From: Jim Mattson <jmattson@google.com>
Date: Thu, 10 Aug 2017 10:14:13 -0700
Subject: kvm: x86: Disallow illegal IA32_APIC_BASE MSR values
Patch-mainline: v4.14-rc1
Git-commit: d3802286fa0f9886700f2e47c05876ddb86dcb77
References: bsc#1077761
Host-initiated writes to the IA32_APIC_BASE MSR do not have to follow
local APIC state transition constraints, but the value written must be
valid.
Signed-off-by: Jim Mattson <jmattson@google.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Acked-by: Alexander Graf <agraf@suse.de>
---
arch/x86/kvm/x86.c | 14 ++++++++------
1 file changed, 8 insertions(+), 6 deletions(-)
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -314,10 +314,10 @@
u64 reserved_bits = ((~0ULL) << cpuid_maxphyaddr(vcpu)) | 0x2ff |
(guest_cpuid_has(vcpu, X86_FEATURE_X2APIC) ? 0 : X2APIC_ENABLE);
+ if ((msr_info->data & reserved_bits) || new_state == X2APIC_ENABLE)
+ return 1;
if (!msr_info->host_initiated &&
- ((msr_info->data & reserved_bits) != 0 ||
- new_state == X2APIC_ENABLE ||
- (new_state == MSR_IA32_APICBASE_ENABLE &&
+ ((new_state == MSR_IA32_APICBASE_ENABLE &&
old_state == (MSR_IA32_APICBASE_ENABLE | X2APIC_ENABLE)) ||
(new_state == (MSR_IA32_APICBASE_ENABLE | X2APIC_ENABLE) &&
old_state == 0)))
@@ -7423,6 +7423,11 @@
(sregs->cr4 & X86_CR4_OSXSAVE))
return -EINVAL;
+ apic_base_msr.data = sregs->apic_base;
+ apic_base_msr.host_initiated = true;
+ if (kvm_set_apic_base(vcpu, &apic_base_msr))
+ return -EINVAL;
+
dt.size = sregs->idt.limit;
dt.address = sregs->idt.base;
kvm_x86_ops->set_idt(vcpu, &dt);
@@ -7439,9 +7444,6 @@
mmu_reset_needed |= vcpu->arch.efer != sregs->efer;
kvm_x86_ops->set_efer(vcpu, sregs->efer);
- apic_base_msr.data = sregs->apic_base;
- apic_base_msr.host_initiated = true;
- kvm_set_apic_base(vcpu, &apic_base_msr);
mmu_reset_needed |= kvm_read_cr0(vcpu) != sregs->cr0;
kvm_x86_ops->set_cr0(vcpu, sregs->cr0);