[Xen-changelog] [xen stable-4.12] x86/microcode: always collect_cpu_info() during boot

[patchbot@xxxxxxx]

commit b465705af2e7fb9bbf0d2a7613622f42eb6971ce
Author:     Sergey Dyasli <sergey.dyasli@xxxxxxxxxx>
AuthorDate: Mon Sep 23 14:17:14 2019 +0200
Commit:     Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Mon Sep 23 14:17:14 2019 +0200

    x86/microcode: always collect_cpu_info() during boot
    
    Currently cpu_sig struct is not updated during boot if no microcode blob
    is specified by "ucode=[<interger>| scan]".
    
    It will result in cpu_sig.rev being 0 which affects APIC's
    check_deadline_errata() and retpoline_safe() functions.
    
    Fix this by getting ucode revision early during boot and SMP bring up.
    While at it, protect early_microcode_update_cpu() for cases when
    microcode_ops is NULL.
    
    Signed-off-by: Sergey Dyasli <sergey.dyasli@xxxxxxxxxx>
    Signed-off-by: Chao Gao <chao.gao@xxxxxxxxx>
    Reviewed-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
    master commit: 2bb2c55cf870e78bc7f514784b2cd8c947d8729c
    master date: 2019-08-01 18:45:32 +0100
---
 xen/arch/x86/microcode.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/xen/arch/x86/microcode.c b/xen/arch/x86/microcode.c
index 4163f50bb7..421d57e925 100644
--- a/xen/arch/x86/microcode.c
+++ b/xen/arch/x86/microcode.c
@@ -383,10 +383,15 @@ static struct notifier_block microcode_percpu_nfb = {
 
 int __init early_microcode_update_cpu(bool start_update)
 {
+    unsigned int cpu = smp_processor_id();
+    struct ucode_cpu_info *uci = &per_cpu(ucode_cpu_info, cpu);
     int rc = 0;
     void *data = NULL;
     size_t len;
 
+    if ( !microcode_ops )
+        return -ENOSYS;
+
     if ( ucode_blob.size )
     {
         len = ucode_blob.size;
@@ -397,6 +402,9 @@ int __init early_microcode_update_cpu(bool start_update)
         len = ucode_mod.mod_end;
         data = bootstrap_map(&ucode_mod);
     }
+
+    microcode_ops->collect_cpu_info(cpu, &uci->cpu_sig);
+
     if ( data )
     {
         if ( start_update && microcode_ops->start_update )
@@ -413,6 +421,8 @@ int __init early_microcode_update_cpu(bool start_update)
 
 int __init early_microcode_init(void)
 {
+    unsigned int cpu = smp_processor_id();
+    struct ucode_cpu_info *uci = &per_cpu(ucode_cpu_info, cpu);
     int rc;
 
     rc = microcode_init_intel();
@@ -425,6 +435,8 @@ int __init early_microcode_init(void)
 
     if ( microcode_ops )
     {
+        microcode_ops->collect_cpu_info(cpu, &uci->cpu_sig);
+
         if ( ucode_mod.mod_end || ucode_blob.size )
             rc = early_microcode_update_cpu(true);
 
--
generated by git-patchbot for /home/xen/git/xen.git#stable-4.12

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