[Xen-changelog] [xen master] x86, idle: add barriers to CLFLUSH workaround

[patchbot@xxxxxxx]

commit 48d32458bcd453e31b458bca868a079a6d0a38af
Author:     H. Peter Anvin <hpa@xxxxxxxxxxxxxxx>
AuthorDate: Tue Sep 9 18:09:08 2014 +0200
Commit:     Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Tue Sep 9 18:09:08 2014 +0200

    x86, idle: add barriers to CLFLUSH workaround
    
    ... since the documentation is explicit that CLFLUSH is only ordered
    with respect to MFENCE.
    
    Signed-off-by: H. Peter Anvin <hpa@xxxxxxxxxxxxxxx>
    Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
---
 xen/arch/x86/acpi/cpu_idle.c |    4 ++++
 1 files changed, 4 insertions(+), 0 deletions(-)

diff --git a/xen/arch/x86/acpi/cpu_idle.c b/xen/arch/x86/acpi/cpu_idle.c
index b05fb39..136c0b6 100644
--- a/xen/arch/x86/acpi/cpu_idle.c
+++ b/xen/arch/x86/acpi/cpu_idle.c
@@ -336,7 +336,11 @@ void mwait_idle_with_hints(unsigned int eax, unsigned int 
ecx)
     s_time_t expires = per_cpu(timer_deadline, cpu);
 
     if ( boot_cpu_has(X86_FEATURE_CLFLUSH_MONITOR) )
+    {
+        mb();
         clflush((void *)&mwait_wakeup(cpu));
+        mb();
+    }
 
     __monitor((void *)&mwait_wakeup(cpu), 0, 0);
     smp_mb();
--
generated by git-patchbot for /home/xen/git/xen.git#master

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