From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:55365) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1aDx5n-0008NS-B6 for qemu-devel@nongnu.org; Tue, 29 Dec 2015 11:25:48 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1aDx5k-0000xe-44 for qemu-devel@nongnu.org; Tue, 29 Dec 2015 11:25:47 -0500 Received: from mail-wm0-x22e.google.com ([2a00:1450:400c:c09::22e]:38525) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1aDx5j-0000x2-Th for qemu-devel@nongnu.org; Tue, 29 Dec 2015 11:25:44 -0500 Received: by mail-wm0-x22e.google.com with SMTP id b14so19214931wmb.1 for ; Tue, 29 Dec 2015 08:25:43 -0800 (PST) Sender: Paolo Bonzini References: <1451277767-9325-1-git-send-email-caoj.fnst@cn.fujitsu.com> <5682747E.8080301@cn.fujitsu.com> <568277CD.7040004@cn.fujitsu.com> From: Paolo Bonzini Message-ID: <5682B402.7060808@redhat.com> Date: Tue, 29 Dec 2015 17:25:38 +0100 MIME-Version: 1.0 In-Reply-To: <568277CD.7040004@cn.fujitsu.com> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 8bit Subject: Re: [Qemu-devel] [PATCH v2] bugfix: passing reference instead of value List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Cao jin , qemu-devel@nongnu.org Cc: stefano.stabellini@eu.citrix.com, mst@redhat.com >>> Separated from previous "igd-passthru convert to realize" patch. Since >>> these two don`t have dependency, can send it solely. >>> >>> Not test since it is easy to find out if reading carefully, just >>> compiled. This patch works but the added conversion to LE is conceptually wrong. The conversion from LE to CPU and vice versa is already done by host_pci_config_read and pci_default_write_config. You don't have it in host_pci_config_read because the code is not portable and x86 is little-endian. Generally, functions that accept/return integers take care themselves of endianness conversions. Paolo >>> hw/pci-host/piix.c | 10 ++++++---- >>> 1 file changed, 6 insertions(+), 4 deletions(-) >>> >>> diff --git a/hw/pci-host/piix.c b/hw/pci-host/piix.c >>> index 715208b..a9cb983 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); >>> } while (rc < 0 && (errno == EINTR || errno == EAGAIN)); >>> if (rc != len) { >>> ret = -errno; >>> } >>> + >>> out: >>> close(config_fd); >>> return ret; >>> @@ -805,11 +807,11 @@ static int igd_pt_i440fx_initfn(struct PCIDevice >>> *pci_dev) >>> for (i = 0; i < num; i++) { >>> pos = igd_host_bridge_infos[i].offset; >>> len = igd_host_bridge_infos[i].len; >>> - rc = host_pci_config_read(pos, len, val); >>> + rc = host_pci_config_read(pos, len, &val); >>> if (rc) { >>> return -ENODEV; >>> } >>> - pci_default_write_config(pci_dev, pos, val, len); >>> + pci_default_write_config(pci_dev, pos, cpu_to_le32(val), len); >>> } >>> >>> return 0; >>> >> >