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

commit 723f2828a98c8ca19842042f418fb30dd8cfc0f7 upstream.

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: 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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/arch/x86/kernel/cpu/microcode/intel.c b/arch/x86/kernel/cpu/microcode/intel.c
index ac8975a652804a19eed6f84528b7ac8c93b0fcc0..abf581ade8d2a79de5ead154b233195d49b57ecb 100644 (file)
--- a/arch/x86/kernel/cpu/microcode/intel.c
+++ b/arch/x86/kernel/cpu/microcode/intel.c
@@ -990,6 +990,18 @@ 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 == 79) {
+               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)
 {
@@ -998,6 +1010,9 @@ 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);
 
@@ -1022,6 +1037,9 @@ 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);
 }