Blame SOURCES/kvm-fix-guest-physical-bits-to-match-host-to-go-beyond-1.patch

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From 4c20b901edfb53e4545aab8fcefb6f40fca25964 Mon Sep 17 00:00:00 2001
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From: Andrea Arcangeli <aarcange@redhat.com>
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Date: Wed, 12 Feb 2014 13:30:18 +0100
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Subject: [PATCH 2/3] fix guest physical bits to match host, to go beyond 1TB guests
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RH-Author: Andrea Arcangeli <aarcange@redhat.com>
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Message-id: <1392211818-14964-2-git-send-email-aarcange@redhat.com>
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Patchwork-id: 57245
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O-Subject: [RHEL-7.0 qemu-kvm PATCH] fix guest physical bits to match host, to go beyond 1TB guests
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Bugzilla: 989677
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RH-Acked-by: Paolo Bonzini <pbonzini@redhat.com>
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RH-Acked-by: Andrew Jones <drjones@redhat.com>
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RH-Acked-by: Marcelo Tosatti <mtosatti@redhat.com>
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Without this patch the guest physical bits are advertised as 40, not
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44 or more depending on the hardware capability of the host.
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That leads to guest kernel crashes with injection of page faults 9
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(see oops: 0009) as bits above 40 in the guest pagetables are
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considered reserved.
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exregion-0206 [324572448] [17] ex_system_memory_space: System-Memory (width 32) R/W 0 Address=00000000FED00000
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BUG: unable to handle kernel paging request at ffffc9006030e000
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IP: [<ffffffff812fbb6f>] acpi_ex_system_memory_space_handler+0x23e/0x2cb
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PGD e01f875067 PUD 1001f075067 PMD e0178d8067 PTE 80000000fed00173
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Oops: 0009 [#1] SMP
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(see PUD with bit >=40 set)
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Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
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Reported-by: Chegu Vinod <chegu_vinod@hp.com>
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---
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 target-i386/cpu.c | 7 ++++++-
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 1 file changed, 6 insertions(+), 1 deletion(-)
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Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
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---
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 target-i386/cpu.c |    7 ++++++-
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 1 files changed, 6 insertions(+), 1 deletions(-)
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diff --git a/target-i386/cpu.c b/target-i386/cpu.c
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index 2959915..31ff568 100644
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--- a/target-i386/cpu.c
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+++ b/target-i386/cpu.c
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@@ -2174,8 +2174,13 @@ void cpu_x86_cpuid(CPUX86State *env, uint32_t index, uint32_t count,
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 /* XXX: This value must match the one used in the MMU code. */
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         if (env->features[FEAT_8000_0001_EDX] & CPUID_EXT2_LM) {
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             /* 64 bit processor */
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-/* XXX: The physical address space is limited to 42 bits in exec.c. */
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             *eax = 0x00003028; /* 48 bits virtual, 40 bits physical */
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+            if (kvm_enabled()) {
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+                uint32_t _eax;
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+                host_cpuid(0x80000000, 0, &_eax, NULL, NULL, NULL);
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+                if (_eax >= 0x80000008)
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+                    host_cpuid(0x80000008, 0, eax, NULL, NULL, NULL);
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+            }
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         } else {
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             if (env->features[FEAT_1_EDX] & CPUID_PSE36) {
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                 *eax = 0x00000024; /* 36 bits physical */
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-- 
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1.7.1
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