From: John Snow <jsnow@redhat.com> To: Peter Maydell <peter.maydell@linaro.org>, Eric Blake <eblake@redhat.com> Cc: Stefan Fritsch <sf@sfritsch.de>, QEMU Developers <qemu-devel@nongnu.org> Subject: Re: [Qemu-devel] [PULL 2/3] ahci: Force ICC bits in PxCMD to zero Date: Tue, 21 Jul 2015 13:41:40 -0400 Message-ID: <55AE8454.6050604@redhat.com> (raw) In-Reply-To: <CAFEAcA9k28cE7BW06=KQeNrgURGSGin_P5ocHBx9TobrTZ3kJA@mail.gmail.com> On 07/21/2015 09:02 AM, Peter Maydell wrote: > On 21 July 2015 at 13:55, Eric Blake <eblake@redhat.com> wrote: >> On 07/21/2015 05:38 AM, Peter Maydell wrote: >>> On 20 July 2015 at 19:29, John Snow <jsnow@redhat.com> wrote: >>>> From: Stefan Fritsch <sf@sfritsch.de> >>>> >>>> The AHCI spec requires that the HBA sets the ICC bits to zero after the >>>> ICC change is done. Since we don't do any ICC change, force the bits to >>>> zero all the time. >>>> >>>> This fixes delays with some OSs (e.g. OpenBSD) waiting for the ICC bits >>>> to change to 0. >>> >>> This change provokes a lot of clang sanitizer warnings: >>> >>> /home/petmay01/linaro/qemu-for-merges/hw/ide/ahci.c:288:49: runtime >>> error: left shift of 15 by 28 places cannot be represented in type >>> 'int' >>> >>> PORT_CMD_ICC_MASK is defined as >>> >>> #define PORT_CMD_ICC_MASK (0xf << 28) /* i/f ICC state mask */ >>> >>> which shifts into the sign bit of a signed integer. >> >> Should be fixable by using (0xfU << 28), right? > > Yes, though it assumes that if you say "~PORT_CMD_ICC_MASK" > you're happy to only get a 32-bit mask. 0xfULL would avoid > that (see discussion on the other thread with Paolo about > the PPC similar issue.) > I think we're happy to admit it's a simple 32bit mask, since it's just a 32bit field and I can't imagine us needing it for any other purpose right now. I'd be worried that ~(0xfULL) would be pretty much the wrong thing in nearly all cases. Same for ~..UL. I'll send a quick patch for Eric's suggestion. > -- PMM > Thanks, --js
next prev parent reply index Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top 2015-07-20 18:29 [Qemu-devel] [PULL 0/3] Ide patches John Snow 2015-07-20 18:29 ` [Qemu-devel] [PULL 1/3] qtest/ide: add another short PRDT test flavor John Snow 2015-07-20 18:29 ` [Qemu-devel] [PULL 2/3] ahci: Force ICC bits in PxCMD to zero John Snow 2015-07-21 11:38 ` Peter Maydell 2015-07-21 12:55 ` Eric Blake 2015-07-21 13:02 ` Peter Maydell 2015-07-21 17:41 ` John Snow [this message] 2015-07-20 18:29 ` [Qemu-devel] [PULL 3/3] tests: Fix broken targets check-report-qtest-* John Snow 2015-07-21 10:18 ` [Qemu-devel] [PULL 0/3] Ide patches Peter Maydell
Reply instructions: You may reply publicly to this message via plain-text email using any one of the following methods: * Save the following mbox file, import it into your mail client, and reply-to-all from there: mbox Avoid top-posting and favor interleaved quoting: https://en.wikipedia.org/wiki/Posting_style#Interleaved_style * Reply using the --to, --cc, and --in-reply-to switches of git-send-email(1): git send-email \ --in-reply-to=55AE8454.6050604@redhat.com \ --to=jsnow@redhat.com \ --cc=eblake@redhat.com \ --cc=peter.maydell@linaro.org \ --cc=qemu-devel@nongnu.org \ --cc=sf@sfritsch.de \ /path/to/YOUR_REPLY https://kernel.org/pub/software/scm/git/docs/git-send-email.html * If your mail client supports setting the In-Reply-To header via mailto: links, try the mailto: link
QEMU-Devel Archive on lore.kernel.org Archives are clonable: git clone --mirror https://lore.kernel.org/qemu-devel/0 qemu-devel/git/0.git git clone --mirror https://lore.kernel.org/qemu-devel/1 qemu-devel/git/1.git git clone --mirror https://lore.kernel.org/qemu-devel/2 qemu-devel/git/2.git # If you have public-inbox 1.1+ installed, you may # initialize and index your mirror using the following commands: public-inbox-init -V2 qemu-devel qemu-devel/ https://lore.kernel.org/qemu-devel \ qemu-devel@nongnu.org public-inbox-index qemu-devel Example config snippet for mirrors Newsgroup available over NNTP: nntp://nntp.lore.kernel.org/org.nongnu.qemu-devel AGPL code for this site: git clone https://public-inbox.org/public-inbox.git