From 4c20b901edfb53e4545aab8fcefb6f40fca25964 Mon Sep 17 00:00:00 2001
From: Andrea Arcangeli <aarcange@redhat.com>
Date: Wed, 12 Feb 2014 13:30:18 +0100
Subject: [PATCH 2/3] fix guest physical bits to match host, to go beyond 1TB guests

RH-Author: Andrea Arcangeli <aarcange@redhat.com>
Message-id: <1392211818-14964-2-git-send-email-aarcange@redhat.com>
Patchwork-id: 57245
O-Subject: [RHEL-7.0 qemu-kvm PATCH] fix guest physical bits to match host, to go beyond 1TB guests
Bugzilla: 989677
RH-Acked-by: Paolo Bonzini <pbonzini@redhat.com>
RH-Acked-by: Andrew Jones <drjones@redhat.com>
RH-Acked-by: Marcelo Tosatti <mtosatti@redhat.com>

Without this patch the guest physical bits are advertised as 40, not
44 or more depending on the hardware capability of the host.

That leads to guest kernel crashes with injection of page faults 9
(see oops: 0009) as bits above 40 in the guest pagetables are
considered reserved.

exregion-0206 [324572448] [17] ex_system_memory_space: System-Memory (width 32) R/W 0 Address=00000000FED00000
BUG: unable to handle kernel paging request at ffffc9006030e000
IP: [<ffffffff812fbb6f>] acpi_ex_system_memory_space_handler+0x23e/0x2cb
PGD e01f875067 PUD 1001f075067 PMD e0178d8067 PTE 80000000fed00173
Oops: 0009 [#1] SMP

(see PUD with bit >=40 set)

Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Reported-by: Chegu Vinod <chegu_vinod@hp.com>
---
 target-i386/cpu.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
---
 target-i386/cpu.c |    7 ++++++-
 1 files changed, 6 insertions(+), 1 deletions(-)

diff --git a/target-i386/cpu.c b/target-i386/cpu.c
index 2959915..31ff568 100644
--- a/target-i386/cpu.c
+++ b/target-i386/cpu.c
@@ -2174,8 +2174,13 @@ void cpu_x86_cpuid(CPUX86State *env, uint32_t index, uint32_t count,
 /* XXX: This value must match the one used in the MMU code. */
         if (env->features[FEAT_8000_0001_EDX] & CPUID_EXT2_LM) {
             /* 64 bit processor */
-/* XXX: The physical address space is limited to 42 bits in exec.c. */
             *eax = 0x00003028; /* 48 bits virtual, 40 bits physical */
+            if (kvm_enabled()) {
+                uint32_t _eax;
+                host_cpuid(0x80000000, 0, &_eax, NULL, NULL, NULL);
+                if (_eax >= 0x80000008)
+                    host_cpuid(0x80000008, 0, eax, NULL, NULL, NULL);
+            }
         } else {
             if (env->features[FEAT_1_EDX] & CPUID_PSE36) {
                 *eax = 0x00000024; /* 36 bits physical */
-- 
1.7.1