[PATCH v5 6/5] x86/hvm: Add a non-FEP path to the #UD handler

[Alejandro Vallejo <alejandro.garciavallejo@xxxxxxx>]

While the #UD handler is dead code when CONFIG_HVM_FEP is disabled it's
helpful to keep the function around. Reinject #UD in the non-FEP case so
DCE can remove the rest.

Signed-off-by: Alejandro Vallejo <alejandro.garciavallejo@xxxxxxx>
---
 xen/arch/x86/hvm/hvm.c | 18 +++++++++---------
 1 file changed, 9 insertions(+), 9 deletions(-)

diff --git a/xen/arch/x86/hvm/hvm.c b/xen/arch/x86/hvm/hvm.c
index 4c00cf4c4fe..0eaeb728382 100644
--- a/xen/arch/x86/hvm/hvm.c
+++ b/xen/arch/x86/hvm/hvm.c
@@ -3835,13 +3835,18 @@ int hvm_descriptor_access_intercept(uint64_t exit_info,
 void hvm_ud_intercept(struct cpu_user_regs *regs)
 {
     struct vcpu *cur = current;
-    bool should_emulate = false;
     struct hvm_emulate_ctxt ctxt;
     const struct segment_register *cs;
     uint32_t walk;
     unsigned long addr;
     char sig[5]; /* ud2; .ascii "xen" */
 
+    if ( !opt_hvm_fep )
+    {
+        ASSERT_UNREACHABLE();
+        goto reinject;
+    }
+
     hvm_emulate_init_once(&ctxt, NULL, regs);
 
     cs = &ctxt.seg_reg[x86_seg_cs];
@@ -3863,20 +3868,15 @@ void hvm_ud_intercept(struct cpu_user_regs *regs)
             regs->rip = (uint32_t)regs->rip;
 
         add_taint(TAINT_HVM_FEP);
-
-        should_emulate = true;
-    }
-
-    if ( !should_emulate )
-    {
-        hvm_inject_hw_exception(X86_EXC_UD, X86_EVENT_NO_EC);
-        return;
     }
+    else
+        goto reinject;
 
     switch ( hvm_emulate_one(&ctxt, VIO_no_completion) )
     {
     case X86EMUL_UNHANDLEABLE:
     case X86EMUL_UNIMPLEMENTED:
+    reinject:
         hvm_inject_hw_exception(X86_EXC_UD, X86_EVENT_NO_EC);
         break;
     case X86EMUL_EXCEPTION:
-- 
2.43.0