x86/spec-ctrl: Rename opt_ibpb to opt_ibpb_ctxt_switch

We are about to introduce the use of IBPB at different points in Xen, making
opt_ibpb ambiguous.  Rename it to opt_ibpb_ctxt_switch.

No functional change.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
(cherry picked from commit a8e5ef079d)

xen/arch/x86/domain.c

@@ -1792,7 +1792,7 @@ void context_switch(struct vcpu *prev, struct vcpu *next)
 
         ctxt_switch_levelling(next);
 
-        if ( opt_ibpb && !is_idle_domain(nextd) )
+        if ( opt_ibpb_ctxt_switch && !is_idle_domain(nextd) )
         {
             static DEFINE_PER_CPU(unsigned int, last);
             unsigned int *last_id = &this_cpu(last);

xen/arch/x86/spec_ctrl.c

@@ -54,7 +54,7 @@ int8_t __initdata opt_stibp = -1;
 bool __read_mostly opt_ssbd;
 int8_t __initdata opt_psfd = -1;
 
-bool __read_mostly opt_ibpb = true;
+bool __read_mostly opt_ibpb_ctxt_switch = true;
 int8_t __read_mostly opt_eager_fpu = -1;
 int8_t __read_mostly opt_l1d_flush = -1;
 bool __read_mostly opt_branch_harden = true;
@@ -118,7 +118,7 @@ static int __init parse_spec_ctrl(const char *s)
 
             opt_thunk = THUNK_JMP;
             opt_ibrs = 0;
-            opt_ibpb = false;
+            opt_ibpb_ctxt_switch = false;
             opt_ssbd = false;
             opt_l1d_flush = 0;
             opt_branch_harden = false;
@@ -239,7 +239,7 @@ static int __init parse_spec_ctrl(const char *s)
 
         /* Misc settings. */
         else if ( (val = parse_boolean("ibpb", s, ss)) >= 0 )
-            opt_ibpb = val;
+            opt_ibpb_ctxt_switch = val;
         else if ( (val = parse_boolean("eager-fpu", s, ss)) >= 0 )
             opt_eager_fpu = val;
         else if ( (val = parse_boolean("l1d-flush", s, ss)) >= 0 )
@@ -455,7 +455,7 @@ static void __init print_details(enum ind_thunk thunk, uint64_t caps)
            (opt_tsx & 1)                             ? " TSX+" : " TSX-",
            !boot_cpu_has(X86_FEATURE_SRBDS_CTRL)     ? "" :
            opt_srb_lock                              ? " SRB_LOCK+" : " SRB_LOCK-",
-           opt_ibpb                                  ? " IBPB"  : "",
+           opt_ibpb_ctxt_switch                      ? " IBPB-ctxt" : "",
            opt_l1d_flush                             ? " L1D_FLUSH" : "",
            opt_md_clear_pv || opt_md_clear_hvm ||
            opt_fb_clear_mmio                         ? " VERW"  : "",
@@ -1170,7 +1170,7 @@ void __init init_speculation_mitigations(void)
 
     /* Check we have hardware IBPB support before using it... */
     if ( !boot_cpu_has(X86_FEATURE_IBRSB) && !boot_cpu_has(X86_FEATURE_IBPB) )
-        opt_ibpb = false;
+        opt_ibpb_ctxt_switch = false;
 
     /* Check whether Eager FPU should be enabled by default. */
     if ( opt_eager_fpu == -1 )

xen/include/asm-x86/spec_ctrl.h

@@ -63,7 +63,7 @@
 void init_speculation_mitigations(void);
 void spec_ctrl_init_domain(struct domain *d);
 
-extern bool opt_ibpb;
+extern bool opt_ibpb_ctxt_switch;
 extern bool opt_ssbd;
 extern int8_t opt_eager_fpu;
 extern int8_t opt_l1d_flush;