x86/IST: Create set_ist() helper function

... to save using open-coded bitwise operations, and update all IST
manipulation sites to use the function.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Committed-by: Jan Beulich <jbeulich@suse.com>

1 files changed, 6 insertions, 6 deletions

diff --git a/xen/arch/x86/hvm/svm/svm.c b/xen/arch/x86/hvm/svm/svm.c
index c3dc048e84..55a5ae5ab5 100644
--- a/xen/arch/x86/hvm/svm/svm.c
+++ b/xen/arch/x86/hvm/svm/svm.c
@@ -869,9 +869,9 @@ static void svm_ctxt_switch_from(struct vcpu *v)
     svm_vmload(per_cpu(root_vmcb, cpu));
 
     /* Resume use of ISTs now that the host TR is reinstated. */
-    idt_tables[cpu][TRAP_double_fault].a  |= IST_DF << 32;
-    idt_tables[cpu][TRAP_nmi].a           |= IST_NMI << 32;
-    idt_tables[cpu][TRAP_machine_check].a |= IST_MCE << 32;
+    set_ist(&idt_tables[cpu][TRAP_double_fault],  IST_DF);
+    set_ist(&idt_tables[cpu][TRAP_nmi],           IST_NMI);
+    set_ist(&idt_tables[cpu][TRAP_machine_check], IST_MCE);
 }
 
 static void svm_ctxt_switch_to(struct vcpu *v)
@@ -893,9 +893,9 @@ static void svm_ctxt_switch_to(struct vcpu *v)
      * Cannot use ISTs for NMI/#MC/#DF while we are running with the guest TR.
      * But this doesn't matter: the IST is only req'd to handle SYSCALL/SYSRET.
      */
-    idt_tables[cpu][TRAP_double_fault].a  &= ~(7UL << 32);
-    idt_tables[cpu][TRAP_nmi].a           &= ~(7UL << 32);
-    idt_tables[cpu][TRAP_machine_check].a &= ~(7UL << 32);
+    set_ist(&idt_tables[cpu][TRAP_double_fault],  IST_NONE);
+    set_ist(&idt_tables[cpu][TRAP_nmi],           IST_NONE);
+    set_ist(&idt_tables[cpu][TRAP_machine_check], IST_NONE);
 
     svm_restore_dr(v);