x86/microcode: Request microcode on the BSP

... so that any newer version can land in the cache and can later be
fished out by the application functions. Do that before grabbing the
hotplug lock.
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: https://lkml.kernel.org/r/20180228102846.13447-7-bp@alien8.de

arch/x86/kernel/cpu/microcode/core.c

@@ -499,15 +499,10 @@ static int check_online_cpus(void)
 static enum ucode_state reload_for_cpu(int cpu)
 {
 	struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
-	enum ucode_state ustate;
 
 	if (!uci->valid)
 		return UCODE_OK;
 
-	ustate = microcode_ops->request_microcode_fw(cpu, &microcode_pdev->dev, true);
-	if (ustate != UCODE_OK)
-		return ustate;
-
 	return apply_microcode_on_target(cpu);
 }
 
@@ -515,11 +510,11 @@ static ssize_t reload_store(struct device *dev,
 			    struct device_attribute *attr,
 			    const char *buf, size_t size)
 {
+	int cpu, bsp = boot_cpu_data.cpu_index;
 	enum ucode_state tmp_ret = UCODE_OK;
 	bool do_callback = false;
 	unsigned long val;
 	ssize_t ret = 0;
-	int cpu;
 
 	ret = kstrtoul(buf, 0, &val);
 	if (ret)
@@ -528,6 +523,10 @@ static ssize_t reload_store(struct device *dev,
 	if (val != 1)
 		return size;
 
+	tmp_ret = microcode_ops->request_microcode_fw(bsp, &microcode_pdev->dev, true);
+	if (tmp_ret != UCODE_OK)
+		return size;
+
 	get_online_cpus();
 
 	ret = check_online_cpus();