x86: fix XCR0 handling

- both VMX and SVM ignored the ECX input to XSETBV
- both SVM and VMX used the full 64-bit RAX when calculating the input
  mask to XSETBV
- faults on XSETBV did not get recovered from

Also consolidate the handling for PV and HVM into a single function,
and make the per-CPU variable "xcr0" static to xstate.c.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Keir Fraser <keir@xen.org>
Acked-by: George Dunlap <george.dunlap@eu.citrix.com>

1 files changed, 2 insertions, 5 deletions

diff --git a/xen/include/asm-x86/xstate.h b/xen/include/asm-x86/xstate.h
index 6d64f37827..49168f3293 100644
--- a/xen/include/asm-x86/xstate.h
+++ b/xen/include/asm-x86/xstate.h
@@ -9,7 +9,6 @@
 #define __ASM_XSTATE_H
 
 #include <xen/types.h>
-#include <xen/percpu.h>
 
 #define FCW_DEFAULT               0x037f
 #define MXCSR_DEFAULT             0x1f80
@@ -34,9 +33,6 @@
 #define XSTATE_NONLAZY (XSTATE_LWP)
 #define XSTATE_LAZY    (XSTATE_ALL & ~XSTATE_NONLAZY)
 
-/* extended state variables */
-DECLARE_PER_CPU(uint64_t, xcr0);
-
 extern unsigned int xsave_cntxt_size;
 extern u64 xfeature_mask;
 
@@ -75,11 +71,12 @@ struct xsave_struct
 } __attribute__ ((packed, aligned (64)));
 
 /* extended state operations */
-void set_xcr0(u64 xfeatures);
+bool_t __must_check set_xcr0(u64 xfeatures);
 uint64_t get_xcr0(void);
 void xsave(struct vcpu *v, uint64_t mask);
 void xrstor(struct vcpu *v, uint64_t mask);
 bool_t xsave_enabled(const struct vcpu *v);
+int __must_check handle_xsetbv(u32 index, u64 new_bv);
 
 /* extended state init and cleanup functions */
 void xstate_free_save_area(struct vcpu *v);