On Mon, May 24, 2010 at 01:39:37PM -0400, Alex Williamson wrote:
> This allows libvirt to open the PCI device sysfs config file prior
> to dropping privileges so qemu can access the full config space.
> Without this, a de-privileged qemu can only access the first 64
> bytes of config space.
>
> Signed-off-by: Alex Williamson <alex.williamson@xxxxxxxxxx>
> ---
>
> Note: this is still dependent on the configfd option being accepted
> into qemu/kvm.
>
> v2:
> - fix qemuargs, two separate args (thanks Chris)
> - don't hardcode pci segment
> - error message of open() fail
>
> v3:
> - add hotplug support
> - incorporate Daniel's comments
>
> src/qemu/qemu_conf.c | 98 +++++++++++++++++++++++++++++++++++++++++++++++-
> src/qemu/qemu_conf.h | 6 ++-
> src/qemu/qemu_driver.c | 28 +++++++++++++-
> 3 files changed, 128 insertions(+), 4 deletions(-)
>
> @@ -7685,8 +7687,26 @@ static int qemudDomainAttachHostPciDevice(struct qemud_driver *driver,
> goto error;
> if (qemuDomainPCIAddressEnsureAddr(priv->pciaddrs, &hostdev->info) < 0)
> goto error;
> + if (qemuCmdFlags & QEMUD_CMD_FLAG_PCI_CONFIGFD) {
> + configfd = qemudOpenPCIConfig(hostdev);
> + if (configfd >= 0) {
> + if (virAsprintf(&configfd_name, "fd-%s",
> + hostdev->info.alias) < 0) {
> + virReportOOMError();
> + goto error;
> + }
> +
> + qemuDomainObjEnterMonitorWithDriver(driver, vm);
> + if (qemuMonitorSendFileHandle(priv->mon, configfd_name,
> + configfd) < 0) {
> + qemuDomainObjExitMonitorWithDriver(driver, vm);
> + goto error;
> + }
> + qemuDomainObjExitMonitorWithDriver(driver, vm);
> + }
> + }
Subtle threading bug. At this point you need to add a check
+ if (!virDomainObjIsActive(vm)) {
+ qemuReportError(VIR_ERR_INTERNAL_ERROR, "%s",
+ _("guest unexpectedly quit during hotplug");
+ goto cleanup;
+ }
This checks for QEMU crashing after we send the file handle,
which means its not valid to send the subsequent device_add
command
>
> - if (!(devstr = qemuBuildPCIHostdevDevStr(hostdev)))
> + if (!(devstr = qemuBuildPCIHostdevDevStr(hostdev, configfd_name)))
> goto error;
>
> qemuDomainObjEnterMonitorWithDriver(driver, vm);
Aside from that addition, this patch looks good to me
Regards,
Daniel
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