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

Pull more KVM fixes from Paolo Bonzini:

 - fixes for CONFIG_KVM_COMPAT=n

 - two updates to the IFU erratum

 - selftests build fix

 - brown paper bag fix

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
  KVM: Add a comment describing the /dev/kvm no_compat handling
  KVM: x86/mmu: Take slots_lock when using kvm_mmu_zap_all_fast()
  KVM: Forbid /dev/kvm being opened by a compat task when CONFIG_KVM_COMPAT=n
  KVM: X86: Reset the three MSR list number variables to 0 in kvm_init_msr_list()
  selftests: kvm: fix build with glibc >= 2.30
  kvm: x86: disable shattered huge page recovery for PREEMPT_RT.

2 files changed, 11 insertions, 3 deletions

diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index fd6012eef9c9..2ce9da58611e 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -51,7 +51,12 @@
 extern bool itlb_multihit_kvm_mitigation;
 
 static int __read_mostly nx_huge_pages = -1;
+#ifdef CONFIG_PREEMPT_RT
+/* Recovery can cause latency spikes, disable it for PREEMPT_RT.  */
+static uint __read_mostly nx_huge_pages_recovery_ratio = 0;
+#else
 static uint __read_mostly nx_huge_pages_recovery_ratio = 60;
+#endif
 
 static int set_nx_huge_pages(const char *val, const struct kernel_param *kp);
 static int set_nx_huge_pages_recovery_ratio(const char *val, const struct kernel_param *kp);
@@ -6280,14 +6285,13 @@ static int set_nx_huge_pages(const char *val, const struct kernel_param *kp)
 
 	if (new_val != old_val) {
 		struct kvm *kvm;
-		int idx;
 
 		mutex_lock(&kvm_lock);
 
 		list_for_each_entry(kvm, &vm_list, vm_list) {
-			idx = srcu_read_lock(&kvm->srcu);
+			mutex_lock(&kvm->slots_lock);
 			kvm_mmu_zap_all_fast(kvm);
-			srcu_read_unlock(&kvm->srcu, idx);
+			mutex_unlock(&kvm->slots_lock);
 
 			wake_up_process(kvm->arch.nx_lpage_recovery_thread);
 		}
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 7db5c8ef35dd..5d530521f11d 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -5130,6 +5130,10 @@ static void kvm_init_msr_list(void)
 
 	perf_get_x86_pmu_capability(&x86_pmu);
 
+	num_msrs_to_save = 0;
+	num_emulated_msrs = 0;
+	num_msr_based_features = 0;
+
 	for (i = 0; i < ARRAY_SIZE(msrs_to_save_all); i++) {
 		if (rdmsr_safe(msrs_to_save_all[i], &dummy[0], &dummy[1]) < 0)
 			continue;