linux-kernel - [PATCH 5.2 182/215] x86/speculation/mds: Apply more accurate check on hypervisor platform

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20190729190811.703371775@linuxfoundation.org>
Date:   Mon, 29 Jul 2019 21:22:58 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Zhenzhong Duan <zhenzhong.duan@...cle.com>,
        Thomas Gleixner <tglx@...utronix.de>
Subject: [PATCH 5.2 182/215] x86/speculation/mds: Apply more accurate check on hypervisor platform

From: Zhenzhong Duan <zhenzhong.duan@...cle.com>

commit 517c3ba00916383af6411aec99442c307c23f684 upstream.

X86_HYPER_NATIVE isn't accurate for checking if running on native platform,
e.g. CONFIG_HYPERVISOR_GUEST isn't set or "nopv" is enabled.

Checking the CPU feature bit X86_FEATURE_HYPERVISOR to determine if it's
running on native platform is more accurate.

This still doesn't cover the platforms on which X86_FEATURE_HYPERVISOR is
unsupported, e.g. VMware, but there is nothing which can be done about this
scenario.

Fixes: 8a4b06d391b0 ("x86/speculation/mds: Add sysfs reporting for MDS")
Signed-off-by: Zhenzhong Duan <zhenzhong.duan@...cle.com>
Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
Cc: stable@...r.kernel.org
Link: https://lkml.kernel.org/r/1564022349-17338-1-git-send-email-zhenzhong.duan@oracle.com
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 arch/x86/kernel/cpu/bugs.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/arch/x86/kernel/cpu/bugs.c
+++ b/arch/x86/kernel/cpu/bugs.c
@@ -1226,7 +1226,7 @@ static ssize_t l1tf_show_state(char *buf
 
 static ssize_t mds_show_state(char *buf)
 {
-	if (!hypervisor_is_type(X86_HYPER_NATIVE)) {
+	if (boot_cpu_has(X86_FEATURE_HYPERVISOR)) {
 		return sprintf(buf, "%s; SMT Host state unknown\n",
 			       mds_strings[mds_mitigation]);
 	}