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

Pull kvm fixes from Paolo Bonzini:
 "x86:

   - Do not register IRQ bypass consumer if posted interrupts not
     supported

   - Fix missed device interrupt due to non-atomic update of IRR

   - Use GFP_KERNEL_ACCOUNT for pid_table in ipiv

   - Make VMREAD error path play nice with noinstr

   - x86: Acquire SRCU read lock when handling fastpath MSR writes

   - Support linking rseq tests statically against glibc 2.35+

   - Fix reference count for stats file descriptors

   - Detect userspace setting invalid CR0

  Non-KVM:

   - Remove coccinelle script that has caused multiple confusion
     ("debugfs, coccinelle: check for obsolete DEFINE_SIMPLE_ATTRIBUTE()
     usage", acked by Greg)"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (21 commits)
  KVM: selftests: Expand x86's sregs test to cover illegal CR0 values
  KVM: VMX: Don't fudge CR0 and CR4 for restricted L2 guest
  KVM: x86: Disallow KVM_SET_SREGS{2} if incoming CR0 is invalid
  Revert "debugfs, coccinelle: check for obsolete DEFINE_SIMPLE_ATTRIBUTE() usage"
  KVM: selftests: Verify stats fd is usable after VM fd has been closed
  KVM: selftests: Verify stats fd can be dup()'d and read
  KVM: selftests: Verify userspace can create "redundant" binary stats files
  KVM: selftests: Explicitly free vcpus array in binary stats test
  KVM: selftests: Clean up stats fd in common stats_test() helper
  KVM: selftests: Use pread() to read binary stats header
  KVM: Grab a reference to KVM for VM and vCPU stats file descriptors
  selftests/rseq: Play nice with binaries statically linked against glibc 2.35+
  Revert "KVM: SVM: Skip WRMSR fastpath on VM-Exit if next RIP isn't valid"
  KVM: x86: Acquire SRCU read lock when handling fastpath MSR writes
  KVM: VMX: Use vmread_error() to report VM-Fail in "goto" path
  KVM: VMX: Make VMREAD error path play nice with noinstr
  KVM: x86/irq: Conditionally register IRQ bypass consumer again
  KVM: X86: Use GFP_KERNEL_ACCOUNT for pid_table in ipiv
  KVM: x86: check the kvm_cpu_get_interrupt result before using it
  KVM: x86: VMX: set irr_pending in kvm_apic_update_irr
  ...

8 files changed, 121 insertions, 56 deletions

diff --git a/arch/x86/include/asm/kvm-x86-ops.h b/arch/x86/include/asm/kvm-x86-ops.h
index 13bc212cd4bc..e3054e3e46d5 100644
--- a/arch/x86/include/asm/kvm-x86-ops.h
+++ b/arch/x86/include/asm/kvm-x86-ops.h
@@ -37,6 +37,7 @@ KVM_X86_OP(get_segment)
 KVM_X86_OP(get_cpl)
 KVM_X86_OP(set_segment)
 KVM_X86_OP(get_cs_db_l_bits)
+KVM_X86_OP(is_valid_cr0)
 KVM_X86_OP(set_cr0)
 KVM_X86_OP_OPTIONAL(post_set_cr3)
 KVM_X86_OP(is_valid_cr4)
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 28bd38303d70..3bc146dfd38d 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -1566,9 +1566,10 @@ struct kvm_x86_ops {
 	void (*set_segment)(struct kvm_vcpu *vcpu,
 			    struct kvm_segment *var, int seg);
 	void (*get_cs_db_l_bits)(struct kvm_vcpu *vcpu, int *db, int *l);
+	bool (*is_valid_cr0)(struct kvm_vcpu *vcpu, unsigned long cr0);
 	void (*set_cr0)(struct kvm_vcpu *vcpu, unsigned long cr0);
 	void (*post_set_cr3)(struct kvm_vcpu *vcpu, unsigned long cr3);
-	bool (*is_valid_cr4)(struct kvm_vcpu *vcpu, unsigned long cr0);
+	bool (*is_valid_cr4)(struct kvm_vcpu *vcpu, unsigned long cr4);
 	void (*set_cr4)(struct kvm_vcpu *vcpu, unsigned long cr4);
 	int (*set_efer)(struct kvm_vcpu *vcpu, u64 efer);
 	void (*get_idt)(struct kvm_vcpu *vcpu, struct desc_ptr *dt);
diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
index 113ca9661ab2..a983a16163b1 100644
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -637,16 +637,22 @@ bool __kvm_apic_update_irr(u32 *pir, void *regs, int *max_irr)
 	*max_irr = -1;
 
 	for (i = vec = 0; i <= 7; i++, vec += 32) {
+		u32 *p_irr = (u32 *)(regs + APIC_IRR + i * 0x10);
+
+		irr_val = *p_irr;
 		pir_val = READ_ONCE(pir[i]);
-		irr_val = *((u32 *)(regs + APIC_IRR + i * 0x10));
+
 		if (pir_val) {
+			pir_val = xchg(&pir[i], 0);
+
 			prev_irr_val = irr_val;
-			irr_val |= xchg(&pir[i], 0);
-			*((u32 *)(regs + APIC_IRR + i * 0x10)) = irr_val;
-			if (prev_irr_val != irr_val) {
-				max_updated_irr =
-					__fls(irr_val ^ prev_irr_val) + vec;
-			}
+			do {
+				irr_val = prev_irr_val | pir_val;
+			} while (prev_irr_val != irr_val &&
+				 !try_cmpxchg(p_irr, &prev_irr_val, irr_val));
+
+			if (prev_irr_val != irr_val)
+				max_updated_irr = __fls(irr_val ^ prev_irr_val) + vec;
 		}
 		if (irr_val)
 			*max_irr = __fls(irr_val) + vec;
@@ -660,8 +666,11 @@ EXPORT_SYMBOL_GPL(__kvm_apic_update_irr);
 bool kvm_apic_update_irr(struct kvm_vcpu *vcpu, u32 *pir, int *max_irr)
 {
 	struct kvm_lapic *apic = vcpu->arch.apic;
+	bool irr_updated = __kvm_apic_update_irr(pir, apic->regs, max_irr);
 
-	return __kvm_apic_update_irr(pir, apic->regs, max_irr);
+	if (unlikely(!apic->apicv_active && irr_updated))
+		apic->irr_pending = true;
+	return irr_updated;
 }
 EXPORT_SYMBOL_GPL(kvm_apic_update_irr);
 
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index d381ad424554..956726d867aa 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -1786,6 +1786,11 @@ static void sev_post_set_cr3(struct kvm_vcpu *vcpu, unsigned long cr3)
 	}
 }
 
+static bool svm_is_valid_cr0(struct kvm_vcpu *vcpu, unsigned long cr0)
+{
+	return true;
+}
+
 void svm_set_cr0(struct kvm_vcpu *vcpu, unsigned long cr0)
 {
 	struct vcpu_svm *svm = to_svm(vcpu);
@@ -3986,14 +3991,8 @@ static int svm_vcpu_pre_run(struct kvm_vcpu *vcpu)
 
 static fastpath_t svm_exit_handlers_fastpath(struct kvm_vcpu *vcpu)
 {
-	struct vmcb_control_area *control = &to_svm(vcpu)->vmcb->control;
-
-	/*
-	 * Note, the next RIP must be provided as SRCU isn't held, i.e. KVM
-	 * can't read guest memory (dereference memslots) to decode the WRMSR.
-	 */
-	if (control->exit_code == SVM_EXIT_MSR && control->exit_info_1 &&
-	    nrips && control->next_rip)
+	if (to_svm(vcpu)->vmcb->control.exit_code == SVM_EXIT_MSR &&
+	    to_svm(vcpu)->vmcb->control.exit_info_1)
 		return handle_fastpath_set_msr_irqoff(vcpu);
 
 	return EXIT_FASTPATH_NONE;
@@ -4815,6 +4814,7 @@ static struct kvm_x86_ops svm_x86_ops __initdata = {
 	.set_segment = svm_set_segment,
 	.get_cpl = svm_get_cpl,
 	.get_cs_db_l_bits = svm_get_cs_db_l_bits,
+	.is_valid_cr0 = svm_is_valid_cr0,
 	.set_cr0 = svm_set_cr0,
 	.post_set_cr3 = sev_post_set_cr3,
 	.is_valid_cr4 = svm_is_valid_cr4,
diff --git a/arch/x86/kvm/vmx/vmenter.S b/arch/x86/kvm/vmx/vmenter.S
index 07e927d4d099..be275a0410a8 100644
--- a/arch/x86/kvm/vmx/vmenter.S
+++ b/arch/x86/kvm/vmx/vmenter.S
@@ -303,10 +303,8 @@ SYM_FUNC_START(vmx_do_nmi_irqoff)
 	VMX_DO_EVENT_IRQOFF call asm_exc_nmi_kvm_vmx
 SYM_FUNC_END(vmx_do_nmi_irqoff)
 
-
-.section .text, "ax"
-
 #ifndef CONFIG_CC_HAS_ASM_GOTO_OUTPUT
+
 /**
  * vmread_error_trampoline - Trampoline from inline asm to vmread_error()
  * @field:	VMCS field encoding that failed
@@ -335,7 +333,7 @@ SYM_FUNC_START(vmread_error_trampoline)
 	mov 3*WORD_SIZE(%_ASM_BP), %_ASM_ARG2
 	mov 2*WORD_SIZE(%_ASM_BP), %_ASM_ARG1
 
-	call vmread_error
+	call vmread_error_trampoline2
 
 	/* Zero out @fault, which will be popped into the result register. */
 	_ASM_MOV $0, 3*WORD_SIZE(%_ASM_BP)
@@ -357,6 +355,8 @@ SYM_FUNC_START(vmread_error_trampoline)
 SYM_FUNC_END(vmread_error_trampoline)
 #endif
 
+.section .text, "ax"
+
 SYM_FUNC_START(vmx_do_interrupt_irqoff)
 	VMX_DO_EVENT_IRQOFF CALL_NOSPEC _ASM_ARG1
 SYM_FUNC_END(vmx_do_interrupt_irqoff)
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 0ecf4be2c6af..df461f387e20 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -441,13 +441,23 @@ do {					\
 	pr_warn_ratelimited(fmt);	\
 } while (0)
 
-void vmread_error(unsigned long field, bool fault)
+noinline void vmread_error(unsigned long field)
 {
-	if (fault)
+	vmx_insn_failed("vmread failed: field=%lx\n", field);
+}
+
+#ifndef CONFIG_CC_HAS_ASM_GOTO_OUTPUT
+noinstr void vmread_error_trampoline2(unsigned long field, bool fault)
+{
+	if (fault) {
 		kvm_spurious_fault();
-	else
-		vmx_insn_failed("vmread failed: field=%lx\n", field);
+	} else {
+		instrumentation_begin();
+		vmread_error(field);
+		instrumentation_end();
+	}
 }
+#endif
 
 noinline void vmwrite_error(unsigned long field, unsigned long value)
 {
@@ -1503,6 +1513,11 @@ void vmx_set_rflags(struct kvm_vcpu *vcpu, unsigned long rflags)
 	struct vcpu_vmx *vmx = to_vmx(vcpu);
 	unsigned long old_rflags;
 
+	/*
+	 * Unlike CR0 and CR4, RFLAGS handling requires checking if the vCPU
+	 * is an unrestricted guest in order to mark L2 as needing emulation
+	 * if L1 runs L2 as a restricted guest.
+	 */
 	if (is_unrestricted_guest(vcpu)) {
 		kvm_register_mark_available(vcpu, VCPU_EXREG_RFLAGS);
 		vmx->rflags = rflags;
@@ -3037,6 +3052,15 @@ static void enter_rmode(struct kvm_vcpu *vcpu)
 	struct vcpu_vmx *vmx = to_vmx(vcpu);
 	struct kvm_vmx *kvm_vmx = to_kvm_vmx(vcpu->kvm);
 
+	/*
+	 * KVM should never use VM86 to virtualize Real Mode when L2 is active,
+	 * as using VM86 is unnecessary if unrestricted guest is enabled, and
+	 * if unrestricted guest is disabled, VM-Enter (from L1) with CR0.PG=0
+	 * should VM-Fail and KVM should reject userspace attempts to stuff
+	 * CR0.PG=0 when L2 is active.
+	 */
+	WARN_ON_ONCE(is_guest_mode(vcpu));
+
 	vmx_get_segment(vcpu, &vmx->rmode.segs[VCPU_SREG_TR], VCPU_SREG_TR);
 	vmx_get_segment(vcpu, &vmx->rmode.segs[VCPU_SREG_ES], VCPU_SREG_ES);
 	vmx_get_segment(vcpu, &vmx->rmode.segs[VCPU_SREG_DS], VCPU_SREG_DS);
@@ -3226,6 +3250,17 @@ void ept_save_pdptrs(struct kvm_vcpu *vcpu)
 #define CR3_EXITING_BITS (CPU_BASED_CR3_LOAD_EXITING | \
 			  CPU_BASED_CR3_STORE_EXITING)
 
+static bool vmx_is_valid_cr0(struct kvm_vcpu *vcpu, unsigned long cr0)
+{
+	if (is_guest_mode(vcpu))
+		return nested_guest_cr0_valid(vcpu, cr0);
+
+	if (to_vmx(vcpu)->nested.vmxon)
+		return nested_host_cr0_valid(vcpu, cr0);
+
+	return true;
+}
+
 void vmx_set_cr0(struct kvm_vcpu *vcpu, unsigned long cr0)
 {
 	struct vcpu_vmx *vmx = to_vmx(vcpu);
@@ -3235,7 +3270,7 @@ void vmx_set_cr0(struct kvm_vcpu *vcpu, unsigned long cr0)
 	old_cr0_pg = kvm_read_cr0_bits(vcpu, X86_CR0_PG);
 
 	hw_cr0 = (cr0 & ~KVM_VM_CR0_ALWAYS_OFF);
-	if (is_unrestricted_guest(vcpu))
+	if (enable_unrestricted_guest)
 		hw_cr0 |= KVM_VM_CR0_ALWAYS_ON_UNRESTRICTED_GUEST;
 	else {
 		hw_cr0 |= KVM_VM_CR0_ALWAYS_ON;
@@ -3263,7 +3298,7 @@ void vmx_set_cr0(struct kvm_vcpu *vcpu, unsigned long cr0)
 	}
 #endif
 
-	if (enable_ept && !is_unrestricted_guest(vcpu)) {
+	if (enable_ept && !enable_unrestricted_guest) {
 		/*
 		 * Ensure KVM has an up-to-date snapshot of the guest's CR3.  If
 		 * the below code _enables_ CR3 exiting, vmx_cache_reg() will
@@ -3394,7 +3429,7 @@ void vmx_set_cr4(struct kvm_vcpu *vcpu, unsigned long cr4)
 	 * this bit, even if host CR4.MCE == 0.
 	 */
 	hw_cr4 = (cr4_read_shadow() & X86_CR4_MCE) | (cr4 & ~X86_CR4_MCE);
-	if (is_unrestricted_guest(vcpu))
+	if (enable_unrestricted_guest)
 		hw_cr4 |= KVM_VM_CR4_ALWAYS_ON_UNRESTRICTED_GUEST;
 	else if (vmx->rmode.vm86_active)
 		hw_cr4 |= KVM_RMODE_VM_CR4_ALWAYS_ON;
@@ -3414,7 +3449,7 @@ void vmx_set_cr4(struct kvm_vcpu *vcpu, unsigned long cr4)
 	vcpu->arch.cr4 = cr4;
 	kvm_register_mark_available(vcpu, VCPU_EXREG_CR4);
 
-	if (!is_unrestricted_guest(vcpu)) {
+	if (!enable_unrestricted_guest) {
 		if (enable_ept) {
 			if (!is_paging(vcpu)) {
 				hw_cr4 &= ~X86_CR4_PAE;
@@ -4651,7 +4686,8 @@ static int vmx_alloc_ipiv_pid_table(struct kvm *kvm)
 	if (kvm_vmx->pid_table)
 		return 0;
 
-	pages = alloc_pages(GFP_KERNEL | __GFP_ZERO, vmx_get_pid_table_order(kvm));
+	pages = alloc_pages(GFP_KERNEL_ACCOUNT | __GFP_ZERO,
+			    vmx_get_pid_table_order(kvm));
 	if (!pages)
 		return -ENOMEM;
 
@@ -5364,18 +5400,11 @@ static int handle_set_cr0(struct kvm_vcpu *vcpu, unsigned long val)
 		val = (val & ~vmcs12->cr0_guest_host_mask) |
 			(vmcs12->guest_cr0 & vmcs12->cr0_guest_host_mask);
 
-		if (!nested_guest_cr0_valid(vcpu, val))
-			return 1;
-
 		if (kvm_set_cr0(vcpu, val))
 			return 1;
 		vmcs_writel(CR0_READ_SHADOW, orig_val);
 		return 0;
 	} else {
-		if (to_vmx(vcpu)->nested.vmxon &&
-		    !nested_host_cr0_valid(vcpu, val))
-			return 1;
-
 		return kvm_set_cr0(vcpu, val);
 	}
 }
@@ -8203,6 +8232,7 @@ static struct kvm_x86_ops vmx_x86_ops __initdata = {
 	.set_segment = vmx_set_segment,
 	.get_cpl = vmx_get_cpl,
 	.get_cs_db_l_bits = vmx_get_cs_db_l_bits,
+	.is_valid_cr0 = vmx_is_valid_cr0,
 	.set_cr0 = vmx_set_cr0,
 	.is_valid_cr4 = vmx_is_valid_cr4,
 	.set_cr4 = vmx_set_cr4,
diff --git a/arch/x86/kvm/vmx/vmx_ops.h b/arch/x86/kvm/vmx/vmx_ops.h
index ce47dc265f89..33af7b4c6eb4 100644
--- a/arch/x86/kvm/vmx/vmx_ops.h
+++ b/arch/x86/kvm/vmx/vmx_ops.h
@@ -10,7 +10,7 @@
 #include "vmcs.h"
 #include "../x86.h"
 
-void vmread_error(unsigned long field, bool fault);
+void vmread_error(unsigned long field);
 void vmwrite_error(unsigned long field, unsigned long value);
 void vmclear_error(struct vmcs *vmcs, u64 phys_addr);
 void vmptrld_error(struct vmcs *vmcs, u64 phys_addr);
@@ -31,6 +31,13 @@ void invept_error(unsigned long ext, u64 eptp, gpa_t gpa);
  * void vmread_error_trampoline(unsigned long field, bool fault);
  */
 extern unsigned long vmread_error_trampoline;
+
+/*
+ * The second VMREAD error trampoline, called from the assembly trampoline,
+ * exists primarily to enable instrumentation for the VM-Fail path.
+ */
+void vmread_error_trampoline2(unsigned long field, bool fault);
+
 #endif
 
 static __always_inline void vmcs_check16(unsigned long field)
@@ -101,8 +108,7 @@ static __always_inline unsigned long __vmcs_readl(unsigned long field)
 
 do_fail:
 	instrumentation_begin();
-	WARN_ONCE(1, KBUILD_MODNAME ": vmread failed: field=%lx\n", field);
-	pr_warn_ratelimited(KBUILD_MODNAME ": vmread failed: field=%lx\n", field);
+	vmread_error(field);
 	instrumentation_end();
 	return 0;
 
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index a6b9bea62fb8..278dbd37dab2 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -906,6 +906,22 @@ int load_pdptrs(struct kvm_vcpu *vcpu, unsigned long cr3)
 }
 EXPORT_SYMBOL_GPL(load_pdptrs);
 
+static bool kvm_is_valid_cr0(struct kvm_vcpu *vcpu, unsigned long cr0)
+{
+#ifdef CONFIG_X86_64
+	if (cr0 & 0xffffffff00000000UL)
+		return false;
+#endif
+
+	if ((cr0 & X86_CR0_NW) && !(cr0 & X86_CR0_CD))
+		return false;
+
+	if ((cr0 & X86_CR0_PG) && !(cr0 & X86_CR0_PE))
+		return false;
+
+	return static_call(kvm_x86_is_valid_cr0)(vcpu, cr0);
+}
+
 void kvm_post_set_cr0(struct kvm_vcpu *vcpu, unsigned long old_cr0, unsigned long cr0)
 {
 	/*
@@ -952,20 +968,13 @@ int kvm_set_cr0(struct kvm_vcpu *vcpu, unsigned long cr0)
 {
 	unsigned long old_cr0 = kvm_read_cr0(vcpu);
 
-	cr0 |= X86_CR0_ET;
-
-#ifdef CONFIG_X86_64
-	if (cr0 & 0xffffffff00000000UL)
+	if (!kvm_is_valid_cr0(vcpu, cr0))
 		return 1;
-#endif
 
-	cr0 &= ~CR0_RESERVED_BITS;
-
-	if ((cr0 & X86_CR0_NW) && !(cr0 & X86_CR0_CD))
-		return 1;
+	cr0 |= X86_CR0_ET;
 
-	if ((cr0 & X86_CR0_PG) && !(cr0 & X86_CR0_PE))
-		return 1;
+	/* Write to CR0 reserved bits are ignored, even on Intel. */
+	cr0 &= ~CR0_RESERVED_BITS;
 
 #ifdef CONFIG_X86_64
 	if ((vcpu->arch.efer & EFER_LME) && !is_paging(vcpu) &&
@@ -2172,6 +2181,8 @@ fastpath_t handle_fastpath_set_msr_irqoff(struct kvm_vcpu *vcpu)
 	u64 data;
 	fastpath_t ret = EXIT_FASTPATH_NONE;
 
+	kvm_vcpu_srcu_read_lock(vcpu);
+
 	switch (msr) {
 	case APIC_BASE_MSR + (APIC_ICR >> 4):
 		data = kvm_read_edx_eax(vcpu);
@@ -2194,6 +2205,8 @@ fastpath_t handle_fastpath_set_msr_irqoff(struct kvm_vcpu *vcpu)
 	if (ret != EXIT_FASTPATH_NONE)
 		trace_kvm_msr_write(msr, data);
 
+	kvm_vcpu_srcu_read_unlock(vcpu);
+
 	return ret;
 }
 EXPORT_SYMBOL_GPL(handle_fastpath_set_msr_irqoff);
@@ -10203,9 +10216,13 @@ static int kvm_check_and_inject_events(struct kvm_vcpu *vcpu,
 		if (r < 0)
 			goto out;
 		if (r) {
-			kvm_queue_interrupt(vcpu, kvm_cpu_get_interrupt(vcpu), false);
-			static_call(kvm_x86_inject_irq)(vcpu, false);
-			WARN_ON(static_call(kvm_x86_interrupt_allowed)(vcpu, true) < 0);
+			int irq = kvm_cpu_get_interrupt(vcpu);
+
+			if (!WARN_ON_ONCE(irq == -1)) {
+				kvm_queue_interrupt(vcpu, irq, false);
+				static_call(kvm_x86_inject_irq)(vcpu, false);
+				WARN_ON(static_call(kvm_x86_interrupt_allowed)(vcpu, true) < 0);
+			}
 		}
 		if (kvm_cpu_has_injectable_intr(vcpu))
 			static_call(kvm_x86_enable_irq_window)(vcpu);
@@ -11460,7 +11477,8 @@ static bool kvm_is_valid_sregs(struct kvm_vcpu *vcpu, struct kvm_sregs *sregs)
 			return false;
 	}
 
-	return kvm_is_valid_cr4(vcpu, sregs->cr4);
+	return kvm_is_valid_cr4(vcpu, sregs->cr4) &&
+	       kvm_is_valid_cr0(vcpu, sregs->cr0);
 }
 
 static int __set_sregs_common(struct kvm_vcpu *vcpu, struct kvm_sregs *sregs,
@@ -13185,7 +13203,7 @@ EXPORT_SYMBOL_GPL(kvm_arch_has_noncoherent_dma);
 
 bool kvm_arch_has_irq_bypass(void)
 {
-	return true;
+	return enable_apicv && irq_remapping_cap(IRQ_POSTING_CAP);
 }
 
 int kvm_arch_irq_bypass_add_producer(struct irq_bypass_consumer *cons,