Patch "x86/microcode: Request microcode on the BSP" has been added to the 4.15-stable tree

This is a note to let you know that I've just added the patch titled

x86/microcode: Request microcode on the BSP

to the 4.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
x86-microcode-request-microcode-on-the-bsp.patch
and it can be found in the queue-4.15 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Borislav Petkov <[email protected]>
Date: Wed, 28 Feb 2018 11:28:45 +0100
Subject: x86/microcode: Request microcode on the BSP

From: Borislav Petkov <[email protected]>

commit cfb52a5a09c8ae3a1dafb44ce549fde5b69e8117 upstream.

... 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.

---
 arch/x86/kernel/cpu/microcode/core.c |   11 +++++------
 1 file changed, 5 insertions(+), 6 deletions(-)

@@ -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 devic
 			    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 devic
 	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();

Patches currently in stable-queue which might be from [email protected] are

queue-4.15/x86-microcode-intel-check-microcode-revision-before-updating-sibling-threads.patch queue-4.15/x86-microcode-attempt-late-loading-only-when-new-microcode-is-present.patch queue-4.15/x86-microcode-propagate-return-value-from-updating-functions.patch queue-4.15/x86-cpu-check-cpu-feature-bits-after-microcode-upgrade.patch queue-4.15/x86-microcode-intel-writeback-and-invalidate-caches-before-updating-microcode.patch queue-4.15/x86-microcode-intel-look-into-the-patch-cache-first.patch queue-4.15/edac-mv64x60-fix-an-error-handling-path.patch queue-4.15/x86-microcode-request-microcode-on-the-bsp.patch queue-4.15/x86-microcode-get-rid-of-struct-apply_microcode_ctx.patch queue-4.15/x86-microcode-fix-cpu-synchronization-routine.patch queue-4.15/x86-microcode-synchronize-late-microcode-loading.patch queue-4.15/x86-microcode-do-not-upload-microcode-if-cpus-are-offline.patch queue-4.15/x86-cpu-add-a-microcode-loader-callback.patch