Merge tag 'stable/for-linus-3.14-rc0-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip

Pull Xen updates from Konrad Rzeszutek Wilk:
 "Two major features that Xen community is excited about:

  The first is event channel scalability by David Vrabel - we switch
  over from an two-level per-cpu bitmap of events (IRQs) - to an FIFO
  queue with priorities.  This lets us be able to handle more events,
  have lower latency, and better scalability.  Good stuff.

  The other is PVH by Mukesh Rathor.  In short, PV is a mode where the
  kernel lets the hypervisor program page-tables, segments, etc.  With
  EPT/NPT capabilities in current processors, the overhead of doing this
  in an HVM (Hardware Virtual Machine) container is much lower than the
  hypervisor doing it for us.

  In short we let a PV guest run without doing page-table, segment,
  syscall, etc updates through the hypervisor - instead it is all done
  within the guest container.  It is a "hybrid" PV - hence the 'PVH'
  name - a PV guest within an HVM container.

  The major benefits are less code to deal with - for example we only
  use one function from the the pv_mmu_ops (which has 39 function
  calls); faster performance for syscall (no context switches into the
  hypervisor); less traps on various operations; etc.

  It is still being baked - the ABI is not yet set in stone.  But it is
  pretty awesome and we are excited about it.

  Lastly, there are some changes to ARM code - you should get a simple
  conflict which has been resolved in #linux-next.

  In short, this pull has awesome features.

  Features:
   - FIFO event channels.  Key advantages: support for over 100,000
     events (2^17), 16 different event priorities, improved fairness in
     event latency through the use of FIFOs.
   - Xen PVH support.  "It’s a fully PV kernel mode, running with
     paravirtualized disk and network, paravirtualized interrupts and
     timers, no emulated devices of any kind (and thus no qemu), no BIOS
     or legacy boot — but instead of requiring PV MMU, it uses the HVM
     hardware extensions to virtualize the pagetables, as well as system
     calls and other privileged operations." (from "The
     Paravirtualization Spectrum, Part 2: From poles to a spectrum")

  Bug-fixes:
   - Fixes in balloon driver (refactor and make it work under ARM)
   - Allow xenfb to be used in HVM guests.
   - Allow xen_platform_pci=0 to work properly.
   - Refactors in event channels"

* tag 'stable/for-linus-3.14-rc0-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip: (52 commits)
  xen/pvh: Set X86_CR0_WP and others in CR0 (v2)
  MAINTAINERS: add git repository for Xen
  xen/pvh: Use 'depend' instead of 'select'.
  xen: delete new instances of __cpuinit usage
  xen/fb: allow xenfb initialization for hvm guests
  xen/evtchn_fifo: fix error return code in evtchn_fifo_setup()
  xen-platform: fix error return code in platform_pci_init()
  xen/pvh: remove duplicated include from enlighten.c
  xen/pvh: Fix compile issues with xen_pvh_domain()
  xen: Use dev_is_pci() to check whether it is pci device
  xen/grant-table: Force to use v1 of grants.
  xen/pvh: Support ParaVirtualized Hardware extensions (v3).
  xen/pvh: Piggyback on PVHVM XenBus.
  xen/pvh: Piggyback on PVHVM for grant driver (v4)
  xen/grant: Implement an grant frame array struct (v3).
  xen/grant-table: Refactor gnttab_init
  xen/grants: Remove gnttab_max_grant_frames dependency on gnttab_init.
  xen/pvh: Piggyback on PVHVM for event channels (v2)
  xen/pvh: Update E820 to work with PVH (v2)
  xen/pvh: Secondary VCPU bringup (non-bootup CPUs)
  ...

1 files changed, 76 insertions, 3 deletions

diff --git a/arch/x86/xen/platform-pci-unplug.c b/arch/x86/xen/platform-pci-unplug.c
index 0a7852483ff..a8261716d58 100644
--- a/arch/x86/xen/platform-pci-unplug.c
+++ b/arch/x86/xen/platform-pci-unplug.c
@@ -30,10 +30,9 @@
 #define XEN_PLATFORM_ERR_PROTOCOL -2
 #define XEN_PLATFORM_ERR_BLACKLIST -3
 
-/* store the value of xen_emul_unplug after the unplug is done */
-int xen_platform_pci_unplug;
-EXPORT_SYMBOL_GPL(xen_platform_pci_unplug);
 #ifdef CONFIG_XEN_PVHVM
+/* store the value of xen_emul_unplug after the unplug is done */
+static int xen_platform_pci_unplug;
 static int xen_emul_unplug;
 
 static int check_platform_magic(void)
@@ -69,6 +68,80 @@ static int check_platform_magic(void)
 	return 0;
 }
 
+bool xen_has_pv_devices()
+{
+	if (!xen_domain())
+		return false;
+
+	/* PV domains always have them. */
+	if (xen_pv_domain())
+		return true;
+
+	/* And user has xen_platform_pci=0 set in guest config as
+	 * driver did not modify the value. */
+	if (xen_platform_pci_unplug == 0)
+		return false;
+
+	if (xen_platform_pci_unplug & XEN_UNPLUG_NEVER)
+		return false;
+
+	if (xen_platform_pci_unplug & XEN_UNPLUG_ALL)
+		return true;
+
+	/* This is an odd one - we are going to run legacy
+	 * and PV drivers at the same time. */
+	if (xen_platform_pci_unplug & XEN_UNPLUG_UNNECESSARY)
+		return true;
+
+	/* And the caller has to follow with xen_pv_{disk,nic}_devices
+	 * to be certain which driver can load. */
+	return false;
+}
+EXPORT_SYMBOL_GPL(xen_has_pv_devices);
+
+static bool __xen_has_pv_device(int state)
+{
+	/* HVM domains might or might not */
+	if (xen_hvm_domain() && (xen_platform_pci_unplug & state))
+		return true;
+
+	return xen_has_pv_devices();
+}
+
+bool xen_has_pv_nic_devices(void)
+{
+	return __xen_has_pv_device(XEN_UNPLUG_ALL_NICS | XEN_UNPLUG_ALL);
+}
+EXPORT_SYMBOL_GPL(xen_has_pv_nic_devices);
+
+bool xen_has_pv_disk_devices(void)
+{
+	return __xen_has_pv_device(XEN_UNPLUG_ALL_IDE_DISKS |
+				   XEN_UNPLUG_AUX_IDE_DISKS | XEN_UNPLUG_ALL);
+}
+EXPORT_SYMBOL_GPL(xen_has_pv_disk_devices);
+
+/*
+ * This one is odd - it determines whether you want to run PV _and_
+ * legacy (IDE) drivers together. This combination is only possible
+ * under HVM.
+ */
+bool xen_has_pv_and_legacy_disk_devices(void)
+{
+	if (!xen_domain())
+		return false;
+
+	/* N.B. This is only ever used in HVM mode */
+	if (xen_pv_domain())
+		return false;
+
+	if (xen_platform_pci_unplug & XEN_UNPLUG_UNNECESSARY)
+		return true;
+
+	return false;
+}
+EXPORT_SYMBOL_GPL(xen_has_pv_and_legacy_disk_devices);
+
 void xen_unplug_emulated_devices(void)
 {
 	int r;