[libvirt] [PATCH] qemu: add the USB devices to the cgroup whitelist
Daniel P. Berrange
berrange at redhat.com
Mon Nov 1 10:26:55 UTC 2010
On Sat, Oct 30, 2010 at 12:25:30AM +0200, Diego Elio Pettenò wrote:
> Add a new interface to hostusb.h to add an USB device abstraction to a
> cgroup whitelist; then use it both when attaching a new USB device and when
> adding it to the commandline so that the device can be accessed by the
> QEmu-specific cgroup.
> ---
> src/libvirt_private.syms | 1 +
> src/qemu/qemu_driver.c | 36 ++++++++++++++++++++++++++++++++++++
> src/util/hostusb.c | 6 ++++++
> src/util/hostusb.h | 4 +++-
> 4 files changed, 46 insertions(+), 1 deletions(-)
>
> diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms
> index cf06256..0c6f308 100644
> --- a/src/libvirt_private.syms
> +++ b/src/libvirt_private.syms
> @@ -707,6 +707,7 @@ virMutexUnlock;
>
>
> # usb.h
> +usbAllowDeviceCgroup;
> usbDeviceFileIterate;
> usbDeviceGetBus;
> usbDeviceGetDevno;
> diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
> index 1eea3a9..acf319e 100644
> --- a/src/qemu/qemu_driver.c
> +++ b/src/qemu/qemu_driver.c
> @@ -3505,6 +3505,23 @@ static int qemuSetupCgroup(struct qemud_driver *driver,
> qemuSetupChardevCgroup,
> cgroup) < 0)
> goto cleanup;
> +
> + for (i = 0; i < vm->def->nhostdevs; i++) {
> + virDomainHostdevDefPtr hostdev = vm->def->hostdevs[i];
> + usbDevice *usb;
> +
> + if (hostdev->mode != VIR_DOMAIN_HOSTDEV_MODE_SUBSYS)
> + continue;
> + if (hostdev->source.subsys.type != VIR_DOMAIN_HOSTDEV_SUBSYS_TYPE_USB)
> + continue;
> +
> + if ((usb = usbFindDevice(hostdev->source.subsys.u.usb.vendor,
> + hostdev->source.subsys.u.usb.product)) == NULL)
> + goto cleanup;
This should actually use usbGetDevice with bus+device, since the
(optional) vendor+product has already been resolved into a bus+device
ID pair.
> + if (usbAllowDeviceCgroup(usb, cgroup) < 0)
> + goto cleanup;
> + }
> }
This should call out to usbDeviceFileIterate, passing a callback
todo the cgroup relabelling.
>
> if ((rc = qemuCgroupControllerActive(driver, VIR_CGROUP_CONTROLLER_MEMORY))) {
> @@ -8454,6 +8471,25 @@ static int qemudDomainAttachHostUsbDevice(struct qemud_driver *driver,
> goto error;
> }
>
> + if (qemuCgroupControllerActive(driver, VIR_CGROUP_CONTROLLER_DEVICES)) {
> + virCgroupPtr cgroup = NULL;
> + usbDevice *usb;
> +
> + if (virCgroupForDomain(driver->cgroup, vm->def->name, &cgroup, 0) !=0 ) {
> + qemuReportError(VIR_ERR_INTERNAL_ERROR,
> + _("Unable to find cgroup for %s\n"),
> + vm->def->name);
> + goto error;
> + }
> +
> + if ((usb = usbFindDevice(hostdev->source.subsys.u.usb.vendor,
> + hostdev->source.subsys.u.usb.product)) == NULL)
> + goto error;
Likewise here.
> +
> + if (usbAllowDeviceCgroup(usb, cgroup) < 0)
> + goto error;
> + }
Also usbDeviceFileIterate.
> +
> qemuDomainObjEnterMonitorWithDriver(driver, vm);
> if (qemuCmdFlags & QEMUD_CMD_FLAG_DEVICE)
> ret = qemuMonitorAddDevice(priv->mon, devstr);
> diff --git a/src/util/hostusb.c b/src/util/hostusb.c
> index 2d6e414..2cbe1fb 100644
> --- a/src/util/hostusb.c
> +++ b/src/util/hostusb.c
> @@ -225,3 +225,9 @@ int usbDeviceFileIterate(usbDevice *dev,
> {
> return (actor)(dev, dev->path, opaque);
> }
> +
> +int usbAllowDeviceCgroup(usbDevice *dev,
> + virCgroupPtr group)
> +{
> + return virCgroupAllowDevicePath(group, dev->path);
> +}
This introduces a strict coupling between the usb + cgroups
code which isn't something we want. Using the usbDeviceFileIterate
API avoids this coupling.
One general point is that the indentation in your patch is not
correct - needs to be 4 space indented rather than 2. See the
HACKING file for .emacs rules.
Regards,
Daniel
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