linux-kernel - [RFC PATCH v2 06/20] x86: Handle reduction in physical address size with SME

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Date:   Mon, 22 Aug 2016 17:36:34 -0500
From:   Tom Lendacky <thomas.lendacky@....com>
To:     <linux-arch@...r.kernel.org>, <linux-efi@...r.kernel.org>,
        <kvm@...r.kernel.org>, <linux-doc@...r.kernel.org>,
        <x86@...nel.org>, <linux-kernel@...r.kernel.org>,
        <kasan-dev@...glegroups.com>, <linux-mm@...ck.org>,
        <iommu@...ts.linux-foundation.org>
CC:     Radim Krčmář <rkrcmar@...hat.com>,
        Arnd Bergmann <arnd@...db.de>,
        Jonathan Corbet <corbet@....net>,
        Matt Fleming <matt@...eblueprint.co.uk>,
        Joerg Roedel <joro@...tes.org>,
        "Konrad Rzeszutek Wilk" <konrad.wilk@...cle.com>,
        Andrey Ryabinin <aryabinin@...tuozzo.com>,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        "Andy Lutomirski" <luto@...nel.org>,
        "H. Peter Anvin" <hpa@...or.com>,
        "Paolo Bonzini" <pbonzini@...hat.com>,
        Alexander Potapenko <glider@...gle.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Dmitry Vyukov <dvyukov@...gle.com>
Subject: [RFC PATCH v2 06/20] x86: Handle reduction in physical address size
 with SME

When System Memory Encryption (SME) is enabled, the physical address
space is reduced. Adjust the x86_phys_bits value to reflect this
reduction.

Signed-off-by: Tom Lendacky <thomas.lendacky@....com>
---
 arch/x86/kernel/cpu/common.c |    2 ++
 1 file changed, 2 insertions(+)

diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index ce7a4c1..c0fe783 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -44,6 +44,7 @@
 #include <asm/pat.h>
 #include <asm/microcode.h>
 #include <asm/microcode_intel.h>
+#include <asm/mem_encrypt.h>
 
 #ifdef CONFIG_X86_LOCAL_APIC
 #include <asm/uv/uv.h>
@@ -736,6 +737,7 @@ void get_cpu_cap(struct cpuinfo_x86 *c)
 
 		c->x86_virt_bits = (eax >> 8) & 0xff;
 		c->x86_phys_bits = eax & 0xff;
+		c->x86_phys_bits -= sme_get_me_loss();
 		c->x86_capability[CPUID_8000_0008_EBX] = ebx;
 	}
 #ifdef CONFIG_X86_32