x86/microcode/intel: Disable late loading on model 79

Blacklist Broadwell X model 79 for late loading due to an erratum.

Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Tony Luck <tony.luck@intel.com>
Cc: <stable@vger.kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20171018111225.25635-1-bp@alien8.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>

diff --git a/arch/x86/kernel/cpu/microcode/intel.c b/arch/x86/kernel/cpu/microcode/intel.c
index 8f7a9bbad514efbec73ed1beb167c7d8432521b2..7dbcb7adf7975f7f29c38651c23c478ad315a34c 100644 (file)
--- a/arch/x86/kernel/cpu/microcode/intel.c
+++ b/arch/x86/kernel/cpu/microcode/intel.c
@@ -34,6 +34,7 @@
 #include <linux/mm.h>
 
 #include <asm/microcode_intel.h>
+#include <asm/intel-family.h>
 #include <asm/processor.h>
 #include <asm/tlbflush.h>
 #include <asm/setup.h>
@@ -918,6 +919,18 @@ static int get_ucode_fw(void *to, const void *from, size_t n)
        return 0;
 }
 
+static bool is_blacklisted(unsigned int cpu)
+{
+       struct cpuinfo_x86 *c = &cpu_data(cpu);
+
+       if (c->x86 == 6 && c->x86_model == INTEL_FAM6_BROADWELL_X) {
+               pr_err_once("late loading on model 79 is disabled.\n");
+               return true;
+       }
+
+       return false;
+}
+
 static enum ucode_state request_microcode_fw(int cpu, struct device *device,
                                             bool refresh_fw)
 {
@@ -926,6 +939,9 @@ static enum ucode_state request_microcode_fw(int cpu, struct device *device,
        const struct firmware *firmware;
        enum ucode_state ret;
 
+       if (is_blacklisted(cpu))
+               return UCODE_NFOUND;
+
        sprintf(name, "intel-ucode/%02x-%02x-%02x",
                c->x86, c->x86_model, c->x86_mask);
 
@@ -950,6 +966,9 @@ static int get_ucode_user(void *to, const void *from, size_t n)
 static enum ucode_state
 request_microcode_user(int cpu, const void __user *buf, size_t size)
 {
+       if (is_blacklisted(cpu))
+               return UCODE_NFOUND;
+
        return generic_load_microcode(cpu, (void *)buf, size, &get_ucode_user);
 }