From: Jan Beulich <jbeulich@suse.com>
Date: Fri, 10 Dec 2021 13:03:56 +0000 (+0100)
Subject: x86/HVM: permit CLFLUSH{,OPT} on execute-only code segments
X-Git-Tag: archive/raspbian/4.17.0-1+rpi1^2~33^2~1233
X-Git-Url: https://dgit.raspbian.org/?a=commitdiff_plain;h=df3e1a5efe700a9f59eced801cac73f9fd02a0e2;p=xen.git

x86/HVM: permit CLFLUSH{,OPT} on execute-only code segments

Both SDM and PM explicitly permit this.

Fixes: 52dba7bd0b36 ("x86emul: generalize wbinvd() hook")
Reported-by: Andrew Cooper <andrew.cooper3@citrix.com>
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Paul Durrant <paul@xen.org>
---

diff --git a/xen/arch/x86/hvm/emulate.c b/xen/arch/x86/hvm/emulate.c
index 425c8ddd97..76a2ccfafe 100644
--- 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;