[PATCH 4.18 038/158] x86/microcode: Update the new microcode revision unconditionally

From: Greg Kroah-Hartman
Date: Mon Sep 17 2018 - 19:10:12 EST


4.18-stable review patch. If anyone has any objections, please let me know.

------------------

From: Filippo Sironi <sironi@xxxxxxxxx>

commit 8da38ebaad23fe1b0c4a205438676f6356607cfc upstream.

Handle the case where microcode gets loaded on the BSP's hyperthread
sibling first and the boot_cpu_data's microcode revision doesn't get
updated because of early exit due to the siblings sharing a microcode
engine.

For that, simply write the updated revision on all CPUs unconditionally.

Signed-off-by: Filippo Sironi <sironi@xxxxxxxxx>
Signed-off-by: Borislav Petkov <bp@xxxxxxx>
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: prarit@xxxxxxxxxx
Cc: stable@xxxxxxxxxxxxxxx
Link: http://lkml.kernel.org/r/1533050970-14385-1-git-send-email-sironi@xxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
arch/x86/kernel/cpu/microcode/amd.c | 22 +++++++++++++---------
arch/x86/kernel/cpu/microcode/intel.c | 13 ++++++++-----
2 files changed, 21 insertions(+), 14 deletions(-)

--- a/arch/x86/kernel/cpu/microcode/amd.c
+++ b/arch/x86/kernel/cpu/microcode/amd.c
@@ -504,6 +504,7 @@ static enum ucode_state apply_microcode_
struct microcode_amd *mc_amd;
struct ucode_cpu_info *uci;
struct ucode_patch *p;
+ enum ucode_state ret;
u32 rev, dummy;

BUG_ON(raw_smp_processor_id() != cpu);
@@ -521,9 +522,8 @@ static enum ucode_state apply_microcode_

/* need to apply patch? */
if (rev >= mc_amd->hdr.patch_id) {
- c->microcode = rev;
- uci->cpu_sig.rev = rev;
- return UCODE_OK;
+ ret = UCODE_OK;
+ goto out;
}

if (__apply_microcode_amd(mc_amd)) {
@@ -531,17 +531,21 @@ static enum ucode_state apply_microcode_
cpu, mc_amd->hdr.patch_id);
return UCODE_ERROR;
}
- pr_info("CPU%d: new patch_level=0x%08x\n", cpu,
- mc_amd->hdr.patch_id);

- uci->cpu_sig.rev = mc_amd->hdr.patch_id;
- c->microcode = mc_amd->hdr.patch_id;
+ rev = mc_amd->hdr.patch_id;
+ ret = UCODE_UPDATED;
+
+ pr_info("CPU%d: new patch_level=0x%08x\n", cpu, rev);
+
+out:
+ uci->cpu_sig.rev = rev;
+ c->microcode = rev;

/* Update boot_cpu_data's revision too, if we're on the BSP: */
if (c->cpu_index == boot_cpu_data.cpu_index)
- boot_cpu_data.microcode = mc_amd->hdr.patch_id;
+ boot_cpu_data.microcode = rev;

- return UCODE_UPDATED;
+ return ret;
}

static int install_equiv_cpu_table(const u8 *buf)
--- a/arch/x86/kernel/cpu/microcode/intel.c
+++ b/arch/x86/kernel/cpu/microcode/intel.c
@@ -795,6 +795,7 @@ static enum ucode_state apply_microcode_
struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
struct cpuinfo_x86 *c = &cpu_data(cpu);
struct microcode_intel *mc;
+ enum ucode_state ret;
static int prev_rev;
u32 rev;

@@ -817,9 +818,8 @@ static enum ucode_state apply_microcode_
*/
rev = intel_get_microcode_revision();
if (rev >= mc->hdr.rev) {
- uci->cpu_sig.rev = rev;
- c->microcode = rev;
- return UCODE_OK;
+ ret = UCODE_OK;
+ goto out;
}

/*
@@ -848,14 +848,17 @@ static enum ucode_state apply_microcode_
prev_rev = rev;
}

+ ret = UCODE_UPDATED;
+
+out:
uci->cpu_sig.rev = rev;
- c->microcode = rev;
+ c->microcode = rev;

/* Update boot_cpu_data's revision too, if we're on the BSP: */
if (c->cpu_index == boot_cpu_data.cpu_index)
boot_cpu_data.microcode = rev;

- return UCODE_UPDATED;
+ return ret;
}

static enum ucode_state generic_load_microcode(int cpu, void *data, size_t size,