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authorNadav Amit <namit@cs.technion.ac.il>2014-09-16 15:10:03 +0300
committerPaolo Bonzini <pbonzini@redhat.com>2014-09-24 14:07:48 +0200
commitdd598091de4aabbc8bd7290a04f364e443c03455 (patch)
tree72123be86eb587d26b0bce0cca474aa05d3a2555 /arch/x86/kvm/cpuid.c
parent3c3c29fd0d7cddc32862c350d0700ce69953e3bd (diff)
downloadop-kernel-dev-dd598091de4aabbc8bd7290a04f364e443c03455.zip
op-kernel-dev-dd598091de4aabbc8bd7290a04f364e443c03455.tar.gz
KVM: x86: Warn if guest virtual address space is not 48-bits
The KVM emulator code assumes that the guest virtual address space (in 64-bit) is 48-bits wide. Fail the KVM_SET_CPUID and KVM_SET_CPUID2 ioctl if userspace tries to create a guest that does not obey this restriction. Signed-off-by: Nadav Amit <namit@cs.technion.ac.il> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86/kvm/cpuid.c')
-rw-r--r--arch/x86/kvm/cpuid.c21
1 files changed, 14 insertions, 7 deletions
diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
index f4bad87..e28d798 100644
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -53,14 +53,14 @@ u64 kvm_supported_xcr0(void)
return xcr0;
}
-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) {
@@ -88,7 +88,17 @@ void kvm_update_cpuid(struct kvm_vcpu *vcpu)
xstate_required_size(vcpu->arch.xcr0);
}
+ /*
+ * 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)
@@ -151,10 +161,9 @@ 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);
@@ -178,9 +187,7 @@ 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;
}
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