From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:45081) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1aFTrd-0002nV-8I for qemu-devel@nongnu.org; Sat, 02 Jan 2016 16:37:30 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1aFTrZ-0005m7-82 for qemu-devel@nongnu.org; Sat, 02 Jan 2016 16:37:29 -0500 Received: from mx1.redhat.com ([209.132.183.28]:38991) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1aFTrZ-0005lF-2X for qemu-devel@nongnu.org; Sat, 02 Jan 2016 16:37:25 -0500 Date: Sat, 2 Jan 2016 23:37:19 +0200 From: "Michael S. Tsirkin" Message-ID: <20160102233646-mutt-send-email-mst@redhat.com> References: <1451721740-6151-1-git-send-email-caoj.fnst@cn.fujitsu.com> <56879302.3050902@weilnetz.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <56879302.3050902@weilnetz.de> Subject: Re: [Qemu-devel] [PATCH v3] bugfix: passing reference instead of value List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Stefan Weil Cc: pbonzini@redhat.com, Cao jin , qemu-devel@nongnu.org, stefano.stabellini@eu.citrix.com On Sat, Jan 02, 2016 at 10:06:10AM +0100, Stefan Weil wrote: > Am 02.01.2016 um 09:02 schrieb Cao jin: > > Fix the bug introduced by 595a4f07: function host_pci_config_read() should be > > pass-by-reference, not value. > > > > Signed-off-by: Cao jin > > --- > > v3 changelog: > > 1. Remove cpu_to_le32() since the code only runs on X86. > > > > hw/pci-host/piix.c | 8 +++++--- > > 1 file changed, 5 insertions(+), 3 deletions(-) > > > > diff --git a/hw/pci-host/piix.c b/hw/pci-host/piix.c > > index 715208b..924f0fa 100644 > > --- a/hw/pci-host/piix.c > > +++ b/hw/pci-host/piix.c > > @@ -761,7 +761,7 @@ static const IGDHostInfo igd_host_bridge_infos[] = { > > {0xa8, 4}, /* SNB: base of GTT stolen memory */ > > }; > > > > -static int host_pci_config_read(int pos, int len, uint32_t val) > > +static int host_pci_config_read(int pos, int len, uint32_t *val) > > { > > char path[PATH_MAX]; > > int config_fd; > > @@ -784,12 +784,14 @@ static int host_pci_config_read(int pos, int len, uint32_t val) > > ret = -errno; > > goto out; > > } > > + > > do { > > - rc = read(config_fd, (uint8_t *)&val, len); > > + rc = read(config_fd, (uint8_t *)val, len); > > The type cast is not needed here, because read accepts any pointer > type for the buffer argument. > > While looking at that code, I noticed more potential issues: > > * The open statement needs O_RDWR | O_BINARY, otherwise the code won't > work on Windows. I pokes at sysfs, it has no chance to work on windows anyway. > * The len argument can obviously be 2 or 4. Will endianness handling > work for both cases? > > Regards, > Stefan > >