| From foo@baz Tue Aug 14 16:14:56 CEST 2018 |
| From: Ashok Raj <ashok.raj@intel.com> |
| Date: Wed, 28 Feb 2018 11:28:43 +0100 |
| Subject: x86/microcode: Do not upload microcode if CPUs are offline |
| |
| From: Ashok Raj <ashok.raj@intel.com> |
| |
| commit 30ec26da9967d0d785abc24073129a34c3211777 upstream. |
| |
| 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. |
| |
| [ Borislav: Massage changelog. ] |
| |
| Signed-off-by: Ashok Raj <ashok.raj@intel.com> |
| Signed-off-by: Borislav Petkov <bp@suse.de> |
| Signed-off-by: Thomas Gleixner <tglx@linutronix.de> |
| Tested-by: Tom Lendacky <thomas.lendacky@amd.com> |
| Tested-by: Ashok Raj <ashok.raj@intel.com> |
| Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com> |
| Cc: Arjan Van De Ven <arjan.van.de.ven@intel.com> |
| Link: http://lkml.kernel.org/r/1519352533-15992-4-git-send-email-ashok.raj@intel.com |
| Link: https://lkml.kernel.org/r/20180228102846.13447-5-bp@alien8.de |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| Signed-off-by: David Woodhouse <dwmw@amazon.co.uk> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| --- |
| arch/x86/kernel/cpu/microcode/core.c | 18 ++++++++++++++++++ |
| 1 file changed, 18 insertions(+) |
| |
| --- a/arch/x86/kernel/cpu/microcode/core.c |
| +++ b/arch/x86/kernel/cpu/microcode/core.c |
| @@ -384,6 +384,16 @@ static void __exit microcode_dev_exit(vo |
| /* 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 int reload_for_cpu(int cpu) |
| { |
| struct ucode_cpu_info *uci = ucode_cpu_info + cpu; |
| @@ -418,7 +428,13 @@ static ssize_t reload_store(struct devic |
| 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 != 0) |
| @@ -431,6 +447,8 @@ static ssize_t reload_store(struct devic |
| if (!ret) |
| perf_check_microcode(); |
| mutex_unlock(µcode_mutex); |
| + |
| +put: |
| put_online_cpus(); |
| |
| if (!ret) |