KarimAllah Ahmed 72a9b18629 xen: Remove event channel notification through Xen PCI platform device ... Ever since commit 254d1a3f02 ("xen/pv-on-hvm kexec: shutdown watches from old kernel") using the INTx interrupt from Xen PCI platform device for event channel notification would just lockup the guest during bootup. postcore_initcall now calls xs_reset_watches which will eventually try to read a value from XenStore and will get stuck on read_reply at XenBus forever since the platform driver is not probed yet and its INTx interrupt handler is not registered yet. That means that the guest can not be notified at this moment of any pending event channels and none of the per-event handlers will ever be invoked (including the XenStore one) and the reply will never be picked up by the kernel. The exact stack where things get stuck during xenbus_init: -xenbus_init -xs_init -xs_reset_watches -xenbus_scanf -xenbus_read -xs_single -xs_single -xs_talkv Vector callbacks have always been the favourite event notification mechanism since their introduction in commit 38e20b07ef ("x86/xen: event channels delivery on HVM.") and the vector callback feature has always been advertised for quite some time by Xen that's why INTx was broken for several years now without impacting anyone. Luckily this also means that event channel notification through INTx is basically dead-code which can be safely removed without impacting anybody since it has been effectively disabled for more than 4 years with nobody complaining about it (at least as far as I'm aware of). This commit removes event channel notification through Xen PCI platform device. Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com> Cc: David Vrabel <david.vrabel@citrix.com> Cc: Juergen Gross <jgross@suse.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: x86@kernel.org Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: Bjorn Helgaas <bhelgaas@google.com> Cc: Stefano Stabellini <stefano.stabellini@eu.citrix.com> Cc: Julien Grall <julien.grall@citrix.com> Cc: Vitaly Kuznetsov <vkuznets@redhat.com> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Ross Lagerwall <ross.lagerwall@citrix.com> Cc: xen-devel@lists.xenproject.org Cc: linux-kernel@vger.kernel.org Cc: linux-pci@vger.kernel.org Cc: Anthony Liguori <aliguori@amazon.com> Signed-off-by: KarimAllah Ahmed <karahmed@amazon.de> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Signed-off-by: David Vrabel <david.vrabel@citrix.com>		2016-09-30 11:44:34 +01:00
..
acpi	treewide: replace obsolete _refok by __ref	2016-08-02 17:31:41 -04:00
asm-generic	locking/qrwlock: Fix write unlock bug on big endian systems	2016-08-10 14:13:27 +02:00
clocksource
crypto	A number of improvements for the /dev/random driver; the most	2016-07-27 15:11:55 -07:00
drm	Merge branch 'drm-next-4.8' of git://people.freedesktop.org/~agd5f/linux into drm-next	2016-08-08 16:45:33 +10:00
dt-bindings	ARM: DT updates for v4.8	2016-08-01 18:37:45 -04:00
keys
kvm	KVM/ARM Changes for v4.8 - Take 2	2016-08-04 13:59:56 +02:00
linux	xen/events: Convert to hotplug state machine	2016-09-30 11:23:04 +01:00
math-emu
media	dma-mapping: use unsigned long for dma_attrs	2016-08-04 08:50:07 -04:00
memory
misc
net	Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net	2016-08-17 17:26:58 -07:00
pcmcia
ras
rdma	Second round of merge items for 4.8	2016-08-04 20:26:31 -04:00
rxrpc
scsi	Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/nab/target-pending	2016-08-04 20:04:37 -04:00
soc	ARM: SoC driver updates for v4.8	2016-08-01 18:36:01 -04:00
sound	Merge tag 'drm-for-v4.8' of git://people.freedesktop.org/~airlied/linux	2016-08-01 21:44:08 -04:00
target
trace	Luiz Capitulino noticed that the tick_stop tracepoint wasn't being parsed	2016-08-09 10:34:09 -07:00
uapi	Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net	2016-08-17 17:26:58 -07:00
video
xen	xen: Remove event channel notification through Xen PCI platform device	2016-09-30 11:44:34 +01:00
Kbuild