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xen-pciback: reconfigure also from backend watch handler

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commit c81d3d24602540f65256f98831d0a25599ea6b87 upstream.

When multiple PCI devices get assigned to a guest right at boot, libxl
incrementally populates the backend tree. The writes for the first of
the devices trigger the backend watch. In turn xen_pcibk_setup_backend()
will set the XenBus state to Initialised, at which point no further
reconfigures would happen unless a device got hotplugged. Arrange for
reconfigure to also get triggered from the backend watch handler.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Cc: stable@vger.kernel.org
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Link: https://lore.kernel.org/r/2337cbd6-94b9-4187-9862-c03ea12e0c61@suse.com
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Jan Beulich 2021-05-18 18:14:07 +02:00 committed by Greg Kroah-Hartman
parent c196031f4f
commit 63a5b38447
1 changed files with 17 additions and 5 deletions
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22
drivers/xen/xen-pciback/xenbus.c
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@ -359,7 +359,8 @@ static int xen_pcibk_publish_pci_root(struct xen_pcibk_device *pdev,
return err;
}
static int xen_pcibk_reconfigure(struct xen_pcibk_device *pdev)
static int xen_pcibk_reconfigure(struct xen_pcibk_device *pdev,
enum xenbus_state state)
{
int err = 0;
int num_devs;
@ -373,9 +374,7 @@ static int xen_pcibk_reconfigure(struct xen_pcibk_device *pdev)
dev_dbg(&pdev->xdev->dev, "Reconfiguring device ...\n");
mutex_lock(&pdev->dev_lock);
/* Make sure we only reconfigure once */
if (xenbus_read_driver_state(pdev->xdev->nodename) !=
XenbusStateReconfiguring)
if (xenbus_read_driver_state(pdev->xdev->nodename) != state)
goto out;
err = xenbus_scanf(XBT_NIL, pdev->xdev->nodename, "num_devs", "%d",
@ -500,6 +499,10 @@ static int xen_pcibk_reconfigure(struct xen_pcibk_device *pdev)
}
}
if (state != XenbusStateReconfiguring)
/* Make sure we only reconfigure once. */
goto out;
err = xenbus_switch_state(pdev->xdev, XenbusStateReconfigured);
if (err) {
xenbus_dev_fatal(pdev->xdev, err,
@ -525,7 +528,7 @@ static void xen_pcibk_frontend_changed(struct xenbus_device *xdev,
break;
case XenbusStateReconfiguring:
xen_pcibk_reconfigure(pdev);
xen_pcibk_reconfigure(pdev, XenbusStateReconfiguring);
break;
case XenbusStateConnected:
@ -664,6 +667,15 @@ static void xen_pcibk_be_watch(struct xenbus_watch *watch,
xen_pcibk_setup_backend(pdev);
break;
case XenbusStateInitialised:
/*
* We typically move to Initialised when the first device was
* added. Hence subsequent devices getting added may need
* reconfiguring.
*/
xen_pcibk_reconfigure(pdev, XenbusStateInitialised);
break;
default:
break;
}