From 3ea6ac6fde5cd46d5d8593a493a75eb29e2ccc9b Mon Sep 17 00:00:00 2001
From: Eduardo Habkost <ehabkost@redhat.com>
Date: Wed, 14 Oct 2009 15:02:27 -0300
Subject: [PATCH] fix MSR_COUNT for kvm_arch_save_regs()

A new register was added to the load/save list on commit
d283d5a65a2bdcc570065267be21848bd6fe3d78, but MSR_COUNT was not updated, leading
to potential stack corruption on kvm_arch_save_regs().

The following registers are saved by kvm_arch_save_regs():

 1) MSR_IA32_SYSENTER_CS
 2) MSR_IA32_SYSENTER_ESP
 3) MSR_IA32_SYSENTER_EIP
 4) MSR_STAR
 5) MSR_IA32_TSC
 6) MSR_VM_HSAVE_PA
 7) MSR_CSTAR (x86_64 only)
 8) MSR_KERNELGSBASE (x86_64 only)
 9) MSR_FMASK (x86_64 only)
10) MSR_LSTAR (x86_64 only)

(cherry picked from commit e7e5448ba387adc20be1cf08411a5b526d684299)

Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Mark McLoughlin <markmc@redhat.com>
Fedora-patch: qemu-fix-msr-count-potential-segfault.patch
---
 qemu-kvm-x86.c |    6 ++++--
 1 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/qemu-kvm-x86.c b/qemu-kvm-x86.c
index 8e0f0b2..89fe77c 100644
--- a/qemu-kvm-x86.c
+++ b/qemu-kvm-x86.c
@@ -116,9 +116,9 @@ static int get_msr_entry(struct kvm_msr_entry *entry, CPUState *env)
 }
 
 #ifdef TARGET_X86_64
-#define MSR_COUNT 9
+#define MSR_COUNT 10
 #else
-#define MSR_COUNT 5
+#define MSR_COUNT 6
 #endif
 
 static void set_v8086_seg(struct kvm_segment *lhs, const SegmentCache *rhs)
@@ -260,6 +260,7 @@ void kvm_arch_load_regs(CPUState *env)
 
     /* msrs */
     n = 0;
+    /* Remember to increase MSR_COUNT if you add new registers below */
     set_msr_entry(&msrs[n++], MSR_IA32_SYSENTER_CS,  env->sysenter_cs);
     set_msr_entry(&msrs[n++], MSR_IA32_SYSENTER_ESP, env->sysenter_esp);
     set_msr_entry(&msrs[n++], MSR_IA32_SYSENTER_EIP, env->sysenter_eip);
@@ -435,6 +436,7 @@ void kvm_arch_save_regs(CPUState *env)
 
     /* msrs */
     n = 0;
+    /* Remember to increase MSR_COUNT if you add new registers below */
     msrs[n++].index = MSR_IA32_SYSENTER_CS;
     msrs[n++].index = MSR_IA32_SYSENTER_ESP;
     msrs[n++].index = MSR_IA32_SYSENTER_EIP;
-- 
1.6.2.5