_cfi01", > - .version_id =3D 1, > + .version_id =3D 2, > .minimum_version_id =3D 1, > .post_load =3D pflash_post_load, > .fields =3D (VMStateField[]) { > @@ -277,10 +277,9 @@ static uint32_t pflash_read(PFlashCFI01 *pfl, hwad= dr offset, > /* This should never happen : reset state & treat it as a read= */ > DPRINTF("%s: unknown command state: %x\n", __func__, pfl->cmd)= ; > pfl->wcycle =3D 0; > - pfl->cmd =3D 0; > + pfl->cmd =3D 0xff; > /* fall through to read code */ > - case 0x00: > - /* Flash area read */ > + case 0xff: /* Read Array */ > ret =3D pflash_data_read(pfl, offset, width, be); > break; > case 0x10: /* Single byte program */ > @@ -448,8 +447,6 @@ static void pflash_write(PFlashCFI01 *pfl, hwaddr o= ffset, > case 0: > /* read mode */ > switch (cmd) { > - case 0x00: /* ??? */ > - goto reset_flash; > case 0x10: /* Single Byte Program */ > case 0x40: /* Single Byte Program */ > DPRINTF("%s: Single Byte Program\n", __func__); > @@ -526,7 +523,7 @@ static void pflash_write(PFlashCFI01 *pfl, hwaddr o= ffset, > if (cmd =3D=3D 0xd0) { /* confirm */ > pfl->wcycle =3D 0; > pfl->status |=3D 0x80; > - } else if (cmd =3D=3D 0xff) { /* read array mode */ > + } else if (cmd =3D=3D 0xff) { /* Read Array */ > goto reset_flash; > } else > goto error_flash; > @@ -553,7 +550,7 @@ static void pflash_write(PFlashCFI01 *pfl, hwaddr o= ffset, > } else if (cmd =3D=3D 0x01) { > pfl->wcycle =3D 0; > pfl->status |=3D 0x80; > - } else if (cmd =3D=3D 0xff) { > + } else if (cmd =3D=3D 0xff) { /* read array mode */ > goto reset_flash; > } else { > DPRINTF("%s: Unknown (un)locking command\n", __func__)= ; > @@ -645,7 +642,7 @@ static void pflash_write(PFlashCFI01 *pfl, hwaddr o= ffset, > trace_pflash_reset(); > memory_region_rom_device_set_romd(&pfl->mem, true); > pfl->wcycle =3D 0; > - pfl->cmd =3D 0; > + pfl->cmd =3D 0xff; > } > =20 > =20 > @@ -761,7 +758,7 @@ static void pflash_cfi01_realize(DeviceState *dev, = Error **errp) > } > =20 > pfl->wcycle =3D 0; > - pfl->cmd =3D 0; > + pfl->cmd =3D 0xff; > pfl->status =3D 0; > /* Hardcoded CFI table */ > /* Standard "QRY" string */ > @@ -1001,5 +998,11 @@ static int pflash_post_load(void *opaque, int ver= sion_id) > pfl->vmstate =3D qemu_add_vm_change_state_handler(postload_upd= ate_cb, > pfl); > } > + if (version_id < 2) { > + /* v1 used incorrect value of 0x00 for the READ_ARRAY command.= */ > + if (pfl->cmd =3D=3D 0x00) { > + pfl->cmd =3D 0xff; > + } > + } > return 0; > } > --=20 > 2.20.1 >=20 >=20 -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK