From: Borislav Petkov <[email protected]>

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

Signed-off-by: Borislav Petkov <[email protected]>
Acked-by: Tony Luck <[email protected]>
Cc: <[email protected]>
---
 arch/x86/kernel/cpu/microcode/intel.c | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/arch/x86/kernel/cpu/microcode/intel.c 
b/arch/x86/kernel/cpu/microcode/intel.c
index 8f7a9bbad514..7dbcb7adf797 100644
--- 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);
 }
 
-- 
2.13.0

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