Merge tag 'kvm-x86-misc-6.12' of https://github.com/kvm-x86/linux into HEAD

KVM x86 misc changes for 6.12

 - Advertise AVX10.1 to userspace (effectively prep work for the "real" AVX10
   functionality that is on the horizon).

 - Rework common MSR handling code to suppress errors on userspace accesses to
   unsupported-but-advertised MSRs.  This will allow removing (almost?) all of
   KVM's exemptions for userspace access to MSRs that shouldn't exist based on
   the vCPU model (the actual cleanup is non-trivial future work).

 - Rework KVM's handling of x2APIC ICR, again, because AMD (x2AVIC) splits the
   64-bit value into the legacy ICR and ICR2 storage, whereas Intel (APICv)
   stores the entire 64-bit value a the ICR offset.

 - Fix a bug where KVM would fail to exit to userspace if one was triggered by
   a fastpath exit handler.

 - Add fastpath handling of HLT VM-Exit to expedite re-entering the guest when
   there's already a pending wake event at the time of the exit.

 - Finally fix the RSM vs. nested VM-Enter WARN by forcing the vCPU out of
   guest mode prior to signalling SHUTDOWN (architecturally, the SHUTDOWN is
   supposed to hit L1, not L2).

17 files changed, 600 insertions, 475 deletions

diff --git a/arch/x86/include/asm/cpuid.h b/arch/x86/include/asm/cpuid.h
index 6b122a31da06..aa21c105eef1 100644
--- a/arch/x86/include/asm/cpuid.h
+++ b/arch/x86/include/asm/cpuid.h
@@ -179,6 +179,7 @@ static __always_inline bool cpuid_function_is_indexed(u32 function)
 	case 0x1d:
 	case 0x1e:
 	case 0x1f:
+	case 0x24:
 	case 0x8000001d:
 		return true;
 	}
diff --git a/arch/x86/include/asm/kvm-x86-ops.h b/arch/x86/include/asm/kvm-x86-ops.h
index 03b7e13f15bb..861d080ed4c6 100644
--- a/arch/x86/include/asm/kvm-x86-ops.h
+++ b/arch/x86/include/asm/kvm-x86-ops.h
@@ -125,7 +125,7 @@ KVM_X86_OP_OPTIONAL(mem_enc_unregister_region)
 KVM_X86_OP_OPTIONAL(vm_copy_enc_context_from)
 KVM_X86_OP_OPTIONAL(vm_move_enc_context_from)
 KVM_X86_OP_OPTIONAL(guest_memory_reclaimed)
-KVM_X86_OP(get_msr_feature)
+KVM_X86_OP(get_feature_msr)
 KVM_X86_OP(check_emulate_instruction)
 KVM_X86_OP(apic_init_signal_blocked)
 KVM_X86_OP_OPTIONAL(enable_l2_tlb_flush)
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 52443ccda320..45852c989559 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -212,6 +212,7 @@ enum exit_fastpath_completion {
 	EXIT_FASTPATH_NONE,
 	EXIT_FASTPATH_REENTER_GUEST,
 	EXIT_FASTPATH_EXIT_HANDLED,
+	EXIT_FASTPATH_EXIT_USERSPACE,
 };
 typedef enum exit_fastpath_completion fastpath_t;
 
@@ -1730,6 +1731,8 @@ struct kvm_x86_ops {
 	void (*enable_nmi_window)(struct kvm_vcpu *vcpu);
 	void (*enable_irq_window)(struct kvm_vcpu *vcpu);
 	void (*update_cr8_intercept)(struct kvm_vcpu *vcpu, int tpr, int irr);
+
+	const bool x2apic_icr_is_split;
 	const unsigned long required_apicv_inhibits;
 	bool allow_apicv_in_x2apic_without_x2apic_virtualization;
 	void (*refresh_apicv_exec_ctrl)(struct kvm_vcpu *vcpu);
@@ -1809,7 +1812,7 @@ struct kvm_x86_ops {
 	int (*vm_move_enc_context_from)(struct kvm *kvm, unsigned int source_fd);
 	void (*guest_memory_reclaimed)(struct kvm *kvm);
 
-	int (*get_msr_feature)(struct kvm_msr_entry *entry);
+	int (*get_feature_msr)(u32 msr, u64 *data);
 
 	int (*check_emulate_instruction)(struct kvm_vcpu *vcpu, int emul_type,
 					 void *insn, int insn_len);
diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
index 2617be544480..41786b834b16 100644
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -705,7 +705,7 @@ void kvm_set_cpu_caps(void)
 
 	kvm_cpu_cap_init_kvm_defined(CPUID_7_1_EDX,
 		F(AVX_VNNI_INT8) | F(AVX_NE_CONVERT) | F(PREFETCHITI) |
-		F(AMX_COMPLEX)
+		F(AMX_COMPLEX) | F(AVX10)
 	);
 
 	kvm_cpu_cap_init_kvm_defined(CPUID_7_2_EDX,
@@ -721,6 +721,10 @@ void kvm_set_cpu_caps(void)
 		SF(SGX1) | SF(SGX2) | SF(SGX_EDECCSSA)
 	);
 
+	kvm_cpu_cap_init_kvm_defined(CPUID_24_0_EBX,
+		F(AVX10_128) | F(AVX10_256) | F(AVX10_512)
+	);
+
 	kvm_cpu_cap_mask(CPUID_8000_0001_ECX,
 		F(LAHF_LM) | F(CMP_LEGACY) | 0 /*SVM*/ | 0 /* ExtApicSpace */ |
 		F(CR8_LEGACY) | F(ABM) | F(SSE4A) | F(MISALIGNSSE) |
@@ -949,7 +953,7 @@ static inline int __do_cpuid_func(struct kvm_cpuid_array *array, u32 function)
 	switch (function) {
 	case 0:
 		/* Limited to the highest leaf implemented in KVM. */
-		entry->eax = min(entry->eax, 0x1fU);
+		entry->eax = min(entry->eax, 0x24U);
 		break;
 	case 1:
 		cpuid_entry_override(entry, CPUID_1_EDX);
@@ -1174,6 +1178,28 @@ static inline int __do_cpuid_func(struct kvm_cpuid_array *array, u32 function)
 			break;
 		}
 		break;
+	case 0x24: {
+		u8 avx10_version;
+
+		if (!kvm_cpu_cap_has(X86_FEATURE_AVX10)) {
+			entry->eax = entry->ebx = entry->ecx = entry->edx = 0;
+			break;
+		}
+
+		/*
+		 * The AVX10 version is encoded in EBX[7:0].  Note, the version
+		 * is guaranteed to be >=1 if AVX10 is supported.  Note #2, the
+		 * version needs to be captured before overriding EBX features!
+		 */
+		avx10_version = min_t(u8, entry->ebx & 0xff, 1);
+		cpuid_entry_override(entry, CPUID_24_0_EBX);
+		entry->ebx |= avx10_version;
+
+		entry->eax = 0;
+		entry->ecx = 0;
+		entry->edx = 0;
+		break;
+	}
 	case KVM_CPUID_SIGNATURE: {
 		const u32 *sigptr = (const u32 *)KVM_SIGNATURE;
 		entry->eax = KVM_CPUID_FEATURES;
diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
index 5bb481aefcbc..c7180cb5f464 100644
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -1944,7 +1944,7 @@ static void start_sw_tscdeadline(struct kvm_lapic *apic)
 	u64 ns = 0;
 	ktime_t expire;
 	struct kvm_vcpu *vcpu = apic->vcpu;
-	unsigned long this_tsc_khz = vcpu->arch.virtual_tsc_khz;
+	u32 this_tsc_khz = vcpu->arch.virtual_tsc_khz;
 	unsigned long flags;
 	ktime_t now;
 
@@ -2453,6 +2453,43 @@ void kvm_lapic_set_eoi(struct kvm_vcpu *vcpu)
 }
 EXPORT_SYMBOL_GPL(kvm_lapic_set_eoi);
 
+#define X2APIC_ICR_RESERVED_BITS (GENMASK_ULL(31, 20) | GENMASK_ULL(17, 16) | BIT(13))
+
+int kvm_x2apic_icr_write(struct kvm_lapic *apic, u64 data)
+{
+	if (data & X2APIC_ICR_RESERVED_BITS)
+		return 1;
+
+	/*
+	 * The BUSY bit is reserved on both Intel and AMD in x2APIC mode, but
+	 * only AMD requires it to be zero, Intel essentially just ignores the
+	 * bit.  And if IPI virtualization (Intel) or x2AVIC (AMD) is enabled,
+	 * the CPU performs the reserved bits checks, i.e. the underlying CPU
+	 * behavior will "win".  Arbitrarily clear the BUSY bit, as there is no
+	 * sane way to provide consistent behavior with respect to hardware.
+	 */
+	data &= ~APIC_ICR_BUSY;
+
+	kvm_apic_send_ipi(apic, (u32)data, (u32)(data >> 32));
+	if (kvm_x86_ops.x2apic_icr_is_split) {
+		kvm_lapic_set_reg(apic, APIC_ICR, data);
+		kvm_lapic_set_reg(apic, APIC_ICR2, data >> 32);
+	} else {
+		kvm_lapic_set_reg64(apic, APIC_ICR, data);
+	}
+	trace_kvm_apic_write(APIC_ICR, data);
+	return 0;
+}
+
+static u64 kvm_x2apic_icr_read(struct kvm_lapic *apic)
+{
+	if (kvm_x86_ops.x2apic_icr_is_split)
+		return (u64)kvm_lapic_get_reg(apic, APIC_ICR) |
+		       (u64)kvm_lapic_get_reg(apic, APIC_ICR2) << 32;
+
+	return kvm_lapic_get_reg64(apic, APIC_ICR);
+}
+
 /* emulate APIC access in a trap manner */
 void kvm_apic_write_nodecode(struct kvm_vcpu *vcpu, u32 offset)
 {
@@ -2470,7 +2507,7 @@ void kvm_apic_write_nodecode(struct kvm_vcpu *vcpu, u32 offset)
 	 * maybe-unecessary write, and both are in the noise anyways.
 	 */
 	if (apic_x2apic_mode(apic) && offset == APIC_ICR)
-		kvm_x2apic_icr_write(apic, kvm_lapic_get_reg64(apic, APIC_ICR));
+		WARN_ON_ONCE(kvm_x2apic_icr_write(apic, kvm_x2apic_icr_read(apic)));
 	else
 		kvm_lapic_reg_write(apic, offset, kvm_lapic_get_reg(apic, offset));
 }
@@ -2990,18 +3027,22 @@ static int kvm_apic_state_fixup(struct kvm_vcpu *vcpu,
 
 		/*
 		 * In x2APIC mode, the LDR is fixed and based on the id.  And
-		 * ICR is internally a single 64-bit register, but needs to be
-		 * split to ICR+ICR2 in userspace for backwards compatibility.
+		 * if the ICR is _not_ split, ICR is internally a single 64-bit
+		 * register, but needs to be split to ICR+ICR2 in userspace for
+		 * backwards compatibility.
 		 */
-		if (set) {
+		if (set)
 			*ldr = kvm_apic_calc_x2apic_ldr(x2apic_id);
 
-			icr = __kvm_lapic_get_reg(s->regs, APIC_ICR) |
-			      (u64)__kvm_lapic_get_reg(s->regs, APIC_ICR2) << 32;
-			__kvm_lapic_set_reg64(s->regs, APIC_ICR, icr);
-		} else {
-			icr = __kvm_lapic_get_reg64(s->regs, APIC_ICR);
-			__kvm_lapic_set_reg(s->regs, APIC_ICR2, icr >> 32);
+		if (!kvm_x86_ops.x2apic_icr_is_split) {
+			if (set) {
+				icr = __kvm_lapic_get_reg(s->regs, APIC_ICR) |
+				      (u64)__kvm_lapic_get_reg(s->regs, APIC_ICR2) << 32;
+				__kvm_lapic_set_reg64(s->regs, APIC_ICR, icr);
+			} else {
+				icr = __kvm_lapic_get_reg64(s->regs, APIC_ICR);
+				__kvm_lapic_set_reg(s->regs, APIC_ICR2, icr >> 32);
+			}
 		}
 	}
 
@@ -3194,22 +3235,12 @@ int kvm_lapic_set_vapic_addr(struct kvm_vcpu *vcpu, gpa_t vapic_addr)
 	return 0;
 }
 
-int kvm_x2apic_icr_write(struct kvm_lapic *apic, u64 data)
-{
-	data &= ~APIC_ICR_BUSY;
-
-	kvm_apic_send_ipi(apic, (u32)data, (u32)(data >> 32));
-	kvm_lapic_set_reg64(apic, APIC_ICR, data);
-	trace_kvm_apic_write(APIC_ICR, data);
-	return 0;
-}
-
 static int kvm_lapic_msr_read(struct kvm_lapic *apic, u32 reg, u64 *data)
 {
 	u32 low;
 
 	if (reg == APIC_ICR) {
-		*data = kvm_lapic_get_reg64(apic, APIC_ICR);
+		*data = kvm_x2apic_icr_read(apic);
 		return 0;
 	}
 
diff --git a/arch/x86/kvm/lapic.h b/arch/x86/kvm/lapic.h
index 7ef8ae73e82d..7c95eedd771e 100644
--- a/arch/x86/kvm/lapic.h
+++ b/arch/x86/kvm/lapic.h
@@ -96,7 +96,6 @@ u64 kvm_lapic_get_cr8(struct kvm_vcpu *vcpu);
 void kvm_lapic_set_tpr(struct kvm_vcpu *vcpu, unsigned long cr8);
 void kvm_lapic_set_eoi(struct kvm_vcpu *vcpu);
 void kvm_lapic_set_base(struct kvm_vcpu *vcpu, u64 value);
-u64 kvm_lapic_get_base(struct kvm_vcpu *vcpu);
 void kvm_recalculate_apic_map(struct kvm *kvm);
 void kvm_apic_set_version(struct kvm_vcpu *vcpu);
 void kvm_apic_after_set_mcg_cap(struct kvm_vcpu *vcpu);
diff --git a/arch/x86/kvm/mmu.h b/arch/x86/kvm/mmu.h
index 4341e0e28571..9dc5dd43ae7f 100644
--- a/arch/x86/kvm/mmu.h
+++ b/arch/x86/kvm/mmu.h
@@ -223,8 +223,6 @@ static inline u8 permission_fault(struct kvm_vcpu *vcpu, struct kvm_mmu *mmu,
 
 bool kvm_mmu_may_ignore_guest_pat(void);
 
-int kvm_arch_write_log_dirty(struct kvm_vcpu *vcpu);
-
 int kvm_mmu_post_init_vm(struct kvm *kvm);
 void kvm_mmu_pre_destroy_vm(struct kvm *kvm);
 
diff --git a/arch/x86/kvm/mmu/mmu_internal.h b/arch/x86/kvm/mmu/mmu_internal.h
index 1721d97743e9..1469a1d9782d 100644
--- a/arch/x86/kvm/mmu/mmu_internal.h
+++ b/arch/x86/kvm/mmu/mmu_internal.h
@@ -349,8 +349,6 @@ int kvm_mmu_max_mapping_level(struct kvm *kvm,
 void kvm_mmu_hugepage_adjust(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault);
 void disallowed_hugepage_adjust(struct kvm_page_fault *fault, u64 spte, int cur_level);
 
-void *mmu_memory_cache_alloc(struct kvm_mmu_memory_cache *mc);
-
 void track_possible_nx_huge_page(struct kvm *kvm, struct kvm_mmu_page *sp);
 void untrack_possible_nx_huge_page(struct kvm *kvm, struct kvm_mmu_page *sp);
 
diff --git a/arch/x86/kvm/reverse_cpuid.h b/arch/x86/kvm/reverse_cpuid.h
index 2f4e155080ba..0d17d6b70639 100644
--- a/arch/x86/kvm/reverse_cpuid.h
+++ b/arch/x86/kvm/reverse_cpuid.h
@@ -17,6 +17,7 @@ enum kvm_only_cpuid_leafs {
 	CPUID_8000_0007_EDX,
 	CPUID_8000_0022_EAX,
 	CPUID_7_2_EDX,
+	CPUID_24_0_EBX,
 	NR_KVM_CPU_CAPS,
 
 	NKVMCAPINTS = NR_KVM_CPU_CAPS - NCAPINTS,
@@ -46,6 +47,7 @@ enum kvm_only_cpuid_leafs {
 #define X86_FEATURE_AVX_NE_CONVERT      KVM_X86_FEATURE(CPUID_7_1_EDX, 5)
 #define X86_FEATURE_AMX_COMPLEX         KVM_X86_FEATURE(CPUID_7_1_EDX, 8)
 #define X86_FEATURE_PREFETCHITI         KVM_X86_FEATURE(CPUID_7_1_EDX, 14)
+#define X86_FEATURE_AVX10               KVM_X86_FEATURE(CPUID_7_1_EDX, 19)
 
 /* Intel-defined sub-features, CPUID level 0x00000007:2 (EDX) */
 #define X86_FEATURE_INTEL_PSFD		KVM_X86_FEATURE(CPUID_7_2_EDX, 0)
@@ -55,6 +57,11 @@ enum kvm_only_cpuid_leafs {
 #define KVM_X86_FEATURE_BHI_CTRL	KVM_X86_FEATURE(CPUID_7_2_EDX, 4)
 #define X86_FEATURE_MCDT_NO		KVM_X86_FEATURE(CPUID_7_2_EDX, 5)
 
+/* Intel-defined sub-features, CPUID level 0x00000024:0 (EBX) */
+#define X86_FEATURE_AVX10_128		KVM_X86_FEATURE(CPUID_24_0_EBX, 16)
+#define X86_FEATURE_AVX10_256		KVM_X86_FEATURE(CPUID_24_0_EBX, 17)
+#define X86_FEATURE_AVX10_512		KVM_X86_FEATURE(CPUID_24_0_EBX, 18)
+
 /* CPUID level 0x80000007 (EDX). */
 #define KVM_X86_FEATURE_CONSTANT_TSC	KVM_X86_FEATURE(CPUID_8000_0007_EDX, 8)
 
@@ -90,6 +97,7 @@ static const struct cpuid_reg reverse_cpuid[] = {
 	[CPUID_8000_0021_EAX] = {0x80000021, 0, CPUID_EAX},
 	[CPUID_8000_0022_EAX] = {0x80000022, 0, CPUID_EAX},
 	[CPUID_7_2_EDX]       = {         7, 2, CPUID_EDX},
+	[CPUID_24_0_EBX]      = {      0x24, 0, CPUID_EBX},
 };
 
 /*
diff --git a/arch/x86/kvm/smm.c b/arch/x86/kvm/smm.c
index 00e3c27d2a87..85241c0c7f56 100644
--- a/arch/x86/kvm/smm.c
+++ b/arch/x86/kvm/smm.c
@@ -624,17 +624,31 @@ int emulator_leave_smm(struct x86_emulate_ctxt *ctxt)
 #endif
 
 	/*
-	 * Give leave_smm() a chance to make ISA-specific changes to the vCPU
-	 * state (e.g. enter guest mode) before loading state from the SMM
-	 * state-save area.
+	 * FIXME: When resuming L2 (a.k.a. guest mode), the transition to guest
+	 * mode should happen _after_ loading state from SMRAM.  However, KVM
+	 * piggybacks the nested VM-Enter flows (which is wrong for many other
+	 * reasons), and so nSVM/nVMX would clobber state that is loaded from
+	 * SMRAM and from the VMCS/VMCB.
 	 */
 	if (kvm_x86_call(leave_smm)(vcpu, &smram))
 		return X86EMUL_UNHANDLEABLE;
 
 #ifdef CONFIG_X86_64
 	if (guest_cpuid_has(vcpu, X86_FEATURE_LM))
-		return rsm_load_state_64(ctxt, &smram.smram64);
+		ret = rsm_load_state_64(ctxt, &smram.smram64);
 	else
 #endif
-		return rsm_load_state_32(ctxt, &smram.smram32);
+		ret = rsm_load_state_32(ctxt, &smram.smram32);
+
+	/*
+	 * If RSM fails and triggers shutdown, architecturally the shutdown
+	 * occurs *before* the transition to guest mode.  But due to KVM's
+	 * flawed handling of RSM to L2 (see above), the vCPU may already be
+	 * in_guest_mode().  Force the vCPU out of guest mode before delivering
+	 * the shutdown, so that L1 enters shutdown instead of seeing a VM-Exit
+	 * that architecturally shouldn't be possible.
+	 */
+	if (ret != X86EMUL_CONTINUE && is_guest_mode(vcpu))
+		kvm_leave_nested(vcpu);
+	return ret;
 }
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index 6b804ec3d1dc..c1062e8c3f50 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -2825,17 +2825,17 @@ static int efer_trap(struct kvm_vcpu *vcpu)
 	return kvm_complete_insn_gp(vcpu, ret);
 }
 
-static int svm_get_msr_feature(struct kvm_msr_entry *msr)
+static int svm_get_feature_msr(u32 msr, u64 *data)
 {
-	msr->data = 0;
+	*data = 0;
 
-	switch (msr->index) {
+	switch (msr) {
 	case MSR_AMD64_DE_CFG:
 		if (cpu_feature_enabled(X86_FEATURE_LFENCE_RDTSC))
-			msr->data |= MSR_AMD64_DE_CFG_LFENCE_SERIALIZE;
+			*data |= MSR_AMD64_DE_CFG_LFENCE_SERIALIZE;
 		break;
 	default:
-		return KVM_MSR_RET_INVALID;
+		return KVM_MSR_RET_UNSUPPORTED;
 	}
 
 	return 0;
@@ -3191,18 +3191,21 @@ static int svm_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr)
 		kvm_pr_unimpl_wrmsr(vcpu, ecx, data);
 		break;
 	case MSR_AMD64_DE_CFG: {
-		struct kvm_msr_entry msr_entry;
+		u64 supported_de_cfg;
 
-		msr_entry.index = msr->index;
-		if (svm_get_msr_feature(&msr_entry))
+		if (svm_get_feature_msr(ecx, &supported_de_cfg))
 			return 1;
 
-		/* Check the supported bits */
-		if (data & ~msr_entry.data)
+		if (data & ~supported_de_cfg)
 			return 1;
 
-		/* Don't allow the guest to change a bit, #GP */
-		if (!msr->host_initiated && (data ^ msr_entry.data))
+		/*
+		 * Don't let the guest change the host-programmed value.  The
+		 * MSR is very model specific, i.e. contains multiple bits that
+		 * are completely unknown to KVM, and the one bit known to KVM
+		 * is simply a reflection of hardware capabilities.
+		 */
+		if (!msr->host_initiated && data != svm->msr_decfg)
 			return 1;
 
 		svm->msr_decfg = data;
@@ -4156,12 +4159,21 @@ static int svm_vcpu_pre_run(struct kvm_vcpu *vcpu)
 
 static fastpath_t svm_exit_handlers_fastpath(struct kvm_vcpu *vcpu)
 {
+	struct vcpu_svm *svm = to_svm(vcpu);
+
 	if (is_guest_mode(vcpu))
 		return EXIT_FASTPATH_NONE;
 
-	if (to_svm(vcpu)->vmcb->control.exit_code == SVM_EXIT_MSR &&
-	    to_svm(vcpu)->vmcb->control.exit_info_1)
+	switch (svm->vmcb->control.exit_code) {
+	case SVM_EXIT_MSR:
+		if (!svm->vmcb->control.exit_info_1)
+			break;
 		return handle_fastpath_set_msr_irqoff(vcpu);
+	case SVM_EXIT_HLT:
+		return handle_fastpath_hlt(vcpu);
+	default:
+		break;
+	}
 
 	return EXIT_FASTPATH_NONE;
 }
@@ -5012,7 +5024,7 @@ static struct kvm_x86_ops svm_x86_ops __initdata = {
 	.vcpu_unblocking = avic_vcpu_unblocking,
 
 	.update_exception_bitmap = svm_update_exception_bitmap,
-	.get_msr_feature = svm_get_msr_feature,
+	.get_feature_msr = svm_get_feature_msr,
 	.get_msr = svm_get_msr,
 	.set_msr = svm_set_msr,
 	.get_segment_base = svm_get_segment_base,
@@ -5063,6 +5075,8 @@ static struct kvm_x86_ops svm_x86_ops __initdata = {
 	.enable_nmi_window = svm_enable_nmi_window,
 	.enable_irq_window = svm_enable_irq_window,
 	.update_cr8_intercept = svm_update_cr8_intercept,
+
+	.x2apic_icr_is_split = true,
 	.set_virtual_apic_mode = avic_refresh_virtual_apic_mode,
 	.refresh_apicv_exec_ctrl = avic_refresh_apicv_exec_ctrl,
 	.apicv_post_state_restore = avic_apicv_post_state_restore,
diff --git a/arch/x86/kvm/vmx/main.c b/arch/x86/kvm/vmx/main.c
index 7e2e78a14257..7668e2fb8043 100644
--- a/arch/x86/kvm/vmx/main.c
+++ b/arch/x86/kvm/vmx/main.c
@@ -43,7 +43,7 @@ struct kvm_x86_ops vt_x86_ops __initdata = {
 	.vcpu_put = vmx_vcpu_put,
 
 	.update_exception_bitmap = vmx_update_exception_bitmap,
-	.get_msr_feature = vmx_get_msr_feature,
+	.get_feature_msr = vmx_get_feature_msr,
 	.get_msr = vmx_get_msr,
 	.set_msr = vmx_set_msr,
 	.get_segment_base = vmx_get_segment_base,
@@ -91,6 +91,8 @@ struct kvm_x86_ops vt_x86_ops __initdata = {
 	.enable_nmi_window = vmx_enable_nmi_window,
 	.enable_irq_window = vmx_enable_irq_window,
 	.update_cr8_intercept = vmx_update_cr8_intercept,
+
+	.x2apic_icr_is_split = false,
 	.set_virtual_apic_mode = vmx_set_virtual_apic_mode,
 	.set_apic_access_page_addr = vmx_set_apic_access_page_addr,
 	.refresh_apicv_exec_ctrl = vmx_refresh_apicv_exec_ctrl,
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 89682832dded..0663b1fea2b9 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -1998,15 +1998,15 @@ static inline bool is_vmx_feature_control_msr_valid(struct vcpu_vmx *vmx,
 	return !(msr->data & ~valid_bits);
 }
 
-int vmx_get_msr_feature(struct kvm_msr_entry *msr)
+int vmx_get_feature_msr(u32 msr, u64 *data)
 {
-	switch (msr->index) {
+	switch (msr) {
 	case KVM_FIRST_EMULATED_VMX_MSR ... KVM_LAST_EMULATED_VMX_MSR:
 		if (!nested)
 			return 1;
-		return vmx_get_vmx_msr(&vmcs_config.nested, msr->index, &msr->data);
+		return vmx_get_vmx_msr(&vmcs_config.nested, msr, data);
 	default:
-		return KVM_MSR_RET_INVALID;
+		return KVM_MSR_RET_UNSUPPORTED;
 	}
 }
 
@@ -7265,6 +7265,8 @@ static fastpath_t vmx_exit_handlers_fastpath(struct kvm_vcpu *vcpu,
 		return handle_fastpath_set_msr_irqoff(vcpu);
 	case EXIT_REASON_PREEMPTION_TIMER:
 		return handle_fastpath_preemption_timer(vcpu, force_immediate_exit);
+	case EXIT_REASON_HLT:
+		return handle_fastpath_hlt(vcpu);
 	default:
 		return EXIT_FASTPATH_NONE;
 	}
diff --git a/arch/x86/kvm/vmx/vmx.h b/arch/x86/kvm/vmx/vmx.h
index 42498fa63abb..3839afb921e2 100644
--- a/arch/x86/kvm/vmx/vmx.h
+++ b/arch/x86/kvm/vmx/vmx.h
@@ -17,10 +17,6 @@
 #include "run_flags.h"
 #include "../mmu.h"
 
-#define MSR_TYPE_R	1
-#define MSR_TYPE_W	2
-#define MSR_TYPE_RW	3
-
 #define X2APIC_MSR(r) (APIC_BASE_MSR + ((r) >> 4))
 
 #ifdef CONFIG_X86_64
diff --git a/arch/x86/kvm/vmx/x86_ops.h b/arch/x86/kvm/vmx/x86_ops.h
index b6a7cfc6ae31..a55981c5216e 100644
--- a/arch/x86/kvm/vmx/x86_ops.h
+++ b/arch/x86/kvm/vmx/x86_ops.h
@@ -57,7 +57,7 @@ bool vmx_has_emulated_msr(struct kvm *kvm, u32 index);
 void vmx_msr_filter_changed(struct kvm_vcpu *vcpu);
 void vmx_prepare_switch_to_guest(struct kvm_vcpu *vcpu);
 void vmx_update_exception_bitmap(struct kvm_vcpu *vcpu);
-int vmx_get_msr_feature(struct kvm_msr_entry *msr);
+int vmx_get_feature_msr(u32 msr, u64 *data);
 int vmx_get_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info);
 u64 vmx_get_segment_base(struct kvm_vcpu *vcpu, int seg);
 void vmx_get_segment(struct kvm_vcpu *vcpu, struct kvm_segment *var, int seg);
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 0f7342b574f9..a877c0764fc5 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -305,24 +305,237 @@ const struct kvm_stats_header kvm_vcpu_stats_header = {
 static struct kmem_cache *x86_emulator_cache;
 
 /*
- * When called, it means the previous get/set msr reached an invalid msr.
- * Return true if we want to ignore/silent this failed msr access.
+ * The three MSR lists(msrs_to_save, emulated_msrs, msr_based_features) track
+ * the set of MSRs that KVM exposes to userspace through KVM_GET_MSRS,
+ * KVM_SET_MSRS, and KVM_GET_MSR_INDEX_LIST.  msrs_to_save holds MSRs that
+ * require host support, i.e. should be probed via RDMSR.  emulated_msrs holds
+ * MSRs that KVM emulates without strictly requiring host support.
+ * msr_based_features holds MSRs that enumerate features, i.e. are effectively
+ * CPUID leafs.  Note, msr_based_features isn't mutually exclusive with
+ * msrs_to_save and emulated_msrs.
  */
-static bool kvm_msr_ignored_check(u32 msr, u64 data, bool write)
+
+static const u32 msrs_to_save_base[] = {
+	MSR_IA32_SYSENTER_CS, MSR_IA32_SYSENTER_ESP, MSR_IA32_SYSENTER_EIP,
+	MSR_STAR,
+#ifdef CONFIG_X86_64
+	MSR_CSTAR, MSR_KERNEL_GS_BASE, MSR_SYSCALL_MASK, MSR_LSTAR,
+#endif
+	MSR_IA32_TSC, MSR_IA32_CR_PAT, MSR_VM_HSAVE_PA,
+	MSR_IA32_FEAT_CTL, MSR_IA32_BNDCFGS, MSR_TSC_AUX,
+	MSR_IA32_SPEC_CTRL, MSR_IA32_TSX_CTRL,
+	MSR_IA32_RTIT_CTL, MSR_IA32_RTIT_STATUS, MSR_IA32_RTIT_CR3_MATCH,
+	MSR_IA32_RTIT_OUTPUT_BASE, MSR_IA32_RTIT_OUTPUT_MASK,
+	MSR_IA32_RTIT_ADDR0_A, MSR_IA32_RTIT_ADDR0_B,
+	MSR_IA32_RTIT_ADDR1_A, MSR_IA32_RTIT_ADDR1_B,
+	MSR_IA32_RTIT_ADDR2_A, MSR_IA32_RTIT_ADDR2_B,
+	MSR_IA32_RTIT_ADDR3_A, MSR_IA32_RTIT_ADDR3_B,
+	MSR_IA32_UMWAIT_CONTROL,
+
+	MSR_IA32_XFD, MSR_IA32_XFD_ERR,
+};
+
+static const u32 msrs_to_save_pmu[] = {
+	MSR_ARCH_PERFMON_FIXED_CTR0, MSR_ARCH_PERFMON_FIXED_CTR1,
+	MSR_ARCH_PERFMON_FIXED_CTR0 + 2,
+	MSR_CORE_PERF_FIXED_CTR_CTRL, MSR_CORE_PERF_GLOBAL_STATUS,
+	MSR_CORE_PERF_GLOBAL_CTRL,
+	MSR_IA32_PEBS_ENABLE, MSR_IA32_DS_AREA, MSR_PEBS_DATA_CFG,
+
+	/* This part of MSRs should match KVM_MAX_NR_INTEL_GP_COUNTERS. */
+	MSR_ARCH_PERFMON_PERFCTR0, MSR_ARCH_PERFMON_PERFCTR1,
+	MSR_ARCH_PERFMON_PERFCTR0 + 2, MSR_ARCH_PERFMON_PERFCTR0 + 3,
+	MSR_ARCH_PERFMON_PERFCTR0 + 4, MSR_ARCH_PERFMON_PERFCTR0 + 5,
+	MSR_ARCH_PERFMON_PERFCTR0 + 6, MSR_ARCH_PERFMON_PERFCTR0 + 7,
+	MSR_ARCH_PERFMON_EVENTSEL0, MSR_ARCH_PERFMON_EVENTSEL1,
+	MSR_ARCH_PERFMON_EVENTSEL0 + 2, MSR_ARCH_PERFMON_EVENTSEL0 + 3,
+	MSR_ARCH_PERFMON_EVENTSEL0 + 4, MSR_ARCH_PERFMON_EVENTSEL0 + 5,
+	MSR_ARCH_PERFMON_EVENTSEL0 + 6, MSR_ARCH_PERFMON_EVENTSEL0 + 7,
+
+	MSR_K7_EVNTSEL0, MSR_K7_EVNTSEL1, MSR_K7_EVNTSEL2, MSR_K7_EVNTSEL3,
+	MSR_K7_PERFCTR0, MSR_K7_PERFCTR1, MSR_K7_PERFCTR2, MSR_K7_PERFCTR3,
+
+	/* This part of MSRs should match KVM_MAX_NR_AMD_GP_COUNTERS. */
+	MSR_F15H_PERF_CTL0, MSR_F15H_PERF_CTL1, MSR_F15H_PERF_CTL2,
+	MSR_F15H_PERF_CTL3, MSR_F15H_PERF_CTL4, MSR_F15H_PERF_CTL5,
+	MSR_F15H_PERF_CTR0, MSR_F15H_PERF_CTR1, MSR_F15H_PERF_CTR2,
+	MSR_F15H_PERF_CTR3, MSR_F15H_PERF_CTR4, MSR_F15H_PERF_CTR5,
+
+	MSR_AMD64_PERF_CNTR_GLOBAL_CTL,
+	MSR_AMD64_PERF_CNTR_GLOBAL_STATUS,
+	MSR_AMD64_PERF_CNTR_GLOBAL_STATUS_CLR,
+};
+
+static u32 msrs_to_save[ARRAY_SIZE(msrs_to_save_base) +
+			ARRAY_SIZE(msrs_to_save_pmu)];
+static unsigned num_msrs_to_save;
+
+static const u32 emulated_msrs_all[] = {
+	MSR_KVM_SYSTEM_TIME, MSR_KVM_WALL_CLOCK,
+	MSR_KVM_SYSTEM_TIME_NEW, MSR_KVM_WALL_CLOCK_NEW,
+
+#ifdef CONFIG_KVM_HYPERV
+	HV_X64_MSR_GUEST_OS_ID, HV_X64_MSR_HYPERCALL,
+	HV_X64_MSR_TIME_REF_COUNT, HV_X64_MSR_REFERENCE_TSC,
+	HV_X64_MSR_TSC_FREQUENCY, HV_X64_MSR_APIC_FREQUENCY,
+	HV_X64_MSR_CRASH_P0, HV_X64_MSR_CRASH_P1, HV_X64_MSR_CRASH_P2,
+	HV_X64_MSR_CRASH_P3, HV_X64_MSR_CRASH_P4, HV_X64_MSR_CRASH_CTL,
+	HV_X64_MSR_RESET,
+	HV_X64_MSR_VP_INDEX,
+	HV_X64_MSR_VP_RUNTIME,
+	HV_X64_MSR_SCONTROL,
+	HV_X64_MSR_STIMER0_CONFIG,
+	HV_X64_MSR_VP_ASSIST_PAGE,
+	HV_X64_MSR_REENLIGHTENMENT_CONTROL, HV_X64_MSR_TSC_EMULATION_CONTROL,
+	HV_X64_MSR_TSC_EMULATION_STATUS, HV_X64_MSR_TSC_INVARIANT_CONTROL,
+	HV_X64_MSR_SYNDBG_OPTIONS,
+	HV_X64_MSR_SYNDBG_CONTROL, HV_X64_MSR_SYNDBG_STATUS,
+	HV_X64_MSR_SYNDBG_SEND_BUFFER, HV_X64_MSR_SYNDBG_RECV_BUFFER,
+	HV_X64_MSR_SYNDBG_PENDING_BUFFER,
+#endif
+
+	MSR_KVM_ASYNC_PF_EN, MSR_KVM_STEAL_TIME,
+	MSR_KVM_PV_EOI_EN, MSR_KVM_ASYNC_PF_INT, MSR_KVM_ASYNC_PF_ACK,
+
+	MSR_IA32_TSC_ADJUST,
+	MSR_IA32_TSC_DEADLINE,
+	MSR_IA32_ARCH_CAPABILITIES,
+	MSR_IA32_PERF_CAPABILITIES,
+	MSR_IA32_MISC_ENABLE,
+	MSR_IA32_MCG_STATUS,
+	MSR_IA32_MCG_CTL,
+	MSR_IA32_MCG_EXT_CTL,
+	MSR_IA32_SMBASE,
+	MSR_SMI_COUNT,
+	MSR_PLATFORM_INFO,
+	MSR_MISC_FEATURES_ENABLES,
+	MSR_AMD64_VIRT_SPEC_CTRL,
+	MSR_AMD64_TSC_RATIO,
+	MSR_IA32_POWER_CTL,
+	MSR_IA32_UCODE_REV,
+
+	/*
+	 * KVM always supports the "true" VMX control MSRs, even if the host
+	 * does not.  The VMX MSRs as a whole are considered "emulated" as KVM
+	 * doesn't strictly require them to exist in the host (ignoring that
+	 * KVM would refuse to load in the first place if the core set of MSRs
+	 * aren't supported).
+	 */
+	MSR_IA32_VMX_BASIC,
+	MSR_IA32_VMX_TRUE_PINBASED_CTLS,
+	MSR_IA32_VMX_TRUE_PROCBASED_CTLS,
+	MSR_IA32_VMX_TRUE_EXIT_CTLS,
+	MSR_IA32_VMX_TRUE_ENTRY_CTLS,
+	MSR_IA32_VMX_MISC,
+	MSR_IA32_VMX_CR0_FIXED0,
+	MSR_IA32_VMX_CR4_FIXED0,
+	MSR_IA32_VMX_VMCS_ENUM,
+	MSR_IA32_VMX_PROCBASED_CTLS2,
+	MSR_IA32_VMX_EPT_VPID_CAP,
+	MSR_IA32_VMX_VMFUNC,
+
+	MSR_K7_HWCR,
+	MSR_KVM_POLL_CONTROL,
+};
+
+static u32 emulated_msrs[ARRAY_SIZE(emulated_msrs_all)];
+static unsigned num_emulated_msrs;
+
+/*
+ * List of MSRs that control the existence of MSR-based features, i.e. MSRs
+ * that are effectively CPUID leafs.  VMX MSRs are also included in the set of
+ * feature MSRs, but are handled separately to allow expedited lookups.
+ */
+static const u32 msr_based_features_all_except_vmx[] = {
+	MSR_AMD64_DE_CFG,
+	MSR_IA32_UCODE_REV,
+	MSR_IA32_ARCH_CAPABILITIES,
+	MSR_IA32_PERF_CAPABILITIES,
+};
+
+static u32 msr_based_features[ARRAY_SIZE(msr_based_features_all_except_vmx) +
+			      (KVM_LAST_EMULATED_VMX_MSR - KVM_FIRST_EMULATED_VMX_MSR + 1)];
+static unsigned int num_msr_based_features;
+
+/*
+ * All feature MSRs except uCode revID, which tracks the currently loaded uCode
+ * patch, are immutable once the vCPU model is defined.
+ */
+static bool kvm_is_immutable_feature_msr(u32 msr)
 {
-	const char *op = write ? "wrmsr" : "rdmsr";
+	int i;
 
-	if (ignore_msrs) {
-		if (report_ignored_msrs)
-			kvm_pr_unimpl("ignored %s: 0x%x data 0x%llx\n",
-				      op, msr, data);
-		/* Mask the error */
+	if (msr >= KVM_FIRST_EMULATED_VMX_MSR && msr <= KVM_LAST_EMULATED_VMX_MSR)
 		return true;
-	} else {
+
+	for (i = 0; i < ARRAY_SIZE(msr_based_features_all_except_vmx); i++) {
+		if (msr == msr_based_features_all_except_vmx[i])
+			return msr != MSR_IA32_UCODE_REV;
+	}
+
+	return false;
+}
+
+static bool kvm_is_advertised_msr(u32 msr_index)
+{
+	unsigned int i;
+
+	for (i = 0; i < num_msrs_to_save; i++) {
+		if (msrs_to_save[i] == msr_index)
+			return true;
+	}
+
+	for (i = 0; i < num_emulated_msrs; i++) {
+		if (emulated_msrs[i] == msr_index)
+			return true;
+	}
+
+	return false;
+}
+
+typedef int (*msr_access_t)(struct kvm_vcpu *vcpu, u32 index, u64 *data,
+			    bool host_initiated);
+
+static __always_inline int kvm_do_msr_access(struct kvm_vcpu *vcpu, u32 msr,
+					     u64 *data, bool host_initiated,
+					     enum kvm_msr_access rw,
+					     msr_access_t msr_access_fn)
+{
+	const char *op = rw == MSR_TYPE_W ? "wrmsr" : "rdmsr";
+	int ret;
+
+	BUILD_BUG_ON(rw != MSR_TYPE_R && rw != MSR_TYPE_W);
+
+	/*
+	 * Zero the data on read failures to avoid leaking stack data to the
+	 * guest and/or userspace, e.g. if the failure is ignored below.
+	 */
+	ret = msr_access_fn(vcpu, msr, data, host_initiated);
+	if (ret && rw == MSR_TYPE_R)
+		*data = 0;
+
+	if (ret != KVM_MSR_RET_UNSUPPORTED)
+		return ret;
+
+	/*
+	 * Userspace is allowed to read MSRs, and write '0' to MSRs, that KVM
+	 * advertises to userspace, even if an MSR isn't fully supported.
+	 * Simply check that @data is '0', which covers both the write '0' case
+	 * and all reads (in which case @data is zeroed on failure; see above).
+	 */
+	if (host_initiated && !*data && kvm_is_advertised_msr(msr))
+		return 0;
+
+	if (!ignore_msrs) {
 		kvm_debug_ratelimited("unhandled %s: 0x%x data 0x%llx\n",
-				      op, msr, data);
-		return false;
+				      op, msr, *data);
+		return ret;
 	}
+
+	if (report_ignored_msrs)
+		kvm_pr_unimpl("ignored %s: 0x%x data 0x%llx\n", op, msr, *data);
+
+	return 0;
 }
 
 static struct kmem_cache *kvm_alloc_emulator_cache(void)
@@ -413,8 +626,7 @@ EXPORT_SYMBOL_GPL(kvm_find_user_return_msr);
 
 static void kvm_user_return_msr_cpu_online(void)
 {
-	unsigned int cpu = smp_processor_id();
-	struct kvm_user_return_msrs *msrs = per_cpu_ptr(user_return_msrs, cpu);
+	struct kvm_user_return_msrs *msrs = this_cpu_ptr(user_return_msrs);
 	u64 value;
 	int i;
 
@@ -621,12 +833,6 @@ static void kvm_queue_exception_vmexit(struct kvm_vcpu *vcpu, unsigned int vecto
 	ex->payload = payload;
 }
 
-/* Forcibly leave the nested mode in cases like a vCPU reset */
-static void kvm_leave_nested(struct kvm_vcpu *vcpu)
-{
-	kvm_x86_ops.nested_ops->leave_nested(vcpu);
-}
-
 static void kvm_multiple_exception(struct kvm_vcpu *vcpu,
 		unsigned nr, bool has_error, u32 error_code,
 	        bool has_payload, unsigned long payload, bool reinject)
@@ -1412,178 +1618,6 @@ int kvm_emulate_rdpmc(struct kvm_vcpu *vcpu)
 EXPORT_SYMBOL_GPL(kvm_emulate_rdpmc);
 
 /*
- * The three MSR lists(msrs_to_save, emulated_msrs, msr_based_features) track
- * the set of MSRs that KVM exposes to userspace through KVM_GET_MSRS,
- * KVM_SET_MSRS, and KVM_GET_MSR_INDEX_LIST.  msrs_to_save holds MSRs that
- * require host support, i.e. should be probed via RDMSR.  emulated_msrs holds
- * MSRs that KVM emulates without strictly requiring host support.
- * msr_based_features holds MSRs that enumerate features, i.e. are effectively
- * CPUID leafs.  Note, msr_based_features isn't mutually exclusive with
- * msrs_to_save and emulated_msrs.
- */
-
-static const u32 msrs_to_save_base[] = {
-	MSR_IA32_SYSENTER_CS, MSR_IA32_SYSENTER_ESP, MSR_IA32_SYSENTER_EIP,
-	MSR_STAR,
-#ifdef CONFIG_X86_64
-	MSR_CSTAR, MSR_KERNEL_GS_BASE, MSR_SYSCALL_MASK, MSR_LSTAR,
-#endif
-	MSR_IA32_TSC, MSR_IA32_CR_PAT, MSR_VM_HSAVE_PA,
-	MSR_IA32_FEAT_CTL, MSR_IA32_BNDCFGS, MSR_TSC_AUX,
-	MSR_IA32_SPEC_CTRL, MSR_IA32_TSX_CTRL,
-	MSR_IA32_RTIT_CTL, MSR_IA32_RTIT_STATUS, MSR_IA32_RTIT_CR3_MATCH,
-	MSR_IA32_RTIT_OUTPUT_BASE, MSR_IA32_RTIT_OUTPUT_MASK,
-	MSR_IA32_RTIT_ADDR0_A, MSR_IA32_RTIT_ADDR0_B,
-	MSR_IA32_RTIT_ADDR1_A, MSR_IA32_RTIT_ADDR1_B,
-	MSR_IA32_RTIT_ADDR2_A, MSR_IA32_RTIT_ADDR2_B,
-	MSR_IA32_RTIT_ADDR3_A, MSR_IA32_RTIT_ADDR3_B,
-	MSR_IA32_UMWAIT_CONTROL,
-
-	MSR_IA32_XFD, MSR_IA32_XFD_ERR,
-};
-
-static const u32 msrs_to_save_pmu[] = {
-	MSR_ARCH_PERFMON_FIXED_CTR0, MSR_ARCH_PERFMON_FIXED_CTR1,
-	MSR_ARCH_PERFMON_FIXED_CTR0 + 2,
-	MSR_CORE_PERF_FIXED_CTR_CTRL, MSR_CORE_PERF_GLOBAL_STATUS,
-	MSR_CORE_PERF_GLOBAL_CTRL,
-	MSR_IA32_PEBS_ENABLE, MSR_IA32_DS_AREA, MSR_PEBS_DATA_CFG,
-
-	/* This part of MSRs should match KVM_MAX_NR_INTEL_GP_COUNTERS. */
-	MSR_ARCH_PERFMON_PERFCTR0, MSR_ARCH_PERFMON_PERFCTR1,
-	MSR_ARCH_PERFMON_PERFCTR0 + 2, MSR_ARCH_PERFMON_PERFCTR0 + 3,
-	MSR_ARCH_PERFMON_PERFCTR0 + 4, MSR_ARCH_PERFMON_PERFCTR0 + 5,
-	MSR_ARCH_PERFMON_PERFCTR0 + 6, MSR_ARCH_PERFMON_PERFCTR0 + 7,
-	MSR_ARCH_PERFMON_EVENTSEL0, MSR_ARCH_PERFMON_EVENTSEL1,
-	MSR_ARCH_PERFMON_EVENTSEL0 + 2, MSR_ARCH_PERFMON_EVENTSEL0 + 3,
-	MSR_ARCH_PERFMON_EVENTSEL0 + 4, MSR_ARCH_PERFMON_EVENTSEL0 + 5,
-	MSR_ARCH_PERFMON_EVENTSEL0 + 6, MSR_ARCH_PERFMON_EVENTSEL0 + 7,
-
-	MSR_K7_EVNTSEL0, MSR_K7_EVNTSEL1, MSR_K7_EVNTSEL2, MSR_K7_EVNTSEL3,
-	MSR_K7_PERFCTR0, MSR_K7_PERFCTR1, MSR_K7_PERFCTR2, MSR_K7_PERFCTR3,
-
-	/* This part of MSRs should match KVM_MAX_NR_AMD_GP_COUNTERS. */
-	MSR_F15H_PERF_CTL0, MSR_F15H_PERF_CTL1, MSR_F15H_PERF_CTL2,
-	MSR_F15H_PERF_CTL3, MSR_F15H_PERF_CTL4, MSR_F15H_PERF_CTL5,
-	MSR_F15H_PERF_CTR0, MSR_F15H_PERF_CTR1, MSR_F15H_PERF_CTR2,
-	MSR_F15H_PERF_CTR3, MSR_F15H_PERF_CTR4, MSR_F15H_PERF_CTR5,
-
-	MSR_AMD64_PERF_CNTR_GLOBAL_CTL,
-	MSR_AMD64_PERF_CNTR_GLOBAL_STATUS,
-	MSR_AMD64_PERF_CNTR_GLOBAL_STATUS_CLR,
-};
-
-static u32 msrs_to_save[ARRAY_SIZE(msrs_to_save_base) +
-			ARRAY_SIZE(msrs_to_save_pmu)];
-static unsigned num_msrs_to_save;
-
-static const u32 emulated_msrs_all[] = {
-	MSR_KVM_SYSTEM_TIME, MSR_KVM_WALL_CLOCK,
-	MSR_KVM_SYSTEM_TIME_NEW, MSR_KVM_WALL_CLOCK_NEW,
-
-#ifdef CONFIG_KVM_HYPERV
-	HV_X64_MSR_GUEST_OS_ID, HV_X64_MSR_HYPERCALL,
-	HV_X64_MSR_TIME_REF_COUNT, HV_X64_MSR_REFERENCE_TSC,
-	HV_X64_MSR_TSC_FREQUENCY, HV_X64_MSR_APIC_FREQUENCY,
-	HV_X64_MSR_CRASH_P0, HV_X64_MSR_CRASH_P1, HV_X64_MSR_CRASH_P2,
-	HV_X64_MSR_CRASH_P3, HV_X64_MSR_CRASH_P4, HV_X64_MSR_CRASH_CTL,
-	HV_X64_MSR_RESET,
-	HV_X64_MSR_VP_INDEX,
-	HV_X64_MSR_VP_RUNTIME,
-	HV_X64_MSR_SCONTROL,
-	HV_X64_MSR_STIMER0_CONFIG,
-	HV_X64_MSR_VP_ASSIST_PAGE,
-	HV_X64_MSR_REENLIGHTENMENT_CONTROL, HV_X64_MSR_TSC_EMULATION_CONTROL,
-	HV_X64_MSR_TSC_EMULATION_STATUS, HV_X64_MSR_TSC_INVARIANT_CONTROL,
-	HV_X64_MSR_SYNDBG_OPTIONS,
-	HV_X64_MSR_SYNDBG_CONTROL, HV_X64_MSR_SYNDBG_STATUS,
-	HV_X64_MSR_SYNDBG_SEND_BUFFER, HV_X64_MSR_SYNDBG_RECV_BUFFER,
-	HV_X64_MSR_SYNDBG_PENDING_BUFFER,
-#endif
-
-	MSR_KVM_ASYNC_PF_EN, MSR_KVM_STEAL_TIME,
-	MSR_KVM_PV_EOI_EN, MSR_KVM_ASYNC_PF_INT, MSR_KVM_ASYNC_PF_ACK,
-
-	MSR_IA32_TSC_ADJUST,
-	MSR_IA32_TSC_DEADLINE,
-	MSR_IA32_ARCH_CAPABILITIES,
-	MSR_IA32_PERF_CAPABILITIES,
-	MSR_IA32_MISC_ENABLE,
-	MSR_IA32_MCG_STATUS,
-	MSR_IA32_MCG_CTL,
-	MSR_IA32_MCG_EXT_CTL,
-	MSR_IA32_SMBASE,
-	MSR_SMI_COUNT,
-	MSR_PLATFORM_INFO,
-	MSR_MISC_FEATURES_ENABLES,
-	MSR_AMD64_VIRT_SPEC_CTRL,
-	MSR_AMD64_TSC_RATIO,
-	MSR_IA32_POWER_CTL,
-	MSR_IA32_UCODE_REV,
-
-	/*
-	 * KVM always supports the "true" VMX control MSRs, even if the host
-	 * does not.  The VMX MSRs as a whole are considered "emulated" as KVM
-	 * doesn't strictly require them to exist in the host (ignoring that
-	 * KVM would refuse to load in the first place if the core set of MSRs
-	 * aren't supported).
-	 */
-	MSR_IA32_VMX_BASIC,
-	MSR_IA32_VMX_TRUE_PINBASED_CTLS,
-	MSR_IA32_VMX_TRUE_PROCBASED_CTLS,
-	MSR_IA32_VMX_TRUE_EXIT_CTLS,
-	MSR_IA32_VMX_TRUE_ENTRY_CTLS,
-	MSR_IA32_VMX_MISC,
-	MSR_IA32_VMX_CR0_FIXED0,
-	MSR_IA32_VMX_CR4_FIXED0,
-	MSR_IA32_VMX_VMCS_ENUM,
-	MSR_IA32_VMX_PROCBASED_CTLS2,
-	MSR_IA32_VMX_EPT_VPID_CAP,
-	MSR_IA32_VMX_VMFUNC,
-
-	MSR_K7_HWCR,
-	MSR_KVM_POLL_CONTROL,
-};
-
-static u32 emulated_msrs[ARRAY_SIZE(emulated_msrs_all)];
-static unsigned num_emulated_msrs;
-
-/*
- * List of MSRs that control the existence of MSR-based features, i.e. MSRs
- * that are effectively CPUID leafs.  VMX MSRs are also included in the set of
- * feature MSRs, but are handled separately to allow expedited lookups.
- */
-static const u32 msr_based_features_all_except_vmx[] = {
-	MSR_AMD64_DE_CFG,
-	MSR_IA32_UCODE_REV,
-	MSR_IA32_ARCH_CAPABILITIES,
-	MSR_IA32_PERF_CAPABILITIES,
-};
-
-static u32 msr_based_features[ARRAY_SIZE(msr_based_features_all_except_vmx) +
-			      (KVM_LAST_EMULATED_VMX_MSR - KVM_FIRST_EMULATED_VMX_MSR + 1)];
-static unsigned int num_msr_based_features;
-
-/*
- * All feature MSRs except uCode revID, which tracks the currently loaded uCode
- * patch, are immutable once the vCPU model is defined.
- */
-static bool kvm_is_immutable_feature_msr(u32 msr)
-{
-	int i;
-
-	if (msr >= KVM_FIRST_EMULATED_VMX_MSR && msr <= KVM_LAST_EMULATED_VMX_MSR)
-		return true;
-
-	for (i = 0; i < ARRAY_SIZE(msr_based_features_all_except_vmx); i++) {
-		if (msr == msr_based_features_all_except_vmx[i])
-			return msr != MSR_IA32_UCODE_REV;
-	}
-
-	return false;
-}
-
-/*
  * Some IA32_ARCH_CAPABILITIES bits have dependencies on MSRs that KVM
  * does not yet virtualize. These include:
  *   10 - MISC_PACKAGE_CTRLS
@@ -1660,40 +1694,31 @@ static u64 kvm_get_arch_capabilities(void)
 	return data;
 }
 
-static int kvm_get_msr_feature(struct kvm_msr_entry *msr)
+static int kvm_get_feature_msr(struct kvm_vcpu *vcpu, u32 index, u64 *data,
+			       bool host_initiated)
 {
-	switch (msr->index) {
+	WARN_ON_ONCE(!host_initiated);
+
+	switch (index) {
 	case MSR_IA32_ARCH_CAPABILITIES:
-		msr->data = kvm_get_arch_capabilities();
+		*data = kvm_get_arch_capabilities();
 		break;
 	case MSR_IA32_PERF_CAPABILITIES:
-		msr->data = kvm_caps.supported_perf_cap;
+		*data = kvm_caps.supported_perf_cap;
 		break;
 	case MSR_IA32_UCODE_REV:
-		rdmsrl_safe(msr->index, &msr->data);
+		rdmsrl_safe(index, data);
 		break;
 	default:
-		return kvm_x86_call(get_msr_feature)(msr);
+		return kvm_x86_call(get_feature_msr)(index, data);
 	}
 	return 0;
 }
 
-static int do_get_msr_feature(struct kvm_vcpu *vcpu, unsigned index, u64 *data)
+static int do_get_feature_msr(struct kvm_vcpu *vcpu, unsigned index, u64 *data)
 {
-	struct kvm_msr_entry msr;
-	int r;
-
-	/* Unconditionally clear the output for simplicity */
-	msr.data = 0;
-	msr.index = index;
-	r = kvm_get_msr_feature(&msr);
-
-	if (r == KVM_MSR_RET_INVALID && kvm_msr_ignored_check(index, 0, false))
-		r = 0;
-
-	*data = msr.data;
-
-	return r;
+	return kvm_do_msr_access(vcpu, index, data, true, MSR_TYPE_R,
+				 kvm_get_feature_msr);
 }
 
 static bool __kvm_valid_efer(struct kvm_vcpu *vcpu, u64 efer)
@@ -1880,16 +1905,17 @@ static int __kvm_set_msr(struct kvm_vcpu *vcpu, u32 index, u64 data,
 	return kvm_x86_call(set_msr)(vcpu, &msr);
 }
 
+static int _kvm_set_msr(struct kvm_vcpu *vcpu, u32 index, u64 *data,
+			bool host_initiated)
+{
+	return __kvm_set_msr(vcpu, index, *data, host_initiated);
+}
+
 static int kvm_set_msr_ignored_check(struct kvm_vcpu *vcpu,
 				     u32 index, u64 data, bool host_initiated)
 {
-	int ret = __kvm_set_msr(vcpu, index, data, host_initiated);
-
-	if (ret == KVM_MSR_RET_INVALID)
-		if (kvm_msr_ignored_check(index, data, true))
-			ret = 0;
-
-	return ret;
+	return kvm_do_msr_access(vcpu, index, &data, host_initiated, MSR_TYPE_W,
+				 _kvm_set_msr);
 }
 
 /*
@@ -1928,16 +1954,8 @@ int __kvm_get_msr(struct kvm_vcpu *vcpu, u32 index, u64 *data,
 static int kvm_get_msr_ignored_check(struct kvm_vcpu *vcpu,
 				     u32 index, u64 *data, bool host_initiated)
 {
-	int ret = __kvm_get_msr(vcpu, index, data, host_initiated);
-
-	if (ret == KVM_MSR_RET_INVALID) {
-		/* Unconditionally clear *data for simplicity */
-		*data = 0;
-		if (kvm_msr_ignored_check(index, 0, false))
-			ret = 0;
-	}
-
-	return ret;
+	return kvm_do_msr_access(vcpu, index, data, host_initiated, MSR_TYPE_R,
+				 __kvm_get_msr);
 }
 
 static int kvm_get_msr_with_filter(struct kvm_vcpu *vcpu, u32 index, u64 *data)
@@ -1999,7 +2017,7 @@ static int complete_fast_rdmsr(struct kvm_vcpu *vcpu)
 static u64 kvm_msr_reason(int r)
 {
 	switch (r) {
-	case KVM_MSR_RET_INVALID:
+	case KVM_MSR_RET_UNSUPPORTED:
 		return KVM_MSR_EXIT_REASON_UNKNOWN;
 	case KVM_MSR_RET_FILTERED:
 		return KVM_MSR_EXIT_REASON_FILTER;
@@ -2162,31 +2180,34 @@ fastpath_t handle_fastpath_set_msr_irqoff(struct kvm_vcpu *vcpu)
 {
 	u32 msr = kvm_rcx_read(vcpu);
 	u64 data;
-	fastpath_t ret = EXIT_FASTPATH_NONE;
+	fastpath_t ret;
+	bool handled;
 
 	kvm_vcpu_srcu_read_lock(vcpu);
 
 	switch (msr) {
 	case APIC_BASE_MSR + (APIC_ICR >> 4):
 		data = kvm_read_edx_eax(vcpu);
-		if (!handle_fastpath_set_x2apic_icr_irqoff(vcpu, data)) {
-			kvm_skip_emulated_instruction(vcpu);
-			ret = EXIT_FASTPATH_EXIT_HANDLED;
-		}
+		handled = !handle_fastpath_set_x2apic_icr_irqoff(vcpu, data);
 		break;
 	case MSR_IA32_TSC_DEADLINE:
 		data = kvm_read_edx_eax(vcpu);
-		if (!handle_fastpath_set_tscdeadline(vcpu, data)) {
-			kvm_skip_emulated_instruction(vcpu);
-			ret = EXIT_FASTPATH_REENTER_GUEST;
-		}
+		handled = !handle_fastpath_set_tscdeadline(vcpu, data);
 		break;
 	default:
+		handled = false;
 		break;
 	}
 
-	if (ret != EXIT_FASTPATH_NONE)
+	if (handled) {
+		if (!kvm_skip_emulated_instruction(vcpu))
+			ret = EXIT_FASTPATH_EXIT_USERSPACE;
+		else
+			ret = EXIT_FASTPATH_REENTER_GUEST;
 		trace_kvm_msr_write(msr, data);
+	} else {
+		ret = EXIT_FASTPATH_NONE;
+	}
 
 	kvm_vcpu_srcu_read_unlock(vcpu);
 
@@ -3746,18 +3767,6 @@ static void record_steal_time(struct kvm_vcpu *vcpu)
 	mark_page_dirty_in_slot(vcpu->kvm, ghc->memslot, gpa_to_gfn(ghc->gpa));
 }
 
-static bool kvm_is_msr_to_save(u32 msr_index)
-{
-	unsigned int i;
-
-	for (i = 0; i < num_msrs_to_save; i++) {
-		if (msrs_to_save[i] == msr_index)
-			return true;
-	}
-
-	return false;
-}
-
 int kvm_set_msr_common(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
 {
 	u32 msr = msr_info->index;
@@ -4139,15 +4148,7 @@ int kvm_set_msr_common(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
 		if (kvm_pmu_is_valid_msr(vcpu, msr))
 			return kvm_pmu_set_msr(vcpu, msr_info);
 
-		/*
-		 * Userspace is allowed to write '0' to MSRs that KVM reports
-		 * as to-be-saved, even if an MSRs isn't fully supported.
-		 */
-		if (msr_info->host_initiated && !data &&
-		    kvm_is_msr_to_save(msr))
-			break;
-
-		return KVM_MSR_RET_INVALID;
+		return KVM_MSR_RET_UNSUPPORTED;
 	}
 	return 0;
 }
@@ -4498,17 +4499,7 @@ int kvm_get_msr_common(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
 		if (kvm_pmu_is_valid_msr(vcpu, msr_info->index))
 			return kvm_pmu_get_msr(vcpu, msr_info);
 
-		/*
-		 * Userspace is allowed to read MSRs that KVM reports as
-		 * to-be-saved, even if an MSR isn't fully supported.
-		 */
-		if (msr_info->host_initiated &&
-		    kvm_is_msr_to_save(msr_info->index)) {
-			msr_info->data = 0;
-			break;
-		}
-
-		return KVM_MSR_RET_INVALID;
+		return KVM_MSR_RET_UNSUPPORTED;
 	}
 	return 0;
 }
@@ -4946,7 +4937,7 @@ long kvm_arch_dev_ioctl(struct file *filp,
 		break;
 	}
 	case KVM_GET_MSRS:
-		r = msr_io(NULL, argp, do_get_msr_feature, 1);
+		r = msr_io(NULL, argp, do_get_feature_msr, 1);
 		break;
 #ifdef CONFIG_KVM_HYPERV
 	case KVM_GET_SUPPORTED_HV_CPUID:
@@ -7383,11 +7374,9 @@ out:
 
 static void kvm_probe_feature_msr(u32 msr_index)
 {
-	struct kvm_msr_entry msr = {
-		.index = msr_index,
-	};
+	u64 data;
 
-	if (kvm_get_msr_feature(&msr))
+	if (kvm_get_feature_msr(NULL, msr_index, &data, true))
 		return;
 
 	msr_based_features[num_msr_based_features++] = msr_index;
@@ -9926,51 +9915,6 @@ void kvm_x86_vendor_exit(void)
 }
 EXPORT_SYMBOL_GPL(kvm_x86_vendor_exit);
 
-static int __kvm_emulate_halt(struct kvm_vcpu *vcpu, int state, int reason)
-{
-	/*
-	 * The vCPU has halted, e.g. executed HLT.  Update the run state if the
-	 * local APIC is in-kernel, the run loop will detect the non-runnable
-	 * state and halt the vCPU.  Exit to userspace if the local APIC is
-	 * managed by userspace, in which case userspace is responsible for
-	 * handling wake events.
-	 */
-	++vcpu->stat.halt_exits;
-	if (lapic_in_kernel(vcpu)) {
-		vcpu->arch.mp_state = state;
-		return 1;
-	} else {
-		vcpu->run->exit_reason = reason;
-		return 0;
-	}
-}
-
-int kvm_emulate_halt_noskip(struct kvm_vcpu *vcpu)
-{
-	return __kvm_emulate_halt(vcpu, KVM_MP_STATE_HALTED, KVM_EXIT_HLT);
-}
-EXPORT_SYMBOL_GPL(kvm_emulate_halt_noskip);
-
-int kvm_emulate_halt(struct kvm_vcpu *vcpu)
-{
-	int ret = kvm_skip_emulated_instruction(vcpu);
-	/*
-	 * TODO: we might be squashing a GUESTDBG_SINGLESTEP-triggered
-	 * KVM_EXIT_DEBUG here.
-	 */
-	return kvm_emulate_halt_noskip(vcpu) && ret;
-}
-EXPORT_SYMBOL_GPL(kvm_emulate_halt);
-
-int kvm_emulate_ap_reset_hold(struct kvm_vcpu *vcpu)
-{
-	int ret = kvm_skip_emulated_instruction(vcpu);
-
-	return __kvm_emulate_halt(vcpu, KVM_MP_STATE_AP_RESET_HOLD,
-					KVM_EXIT_AP_RESET_HOLD) && ret;
-}
-EXPORT_SYMBOL_GPL(kvm_emulate_ap_reset_hold);
-
 #ifdef CONFIG_X86_64
 static int kvm_pv_clock_pairing(struct kvm_vcpu *vcpu, gpa_t paddr,
 			        unsigned long clock_type)
@@ -11207,6 +11151,9 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu)
 	if (vcpu->arch.apic_attention)
 		kvm_lapic_sync_from_vapic(vcpu);
 
+	if (unlikely(exit_fastpath == EXIT_FASTPATH_EXIT_USERSPACE))
+		return 0;
+
 	r = kvm_x86_call(handle_exit)(vcpu, exit_fastpath);
 	return r;
 
@@ -11220,6 +11167,67 @@ out:
 	return r;
 }
 
+static bool kvm_vcpu_running(struct kvm_vcpu *vcpu)
+{
+	return (vcpu->arch.mp_state == KVM_MP_STATE_RUNNABLE &&
+		!vcpu->arch.apf.halted);
+}
+
+static bool kvm_vcpu_has_events(struct kvm_vcpu *vcpu)
+{
+	if (!list_empty_careful(&vcpu->async_pf.done))
+		return true;
+
+	if (kvm_apic_has_pending_init_or_sipi(vcpu) &&
+	    kvm_apic_init_sipi_allowed(vcpu))
+		return true;
+
+	if (vcpu->arch.pv.pv_unhalted)
+		return true;
+
+	if (kvm_is_exception_pending(vcpu))
+		return true;
+
+	if (kvm_test_request(KVM_REQ_NMI, vcpu) ||
+	    (vcpu->arch.nmi_pending &&
+	     kvm_x86_call(nmi_allowed)(vcpu, false)))
+		return true;
+
+#ifdef CONFIG_KVM_SMM
+	if (kvm_test_request(KVM_REQ_SMI, vcpu) ||
+	    (vcpu->arch.smi_pending &&
+	     kvm_x86_call(smi_allowed)(vcpu, false)))
+		return true;
+#endif
+
+	if (kvm_test_request(KVM_REQ_PMI, vcpu))
+		return true;
+
+	if (kvm_test_request(KVM_REQ_UPDATE_PROTECTED_GUEST_STATE, vcpu))
+		return true;
+
+	if (kvm_arch_interrupt_allowed(vcpu) && kvm_cpu_has_interrupt(vcpu))
+		return true;
+
+	if (kvm_hv_has_stimer_pending(vcpu))
+		return true;
+
+	if (is_guest_mode(vcpu) &&
+	    kvm_x86_ops.nested_ops->has_events &&
+	    kvm_x86_ops.nested_ops->has_events(vcpu, false))
+		return true;
+
+	if (kvm_xen_has_pending_events(vcpu))
+		return true;
+
+	return false;
+}
+
+int kvm_arch_vcpu_runnable(struct kvm_vcpu *vcpu)
+{
+	return kvm_vcpu_running(vcpu) || kvm_vcpu_has_events(vcpu);
+}
+
 /* Called within kvm->srcu read side.  */
 static inline int vcpu_block(struct kvm_vcpu *vcpu)
 {
@@ -11291,12 +11299,6 @@ static inline int vcpu_block(struct kvm_vcpu *vcpu)
 	return 1;
 }
 
-static inline bool kvm_vcpu_running(struct kvm_vcpu *vcpu)
-{
-	return (vcpu->arch.mp_state == KVM_MP_STATE_RUNNABLE &&
-		!vcpu->arch.apf.halted);
-}
-
 /* Called within kvm->srcu read side.  */
 static int vcpu_run(struct kvm_vcpu *vcpu)
 {
@@ -11348,6 +11350,98 @@ static int vcpu_run(struct kvm_vcpu *vcpu)
 	return r;
 }
 
+static int __kvm_emulate_halt(struct kvm_vcpu *vcpu, int state, int reason)
+{
+	/*
+	 * The vCPU has halted, e.g. executed HLT.  Update the run state if the
+	 * local APIC is in-kernel, the run loop will detect the non-runnable
+	 * state and halt the vCPU.  Exit to userspace if the local APIC is
+	 * managed by userspace, in which case userspace is responsible for
+	 * handling wake events.
+	 */
+	++vcpu->stat.halt_exits;
+	if (lapic_in_kernel(vcpu)) {
+		if (kvm_vcpu_has_events(vcpu))
+			vcpu->arch.pv.pv_unhalted = false;
+		else
+			vcpu->arch.mp_state = state;
+		return 1;
+	} else {
+		vcpu->run->exit_reason = reason;
+		return 0;
+	}
+}
+
+int kvm_emulate_halt_noskip(struct kvm_vcpu *vcpu)
+{
+	return __kvm_emulate_halt(vcpu, KVM_MP_STATE_HALTED, KVM_EXIT_HLT);
+}
+EXPORT_SYMBOL_GPL(kvm_emulate_halt_noskip);
+
+int kvm_emulate_halt(struct kvm_vcpu *vcpu)
+{
+	int ret = kvm_skip_emulated_instruction(vcpu);
+	/*
+	 * TODO: we might be squashing a GUESTDBG_SINGLESTEP-triggered
+	 * KVM_EXIT_DEBUG here.
+	 */
+	return kvm_emulate_halt_noskip(vcpu) && ret;
+}
+EXPORT_SYMBOL_GPL(kvm_emulate_halt);
+
+fastpath_t handle_fastpath_hlt(struct kvm_vcpu *vcpu)
+{
+	int ret;
+
+	kvm_vcpu_srcu_read_lock(vcpu);
+	ret = kvm_emulate_halt(vcpu);
+	kvm_vcpu_srcu_read_unlock(vcpu);
+
+	if (!ret)
+		return EXIT_FASTPATH_EXIT_USERSPACE;
+
+	if (kvm_vcpu_running(vcpu))
+		return EXIT_FASTPATH_REENTER_GUEST;
+
+	return EXIT_FASTPATH_EXIT_HANDLED;
+}
+EXPORT_SYMBOL_GPL(handle_fastpath_hlt);
+
+int kvm_emulate_ap_reset_hold(struct kvm_vcpu *vcpu)
+{
+	int ret = kvm_skip_emulated_instruction(vcpu);
+
+	return __kvm_emulate_halt(vcpu, KVM_MP_STATE_AP_RESET_HOLD,
+					KVM_EXIT_AP_RESET_HOLD) && ret;
+}
+EXPORT_SYMBOL_GPL(kvm_emulate_ap_reset_hold);
+
+bool kvm_arch_dy_has_pending_interrupt(struct kvm_vcpu *vcpu)
+{
+	return kvm_vcpu_apicv_active(vcpu) &&
+	       kvm_x86_call(dy_apicv_has_pending_interrupt)(vcpu);
+}
+
+bool kvm_arch_vcpu_preempted_in_kernel(struct kvm_vcpu *vcpu)
+{
+	return vcpu->arch.preempted_in_kernel;
+}
+
+bool kvm_arch_dy_runnable(struct kvm_vcpu *vcpu)
+{
+	if (READ_ONCE(vcpu->arch.pv.pv_unhalted))
+		return true;
+
+	if (kvm_test_request(KVM_REQ_NMI, vcpu) ||
+#ifdef CONFIG_KVM_SMM
+		kvm_test_request(KVM_REQ_SMI, vcpu) ||
+#endif
+		 kvm_test_request(KVM_REQ_EVENT, vcpu))
+		return true;
+
+	return kvm_arch_dy_has_pending_interrupt(vcpu);
+}
+
 static inline int complete_emulated_io(struct kvm_vcpu *vcpu)
 {
 	return kvm_emulate_instruction(vcpu, EMULTYPE_NO_DECODE);
@@ -13172,87 +13266,6 @@ void kvm_arch_commit_memory_region(struct kvm *kvm,
 		kvm_arch_free_memslot(kvm, old);
 }
 
-static inline bool kvm_vcpu_has_events(struct kvm_vcpu *vcpu)
-{
-	if (!list_empty_careful(&vcpu->async_pf.done))
-		return true;
-
-	if (kvm_apic_has_pending_init_or_sipi(vcpu) &&
-	    kvm_apic_init_sipi_allowed(vcpu))
-		return true;
-
-	if (vcpu->arch.pv.pv_unhalted)
-		return true;
-
-	if (kvm_is_exception_pending(vcpu))
-		return true;
-
-	if (kvm_test_request(KVM_REQ_NMI, vcpu) ||
-	    (vcpu->arch.nmi_pending &&
-	     kvm_x86_call(nmi_allowed)(vcpu, false)))
-		return true;
-
-#ifdef CONFIG_KVM_SMM
-	if (kvm_test_request(KVM_REQ_SMI, vcpu) ||
-	    (vcpu->arch.smi_pending &&
-	     kvm_x86_call(smi_allowed)(vcpu, false)))
-		return true;
-#endif
-
-	if (kvm_test_request(KVM_REQ_PMI, vcpu))
-		return true;
-
-	if (kvm_test_request(KVM_REQ_UPDATE_PROTECTED_GUEST_STATE, vcpu))
-		return true;
-
-	if (kvm_arch_interrupt_allowed(vcpu) && kvm_cpu_has_interrupt(vcpu))
-		return true;
-
-	if (kvm_hv_has_stimer_pending(vcpu))
-		return true;
-
-	if (is_guest_mode(vcpu) &&
-	    kvm_x86_ops.nested_ops->has_events &&
-	    kvm_x86_ops.nested_ops->has_events(vcpu, false))
-		return true;
-
-	if (kvm_xen_has_pending_events(vcpu))
-		return true;
-
-	return false;
-}
-
-int kvm_arch_vcpu_runnable(struct kvm_vcpu *vcpu)
-{
-	return kvm_vcpu_running(vcpu) || kvm_vcpu_has_events(vcpu);
-}
-
-bool kvm_arch_dy_has_pending_interrupt(struct kvm_vcpu *vcpu)
-{
-	return kvm_vcpu_apicv_active(vcpu) &&
-	       kvm_x86_call(dy_apicv_has_pending_interrupt)(vcpu);
-}
-
-bool kvm_arch_vcpu_preempted_in_kernel(struct kvm_vcpu *vcpu)
-{
-	return vcpu->arch.preempted_in_kernel;
-}
-
-bool kvm_arch_dy_runnable(struct kvm_vcpu *vcpu)
-{
-	if (READ_ONCE(vcpu->arch.pv.pv_unhalted))
-		return true;
-
-	if (kvm_test_request(KVM_REQ_NMI, vcpu) ||
-#ifdef CONFIG_KVM_SMM
-		kvm_test_request(KVM_REQ_SMI, vcpu) ||
-#endif
-		 kvm_test_request(KVM_REQ_EVENT, vcpu))
-		return true;
-
-	return kvm_arch_dy_has_pending_interrupt(vcpu);
-}
-
 bool kvm_arch_vcpu_in_kernel(struct kvm_vcpu *vcpu)
 {
 	if (vcpu->arch.guest_state_protected)
diff --git a/arch/x86/kvm/x86.h b/arch/x86/kvm/x86.h
index 50596f6f8320..121f5c19613e 100644
--- a/arch/x86/kvm/x86.h
+++ b/arch/x86/kvm/x86.h
@@ -108,6 +108,12 @@ static inline unsigned int __shrink_ple_window(unsigned int val,
 void kvm_service_local_tlb_flush_requests(struct kvm_vcpu *vcpu);
 int kvm_check_nested_events(struct kvm_vcpu *vcpu);
 
+/* Forcibly leave the nested mode in cases like a vCPU reset */
+static inline void kvm_leave_nested(struct kvm_vcpu *vcpu)
+{
+	kvm_x86_ops.nested_ops->leave_nested(vcpu);
+}
+
 static inline bool kvm_vcpu_has_run(struct kvm_vcpu *vcpu)
 {
 	return vcpu->arch.last_vmentry_cpu != -1;
@@ -334,6 +340,7 @@ int x86_decode_emulated_instruction(struct kvm_vcpu *vcpu, int emulation_type,
 int x86_emulate_instruction(struct kvm_vcpu *vcpu, gpa_t cr2_or_gpa,
 			    int emulation_type, void *insn, int insn_len);
 fastpath_t handle_fastpath_set_msr_irqoff(struct kvm_vcpu *vcpu);
+fastpath_t handle_fastpath_hlt(struct kvm_vcpu *vcpu);
 
 extern struct kvm_caps kvm_caps;
 extern struct kvm_host_values kvm_host;
@@ -504,13 +511,26 @@ int kvm_handle_memory_failure(struct kvm_vcpu *vcpu, int r,
 int kvm_handle_invpcid(struct kvm_vcpu *vcpu, unsigned long type, gva_t gva);
 bool kvm_msr_allowed(struct kvm_vcpu *vcpu, u32 index, u32 type);
 
+enum kvm_msr_access {
+	MSR_TYPE_R	= BIT(0),
+	MSR_TYPE_W	= BIT(1),
+	MSR_TYPE_RW	= MSR_TYPE_R | MSR_TYPE_W,
+};
+
 /*
  * Internal error codes that are used to indicate that MSR emulation encountered
- * an error that should result in #GP in the guest, unless userspace
- * handles it.
+ * an error that should result in #GP in the guest, unless userspace handles it.
+ * Note, '1', '0', and negative numbers are off limits, as they are used by KVM
+ * as part of KVM's lightly documented internal KVM_RUN return codes.
+ *
+ * UNSUPPORTED	- The MSR isn't supported, either because it is completely
+ *		  unknown to KVM, or because the MSR should not exist according
+ *		  to the vCPU model.
+ *
+ * FILTERED	- Access to the MSR is denied by a userspace MSR filter.
  */
-#define  KVM_MSR_RET_INVALID	2	/* in-kernel MSR emulation #GP condition */
-#define  KVM_MSR_RET_FILTERED	3	/* #GP due to userspace MSR filter */
+#define  KVM_MSR_RET_UNSUPPORTED	2
+#define  KVM_MSR_RET_FILTERED		3
 
 #define __cr4_reserved_bits(__cpu_has, __c)             \
 ({                                                      \