[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH] xen/xenbus: Add quirk to deal with misconfigured backends.
On Thu, Apr 19, 2012 at 12:37:42PM +0100, Stefano Stabellini wrote: > On Wed, 18 Apr 2012, Konrad Rzeszutek Wilk wrote: > > From: konrad <konrad@xxxxxxxxxxxxxxxxxxxxx> > > wrong email address Yeah :-) > > > > A rather annoying and common case is when booting a PVonHVM guest > > and exposing the PV KBD and PV VFB - as both of those do not > > make any sense. > > I would rather write: "as broken toolstacks don't always initialize the > backends correctly." OK. > > > > The HVM guest is using the VGA driver and the emulated > > keyboard for this. So we provide a very basic quirk framework > > (can be expanded in the future) to not wait for 6 minutes for those devices > > to initialize - they never wont. > > > > To trigger this, put this in your guest config: > > > > vfb = [ 'vnc=1, vnclisten=0.0.0.0 ,vncunused=1'] > > > > instead of this: > > vnc=1 > > vnclisten="0.0.0.0" > > > > [v3: Split delay in non-essential (30 seconds) and essential > > devices per Ian and Stefano suggestion] > > Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>quirk > > --- > > drivers/xen/xenbus/xenbus_probe_frontend.c | 69 > > +++++++++++++++++++++------ > > 1 files changed, 53 insertions(+), 16 deletions(-) > > > > diff --git a/drivers/xen/xenbus/xenbus_probe_frontend.c > > b/drivers/xen/xenbus/xenbus_probe_frontend.c > > index f20c5f1..7422913 100644 > > --- a/drivers/xen/xenbus/xenbus_probe_frontend.c > > +++ b/drivers/xen/xenbus/xenbus_probe_frontend.c > > @@ -135,7 +135,7 @@ static int read_backend_details(struct xenbus_device > > *xendev) > > return xenbus_read_otherend_details(xendev, "backend-id", "backend"); > > } > > > > -static int is_device_connecting(struct device *dev, void *data) > > +static int is_device_connecting(struct device *dev, void *data, bool > > ignore_vkbd) > > { > > struct xenbus_device *xendev = to_xenbus_device(dev); > > struct device_driver *drv = data; > > @@ -152,16 +152,41 @@ static int is_device_connecting(struct device *dev, > > void *data) > > if (drv && (dev->driver != drv)) > > return 0; > > > > + if (ignore_vkbd) { > > I would name the parameter ignore_nonessential, just to make it clearer > that is not just about vkbd OK. > > > > + /* With older QEMU, for PVonHVM guests the guest config files > > + * could contain: vfb = [ 'vnc=1, vnclisten=0.0.0.0'] > > + * which is nonsensical as there is no PV FB (there can be > > + * a PVKB) running as HVM guest. */ > > + > > + if ((strncmp(xendev->nodename, "device/vkbd", 11) == 0)) > > + return 0; > > + > > + if ((strncmp(xendev->nodename, "device/vfb", 10) == 0)) > > + return 0; > > + } > > xendrv = to_xenbus_driver(dev->driver); > > return (xendev->state < XenbusStateConnected || > > (xendev->state == XenbusStateConnected && > > xendrv->is_ready && !xendrv->is_ready(xendev))); > > } > > +static int essential_device_connecting(struct device *dev, void *data) > > +{ > > + return is_device_connecting(dev, data, true /* ignore PVKB+PVDB */); > > +} > > the comment is wrong Oh, PVKBD + PVFB. Right. > > > > +static int non_essential_device_connecting(struct device *dev, void *data) > > +{ > > + return is_device_connecting(dev, data, false); > > +} > > > > -static int exists_connecting_device(struct device_driver *drv) > > +static int exists_essential_connecting_device(struct device_driver *drv) > > { > > return bus_for_each_dev(&xenbus_frontend.bus, NULL, drv, > > - is_device_connecting); > > + essential_device_connecting); > > +} > > +static int exists_non_essential_connecting_device(struct device_driver > > *drv) > > +{ > > + return bus_for_each_dev(&xenbus_frontend.bus, NULL, drv, > > + non_essential_device_connecting); > > } > > > > static int print_device_status(struct device *dev, void *data) > > @@ -192,6 +217,23 @@ static int print_device_status(struct device *dev, > > void *data) > > /* We only wait for device setup after most initcalls have run. */ > > static int ready_to_wait_for_devices; > > > > +static bool wait_loop(unsigned long start, unsigned int max_delay, > > + unsigned int *seconds_waited) > > +{ > > + if (time_after(jiffies, start + (*seconds_waited+5)*HZ)) { > > + if (!*seconds_waited) > > + printk(KERN_WARNING "XENBUS: Waiting for " > > + "devices to initialise: "); > > + *seconds_waited += 5; > > + printk("%us...", max_delay - *seconds_waited); > > + if (*seconds_waited == max_delay) > > + return true; > > + } > > + > > + schedule_timeout_interruptible(HZ/10); > > + > > + return false; > > +} > > /* > > * On a 5-minute timeout, wait for all devices currently configured. We > > need > > * to do this to guarantee that the filesystems and / or network devices > > @@ -215,19 +257,14 @@ static void wait_for_devices(struct xenbus_driver > > *xendrv) > > if (!ready_to_wait_for_devices || !xen_domain()) > > return; > > > > - while (exists_connecting_device(drv)) { > > - if (time_after(jiffies, start + (seconds_waited+5)*HZ)) { > > - if (!seconds_waited) > > - printk(KERN_WARNING "XENBUS: Waiting for " > > - "devices to initialise: "); > > - seconds_waited += 5; > > - printk("%us...", 300 - seconds_waited); > > - if (seconds_waited == 300) > > - break; > > - } > > - > > - schedule_timeout_interruptible(HZ/10); > > - } > > + while (exists_non_essential_connecting_device(drv)) > > + if (wait_loop(start, 30, &seconds_waited)) > > + break; > > + > > + /* Skips PVKB and PVFB check.*/ > > + while (exists_essential_connecting_device(drv)) > > + if (wait_loop(start, 270, &seconds_waited)) > > + break; > > > > if (seconds_waited) > > printk("\n"); > > -- > > 1.7.7.5 > > > > Other than the comments I wrote above, I think the patch is good Sweet. thx! _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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