x86-64: move unlazy_fpu() into lazy cpu state part of context switch
Make sure that unlazy_fpu()'s stts gets batched along with the other
cpu state changes during context switch. (32-bit already does this.)
This makes sure it gets batched when running paravirtualized.
[ Impact: optimise paravirtual FPU context switch ]
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Cc: Alok Kataria <akataria@vmware.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
index ebefb54..c9b8904 100644
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -419,6 +419,9 @@
load_TLS(next, cpu);
+ /* Must be after DS reload */
+ unlazy_fpu(prev_p);
+
/*
* Leave lazy mode, flushing any hypercalls made here.
* This must be done before restoring TLS segments so
@@ -459,9 +462,6 @@
wrmsrl(MSR_KERNEL_GS_BASE, next->gs);
prev->gsindex = gsindex;
- /* Must be after DS reload */
- unlazy_fpu(prev_p);
-
/*
* Switch the PDA and FPU contexts.
*/