[v9,03/15] microcode/amd: distinguish old and mismatched ucode in microcode_fits()

Commit Message

Chao Gao Aug. 19, 2019, 1:25 a.m. UTC

Sometimes, an ucode with a level lower than or equal to current CPU's
patch level is useful. For example, to work around a broken bios which
only loads ucode for BSP, when BSP parses an ucode blob during bootup,
it is better to save an ucode with lower or equal level for APs

No functional change is made in this patch. But following patch would
handle "old ucode" and "mismatched ucode" separately.

Signed-off-by: Chao Gao <[e-mail]>
Reviewed-by: Jan Beulich <[e-mail]>
---
Changes in v8:
 - new
---
 xen/arch/x86/microcode_amd.c | 18 +++++++++---------
 1 file changed, 9 insertions(+), 9 deletions(-)

Patch

diff --git a/xen/arch/x86/microcode_amd.c b/xen/arch/x86/microcode_amd.c
index 3069784..3db3555 100644
--- a/xen/arch/x86/microcode_amd.c
+++ b/xen/arch/x86/microcode_amd.c
@@ -152,8 +152,8 @@  static bool_t find_equiv_cpu_id(const struct equiv_cpu_entry *equiv_cpu_table,
     return 0;
 }
 
-static bool_t microcode_fits(const struct microcode_amd *mc_amd,
-                             unsigned int cpu)
+static enum microcode_match_result microcode_fits(
+    const struct microcode_amd *mc_amd, unsigned int cpu)
 {
     struct ucode_cpu_info *uci = &per_cpu(ucode_cpu_info, cpu);
     const struct microcode_header_amd *mc_header = mc_amd->mpb;
@@ -167,27 +167,27 @@  static bool_t microcode_fits(const struct microcode_amd *mc_amd,
     current_cpu_id = cpuid_eax(0x00000001);
 
     if ( !find_equiv_cpu_id(equiv_cpu_table, current_cpu_id, &equiv_cpu_id) )
-        return 0;
+        return MIS_UCODE;
 
     if ( (mc_header->processor_rev_id) != equiv_cpu_id )
-        return 0;
+        return MIS_UCODE;
 
     if ( !verify_patch_size(mc_amd->mpb_size) )
     {
         pr_debug("microcode: patch size mismatch\n");
-        return 0;
+        return MIS_UCODE;
     }
 
     if ( mc_header->patch_id <= uci->cpu_sig.rev )
     {
         pr_debug("microcode: patch is already at required level or greater.\n");
-        return 0;
+        return OLD_UCODE;
     }
 
     pr_debug("microcode: CPU%d found a matching microcode update with version %#x (current=%#x)\n",
              cpu, mc_header->patch_id, uci->cpu_sig.rev);
 
-    return 1;
+    return NEW_UCODE;
 }
 
 static int apply_microcode(unsigned int cpu)
@@ -496,7 +496,7 @@  static int cpu_request_microcode(unsigned int cpu, const void *buf,
     while ( (error = get_ucode_from_buffer_amd(mc_amd, buf, bufsize,
                                                &offset)) == 0 )
     {
-        if ( microcode_fits(mc_amd, cpu) )
+        if ( microcode_fits(mc_amd, cpu) == NEW_UCODE )
         {
             error = apply_microcode(cpu);
             if ( error )
@@ -576,7 +576,7 @@  static int microcode_resume_match(unsigned int cpu, const void *mc)
     struct microcode_amd *mc_amd = uci->mc.mc_amd;
     const struct microcode_amd *src = mc;
 
-    if ( !microcode_fits(src, cpu) )
+    if ( microcode_fits(src, cpu) != NEW_UCODE )
         return 0;
 
     if ( src != mc_amd )