x86: allow pv guests to disable TSC for applications

Linux, under CONFIG_SECCOMP, has been capable of hiding the TSC from
processes for quite a while. This patch enables this to actually work
for pv kernels, by allowing them to control CR4.TSD (and, as a simple
thing to do at the same time, CR4.DE).

Applies cleanly only on top of the previously submitted debug register
handling patch.

Signed-off-by: Jan Beulich <jbeulich@novell.com>

Also clean up CR4 and EFER handling, and hack-n-slash header file
inclusion madness to get the tree building again.

Signed-off-by: Keir Fraser <keir@xensource.com>

1 files changed, 3 insertions, 5 deletions

diff --git a/xen/include/asm-x86/msr.h b/xen/include/asm-x86/msr.h
index 79d37a33ad..96a078824e 100644
--- a/xen/include/asm-x86/msr.h
+++ b/xen/include/asm-x86/msr.h
@@ -90,16 +90,14 @@ static inline void wrmsrl(unsigned int msr, __u64 val)
 			  : "c" (counter))
 
 
-DECLARE_PER_CPU(__u64, efer);
+DECLARE_PER_CPU(u64, efer);
 
-static inline __u64 read_efer(void)
+static inline u64 read_efer(void)
 {
-    if (!this_cpu(efer))
-        rdmsrl(MSR_EFER, this_cpu(efer));
     return this_cpu(efer);
 }
 
-static inline void write_efer(__u64 val)
+static inline void write_efer(u64 val)
 {
     this_cpu(efer) = val;
     wrmsrl(MSR_EFER, val);