kvm: nVMX: Fix nested_vmx_check_msr_bitmap_controls

Allow the L1 guest to specify the last page of addressable guest
physical memory for an L2 MSR permission bitmap. Also remove the
vmcs12_read_any() check that should never fail.

Fixes: 3af18d9c5fe95 ("KVM: nVMX: Prepare for using hardware MSR bitmap")
Signed-off-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 22034ac4b5f2cb899241a298a0ff694d346f3776..e02c7004b64b5c9a00d5ecb94415a75c20d11aca 100644 (file)
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -4634,6 +4634,11 @@ static bool guest_state_valid(struct kvm_vcpu *vcpu)
        return true;
 }
 
+static bool page_address_valid(struct kvm_vcpu *vcpu, gpa_t gpa)
+{
+       return PAGE_ALIGNED(gpa) && !(gpa >> cpuid_maxphyaddr(vcpu));
+}
+
 static int init_rmode_tss(struct kvm *kvm)
 {
        gfn_t fn;
@@ -9611,20 +9616,10 @@ static int nested_vmx_check_io_bitmap_controls(struct kvm_vcpu *vcpu,
 static int nested_vmx_check_msr_bitmap_controls(struct kvm_vcpu *vcpu,
                                                struct vmcs12 *vmcs12)
 {
-       int maxphyaddr;
-       u64 addr;
-
        if (!nested_cpu_has(vmcs12, CPU_BASED_USE_MSR_BITMAPS))
                return 0;
 
-       if (vmcs12_read_any(vcpu, MSR_BITMAP, &addr)) {
-               WARN_ON(1);
-               return -EINVAL;
-       }
-       maxphyaddr = cpuid_maxphyaddr(vcpu);
-
-       if (!PAGE_ALIGNED(vmcs12->msr_bitmap) ||
-          ((addr + PAGE_SIZE) >> maxphyaddr))
+       if (!page_address_valid(vcpu, vmcs12->msr_bitmap))
                return -EINVAL;
 
        return 0;