Merge tag 'kvm-4.13-2' of git://git.kernel.org/pub/scm/virt/kvm/kvm

Pull more KVM updates from Radim Krčmář:
 "Second batch of KVM updates for v4.13

  Common:
   - add uevents for VM creation/destruction
   - annotate and properly access RCU-protected objects

  s390:
   - rename IOCTL added in the first v4.13 merge

  x86:
   - emulate VMLOAD VMSAVE feature in SVM
   - support paravirtual asynchronous page fault while nested
   - add Hyper-V userspace interfaces for better migration
   - improve master clock corner cases
   - extend internal error reporting after EPT misconfig
   - correct single-stepping of emulated instructions in SVM
   - handle MCE during VM entry
   - fix nVMX VM entry checks and nVMX VMCS shadowing"

* tag 'kvm-4.13-2' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (28 commits)
  kvm: x86: hyperv: make VP_INDEX managed by userspace
  KVM: async_pf: Let guest support delivery of async_pf from guest mode
  KVM: async_pf: Force a nested vmexit if the injected #PF is async_pf
  KVM: async_pf: Add L1 guest async_pf #PF vmexit handler
  KVM: x86: Simplify kvm_x86_ops->queue_exception parameter list
  kvm: x86: hyperv: add KVM_CAP_HYPERV_SYNIC2
  KVM: x86: make backwards_tsc_observed a per-VM variable
  KVM: trigger uevents when creating or destroying a VM
  KVM: SVM: Enable Virtual VMLOAD VMSAVE feature
  KVM: SVM: Add Virtual VMLOAD VMSAVE feature definition
  KVM: SVM: Rename lbr_ctl field in the vmcb control area
  KVM: SVM: Prepare for new bit definition in lbr_ctl
  KVM: SVM: handle singlestep exception when skipping emulated instructions
  KVM: x86: take slots_lock in kvm_free_pit
  KVM: s390: Fix KVM_S390_GET_CMMA_BITS ioctl definition
  kvm: vmx: Properly handle machine check during VM-entry
  KVM: x86: update master clock before computing kvmclock_offset
  kvm: nVMX: Shadow "high" parts of shadowed 64-bit VMCS fields
  kvm: nVMX: Fix nested_vmx_check_msr_bitmap_controls
  kvm: nVMX: Validate the I/O bitmaps on nested VM-entry
  ...

1 files changed, 6 insertions, 1 deletions

diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c
index 43e10d6fdbed..71c17a5be983 100644
--- a/arch/x86/kernel/kvm.c
+++ b/arch/x86/kernel/kvm.c
@@ -330,7 +330,12 @@ static void kvm_guest_cpu_init(void)
 #ifdef CONFIG_PREEMPT
 		pa |= KVM_ASYNC_PF_SEND_ALWAYS;
 #endif
-		wrmsrl(MSR_KVM_ASYNC_PF_EN, pa | KVM_ASYNC_PF_ENABLED);
+		pa |= KVM_ASYNC_PF_ENABLED;
+
+		/* Async page fault support for L1 hypervisor is optional */
+		if (wrmsr_safe(MSR_KVM_ASYNC_PF_EN,
+			(pa | KVM_ASYNC_PF_DELIVERY_AS_PF_VMEXIT) & 0xffffffff, pa >> 32) < 0)
+			wrmsrl(MSR_KVM_ASYNC_PF_EN, pa);
 		__this_cpu_write(apf_reason.enabled, 1);
 		printk(KERN_INFO"KVM setup async PF for cpu %d\n",
 		       smp_processor_id());