Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm

Pull KVM fixes from Paolo Bonzini:
 "Many patches, pretty much all of them small, that accumulated while I
  was on vacation.

  ARM:

   - Remove the last leftovers of the ill-fated FPSIMD host state
     mapping at EL2 stage-1

   - Fix unexpected advertisement to the guest of unimplemented S2 base
     granule sizes

   - Gracefully fail initialising pKVM if the interrupt controller isn't
     GICv3

   - Also gracefully fail initialising pKVM if the carveout allocation
     fails

   - Fix the computing of the minimum MMIO range required for the host
     on stage-2 fault

   - Fix the generation of the GICv3 Maintenance Interrupt in nested
     mode

  x86:

   - Reject SEV{-ES} intra-host migration if one or more vCPUs are
     actively being created, so as not to create a non-SEV{-ES} vCPU in
     an SEV{-ES} VM

   - Use a pre-allocated, per-vCPU buffer for handling de-sparsification
     of vCPU masks in Hyper-V hypercalls; fixes a "stack frame too
     large" issue

   - Allow out-of-range/invalid Xen event channel ports when configuring
     IRQ routing, to avoid dictating a specific ioctl() ordering to
     userspace

   - Conditionally reschedule when setting memory attributes to avoid
     soft lockups when userspace converts huge swaths of memory to/from
     private

   - Add back MWAIT as a required feature for the MONITOR/MWAIT selftest

   - Add a missing field in struct sev_data_snp_launch_start that
     resulted in the guest-visible workarounds field being filled at the
     wrong offset

   - Skip non-canonical address when processing Hyper-V PV TLB flushes
     to avoid VM-Fail on INVVPID

   - Advertise supported TDX TDVMCALLs to userspace

   - Pass SetupEventNotifyInterrupt arguments to userspace

   - Fix TSC frequency underflow"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
  KVM: x86: avoid underflow when scaling TSC frequency
  KVM: arm64: Remove kvm_arch_vcpu_run_map_fp()
  KVM: arm64: Fix handling of FEAT_GTG for unimplemented granule sizes
  KVM: arm64: Don't free hyp pages with pKVM on GICv2
  KVM: arm64: Fix error path in init_hyp_mode()
  KVM: arm64: Adjust range correctly during host stage-2 faults
  KVM: arm64: nv: Fix MI line level calculation in vgic_v3_nested_update_mi()
  KVM: x86/hyper-v: Skip non-canonical addresses during PV TLB flush
  KVM: SVM: Add missing member in SNP_LAUNCH_START command structure
  Documentation: KVM: Fix unexpected unindent warnings
  KVM: selftests: Add back the missing check of MONITOR/MWAIT availability
  KVM: Allow CPU to reschedule while setting per-page memory attributes
  KVM: x86/xen: Allow 'out of range' event channel ports in IRQ routing table.
  KVM: x86/hyper-v: Use preallocated per-vCPU buffer for de-sparsified vCPU masks
  KVM: SVM: Initialize vmsa_pa in VMCB to INVALID_PAGE if VMSA page is NULL
  KVM: SVM: Reject SEV{-ES} intra host migration if vCPU creation is in-flight
  KVM: TDX: Report supported optional TDVMCALLs in TDX capabilities
  KVM: TDX: Exit to userspace for SetupEventNotifyInterrupt

1 files changed, 13 insertions, 2 deletions

diff --git a/arch/x86/kvm/xen.c b/arch/x86/kvm/xen.c
index 9b029bb29a16..5fa2cca43653 100644
--- a/arch/x86/kvm/xen.c
+++ b/arch/x86/kvm/xen.c
@@ -1971,8 +1971,19 @@ int kvm_xen_setup_evtchn(struct kvm *kvm,
 {
 	struct kvm_vcpu *vcpu;
 
-	if (ue->u.xen_evtchn.port >= max_evtchn_port(kvm))
-		return -EINVAL;
+	/*
+	 * Don't check for the port being within range of max_evtchn_port().
+	 * Userspace can configure what ever targets it likes; events just won't
+	 * be delivered if/while the target is invalid, just like userspace can
+	 * configure MSIs which target non-existent APICs.
+	 *
+	 * This allow on Live Migration and Live Update, the IRQ routing table
+	 * can be restored *independently* of other things like creating vCPUs,
+	 * without imposing an ordering dependency on userspace.  In this
+	 * particular case, the problematic ordering would be with setting the
+	 * Xen 'long mode' flag, which changes max_evtchn_port() to allow 4096
+	 * instead of 1024 event channels.
+	 */
 
 	/* We only support 2 level event channels for now */
 	if (ue->u.xen_evtchn.priority != KVM_IRQ_ROUTING_XEN_EVTCHN_PRIO_2LEVEL)