From: Tom Hughes <tom@compton.nu>
Date: Thu, 14 Mar 2019 15:15:41 +0000 (+0000)
Subject: Suppress FSGSBASE flag from cpuid results
X-Git-Tag: VALGRIND_3_15_0~54
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=09566120e705d8831aaa7076b439d3ad90b78773;p=thirdparty%2Fvalgrind.git

Suppress FSGSBASE flag from cpuid results

We don't support {rd,wr}{fs,gs}base so we shouldn't say we do.
---

diff --git a/VEX/priv/guest_amd64_helpers.c b/VEX/priv/guest_amd64_helpers.c
index 30e82db06a..f12b71e944 100644
--- a/VEX/priv/guest_amd64_helpers.c
+++ b/VEX/priv/guest_amd64_helpers.c
@@ -3361,7 +3361,8 @@ void amd64g_dirtyhelper_CPUID_avx2 ( VexGuestAMD64State* st )
          break;
       case 0x00000007:
          switch (old_ecx) {
-            case 0x00000000: SET_ABCD(0x00000000, 0x000027ab,
+            /* Don't advertise FSGSBASE support, bit 0 in EBX.  */
+            case 0x00000000: SET_ABCD(0x00000000, 0x000027aa,
                                       0x00000000, 0x00000000); break;
             default:         SET_ABCD(0x00000000, 0x00000000,
                                       0x00000000, 0x00000000); break;