Merge remote-tracking branch 'linus/master' into staging/for_v3.8

* linus/master: (1428 commits)
  futex: avoid wake_futex() for a PI futex_q
  watchdog: using u64 in get_sample_period()
  writeback: put unused inodes to LRU after writeback completion
  mm: vmscan: check for fatal signals iff the process was throttled
  Revert "mm: remove __GFP_NO_KSWAPD"
  proc: check vma->vm_file before dereferencing
  UAPI: strip the _UAPI prefix from header guards during header installation
  include/linux/bug.h: fix sparse warning related to BUILD_BUG_ON_INVALID
  Linux 3.7-rc7
  powerpc/eeh: Do not invalidate PE properly
  ALSA: hda - Fix build without CONFIG_PM
  of/address: sparc: Declare of_iomap as an extern function for sparc again
  PM / QoS: fix wrong error-checking condition
  bnx2x: remove redundant warning log
  vxlan: fix command usage in its doc
  8139cp: revert "set ring address before enabling receiver"
  MPI: Fix compilation on MIPS with GCC 4.4 and newer
  MIPS: Fix crash that occurs when function tracing is enabled
  MIPS: Merge overlapping bootmem ranges
  jbd: Fix lock ordering bug in journal_unmap_buffer()
  ...

1 files changed, 12 insertions, 4 deletions

diff --git a/arch/x86/kernel/cpu/perf_event.c b/arch/x86/kernel/cpu/perf_event.c
index 915b876edd1e..4a3374e61a93 100644
--- a/arch/x86/kernel/cpu/perf_event.c
+++ b/arch/x86/kernel/cpu/perf_event.c
@@ -208,12 +208,14 @@ static bool check_hw_exists(void)
 	}
 
 	/*
-	 * Now write a value and read it back to see if it matches,
-	 * this is needed to detect certain hardware emulators (qemu/kvm)
-	 * that don't trap on the MSR access and always return 0s.
+	 * Read the current value, change it and read it back to see if it
+	 * matches, this is needed to detect certain hardware emulators
+	 * (qemu/kvm) that don't trap on the MSR access and always return 0s.
 	 */
-	val = 0xabcdUL;
 	reg = x86_pmu_event_addr(0);
+	if (rdmsrl_safe(reg, &val))
+		goto msr_fail;
+	val ^= 0xffffUL;
 	ret = wrmsrl_safe(reg, val);
 	ret |= rdmsrl_safe(reg, &val_new);
 	if (ret || val != val_new)
@@ -338,6 +340,9 @@ int x86_setup_perfctr(struct perf_event *event)
 		/* BTS is currently only allowed for user-mode. */
 		if (!attr->exclude_kernel)
 			return -EOPNOTSUPP;
+
+		if (!attr->exclude_guest)
+			return -EOPNOTSUPP;
 	}
 
 	hwc->config |= config;
@@ -380,6 +385,9 @@ int x86_pmu_hw_config(struct perf_event *event)
 	if (event->attr.precise_ip) {
 		int precise = 0;
 
+		if (!event->attr.exclude_guest)
+			return -EOPNOTSUPP;
+
 		/* Support for constant skid */
 		if (x86_pmu.pebs_active && !x86_pmu.pebs_broken) {
 			precise++;