| Message ID | alpine.DEB.2.02.1509101122570.2672@kaball.uk.xensource.com |
|---|---|
| State | New |
| Headers | show |
On Thu, Sep 10, 2015 at 11:29:18AM +0100, Stefano Stabellini wrote: > CC Michael > > On Thu, 10 Sep 2015, Stefano Stabellini wrote: > > On Thu, 10 Sep 2015, Chen, Tiejun wrote: > > > > xen-host-pci-device.c is only compiled if CONFIG_XEN_PCI_PASSTHROUGH > > > > was set by configure. That won't be the case on OSX or Windows, where > > > > the Xen headers don't exist. > > > > > > > > > > Okay. This actually shouldn't be enabled on Windows so what about this? > > > > I think it would be nicer to replace the pread than introducing ifdefs. > > Something like: > > --- > Replace pread with read to avoid build breakages on Windows > > Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com> I'd prefer a wrapper that does the right thing. No sense in doubling the # of system calls for everyone. > > diff --git a/hw/pci-host/piix.c b/hw/pci-host/piix.c > index 58a33fb..9a40429 100644 > --- a/hw/pci-host/piix.c > +++ b/hw/pci-host/piix.c > @@ -774,8 +774,11 @@ static int host_pci_config_read(int pos, int len, uint32_t val) > return -ENODEV; > } > > + if (lseek(config_fd, pos, SEEK_SET) != pos) { > + return -errno; > + } > do { > - rc = pread(config_fd, (uint8_t *)&val, len, pos); > + rc = read(config_fd, (uint8_t *)&val, len); > } while (rc < 0 && (errno == EINTR || errno == EAGAIN)); > if (rc != len) { > return -errno;
On Thu, 10 Sep 2015, Michael S. Tsirkin wrote: > On Thu, Sep 10, 2015 at 11:29:18AM +0100, Stefano Stabellini wrote: > > CC Michael > > > > On Thu, 10 Sep 2015, Stefano Stabellini wrote: > > > On Thu, 10 Sep 2015, Chen, Tiejun wrote: > > > > > xen-host-pci-device.c is only compiled if CONFIG_XEN_PCI_PASSTHROUGH > > > > > was set by configure. That won't be the case on OSX or Windows, where > > > > > the Xen headers don't exist. > > > > > > > > > > > > > Okay. This actually shouldn't be enabled on Windows so what about this? > > > > > > I think it would be nicer to replace the pread than introducing ifdefs. > > > > Something like: > > > > --- > > Replace pread with read to avoid build breakages on Windows > > > > Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com> > > I'd prefer a wrapper that does the right thing. > No sense in doubling the # of system calls for everyone. If this was done on an hot path I would agree with you, but it is just one call at initialization time (igd_pt_i440fx_initfn). > > diff --git a/hw/pci-host/piix.c b/hw/pci-host/piix.c > > index 58a33fb..9a40429 100644 > > --- a/hw/pci-host/piix.c > > +++ b/hw/pci-host/piix.c > > @@ -774,8 +774,11 @@ static int host_pci_config_read(int pos, int len, uint32_t val) > > return -ENODEV; > > } > > > > + if (lseek(config_fd, pos, SEEK_SET) != pos) { > > + return -errno; > > + } > > do { > > - rc = pread(config_fd, (uint8_t *)&val, len, pos); > > + rc = read(config_fd, (uint8_t *)&val, len); > > } while (rc < 0 && (errno == EINTR || errno == EAGAIN)); > > if (rc != len) { > > return -errno; >
On Thu, Sep 10, 2015 at 12:26:21PM +0100, Stefano Stabellini wrote: > On Thu, 10 Sep 2015, Michael S. Tsirkin wrote: > > On Thu, Sep 10, 2015 at 11:29:18AM +0100, Stefano Stabellini wrote: > > > CC Michael > > > > > > On Thu, 10 Sep 2015, Stefano Stabellini wrote: > > > > On Thu, 10 Sep 2015, Chen, Tiejun wrote: > > > > > > xen-host-pci-device.c is only compiled if CONFIG_XEN_PCI_PASSTHROUGH > > > > > > was set by configure. That won't be the case on OSX or Windows, where > > > > > > the Xen headers don't exist. > > > > > > > > > > > > > > > > Okay. This actually shouldn't be enabled on Windows so what about this? > > > > > > > > I think it would be nicer to replace the pread than introducing ifdefs. > > > > > > Something like: > > > > > > --- > > > Replace pread with read to avoid build breakages on Windows > > > > > > Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com> > > > > I'd prefer a wrapper that does the right thing. > > No sense in doubling the # of system calls for everyone. > > If this was done on an hot path I would agree with you, but it is just > one call at initialization time (igd_pt_i440fx_initfn). I missed this fact. OK then. > > > > diff --git a/hw/pci-host/piix.c b/hw/pci-host/piix.c > > > index 58a33fb..9a40429 100644 > > > --- a/hw/pci-host/piix.c > > > +++ b/hw/pci-host/piix.c > > > @@ -774,8 +774,11 @@ static int host_pci_config_read(int pos, int len, uint32_t val) > > > return -ENODEV; > > > } > > > > > > + if (lseek(config_fd, pos, SEEK_SET) != pos) { > > > + return -errno; > > > + } > > > do { > > > - rc = pread(config_fd, (uint8_t *)&val, len, pos); > > > + rc = read(config_fd, (uint8_t *)&val, len); > > > } while (rc < 0 && (errno == EINTR || errno == EAGAIN)); > > > if (rc != len) { > > > return -errno; > >
On Thu, 10 Sep 2015, Michael S. Tsirkin wrote: > On Thu, Sep 10, 2015 at 12:26:21PM +0100, Stefano Stabellini wrote: > > On Thu, 10 Sep 2015, Michael S. Tsirkin wrote: > > > On Thu, Sep 10, 2015 at 11:29:18AM +0100, Stefano Stabellini wrote: > > > > CC Michael > > > > > > > > On Thu, 10 Sep 2015, Stefano Stabellini wrote: > > > > > On Thu, 10 Sep 2015, Chen, Tiejun wrote: > > > > > > > xen-host-pci-device.c is only compiled if CONFIG_XEN_PCI_PASSTHROUGH > > > > > > > was set by configure. That won't be the case on OSX or Windows, where > > > > > > > the Xen headers don't exist. > > > > > > > > > > > > > > > > > > > Okay. This actually shouldn't be enabled on Windows so what about this? > > > > > > > > > > I think it would be nicer to replace the pread than introducing ifdefs. > > > > > > > > Something like: > > > > > > > > --- > > > > Replace pread with read to avoid build breakages on Windows > > > > > > > > Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com> > > > > > > I'd prefer a wrapper that does the right thing. > > > No sense in doubling the # of system calls for everyone. > > > > If this was done on an hot path I would agree with you, but it is just > > one call at initialization time (igd_pt_i440fx_initfn). > > I missed this fact. OK then. Thanks! I'll fold it the offending patch (http://marc.info/?l=qemu-devel&m=144174596628052&w=2) and resend. > > > > diff --git a/hw/pci-host/piix.c b/hw/pci-host/piix.c > > > > index 58a33fb..9a40429 100644 > > > > --- a/hw/pci-host/piix.c > > > > +++ b/hw/pci-host/piix.c > > > > @@ -774,8 +774,11 @@ static int host_pci_config_read(int pos, int len, uint32_t val) > > > > return -ENODEV; > > > > } > > > > > > > > + if (lseek(config_fd, pos, SEEK_SET) != pos) { > > > > + return -errno; > > > > + } > > > > do { > > > > - rc = pread(config_fd, (uint8_t *)&val, len, pos); > > > > + rc = read(config_fd, (uint8_t *)&val, len); > > > > } while (rc < 0 && (errno == EINTR || errno == EAGAIN)); > > > > if (rc != len) { > > > > return -errno; > > > >
On Thu, Sep 10, 2015 at 01:00:35PM +0100, Stefano Stabellini wrote: > On Thu, 10 Sep 2015, Michael S. Tsirkin wrote: > > On Thu, Sep 10, 2015 at 12:26:21PM +0100, Stefano Stabellini wrote: > > > On Thu, 10 Sep 2015, Michael S. Tsirkin wrote: > > > > On Thu, Sep 10, 2015 at 11:29:18AM +0100, Stefano Stabellini wrote: > > > > > CC Michael > > > > > > > > > > On Thu, 10 Sep 2015, Stefano Stabellini wrote: > > > > > > On Thu, 10 Sep 2015, Chen, Tiejun wrote: > > > > > > > > xen-host-pci-device.c is only compiled if CONFIG_XEN_PCI_PASSTHROUGH > > > > > > > > was set by configure. That won't be the case on OSX or Windows, where > > > > > > > > the Xen headers don't exist. > > > > > > > > > > > > > > > > > > > > > > Okay. This actually shouldn't be enabled on Windows so what about this? > > > > > > > > > > > > I think it would be nicer to replace the pread than introducing ifdefs. > > > > > > > > > > Something like: > > > > > > > > > > --- > > > > > Replace pread with read to avoid build breakages on Windows > > > > > > > > > > Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com> > > > > > > > > I'd prefer a wrapper that does the right thing. > > > > No sense in doubling the # of system calls for everyone. > > > > > > If this was done on an hot path I would agree with you, but it is just > > > one call at initialization time (igd_pt_i440fx_initfn). > > > > I missed this fact. OK then. > > Thanks! I'll fold it the offending patch > (http://marc.info/?l=qemu-devel&m=144174596628052&w=2) and resend. > Reviewed-by: Michael S. Tsirkin <mst@redhat.com> > > > > > diff --git a/hw/pci-host/piix.c b/hw/pci-host/piix.c > > > > > index 58a33fb..9a40429 100644 > > > > > --- a/hw/pci-host/piix.c > > > > > +++ b/hw/pci-host/piix.c > > > > > @@ -774,8 +774,11 @@ static int host_pci_config_read(int pos, int len, uint32_t val) > > > > > return -ENODEV; > > > > > } > > > > > > > > > > + if (lseek(config_fd, pos, SEEK_SET) != pos) { > > > > > + return -errno; > > > > > + } > > > > > do { > > > > > - rc = pread(config_fd, (uint8_t *)&val, len, pos); > > > > > + rc = read(config_fd, (uint8_t *)&val, len); > > > > > } while (rc < 0 && (errno == EINTR || errno == EAGAIN)); > > > > > if (rc != len) { > > > > > return -errno; > > > > > >
>> Thanks! I'll fold it the offending patch >> (http://marc.info/?l=qemu-devel&m=144174596628052&w=2) and resend. >> > > Reviewed-by: Michael S. Tsirkin <mst@redhat.com> > Michale and Stefano, Thanks a lot :) Tiejun
On 10/09/2015 12:29, Stefano Stabellini wrote: > + if (lseek(config_fd, pos, SEEK_SET) != pos) { > + return -errno; > + } > do { > - rc = pread(config_fd, (uint8_t *)&val, len, pos); > + rc = read(config_fd, (uint8_t *)&val, len); > } while (rc < 0 && (errno == EINTR || errno == EAGAIN)); This leaks config_fd. Paolo
On Mon, 14 Sep 2015, Paolo Bonzini wrote: > On 10/09/2015 12:29, Stefano Stabellini wrote: > > + if (lseek(config_fd, pos, SEEK_SET) != pos) { > > + return -errno; > > + } > > do { > > - rc = pread(config_fd, (uint8_t *)&val, len, pos); > > + rc = read(config_fd, (uint8_t *)&val, len); > > } while (rc < 0 && (errno == EINTR || errno == EAGAIN)); > > This leaks config_fd. I don't follow, it leaks config_fd where?
On 15/09/2015 11:55, Stefano Stabellini wrote: > On Mon, 14 Sep 2015, Paolo Bonzini wrote: >> > On 10/09/2015 12:29, Stefano Stabellini wrote: >>> > > + if (lseek(config_fd, pos, SEEK_SET) != pos) { >>> > > + return -errno; >>> > > + } >>> > > do { >>> > > - rc = pread(config_fd, (uint8_t *)&val, len, pos); >>> > > + rc = read(config_fd, (uint8_t *)&val, len); >>> > > } while (rc < 0 && (errno == EINTR || errno == EAGAIN)); >> > >> > This leaks config_fd. > I don't follow, it leaks config_fd where? Where lseek returns -errno (and IIRC in other places in the same function). Paolo
diff --git a/hw/pci-host/piix.c b/hw/pci-host/piix.c index 58a33fb..9a40429 100644 --- a/hw/pci-host/piix.c +++ b/hw/pci-host/piix.c @@ -774,8 +774,11 @@ static int host_pci_config_read(int pos, int len, uint32_t val) return -ENODEV; } + if (lseek(config_fd, pos, SEEK_SET) != pos) { + return -errno; + } do { - rc = pread(config_fd, (uint8_t *)&val, len, pos); + rc = read(config_fd, (uint8_t *)&val, len); } while (rc < 0 && (errno == EINTR || errno == EAGAIN)); if (rc != len) { return -errno;