Merge tag 'stable/for-linus-3.7-rc0-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen

Pull Xen fixes from Konrad Rzeszutek Wilk:
 "This has four bug-fixes and one tiny feature that I forgot to put
  initially in my tree due to oversight.

  The feature is for kdump kernels to speed up the /proc/vmcore reading.
  There is a ram_is_pfn helper function that the different platforms can
  register for.  We are now doing that.

  The bug-fixes cover some embarrassing struct pv_cpu_ops variables
  being set to NULL on Xen (but not baremetal).  We had a similar issue
  in the past with {write|read}_msr_safe and this fills the three
  missing ones.  The other bug-fix is to make the console output (hvc)
  be capable of dealing with misbehaving backends and not fall flat on
  its face.  Lastly, a quirk for older XenBus implementations that came
  with an ancient v3.4 hypervisor (so RHEL5 based) - reading of certain
  non-existent attributes just hangs the guest during bootup - so we
  take precaution of not doing that on such older installations.

  Feature:
   - Register a pfn_is_ram helper to speed up reading of /proc/vmcore.
  Bug-fixes:
   - Three pvops call for Xen were undefined causing BUG_ONs.
   - Add a quirk so that the shutdown watches (used by kdump) are not
     used with older Xen (3.4).
   - Fix ungraceful state transition for the HVC console."

* tag 'stable/for-linus-3.7-rc0-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen:
  xen/pv-on-hvm kexec: add quirk for Xen 3.4 and shutdown watches.
  xen/bootup: allow {read|write}_cr8 pvops call.
  xen/bootup: allow read_tscp call for Xen PV guests.
  xen pv-on-hvm: add pfn_is_ram helper for kdump
  xen/hvc: handle backend CLOSED without CLOSING

1 files changed, 17 insertions, 1 deletions

diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c
index bf788d34530d..e3497f240eab 100644
--- a/arch/x86/xen/enlighten.c
+++ b/arch/x86/xen/enlighten.c
@@ -987,7 +987,16 @@ static void xen_write_cr4(unsigned long cr4)
 
         native_write_cr4(cr4);
 }
-
+#ifdef CONFIG_X86_64
+static inline unsigned long xen_read_cr8(void)
+{
+        return 0;
+}
+static inline void xen_write_cr8(unsigned long val)
+{
+        BUG_ON(val);
+}
+#endif
 static int xen_write_msr_safe(unsigned int msr, unsigned low, unsigned high)
 {
         int ret;
@@ -1156,6 +1165,11 @@ static const struct pv_cpu_ops xen_cpu_ops __initconst = {
         .read_cr4_safe = native_read_cr4_safe,
         .write_cr4 = xen_write_cr4,
 
+#ifdef CONFIG_X86_64
+        .read_cr8 = xen_read_cr8,
+        .write_cr8 = xen_write_cr8,
+#endif
+
         .wbinvd = native_wbinvd,
 
         .read_msr = native_read_msr_safe,
@@ -1164,6 +1178,8 @@ static const struct pv_cpu_ops xen_cpu_ops __initconst = {
         .read_tsc = native_read_tsc,
         .read_pmc = native_read_pmc,
 
+        .read_tscp = native_read_tscp,
+
         .iret = xen_iret,
         .irq_enable_sysexit = xen_sysexit,
 #ifdef CONFIG_X86_64