From: Josh Poimboeuf <jpoimboe@redhat.com>
To: speck@linutronix.de
Subject: [MODERATED] [PATCH RFC 3/4] 3
Date: Sun, 3 Mar 2019 19:24:55 -0600 [thread overview]
Message-ID: <20190304012455.xi23xfddnexvdz2r@treble> (raw)
In-Reply-To: <20190304012138.gikabpafseh2swre@treble>
From: Josh Poimboeuf <jpoimboe@redhat.com>
Subject: [PATCH RFC 3/4] x86/speculation/mds: Add SMT warning message
MDS is vulnerable with SMT. Make that clear with a one-time printk
whenever SMT first gets enabled.
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
---
arch/x86/kernel/cpu/bugs.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c
index 9e20aef01d38..346f0f05879d 100644
--- a/arch/x86/kernel/cpu/bugs.c
+++ b/arch/x86/kernel/cpu/bugs.c
@@ -691,6 +691,8 @@ static void update_mds_branch_idle(void)
static_branch_disable(&mds_idle_clear);
}
+#define MDS_MSG_SMT "MDS CPU bug present and SMT on, data leak possible. See https://www.kernel.org/doc/html/latest/admin-guide/hw-vuln/mds.html for more details.\n"
+
void arch_smt_update(void)
{
/* Enhanced IBRS implies STIBP. No update required. */
@@ -715,6 +717,8 @@ void arch_smt_update(void)
switch(mds_mitigation) {
case MDS_MITIGATION_FULL:
case MDS_MITIGATION_VMWERV:
+ if (sched_smt_active() && !boot_cpu_has(X86_BUG_MSBDS_ONLY))
+ pr_warn_once(MDS_MSG_SMT);
update_mds_branch_idle();
break;
case MDS_MITIGATION_OFF:
--
2.17.2
next prev parent reply other threads:[~2019-03-04 1:26 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-03-04 1:21 [MODERATED] [PATCH RFC 0/4] Proposed cmdline improvements Josh Poimboeuf
2019-03-04 1:23 ` [MODERATED] [PATCH RFC 1/4] 1 Josh Poimboeuf
2019-03-04 3:55 ` [MODERATED] Encrypted Message Jon Masters
2019-03-04 17:06 ` [MODERATED] " Josh Poimboeuf
2019-03-04 7:30 ` [MODERATED] Re: [PATCH RFC 1/4] 1 Greg KH
2019-03-04 7:45 ` [MODERATED] Encrypted Message Jon Masters
2019-03-04 1:24 ` [MODERATED] [PATCH RFC 2/4] 2 Josh Poimboeuf
2019-03-04 7:31 ` [MODERATED] " Greg KH
2019-03-04 17:11 ` Josh Poimboeuf
2019-03-04 1:24 ` Josh Poimboeuf [this message]
2019-03-04 3:58 ` [MODERATED] Encrypted Message Jon Masters
2019-03-04 17:17 ` [MODERATED] " Josh Poimboeuf
2019-03-06 16:22 ` [MODERATED] " Jon Masters
2019-03-04 7:33 ` [MODERATED] Re: [PATCH RFC 3/4] 3 Greg KH
2019-03-04 17:18 ` Josh Poimboeuf
2019-03-04 1:25 ` [MODERATED] [PATCH RFC 4/4] 4 Josh Poimboeuf
2019-03-04 4:07 ` [MODERATED] Encrypted Message Jon Masters
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