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

Pull x86 kvm fixes from Paolo Bonzini:
 "x86 fixes.  Everyone else is already in holiday mood apparently.

   - Add a missing 'break' to fix param parsing in the rseq selftest

   - Apply runtime updates to the _current_ CPUID when userspace is
     setting CPUID, e.g. as part of vCPU hotplug, to fix a false
     positive and to avoid dropping the pending update

   - Disallow toggling KVM_MEM_GUEST_MEMFD on an existing memslot, as
     it's not supported by KVM and leads to a use-after-free due to KVM
     failing to unbind the memslot from the previously-associated
     guest_memfd instance

   - Harden against similar KVM_MEM_GUEST_MEMFD goofs, and prepare for
     supporting flags-only changes on KVM_MEM_GUEST_MEMFD memlslots,
     e.g. for dirty logging

   - Set exit_code[63:32] to -1 (all 0xffs) when synthesizing a nested
     SVM_EXIT_ERR (a.k.a. VMEXIT_INVALID) #VMEXIT, as VMEXIT_INVALID is
     defined as -1ull (a 64-bit value)

   - Update SVI when activating APICv to fix a bug where a
     post-activation EOI for an in-service IRQ would effective be lost
     due to SVI being stale

   - Immediately refresh APICv controls (if necessary) on a nested
     VM-Exit instead of deferring the update via KVM_REQ_APICV_UPDATE,
     as the request is effectively ignored because KVM thinks the vCPU
     already has the correct APICv settings"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
  KVM: nVMX: Immediately refresh APICv controls as needed on nested VM-Exit
  KVM: VMX: Update SVI during runtime APICv activation
  KVM: nSVM: Set exit_code_hi to -1 when synthesizing SVM_EXIT_ERR (failed VMRUN)
  KVM: nSVM: Clear exit_code_hi in VMCB when synthesizing nested VM-Exits
  KVM: Harden and prepare for modifying existing guest_memfd memslots
  KVM: Disallow toggling KVM_MEM_GUEST_MEMFD on an existing memslot
  KVM: selftests: Add a CPUID testcase for KVM_SET_CPUID2 with runtime updates
  KVM: x86: Apply runtime updates to current CPUID during KVM_SET_CPUID{,2}
  KVM: selftests: Add missing "break" in rseq_test's param parsing

7 files changed, 26 insertions, 17 deletions

diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
index d563a948318b..88a5426674a1 100644
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -510,10 +510,17 @@ static int kvm_set_cpuid(struct kvm_vcpu *vcpu, struct kvm_cpuid_entry2 *e2,
 	int r;
 
 	/*
+	 * Apply pending runtime CPUID updates to the current CPUID entries to
+	 * avoid false positives due to mismatches on KVM-owned feature flags.
+	 */
+	if (vcpu->arch.cpuid_dynamic_bits_dirty)
+		kvm_update_cpuid_runtime(vcpu);
+
+	/*
 	 * Swap the existing (old) entries with the incoming (new) entries in
 	 * order to massage the new entries, e.g. to account for dynamic bits
-	 * that KVM controls, without clobbering the current guest CPUID, which
-	 * KVM needs to preserve in order to unwind on failure.
+	 * that KVM controls, without losing the current guest CPUID, which KVM
+	 * needs to preserve in order to unwind on failure.
 	 *
 	 * Similarly, save the vCPU's current cpu_caps so that the capabilities
 	 * can be updated alongside the CPUID entries when performing runtime
diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c
index c81005b24522..ba0f11c68372 100644
--- a/arch/x86/kvm/svm/nested.c
+++ b/arch/x86/kvm/svm/nested.c
@@ -985,7 +985,7 @@ int nested_svm_vmrun(struct kvm_vcpu *vcpu)
 	if (!nested_vmcb_check_save(vcpu) ||
 	    !nested_vmcb_check_controls(vcpu)) {
 		vmcb12->control.exit_code    = SVM_EXIT_ERR;
-		vmcb12->control.exit_code_hi = 0;
+		vmcb12->control.exit_code_hi = -1u;
 		vmcb12->control.exit_info_1  = 0;
 		vmcb12->control.exit_info_2  = 0;
 		goto out;
@@ -1018,7 +1018,7 @@ out_exit_err:
 	svm->soft_int_injected = false;
 
 	svm->vmcb->control.exit_code    = SVM_EXIT_ERR;
-	svm->vmcb->control.exit_code_hi = 0;
+	svm->vmcb->control.exit_code_hi = -1u;
 	svm->vmcb->control.exit_info_1  = 0;
 	svm->vmcb->control.exit_info_2  = 0;
 
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index f56c2d895011..24d59ccfa40d 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -2443,6 +2443,7 @@ static bool check_selective_cr0_intercepted(struct kvm_vcpu *vcpu,
 
 	if (cr0 ^ val) {
 		svm->vmcb->control.exit_code = SVM_EXIT_CR0_SEL_WRITE;
+		svm->vmcb->control.exit_code_hi = 0;
 		ret = (nested_svm_exit_handled(svm) == NESTED_EXIT_DONE);
 	}
 
@@ -4617,6 +4618,7 @@ static int svm_check_intercept(struct kvm_vcpu *vcpu,
 	if (static_cpu_has(X86_FEATURE_NRIPS))
 		vmcb->control.next_rip  = info->next_rip;
 	vmcb->control.exit_code = icpt_info.exit_code;
+	vmcb->control.exit_code_hi = 0;
 	vmexit = nested_svm_exit_handled(svm);
 
 	ret = (vmexit == NESTED_EXIT_DONE) ? X86EMUL_INTERCEPTED
diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h
index 9e151dbdef25..01be93a53d07 100644
--- a/arch/x86/kvm/svm/svm.h
+++ b/arch/x86/kvm/svm/svm.h
@@ -761,9 +761,10 @@ int nested_svm_vmexit(struct vcpu_svm *svm);
 
 static inline int nested_svm_simple_vmexit(struct vcpu_svm *svm, u32 exit_code)
 {
-	svm->vmcb->control.exit_code   = exit_code;
-	svm->vmcb->control.exit_info_1 = 0;
-	svm->vmcb->control.exit_info_2 = 0;
+	svm->vmcb->control.exit_code	= exit_code;
+	svm->vmcb->control.exit_code_hi	= 0;
+	svm->vmcb->control.exit_info_1	= 0;
+	svm->vmcb->control.exit_info_2	= 0;
 	return nested_svm_vmexit(svm);
 }
 
diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
index 40777278eabb..6137e5307d0f 100644
--- a/arch/x86/kvm/vmx/nested.c
+++ b/arch/x86/kvm/vmx/nested.c
@@ -19,6 +19,7 @@
 #include "trace.h"
 #include "vmx.h"
 #include "smm.h"
+#include "x86_ops.h"
 
 static bool __read_mostly enable_shadow_vmcs = 1;
 module_param_named(enable_shadow_vmcs, enable_shadow_vmcs, bool, S_IRUGO);
@@ -5165,7 +5166,7 @@ void __nested_vmx_vmexit(struct kvm_vcpu *vcpu, u32 vm_exit_reason,
 
 	if (vmx->nested.update_vmcs01_apicv_status) {
 		vmx->nested.update_vmcs01_apicv_status = false;
-		kvm_make_request(KVM_REQ_APICV_UPDATE, vcpu);
+		vmx_refresh_apicv_exec_ctrl(vcpu);
 	}
 
 	if (vmx->nested.update_vmcs01_hwapic_isr) {
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 4cbe8c84b636..6b96f7aea20b 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -6937,15 +6937,6 @@ void vmx_hwapic_isr_update(struct kvm_vcpu *vcpu, int max_isr)
 	 * VM-Exit, otherwise L1 with run with a stale SVI.
 	 */
 	if (is_guest_mode(vcpu)) {
-		/*
-		 * KVM is supposed to forward intercepted L2 EOIs to L1 if VID
-		 * is enabled in vmcs12; as above, the EOIs affect L2's vAPIC.
-		 * Note, userspace can stuff state while L2 is active; assert
-		 * that VID is disabled if and only if the vCPU is in KVM_RUN
-		 * to avoid false positives if userspace is setting APIC state.
-		 */
-		WARN_ON_ONCE(vcpu->wants_to_run &&
-			     nested_cpu_has_vid(get_vmcs12(vcpu)));
 		to_vmx(vcpu)->nested.update_vmcs01_hwapic_isr = true;
 		return;
 	}
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 0c6d899d53dd..ff8812f3a129 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -10886,9 +10886,16 @@ void __kvm_vcpu_update_apicv(struct kvm_vcpu *vcpu)
 	 * pending. At the same time, KVM_REQ_EVENT may not be set as APICv was
 	 * still active when the interrupt got accepted. Make sure
 	 * kvm_check_and_inject_events() is called to check for that.
+	 *
+	 * Update SVI when APICv gets enabled, otherwise SVI won't reflect the
+	 * highest bit in vISR and the next accelerated EOI in the guest won't
+	 * be virtualized correctly (the CPU uses SVI to determine which vISR
+	 * vector to clear).
 	 */
 	if (!apic->apicv_active)
 		kvm_make_request(KVM_REQ_EVENT, vcpu);
+	else
+		kvm_apic_update_hwapic_isr(vcpu);
 
 out:
 	preempt_enable();