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

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Message-ID: <20160816175008.GA10538@nazgul.tnic>
Date:	Tue, 16 Aug 2016 19:50:08 +0200
From:	Borislav Petkov <bp@...en8.de>
To:	Brian Gerst <brgerst@...il.com>
Cc:	Baoquan He <bhe@...hat.com>, Yinghai Lu <yinghai@...nel.org>,
	Juergen Gross <jgross@...e.com>,
	Thomas Garnier <thgarnie@...gle.com>,
	Andy Lutomirski <luto@...nel.org>,
	"H. Peter Anvin" <hpa@...or.com>,
	Alexander Kuleshov <kuleshovmail@...il.com>,
	Josh Poimboeuf <jpoimboe@...hat.com>, borntraeger@...ibm.com,
	sds@...ho.nsa.gov, kirill.shutemov@...ux.intel.com,
	jroedel@...e.de, Kees Cook <keescook@...omium.org>,
	"Williams, Dan J" <dan.j.williams@...el.com>,
	Mark Salter <msalter@...hat.com>, Borislav Petkov <bp@...e.de>,
	Jonathan Corbet <corbet@....net>, matt@...eblueprint.co.uk,
	guangrong.xiao@...ux.intel.com, aneesh.kumar@...ux.vnet.ibm.com,
	Ingo Molnar <mingo@...nel.org>,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	Dave Hansen <dave.hansen@...ux.intel.com>, toshi.kani@....com,
	alpopov@...ecurity.com,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	Jan Beulich <JBeulich@...e.com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Boris Ostrovsky <boris.ostrovsky@...cle.com>,
	Denys Vlasenko <dvlasenk@...hat.com>,
	Peter Zijlstra <peterz@...radead.org>, dyoung@...hat.com,
	Thomas Gleixner <tglx@...utronix.de>,
	Dmitry Vyukov <dvyukov@...gle.com>, lv.zheng@...el.com,
	schwidefsky@...ibm.com, linux-tip-commits@...r.kernel.org
Subject: Re: [tip:x86/boot] x86/mm: Enable KASLR for physical mapping memory
 regions

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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