On Tue, 2010-05-25 at 08:43 +0200, Markus Armbruster wrote:
> Alex Williamson <alex.williamson@xxxxxxxxxx> writes:
>
> > On Wed, 2010-05-19 at 12:00 -0700, Chris Wright wrote:
> >> When libvirt launches a guest it first chowns the relevenat
> >> /sys/bus/pci/.../config file for an assigned device then drops privileges.
> >>
> >> This causes an issue for device assignment because despite being file
> >> owner, the sysfs config space file checks for CAP_SYS_ADMIN before
> >> allowing access to device dependent config space.
> >>
> >> This adds a new qdev configfd property which allows libvirt to open the
> >> sysfs config space file and give qemu an already opened file descriptor.
> >> Along with a change pending for the 2.6.35 kernel, this allows the
> >> capability check to compare against privileges from when the file was
> >> opened.
> >
> > We need to make configfd be a string option so that we can pass a
> > descriptor from libvirt for the hotplug case. Here's a rework.
> >
> > Signed-off-by: Chris Wright <chrisw@xxxxxxxxxx>
> > Signed-off-by: Alex Williamson <alex.williamson@xxxxxxxxxx>
> > ---
> >
> > diff --git a/hw/device-assignment.c b/hw/device-assignment.c
> > index eb31c78..3c5184f 100644
> > --- a/hw/device-assignment.c
> > +++ b/hw/device-assignment.c
> > @@ -37,6 +37,7 @@
> > #include "console.h"
> > #include "device-assignment.h"
> > #include "loader.h"
> > +#include "monitor.h"
> > #include <pci/pci.h>
> >
> > /* From linux/ioport.h */
> > @@ -612,14 +613,28 @@ static int get_real_device(AssignedDevice *pci_dev, uint16_t r_seg,
> >
> > snprintf(name, sizeof(name), "%sconfig", dir);
> >
> > - fd = open(name, O_RDWR);
> > - if (fd == -1) {
> > - fprintf(stderr, "%s: %s: %m\n", __func__, name);
> > - return 1;
> > + if (pci_dev->configfd_name && *pci_dev->configfd_name) {
> > + if (qemu_isdigit(pci_dev->configfd_name[0])) {
> > + dev->config_fd = strtol(pci_dev->configfd_name, NULL, 0);
> > + } else {
> > + dev->config_fd = monitor_get_fd(cur_mon, pci_dev->configfd_name);
> > + if (dev->config_fd < 0) {
> > + fprintf(stderr, "%s: (%s) unkown\n", __func__,
> > + pci_dev->configfd_name);
> > + return 1;
> > + }
> > + }
>
> Similar to net_handle_fd_param(). What about factoring into a common
> helper?
Yep, maybe we should move that into monitor.c. Thanks,
Alex
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