[v2,2/3] kvm: nVMX: Fix nested_vmx_check_msr_bitmap_controls

Commit Message

Jim Mattson July 10, 2017, 7:29 p.m. UTC

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")
Change-Id: I37f0482f32c4e77e403f6726e63bbe99880a185b
---
 arch/x86/kvm/vmx.c | 17 ++++++-----------
 1 file changed, 6 insertions(+), 11 deletions(-)

Patch

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 7ffe1c8438c2..eec9e0191311 100644
--- 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;
@@ -9592,20 +9597,10 @@  static void vmx_start_preemption_timer(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;