| Message ID | 20240422181434.3463252-5-andrew.cooper3@citrix.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | x86/alternatives: Adjust all insn-relative fields | expand |
On 22.04.2024 20:14, Andrew Cooper wrote: > 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@citrix.com> Acked-by: Jan Beulich <jbeulich@suse.com>
diff --git a/xen/arch/x86/alternative.c b/xen/arch/x86/alternative.c index 2ca4dfd569bc..c86ea235e865 100644 --- a/xen/arch/x86/alternative.c +++ b/xen/arch/x86/alternative.c @@ -308,7 +308,15 @@ static void 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 + * process it the next time around. + */ + goto skip_this_alternative; + } } else if ( force && system_state < SYS_STATE_active ) ASSERT_UNREACHABLE(); @@ -323,6 +331,7 @@ static void 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:; } /*
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@citrix.com> --- CC: Jan Beulich <JBeulich@suse.com> CC: Roger Pau Monné <roger.pau@citrix.com> --- xen/arch/x86/alternative.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-)