x86/tsc: Remove incorrect assertion from cstate_restore_tsc()...

..fix and move to write_tsc().

Signed-off-by: Keir Fraser <keir@xen.org>
xen-unstable changeset:   23342:16d12acccacf
xen-unstable date:        Mon May 16 13:24:05 2011 +0100

diff --git a/xen/arch/x86/time.c b/xen/arch/x86/time.c
index c08f815b17b3688d15dadfae7deec594811d6f6f..286281f16b1971d5bc8d3100b4db7c0d7ec4ba96 100644 (file)
--- a/xen/arch/x86/time.c
+++ b/xen/arch/x86/time.c
@@ -724,8 +724,6 @@ void cstate_restore_tsc(void)
 
     new_tsc = t->local_tsc_stamp + scale_delta(stime_delta, &sys_to_tsc);
 
-    ASSERT(boot_cpu_has(X86_FEATURE_TSC_RELIABLE));
-
     write_tsc(new_tsc);
 }
 

diff --git a/xen/include/asm-x86/msr.h b/xen/include/asm-x86/msr.h
index f84c0dddf86f5b176f34a2be82ea1f8dc65c8b58..4335bf551f06022fa84b21a6e32211db8d1ff11a 100644 (file)
--- a/xen/include/asm-x86/msr.h
+++ b/xen/include/asm-x86/msr.h
@@ -82,7 +82,13 @@ static inline void wrmsrl(unsigned int msr, __u64 val)
 } while(0)
 #endif
 
-#define write_tsc(val) wrmsrl(MSR_IA32_TSC, val)
+#define __write_tsc(val) wrmsrl(MSR_IA32_TSC, val)
+#define write_tsc(val) ({                                       \
+    /* Reliable TSCs are in lockstep across all CPUs. We should \
+     * never write to them. */                                  \
+    ASSERT(!boot_cpu_has(X86_FEATURE_TSC_RELIABLE));            \
+    __write_tsc(val);                                           \
+})
 
 #define write_rdtscp_aux(val) wrmsr(MSR_TSC_AUX, (val), 0)