[PATCH 1/3] x86/HVM: permit CLFLUSH{,OPT} on execute-only code segments

[Jan Beulich]

The SDM explicitly permits this, and since that's sensible behavior
don't special case AMD (where the PM doesn't explicitly say so).

Fixes: 52dba7bd0b36 ("x86emul: generalize wbinvd() hook")
Reported-by: Andrew Cooper <andrew.coop...@citrix.com>
Signed-off-by: Jan Beulich <jbeul...@suse.com>

--- a/xen/arch/x86/hvm/emulate.c
+++ b/xen/arch/x86/hvm/emulate.c
@@ -2310,7 +2310,9 @@ static int hvmemul_cache_op(
         ASSERT(!is_x86_system_segment(seg));
 
         rc = hvmemul_virtual_to_linear(seg, offset, 0, NULL,
-                                       hvm_access_read, hvmemul_ctxt, &addr);
+                                       op != x86emul_clwb ? hvm_access_none
+                                                          : hvm_access_read,
+                                       hvmemul_ctxt, &addr);
         if ( rc != X86EMUL_OKAY )
             break;