From: Borislav Petkov <bp@alien8.de>
To: X86 ML <x86@kernel.org>
Cc: Arjan Van De Ven <arjan.van.de.ven@intel.com>,
Ashok Raj <ashok.raj@intel.com>,
Tom Lendacky <thomas.lendacky@amd.com>,
LKML <linux-kernel@vger.kernel.org>
Subject: [PATCH 4/7] x86/microcode: Do not upload microcode if CPUs are offline
Date: Wed, 28 Feb 2018 11:28:43 +0100 [thread overview]
Message-ID: <20180228102846.13447-5-bp@alien8.de> (raw)
In-Reply-To: <20180228102846.13447-1-bp@alien8.de>
From: Ashok Raj <ashok.raj@intel.com>
Avoid loading microcode if any of the CPUs are offline, and issue a
warning. Having different microcode revisions on the system at any time
is outright dangerous.
Signed-off-by: Ashok Raj <ashok.raj@intel.com>
Cc: x86-ml <x86@kernel.org>
Link: http://lkml.kernel.org/r/1519352533-15992-4-git-send-email-ashok.raj@intel.com
[ Massage it. ]
Signed-off-by: Borislav Petkov <bp@suse.de>
---
arch/x86/kernel/cpu/microcode/core.c | 18 ++++++++++++++++++
1 file changed, 18 insertions(+)
diff --git a/arch/x86/kernel/cpu/microcode/core.c b/arch/x86/kernel/cpu/microcode/core.c
index 63370651e376..fa32cb3dcca5 100644
--- a/arch/x86/kernel/cpu/microcode/core.c
+++ b/arch/x86/kernel/cpu/microcode/core.c
@@ -486,6 +486,16 @@ static void __exit microcode_dev_exit(void)
/* fake device for request_firmware */
static struct platform_device *microcode_pdev;
+static int check_online_cpus(void)
+{
+ if (num_online_cpus() == num_present_cpus())
+ return 0;
+
+ pr_err("Not all CPUs online, aborting microcode update.\n");
+
+ return -EINVAL;
+}
+
static enum ucode_state reload_for_cpu(int cpu)
{
struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
@@ -519,7 +529,13 @@ static ssize_t reload_store(struct device *dev,
return size;
get_online_cpus();
+
+ ret = check_online_cpus();
+ if (ret)
+ goto put;
+
mutex_lock(µcode_mutex);
+
for_each_online_cpu(cpu) {
tmp_ret = reload_for_cpu(cpu);
if (tmp_ret > UCODE_NFOUND) {
@@ -538,6 +554,8 @@ static ssize_t reload_store(struct device *dev,
microcode_check();
mutex_unlock(µcode_mutex);
+
+put:
put_online_cpus();
if (!ret)
--
2.13.0
next prev parent reply other threads:[~2018-02-28 10:31 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-02-28 10:28 [PATCH 0/7] x86/microcode: Improve late loading Borislav Petkov
2018-02-28 10:28 ` [PATCH 1/7] x86/microcode: Get rid of struct apply_microcode_ctx Borislav Petkov
2018-03-08 9:25 ` [tip:x86/pti] " tip-bot for Borislav Petkov
2018-02-28 10:28 ` [PATCH 2/7] x86/microcode/intel: Check microcode revision before updating sibling threads Borislav Petkov
2018-03-08 9:25 ` [tip:x86/pti] " tip-bot for Ashok Raj
2018-02-28 10:28 ` [PATCH 3/7] x86/microcode/intel: Writeback and invalidate caches before updating microcode Borislav Petkov
2018-03-08 9:26 ` [tip:x86/pti] " tip-bot for Ashok Raj
2018-02-28 10:28 ` Borislav Petkov [this message]
2018-02-28 13:11 ` [PATCH 4/7] x86/microcode: Do not upload microcode if CPUs are offline Henrique de Moraes Holschuh
2018-02-28 13:26 ` Raj, Ashok
2018-02-28 19:07 ` Henrique de Moraes Holschuh
2018-03-05 22:06 ` Tom Lendacky
2018-03-08 9:26 ` [tip:x86/pti] " tip-bot for Ashok Raj
2018-02-28 10:28 ` [PATCH 5/7] x86/microcode/intel: Look into the patch cache first Borislav Petkov
2018-03-08 9:27 ` [tip:x86/pti] " tip-bot for Borislav Petkov
2018-02-28 10:28 ` [PATCH 6/7] x86/microcode: Request microcode on the BSP Borislav Petkov
2018-03-05 22:08 ` Tom Lendacky
2018-03-08 9:27 ` [tip:x86/pti] " tip-bot for Borislav Petkov
2018-02-28 10:28 ` [PATCH 7/7] x86/microcode: Synchronize late microcode loading Borislav Petkov
2018-02-28 13:59 ` Henrique de Moraes Holschuh
2018-02-28 14:08 ` Borislav Petkov
2018-02-28 17:48 ` Henrique de Moraes Holschuh
2018-03-05 22:09 ` Tom Lendacky
2018-03-08 9:28 ` [tip:x86/pti] " tip-bot for Ashok Raj
2018-03-05 22:12 ` [PATCH 0/7] x86/microcode: Improve late loading Tom Lendacky
2018-03-05 23:51 ` Raj, Ashok
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