x86/microcode/intel: Look into the patch cache first

The cache might contain a newer patch - look in there first.

A follow-on change will make sure newest patches are loaded into the
cache of microcode patches.

Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Tom Lendacky <thomas.lendacky@amd.com>
Tested-by: Ashok Raj <ashok.raj@intel.com>
Cc: Arjan Van De Ven <arjan.van.de.ven@intel.com>
Link: https://lkml.kernel.org/r/20180228102846.13447-6-bp@alien8.de

diff --git a/arch/x86/kernel/cpu/microcode/intel.c b/arch/x86/kernel/cpu/microcode/intel.c
index e2864bc..2aded9d 100644 (file)
--- a/arch/x86/kernel/cpu/microcode/intel.c
+++ b/arch/x86/kernel/cpu/microcode/intel.c
@@ -791,9 +791,9 @@ static int collect_cpu_info(int cpu_num, struct cpu_signature *csig)
 
 static enum ucode_state apply_microcode_intel(int cpu)
 {
-       struct microcode_intel *mc;
-       struct ucode_cpu_info *uci;
+       struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
        struct cpuinfo_x86 *c = &cpu_data(cpu);
+       struct microcode_intel *mc;
        static int prev_rev;
        u32 rev;
 
@@ -801,11 +801,10 @@ static enum ucode_state apply_microcode_intel(int cpu)
        if (WARN_ON(raw_smp_processor_id() != cpu))
                return UCODE_ERROR;
 
-       uci = ucode_cpu_info + cpu;
-       mc = uci->mc;
+       /* Look for a newer patch in our cache: */
+       mc = find_patch(uci);
        if (!mc) {
-               /* Look for a newer patch in our cache: */
-               mc = find_patch(uci);
+               mc = uci->mc;
                if (!mc)
                        return UCODE_NFOUND;
        }