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

Pull KVM updates from Paolo Bonzini:
 "s390:
   - ioctl hardening
   - selftests

  ARM:
   - ITS translation cache
   - support for 512 vCPUs
   - various cleanups and bugfixes

  PPC:
   - various minor fixes and preparation

  x86:
   - bugfixes all over the place (posted interrupts, SVM, emulation
     corner cases, blocked INIT)
   - some IPI optimizations"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (75 commits)
  KVM: X86: Use IPI shorthands in kvm guest when support
  KVM: x86: Fix INIT signal handling in various CPU states
  KVM: VMX: Introduce exit reason for receiving INIT signal on guest-mode
  KVM: VMX: Stop the preemption timer during vCPU reset
  KVM: LAPIC: Micro optimize IPI latency
  kvm: Nested KVM MMUs need PAE root too
  KVM: x86: set ctxt->have_exception in x86_decode_insn()
  KVM: x86: always stop emulation on page fault
  KVM: nVMX: trace nested VM-Enter failures detected by H/W
  KVM: nVMX: add tracepoint for failed nested VM-Enter
  x86: KVM: svm: Fix a check in nested_svm_vmrun()
  KVM: x86: Return to userspace with internal error on unexpected exit reason
  KVM: x86: Add kvm_emulate_{rd,wr}msr() to consolidate VXM/SVM code
  KVM: x86: Refactor up kvm_{g,s}et_msr() to simplify callers
  doc: kvm: Fix return description of KVM_SET_MSRS
  KVM: X86: Tune PLE Window tracepoint
  KVM: VMX: Change ple_window type to unsigned int
  KVM: X86: Remove tailing newline for tracepoints
  KVM: X86: Trace vcpu_id for vmexit
  KVM: x86: Manually calculate reserved bits when loading PDPTRS
  ...

1 files changed, 13 insertions, 1 deletions

diff --git a/arch/arm64/kvm/hyp/tlb.c b/arch/arm64/kvm/hyp/tlb.c
index d49a14497715..c466060b76d6 100644
--- a/arch/arm64/kvm/hyp/tlb.c
+++ b/arch/arm64/kvm/hyp/tlb.c
@@ -193,6 +193,18 @@ void __hyp_text __kvm_flush_vm_context(void)
 {
 	dsb(ishst);
 	__tlbi(alle1is);
-	asm volatile("ic ialluis" : : );
+
+	/*
+	 * VIPT and PIPT caches are not affected by VMID, so no maintenance
+	 * is necessary across a VMID rollover.
+	 *
+	 * VPIPT caches constrain lookup and maintenance to the active VMID,
+	 * so we need to invalidate lines with a stale VMID to avoid an ABA
+	 * race after multiple rollovers.
+	 *
+	 */
+	if (icache_is_vpipt())
+		asm volatile("ic ialluis");
+
 	dsb(ish);
 }