Re: [tip:x86/boot] x86/mm: Enable KASLR for physical mapping memory regions

[Borislav Petkov]

On Tue, Aug 16, 2016 at 05:54:12PM +0200, Borislav Petkov wrote:
> Ok, I ran this in a guest and it finds the microcode patches properly.

Here's a better version to take care of the APs too:

---
diff --git a/arch/x86/kernel/cpu/microcode/amd.c 
b/arch/x86/kernel/cpu/microcode/amd.c
index 27a0228c9cae..05242322e324 100644
--- a/arch/x86/kernel/cpu/microcode/amd.c
+++ b/arch/x86/kernel/cpu/microcode/amd.c
@@ -355,6 +355,7 @@ void load_ucode_amd_ap(void)
        unsigned int cpu = smp_processor_id();
        struct equiv_cpu_entry *eq;
        struct microcode_amd *mc;
+       u8 *cont;
        u32 rev, eax;
        u16 eq_id;
 
@@ -371,8 +372,12 @@ void load_ucode_amd_ap(void)
        if (check_current_patch_level(&rev, false))
                return;
 
+#ifdef CONFIG_RANDOMIZE_MEMORY
+       cont = container + PAGE_OFFSET - __PAGE_OFFSET_BASE;
+#endif
+
        eax = cpuid_eax(0x00000001);
-       eq  = (struct equiv_cpu_entry *)(container + CONTAINER_HDR_SZ);
+       eq  = (struct equiv_cpu_entry *)(cont + CONTAINER_HDR_SZ);
 
        eq_id = find_equiv_id(eq, eax);
        if (!eq_id)
@@ -434,6 +439,10 @@ int __init save_microcode_in_initrd_amd(void)
        else
                container = cont_va;
 
+#ifdef CONFIG_RANDOMIZE_MEMORY
+       container += PAGE_OFFSET - __PAGE_OFFSET_BASE;
+#endif
+
        eax   = cpuid_eax(0x00000001);
        eax   = ((eax >> 8) & 0xf) + ((eax >> 20) & 0xff);
 

-- 
Regards/Gruss,
    Boris.

ECO tip #101: Trim your mails when you reply.
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