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, 4 deletions

diff --git a/xen/arch/x86/hvm/vmx/vmx.c b/xen/arch/x86/hvm/vmx/vmx.c
index d0de44a2ae..059d258d2d 100644
--- a/xen/arch/x86/hvm/vmx/vmx.c
+++ b/xen/arch/x86/hvm/vmx/vmx.c
@@ -2827,12 +2827,10 @@ void vmx_vmexit_handler(struct cpu_user_regs *regs)
         break;
 
     case EXIT_REASON_XSETBV:
-    {
-        u64 new_bv = (((u64)regs->edx) << 32) | regs->eax;
-        if ( hvm_handle_xsetbv(new_bv) == 0 )
+        if ( hvm_handle_xsetbv(regs->ecx,
+                               (regs->rdx << 32) | regs->_eax) == 0 )
             update_guest_eip(); /* Safe: XSETBV */
         break;
-    }
 
     case EXIT_REASON_APIC_WRITE:
         if ( vmx_handle_apic_write() )