[PATCH v2 5/7] x86/alternative: Replace a continue with a goto

[Andrew Cooper <andrew.cooper3@xxxxxxxxxx>]

A subsequent patch is going to insert a loop, which interferes with the
continue in the devirtualisation logic.

Replace it with a goto, and a paragraph explaining why we intentionally avoid
setting a->priv = 1.

No functional change.

Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
Acked-by: Jan Beulich <jbeulich@xxxxxxxx>
---
CC: Jan Beulich <JBeulich@xxxxxxxx>
CC: Roger Pau Monné <roger.pau@xxxxxxxxxx>
---
 xen/arch/x86/alternative.c | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/xen/arch/x86/alternative.c b/xen/arch/x86/alternative.c
index 5ea7f51b007c..b745f112154a 100644
--- a/xen/arch/x86/alternative.c
+++ b/xen/arch/x86/alternative.c
@@ -328,7 +328,15 @@ static int init_or_livepatch _apply_alternatives(struct 
alt_instr *start,
                         buf[4] = 0xff;
                     }
                     else
-                        continue;
+                    {
+                        /*
+                         * The function pointer we're wanting to devirtualise
+                         * is still NULL, and we're not sealing yet.  Leave
+                         * the alternative fully un-processed, in order to try
+                         * again next time around.
+                         */
+                        goto skip_this_alternative;
+                    }
                 }
                 else if ( force && system_state < SYS_STATE_active )
                     ASSERT_UNREACHABLE();
@@ -343,6 +351,7 @@ static int init_or_livepatch _apply_alternatives(struct 
alt_instr *start,
 
         add_nops(buf + a->repl_len, total_len - a->repl_len);
         text_poke(orig, buf, total_len);
+    skip_this_alternative:;
     }
 
     /*
-- 
2.39.5