From: Nadav Amit <namit@xxxxxxxxxxxxxxxxx>
3.12-stable review patch. If anyone has any objections, please let me know.
===============
commit dd598091de4aabbc8bd7290a04f364e443c03455 upstream.
The KVM emulator code assumes that the guest virtual address space (in 64-bit)
is 48-bits wide. Since we are about to add more code that makes the same
assumption, this patch adds an assertion to make sure guest virtual address
space is indeed 48-bits wide.
Signed-off-by: Nadav Amit <namit@xxxxxxxxxxxxxxxxx>
Signed-off-by: Bruce Rogers <brogers@xxxxxxxx>
Signed-off-by: Jiri Slaby <jslaby@xxxxxxx>
---
arch/x86/kvm/cpuid.c | 19 ++++++++++++-------
arch/x86/kvm/cpuid.h | 2 +-
2 files changed, 13 insertions(+), 8 deletions(-)
diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
index b110fe6c03d4..b132551528e5 100644
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -23,14 +23,14 @@
#include "mmu.h"
#include "trace.h"
-void kvm_update_cpuid(struct kvm_vcpu *vcpu)
+int kvm_update_cpuid(struct kvm_vcpu *vcpu)
{
struct kvm_cpuid_entry2 *best;
struct kvm_lapic *apic = vcpu->arch.apic;
best = kvm_find_cpuid_entry(vcpu, 1, 0);
if (!best)
- return;
+ return 0;
/* Update OSXSAVE bit */
if (cpu_has_xsave && best->function == 0x1) {
@@ -46,7 +46,15 @@ void kvm_update_cpuid(struct kvm_vcpu *vcpu)
apic->lapic_timer.timer_mode_mask = 1 << 17;
}
+ /* The existing code assumes virtual address is 48-bit in the canonical
+ * address checks; exit if it is ever changed */
+ best = kvm_find_cpuid_entry(vcpu, 0x80000008, 0);
+ if (best && ((best->eax & 0xff00) >> 8) != 48 &&
+ ((best->eax & 0xff00) >> 8) != 0)
+ return -EINVAL;
+
kvm_pmu_cpuid_update(vcpu);
+ return 0;
}
static int is_efer_nx(void)
@@ -109,10 +117,9 @@ int kvm_vcpu_ioctl_set_cpuid(struct kvm_vcpu *vcpu,
}
vcpu->arch.cpuid_nent = cpuid->nent;
cpuid_fix_nx_cap(vcpu);
- r = 0;
kvm_apic_set_version(vcpu);
kvm_x86_ops->cpuid_update(vcpu);
- kvm_update_cpuid(vcpu);
+ r = kvm_update_cpuid(vcpu);
out_free:
vfree(cpuid_entries);
@@ -136,9 +143,7 @@ int kvm_vcpu_ioctl_set_cpuid2(struct kvm_vcpu *vcpu,
vcpu->arch.cpuid_nent = cpuid->nent;
kvm_apic_set_version(vcpu);
kvm_x86_ops->cpuid_update(vcpu);
- kvm_update_cpuid(vcpu);
- return 0;
-
+ r = kvm_update_cpuid(vcpu);
out:
return r;
}
diff --git a/arch/x86/kvm/cpuid.h b/arch/x86/kvm/cpuid.h
index b7fd07984888..6c458e37defb 100644
--- a/arch/x86/kvm/cpuid.h
+++ b/arch/x86/kvm/cpuid.h
@@ -3,7 +3,7 @@
#include "x86.h"
-void kvm_update_cpuid(struct kvm_vcpu *vcpu);
+int kvm_update_cpuid(struct kvm_vcpu *vcpu);
struct kvm_cpuid_entry2 *kvm_find_cpuid_entry(struct kvm_vcpu *vcpu,
u32 function, u32 index);
int kvm_dev_ioctl_get_supported_cpuid(struct kvm_cpuid2 *cpuid,
--
2.2.2
--
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