[PATCH v9 19/22] KVM: nVMX: Handle FRED VMCS fields in nested VMX context

Xin Li (Intel) posted 22 patches 1 month, 2 weeks ago
[PATCH v9 19/22] KVM: nVMX: Handle FRED VMCS fields in nested VMX context
Posted by Xin Li (Intel) 1 month, 2 weeks ago
From: Xin Li <xin3.li@intel.com>

Extend nested VMX context management to include FRED-related VMCS fields,
enabling proper handling of FRED state during nested virtualization.

Because KVM always sets SECONDARY_VM_EXIT_SAVE_IA32_FRED, FRED MSRs are
always saved to vmcs02.  However an L1 VMM may choose to clear this bit,
i.e., not to save FRED MSRs to vmcs12.  This is not a problem when the L1
VMM sets SECONDARY_VM_EXIT_LOAD_IA32_FRED, as KVM then immediately loads
host FRED MSRs of vmcs12 to guest FRED MSRs of vmcs01.  However if the L1
VMM clears SECONDARY_VM_EXIT_LOAD_IA32_FRED, KVM should retain FRED MSRs
to run the L1 VMM.

To propagate guest FRED MSRs from vmcs02 to vmcs01, save them in
sync_vmcs02_to_vmcs12() regardless of whether
SECONDARY_VM_EXIT_SAVE_IA32_FRED is set in vmcs12.  Then, use the saved
values to set guest FRED MSRs in vmcs01 within load_vmcs12_host_state()
when !nested_cpu_load_host_fred_state().

Signed-off-by: Xin Li <xin3.li@intel.com>
Signed-off-by: Xin Li (Intel) <xin@zytor.com>
Tested-by: Shan Kang <shan.kang@intel.com>
Tested-by: Xuelian Guo <xuelian.guo@intel.com>
---

Changes in v9:
* Rebase to kvm-x86/next.
* Guard FRED state save/restore with guest_cpu_cap_has(vcpu, X86_FEATURE_FRED)
  (syzbot & Chao).

Changes in v8:
* Make the newly added FRED fields 64-bit aligned in vmcs12 (Isaku).
* Remove the change to Documentation/virt/kvm/x86/nested-vmx.rst.

Change in v6:
* Handle FRED MSR pre-vmenter save/restore (Chao Gao).
* Save FRED MSRs of vmcs02 at VM-Exit even an L1 VMM clears
  SECONDARY_VM_EXIT_SAVE_IA32_FRED.
* Save FRED MSRs in sync_vmcs02_to_vmcs12() instead of its rare version.

Change in v5:
* Add TB from Xuelian Guo.

Changes in v4:
* Advertise VMX nested exception as if the CPU supports it (Chao Gao).
* Split FRED state management controls (Chao Gao).

Changes in v3:
* Add and use nested_cpu_has_fred(vmcs12) because vmcs02 should be set
  from vmcs12 if and only if the field is enabled in L1's VMX config
  (Sean Christopherson).
* Fix coding style issues (Sean Christopherson).

Changes in v2:
* Remove hyperv TLFS related changes (Jeremi Piotrowski).
* Use kvm_cpu_cap_has() instead of cpu_feature_enabled() (Chao Gao).
---
 arch/x86/kvm/vmx/capabilities.h       |   5 ++
 arch/x86/kvm/vmx/nested.c             | 118 +++++++++++++++++++++++++-
 arch/x86/kvm/vmx/nested.h             |  22 +++++
 arch/x86/kvm/vmx/vmcs12.c             |  18 ++++
 arch/x86/kvm/vmx/vmcs12.h             |  37 ++++++++
 arch/x86/kvm/vmx/vmcs_shadow_fields.h |   4 +
 arch/x86/kvm/vmx/vmx.h                |  41 +++++++++
 7 files changed, 243 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kvm/vmx/capabilities.h b/arch/x86/kvm/vmx/capabilities.h
index f390f9f883c3..5eba2530ffb4 100644
--- a/arch/x86/kvm/vmx/capabilities.h
+++ b/arch/x86/kvm/vmx/capabilities.h
@@ -80,6 +80,11 @@ static inline bool cpu_has_vmx_basic_no_hw_errcode_cc(void)
 	return	vmcs_config.basic & VMX_BASIC_NO_HW_ERROR_CODE_CC;
 }
 
+static inline bool cpu_has_vmx_nested_exception(void)
+{
+	return vmcs_config.basic & VMX_BASIC_NESTED_EXCEPTION;
+}
+
 static inline bool cpu_has_virtual_nmis(void)
 {
 	return vmcs_config.pin_based_exec_ctrl & PIN_BASED_VIRTUAL_NMIS &&
diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
index cbb682424a5b..63cdfffba58b 100644
--- a/arch/x86/kvm/vmx/nested.c
+++ b/arch/x86/kvm/vmx/nested.c
@@ -708,6 +708,9 @@ static inline bool nested_vmx_prepare_msr_bitmap(struct kvm_vcpu *vcpu,
 
 	nested_vmx_set_intercept_for_msr(vmx, msr_bitmap_l1, msr_bitmap_l0,
 					 MSR_KERNEL_GS_BASE, MSR_TYPE_RW);
+
+	nested_vmx_set_intercept_for_msr(vmx, msr_bitmap_l1, msr_bitmap_l0,
+					 MSR_IA32_FRED_RSP0, MSR_TYPE_RW);
 #endif
 	nested_vmx_set_intercept_for_msr(vmx, msr_bitmap_l1, msr_bitmap_l0,
 					 MSR_IA32_SPEC_CTRL, MSR_TYPE_RW);
@@ -1294,9 +1297,11 @@ static int vmx_restore_vmx_basic(struct vcpu_vmx *vmx, u64 data)
 	const u64 feature_bits = VMX_BASIC_DUAL_MONITOR_TREATMENT |
 				 VMX_BASIC_INOUT |
 				 VMX_BASIC_TRUE_CTLS |
-				 VMX_BASIC_NO_HW_ERROR_CODE_CC;
+				 VMX_BASIC_NO_HW_ERROR_CODE_CC |
+				 VMX_BASIC_NESTED_EXCEPTION;
 
-	const u64 reserved_bits = GENMASK_ULL(63, 57) |
+	const u64 reserved_bits = GENMASK_ULL(63, 59) |
+				  BIT_ULL(57) |
 				  GENMASK_ULL(47, 45) |
 				  BIT_ULL(31);
 
@@ -2539,6 +2544,8 @@ static void prepare_vmcs02_early(struct vcpu_vmx *vmx, struct loaded_vmcs *vmcs0
 			     vmcs12->vm_entry_instruction_len);
 		vmcs_write32(GUEST_INTERRUPTIBILITY_INFO,
 			     vmcs12->guest_interruptibility_info);
+		if (cpu_has_vmx_fred())
+			vmcs_write64(INJECTED_EVENT_DATA, vmcs12->injected_event_data);
 		vmx->loaded_vmcs->nmi_known_unmasked =
 			!(vmcs12->guest_interruptibility_info & GUEST_INTR_STATE_NMI);
 	} else {
@@ -2693,6 +2700,18 @@ static void prepare_vmcs02_rare(struct vcpu_vmx *vmx, struct vmcs12 *vmcs12)
 				     vmcs12->guest_ssp, vmcs12->guest_ssp_tbl);
 
 	set_cr4_guest_host_mask(vmx);
+
+	if (guest_cpu_cap_has(&vmx->vcpu, X86_FEATURE_FRED) &&
+	    nested_cpu_load_guest_fred_state(vmcs12)) {
+		vmcs_write64(GUEST_IA32_FRED_CONFIG, vmcs12->guest_ia32_fred_config);
+		vmcs_write64(GUEST_IA32_FRED_RSP1, vmcs12->guest_ia32_fred_rsp1);
+		vmcs_write64(GUEST_IA32_FRED_RSP2, vmcs12->guest_ia32_fred_rsp2);
+		vmcs_write64(GUEST_IA32_FRED_RSP3, vmcs12->guest_ia32_fred_rsp3);
+		vmcs_write64(GUEST_IA32_FRED_STKLVLS, vmcs12->guest_ia32_fred_stklvls);
+		vmcs_write64(GUEST_IA32_FRED_SSP1, vmcs12->guest_ia32_fred_ssp1);
+		vmcs_write64(GUEST_IA32_FRED_SSP2, vmcs12->guest_ia32_fred_ssp2);
+		vmcs_write64(GUEST_IA32_FRED_SSP3, vmcs12->guest_ia32_fred_ssp3);
+	}
 }
 
 /*
@@ -2759,6 +2778,18 @@ static int prepare_vmcs02(struct kvm_vcpu *vcpu, struct vmcs12 *vmcs12,
 		vmcs_write64(GUEST_IA32_PAT, vcpu->arch.pat);
 	}
 
+	if (guest_cpu_cap_has(vcpu, X86_FEATURE_FRED) &&
+	    (!vmx->nested.nested_run_pending || !nested_cpu_load_guest_fred_state(vmcs12))) {
+		vmcs_write64(GUEST_IA32_FRED_CONFIG, vmx->nested.pre_vmenter_fred_config);
+		vmcs_write64(GUEST_IA32_FRED_RSP1, vmx->nested.pre_vmenter_fred_rsp1);
+		vmcs_write64(GUEST_IA32_FRED_RSP2, vmx->nested.pre_vmenter_fred_rsp2);
+		vmcs_write64(GUEST_IA32_FRED_RSP3, vmx->nested.pre_vmenter_fred_rsp3);
+		vmcs_write64(GUEST_IA32_FRED_STKLVLS, vmx->nested.pre_vmenter_fred_stklvls);
+		vmcs_write64(GUEST_IA32_FRED_SSP1, vmx->nested.pre_vmenter_fred_ssp1);
+		vmcs_write64(GUEST_IA32_FRED_SSP2, vmx->nested.pre_vmenter_fred_ssp2);
+		vmcs_write64(GUEST_IA32_FRED_SSP3, vmx->nested.pre_vmenter_fred_ssp3);
+	}
+
 	vcpu->arch.tsc_offset = kvm_calc_nested_tsc_offset(
 			vcpu->arch.l1_tsc_offset,
 			vmx_get_l2_tsc_offset(vcpu),
@@ -3631,6 +3662,18 @@ enum nvmx_vmentry_status nested_vmx_enter_non_root_mode(struct kvm_vcpu *vcpu,
 				    &vmx->nested.pre_vmenter_ssp,
 				    &vmx->nested.pre_vmenter_ssp_tbl);
 
+	if (guest_cpu_cap_has(vcpu, X86_FEATURE_FRED) &&
+	    (!vmx->nested.nested_run_pending || !nested_cpu_load_guest_fred_state(vmcs12))) {
+		vmx->nested.pre_vmenter_fred_config = vmcs_read64(GUEST_IA32_FRED_CONFIG);
+		vmx->nested.pre_vmenter_fred_rsp1 = vmcs_read64(GUEST_IA32_FRED_RSP1);
+		vmx->nested.pre_vmenter_fred_rsp2 = vmcs_read64(GUEST_IA32_FRED_RSP2);
+		vmx->nested.pre_vmenter_fred_rsp3 = vmcs_read64(GUEST_IA32_FRED_RSP3);
+		vmx->nested.pre_vmenter_fred_stklvls = vmcs_read64(GUEST_IA32_FRED_STKLVLS);
+		vmx->nested.pre_vmenter_fred_ssp1 = vmcs_read64(GUEST_IA32_FRED_SSP1);
+		vmx->nested.pre_vmenter_fred_ssp2 = vmcs_read64(GUEST_IA32_FRED_SSP2);
+		vmx->nested.pre_vmenter_fred_ssp3 = vmcs_read64(GUEST_IA32_FRED_SSP3);
+	}
+
 	/*
 	 * Overwrite vmcs01.GUEST_CR3 with L1's CR3 if EPT is disabled.  In the
 	 * event of a "late" VM-Fail, i.e. a VM-Fail detected by hardware but
@@ -3934,6 +3977,8 @@ static void vmcs12_save_pending_event(struct kvm_vcpu *vcpu,
 	u32 idt_vectoring;
 	unsigned int nr;
 
+	vmcs12->original_event_data = 0;
+
 	/*
 	 * Per the SDM, VM-Exits due to double and triple faults are never
 	 * considered to occur during event delivery, even if the double/triple
@@ -3972,6 +4017,13 @@ static void vmcs12_save_pending_event(struct kvm_vcpu *vcpu,
 				vcpu->arch.exception.error_code;
 		}
 
+		if ((vmcs12->vm_entry_controls & VM_ENTRY_IA32E_MODE) &&
+		    (vmcs12->guest_cr4 & X86_CR4_FRED) &&
+		    (vcpu->arch.exception.nested))
+			idt_vectoring |= VECTORING_INFO_NESTED_EXCEPTION_MASK;
+
+		vmcs12->original_event_data = vcpu->arch.exception.event_data;
+
 		vmcs12->idt_vectoring_info_field = idt_vectoring;
 	} else if (vcpu->arch.nmi_injected) {
 		vmcs12->idt_vectoring_info_field =
@@ -4714,6 +4766,28 @@ static void sync_vmcs02_to_vmcs12(struct kvm_vcpu *vcpu, struct vmcs12 *vmcs12)
 	vmcs_read_cet_state(&vmx->vcpu, &vmcs12->guest_s_cet,
 			    &vmcs12->guest_ssp,
 			    &vmcs12->guest_ssp_tbl);
+
+	if (guest_cpu_cap_has(vcpu, X86_FEATURE_FRED)) {
+		vmx->nested.fred_msr_at_vmexit.fred_config = vmcs_read64(GUEST_IA32_FRED_CONFIG);
+		vmx->nested.fred_msr_at_vmexit.fred_rsp1 = vmcs_read64(GUEST_IA32_FRED_RSP1);
+		vmx->nested.fred_msr_at_vmexit.fred_rsp2 = vmcs_read64(GUEST_IA32_FRED_RSP2);
+		vmx->nested.fred_msr_at_vmexit.fred_rsp3 = vmcs_read64(GUEST_IA32_FRED_RSP3);
+		vmx->nested.fred_msr_at_vmexit.fred_stklvls = vmcs_read64(GUEST_IA32_FRED_STKLVLS);
+		vmx->nested.fred_msr_at_vmexit.fred_ssp1 = vmcs_read64(GUEST_IA32_FRED_SSP1);
+		vmx->nested.fred_msr_at_vmexit.fred_ssp2 = vmcs_read64(GUEST_IA32_FRED_SSP2);
+		vmx->nested.fred_msr_at_vmexit.fred_ssp3 = vmcs_read64(GUEST_IA32_FRED_SSP3);
+
+		if (nested_cpu_save_guest_fred_state(vmcs12)) {
+			vmcs12->guest_ia32_fred_config = vmx->nested.fred_msr_at_vmexit.fred_config;
+			vmcs12->guest_ia32_fred_rsp1 = vmx->nested.fred_msr_at_vmexit.fred_rsp1;
+			vmcs12->guest_ia32_fred_rsp2 = vmx->nested.fred_msr_at_vmexit.fred_rsp2;
+			vmcs12->guest_ia32_fred_rsp3 = vmx->nested.fred_msr_at_vmexit.fred_rsp3;
+			vmcs12->guest_ia32_fred_stklvls = vmx->nested.fred_msr_at_vmexit.fred_stklvls;
+			vmcs12->guest_ia32_fred_ssp1 = vmx->nested.fred_msr_at_vmexit.fred_ssp1;
+			vmcs12->guest_ia32_fred_ssp2 = vmx->nested.fred_msr_at_vmexit.fred_ssp2;
+			vmcs12->guest_ia32_fred_ssp3 = vmx->nested.fred_msr_at_vmexit.fred_ssp3;
+		}
+	}
 }
 
 /*
@@ -4758,6 +4832,21 @@ static void prepare_vmcs12(struct kvm_vcpu *vcpu, struct vmcs12 *vmcs12,
 
 		vmcs12->vm_exit_intr_info = exit_intr_info;
 		vmcs12->vm_exit_instruction_len = exit_insn_len;
+
+		/*
+		 * When there is a valid original event, the exiting event is a nested
+		 * event during delivery of the earlier original event.
+		 *
+		 * FRED event delivery reflects this relationship by setting the value
+		 * of the nested exception bit of VM-exit interruption information
+		 * (aka exiting-event identification) to that of the valid bit of the
+		 * IDT-vectoring information (aka original-event identification).
+		 */
+		if ((vmcs12->idt_vectoring_info_field & VECTORING_INFO_VALID_MASK) &&
+		    (vmcs12->vm_entry_controls & VM_ENTRY_IA32E_MODE) &&
+		    (vmcs12->guest_cr4 & X86_CR4_FRED))
+			vmcs12->vm_exit_intr_info |= INTR_INFO_NESTED_EXCEPTION_MASK;
+
 		vmcs12->vmx_instruction_info = vmcs_read32(VMX_INSTRUCTION_INFO);
 
 		/*
@@ -4786,6 +4875,7 @@ static void prepare_vmcs12(struct kvm_vcpu *vcpu, struct vmcs12 *vmcs12,
 static void load_vmcs12_host_state(struct kvm_vcpu *vcpu,
 				   struct vmcs12 *vmcs12)
 {
+	struct vcpu_vmx *vmx = to_vmx(vcpu);
 	enum vm_entry_failure_code ignored;
 	struct kvm_segment seg;
 
@@ -4860,6 +4950,28 @@ static void load_vmcs12_host_state(struct kvm_vcpu *vcpu,
 		WARN_ON_ONCE(__kvm_emulate_msr_write(vcpu, MSR_CORE_PERF_GLOBAL_CTRL,
 						     vmcs12->host_ia32_perf_global_ctrl));
 
+	if (guest_cpu_cap_has(vcpu, X86_FEATURE_FRED)) {
+		if (nested_cpu_load_host_fred_state(vmcs12)) {
+			vmcs_write64(GUEST_IA32_FRED_CONFIG, vmcs12->host_ia32_fred_config);
+			vmcs_write64(GUEST_IA32_FRED_RSP1, vmcs12->host_ia32_fred_rsp1);
+			vmcs_write64(GUEST_IA32_FRED_RSP2, vmcs12->host_ia32_fred_rsp2);
+			vmcs_write64(GUEST_IA32_FRED_RSP3, vmcs12->host_ia32_fred_rsp3);
+			vmcs_write64(GUEST_IA32_FRED_STKLVLS, vmcs12->host_ia32_fred_stklvls);
+			vmcs_write64(GUEST_IA32_FRED_SSP1, vmcs12->host_ia32_fred_ssp1);
+			vmcs_write64(GUEST_IA32_FRED_SSP2, vmcs12->host_ia32_fred_ssp2);
+			vmcs_write64(GUEST_IA32_FRED_SSP3, vmcs12->host_ia32_fred_ssp3);
+		} else {
+			vmcs_write64(GUEST_IA32_FRED_CONFIG, vmx->nested.fred_msr_at_vmexit.fred_config);
+			vmcs_write64(GUEST_IA32_FRED_RSP1, vmx->nested.fred_msr_at_vmexit.fred_rsp1);
+			vmcs_write64(GUEST_IA32_FRED_RSP2, vmx->nested.fred_msr_at_vmexit.fred_rsp2);
+			vmcs_write64(GUEST_IA32_FRED_RSP3, vmx->nested.fred_msr_at_vmexit.fred_rsp3);
+			vmcs_write64(GUEST_IA32_FRED_STKLVLS, vmx->nested.fred_msr_at_vmexit.fred_stklvls);
+			vmcs_write64(GUEST_IA32_FRED_SSP1, vmx->nested.fred_msr_at_vmexit.fred_ssp1);
+			vmcs_write64(GUEST_IA32_FRED_SSP2, vmx->nested.fred_msr_at_vmexit.fred_ssp2);
+			vmcs_write64(GUEST_IA32_FRED_SSP3, vmx->nested.fred_msr_at_vmexit.fred_ssp3);
+		}
+	}
+
 	/* Set L1 segment info according to Intel SDM
 	    27.5.2 Loading Host Segment and Descriptor-Table Registers */
 	seg = (struct kvm_segment) {
@@ -7339,6 +7451,8 @@ static void nested_vmx_setup_basic(struct nested_vmx_msrs *msrs)
 		msrs->basic |= VMX_BASIC_INOUT;
 	if (cpu_has_vmx_basic_no_hw_errcode_cc())
 		msrs->basic |= VMX_BASIC_NO_HW_ERROR_CODE_CC;
+	if (cpu_has_vmx_nested_exception())
+		msrs->basic |= VMX_BASIC_NESTED_EXCEPTION;
 }
 
 static void nested_vmx_setup_cr_fixed(struct nested_vmx_msrs *msrs)
diff --git a/arch/x86/kvm/vmx/nested.h b/arch/x86/kvm/vmx/nested.h
index 983484d42ebf..a99d3d83d58e 100644
--- a/arch/x86/kvm/vmx/nested.h
+++ b/arch/x86/kvm/vmx/nested.h
@@ -249,6 +249,11 @@ static inline bool nested_cpu_has_save_preemption_timer(struct vmcs12 *vmcs12)
 	    VM_EXIT_SAVE_VMX_PREEMPTION_TIMER;
 }
 
+static inline bool nested_cpu_has_secondary_vm_exit_controls(struct vmcs12 *vmcs12)
+{
+	return vmcs12->vm_exit_controls & VM_EXIT_ACTIVATE_SECONDARY_CONTROLS;
+}
+
 static inline bool nested_exit_on_nmi(struct kvm_vcpu *vcpu)
 {
 	return nested_cpu_has_nmi_exiting(get_vmcs12(vcpu));
@@ -269,6 +274,23 @@ static inline bool nested_cpu_has_encls_exit(struct vmcs12 *vmcs12)
 	return nested_cpu_has2(vmcs12, SECONDARY_EXEC_ENCLS_EXITING);
 }
 
+static inline bool nested_cpu_load_guest_fred_state(struct vmcs12 *vmcs12)
+{
+	return vmcs12->vm_entry_controls & VM_ENTRY_LOAD_IA32_FRED;
+}
+
+static inline bool nested_cpu_save_guest_fred_state(struct vmcs12 *vmcs12)
+{
+	return nested_cpu_has_secondary_vm_exit_controls(vmcs12) &&
+	       vmcs12->secondary_vm_exit_controls & SECONDARY_VM_EXIT_SAVE_IA32_FRED;
+}
+
+static inline bool nested_cpu_load_host_fred_state(struct vmcs12 *vmcs12)
+{
+	return nested_cpu_has_secondary_vm_exit_controls(vmcs12) &&
+	       vmcs12->secondary_vm_exit_controls & SECONDARY_VM_EXIT_LOAD_IA32_FRED;
+}
+
 /*
  * if fixed0[i] == 1: val[i] must be 1
  * if fixed1[i] == 0: val[i] must be 0
diff --git a/arch/x86/kvm/vmx/vmcs12.c b/arch/x86/kvm/vmx/vmcs12.c
index 3b01175f392a..9691e709061f 100644
--- a/arch/x86/kvm/vmx/vmcs12.c
+++ b/arch/x86/kvm/vmx/vmcs12.c
@@ -67,6 +67,24 @@ const unsigned short vmcs12_field_offsets[] = {
 	FIELD64(HOST_IA32_EFER, host_ia32_efer),
 	FIELD64(HOST_IA32_PERF_GLOBAL_CTRL, host_ia32_perf_global_ctrl),
 	FIELD64(SECONDARY_VM_EXIT_CONTROLS, secondary_vm_exit_controls),
+	FIELD64(INJECTED_EVENT_DATA, injected_event_data),
+	FIELD64(ORIGINAL_EVENT_DATA, original_event_data),
+	FIELD64(GUEST_IA32_FRED_CONFIG, guest_ia32_fred_config),
+	FIELD64(GUEST_IA32_FRED_RSP1, guest_ia32_fred_rsp1),
+	FIELD64(GUEST_IA32_FRED_RSP2, guest_ia32_fred_rsp2),
+	FIELD64(GUEST_IA32_FRED_RSP3, guest_ia32_fred_rsp3),
+	FIELD64(GUEST_IA32_FRED_STKLVLS, guest_ia32_fred_stklvls),
+	FIELD64(GUEST_IA32_FRED_SSP1, guest_ia32_fred_ssp1),
+	FIELD64(GUEST_IA32_FRED_SSP2, guest_ia32_fred_ssp2),
+	FIELD64(GUEST_IA32_FRED_SSP3, guest_ia32_fred_ssp3),
+	FIELD64(HOST_IA32_FRED_CONFIG, host_ia32_fred_config),
+	FIELD64(HOST_IA32_FRED_RSP1, host_ia32_fred_rsp1),
+	FIELD64(HOST_IA32_FRED_RSP2, host_ia32_fred_rsp2),
+	FIELD64(HOST_IA32_FRED_RSP3, host_ia32_fred_rsp3),
+	FIELD64(HOST_IA32_FRED_STKLVLS, host_ia32_fred_stklvls),
+	FIELD64(HOST_IA32_FRED_SSP1, host_ia32_fred_ssp1),
+	FIELD64(HOST_IA32_FRED_SSP2, host_ia32_fred_ssp2),
+	FIELD64(HOST_IA32_FRED_SSP3, host_ia32_fred_ssp3),
 	FIELD(PIN_BASED_VM_EXEC_CONTROL, pin_based_vm_exec_control),
 	FIELD(CPU_BASED_VM_EXEC_CONTROL, cpu_based_vm_exec_control),
 	FIELD(EXCEPTION_BITMAP, exception_bitmap),
diff --git a/arch/x86/kvm/vmx/vmcs12.h b/arch/x86/kvm/vmx/vmcs12.h
index fa5306dc0311..051016a3afba 100644
--- a/arch/x86/kvm/vmx/vmcs12.h
+++ b/arch/x86/kvm/vmx/vmcs12.h
@@ -191,6 +191,25 @@ struct __packed vmcs12 {
 	u16 host_gs_selector;
 	u16 host_tr_selector;
 	u16 guest_pml_index;
+	u16 padding16[1]; /* align to 64-bit boundary */
+	u64 guest_ia32_fred_config;
+	u64 guest_ia32_fred_rsp1;
+	u64 guest_ia32_fred_rsp2;
+	u64 guest_ia32_fred_rsp3;
+	u64 guest_ia32_fred_stklvls;
+	u64 guest_ia32_fred_ssp1;
+	u64 guest_ia32_fred_ssp2;
+	u64 guest_ia32_fred_ssp3;
+	u64 host_ia32_fred_config;
+	u64 host_ia32_fred_rsp1;
+	u64 host_ia32_fred_rsp2;
+	u64 host_ia32_fred_rsp3;
+	u64 host_ia32_fred_stklvls;
+	u64 host_ia32_fred_ssp1;
+	u64 host_ia32_fred_ssp2;
+	u64 host_ia32_fred_ssp3;
+	u64 injected_event_data;
+	u64 original_event_data;
 };
 
 /*
@@ -373,6 +392,24 @@ static inline void vmx_check_vmcs12_offsets(void)
 	CHECK_OFFSET(host_gs_selector, 992);
 	CHECK_OFFSET(host_tr_selector, 994);
 	CHECK_OFFSET(guest_pml_index, 996);
+	CHECK_OFFSET(guest_ia32_fred_config, 1000);
+	CHECK_OFFSET(guest_ia32_fred_rsp1, 1008);
+	CHECK_OFFSET(guest_ia32_fred_rsp2, 1016);
+	CHECK_OFFSET(guest_ia32_fred_rsp3, 1024);
+	CHECK_OFFSET(guest_ia32_fred_stklvls, 1032);
+	CHECK_OFFSET(guest_ia32_fred_ssp1, 1040);
+	CHECK_OFFSET(guest_ia32_fred_ssp2, 1048);
+	CHECK_OFFSET(guest_ia32_fred_ssp3, 1056);
+	CHECK_OFFSET(host_ia32_fred_config, 1064);
+	CHECK_OFFSET(host_ia32_fred_rsp1, 1072);
+	CHECK_OFFSET(host_ia32_fred_rsp2, 1080);
+	CHECK_OFFSET(host_ia32_fred_rsp3, 1088);
+	CHECK_OFFSET(host_ia32_fred_stklvls, 1096);
+	CHECK_OFFSET(host_ia32_fred_ssp1, 1104);
+	CHECK_OFFSET(host_ia32_fred_ssp2, 1112);
+	CHECK_OFFSET(host_ia32_fred_ssp3, 1120);
+	CHECK_OFFSET(injected_event_data, 1128);
+	CHECK_OFFSET(original_event_data, 1136);
 }
 
 extern const unsigned short vmcs12_field_offsets[];
diff --git a/arch/x86/kvm/vmx/vmcs_shadow_fields.h b/arch/x86/kvm/vmx/vmcs_shadow_fields.h
index cad128d1657b..da338327c2b3 100644
--- a/arch/x86/kvm/vmx/vmcs_shadow_fields.h
+++ b/arch/x86/kvm/vmx/vmcs_shadow_fields.h
@@ -74,6 +74,10 @@ SHADOW_FIELD_RW(HOST_GS_BASE, host_gs_base)
 /* 64-bit */
 SHADOW_FIELD_RO(GUEST_PHYSICAL_ADDRESS, guest_physical_address)
 SHADOW_FIELD_RO(GUEST_PHYSICAL_ADDRESS_HIGH, guest_physical_address)
+SHADOW_FIELD_RO(ORIGINAL_EVENT_DATA, original_event_data)
+SHADOW_FIELD_RO(ORIGINAL_EVENT_DATA_HIGH, original_event_data)
+SHADOW_FIELD_RW(INJECTED_EVENT_DATA, injected_event_data)
+SHADOW_FIELD_RW(INJECTED_EVENT_DATA_HIGH, injected_event_data)
 
 #undef SHADOW_FIELD_RO
 #undef SHADOW_FIELD_RW
diff --git a/arch/x86/kvm/vmx/vmx.h b/arch/x86/kvm/vmx/vmx.h
index 48a5ab12cccf..cedb714bc082 100644
--- a/arch/x86/kvm/vmx/vmx.h
+++ b/arch/x86/kvm/vmx/vmx.h
@@ -67,6 +67,37 @@ struct pt_desc {
 	struct pt_ctx guest;
 };
 
+/*
+ * Used to snapshot FRED MSRs that may NOT be saved to vmcs12 as specified
+ * in the VM-Exit controls of vmcs12 configured by L1 VMM.
+ *
+ * FRED MSRs are *always* saved into vmcs02 because KVM always sets
+ * SECONDARY_VM_EXIT_SAVE_IA32_FRED.  However an L1 VMM may choose to clear
+ * this bit, resulting in FRED MSRs not being propagated to vmcs12 from
+ * vmcs02.  When the L1 VMM sets SECONDARY_VM_EXIT_LOAD_IA32_FRED, this is
+ * not a problem, since KVM then immediately loads the host FRED MSRs of
+ * vmcs12 to the guest FRED MSRs of vmcs01.
+ *
+ * But if the L1 VMM clears SECONDARY_VM_EXIT_LOAD_IA32_FRED, KVM should
+ * retain the FRED MSRs, i.e., propagate the guest FRED MSRs of vmcs02 to
+ * the guest FRED MSRs of vmcs01.
+ *
+ * This structure stores guest FRED MSRs that an L1 VMM opts not to save
+ * during VM-Exits from L2 to L1.  These MSRs may still be retained for
+ * running the L1 VMM if SECONDARY_VM_EXIT_LOAD_IA32_FRED is cleared in
+ * vmcs12.
+ */
+struct fred_msr_at_vmexit {
+	u64 fred_config;
+	u64 fred_rsp1;
+	u64 fred_rsp2;
+	u64 fred_rsp3;
+	u64 fred_stklvls;
+	u64 fred_ssp1;
+	u64 fred_ssp2;
+	u64 fred_ssp3;
+};
+
 /*
  * The nested_vmx structure is part of vcpu_vmx, and holds information we need
  * for correct emulation of VMX (i.e., nested VMX) on this vcpu.
@@ -184,6 +215,16 @@ struct nested_vmx {
 	u64 pre_vmenter_s_cet;
 	u64 pre_vmenter_ssp;
 	u64 pre_vmenter_ssp_tbl;
+	u64 pre_vmenter_fred_config;
+	u64 pre_vmenter_fred_rsp1;
+	u64 pre_vmenter_fred_rsp2;
+	u64 pre_vmenter_fred_rsp3;
+	u64 pre_vmenter_fred_stklvls;
+	u64 pre_vmenter_fred_ssp1;
+	u64 pre_vmenter_fred_ssp2;
+	u64 pre_vmenter_fred_ssp3;
+
+	struct fred_msr_at_vmexit fred_msr_at_vmexit;
 
 	/* to migrate it to L1 if L2 writes to L1's CR8 directly */
 	int l1_tpr_threshold;
-- 
2.51.0
Re: [PATCH v9 19/22] KVM: nVMX: Handle FRED VMCS fields in nested VMX context
Posted by Sean Christopherson 5 days, 23 hours ago
On Sun, Oct 26, 2025, Xin Li (Intel) wrote:
> diff --git a/arch/x86/kvm/vmx/vmcs_shadow_fields.h b/arch/x86/kvm/vmx/vmcs_shadow_fields.h
> index cad128d1657b..da338327c2b3 100644
> --- a/arch/x86/kvm/vmx/vmcs_shadow_fields.h
> +++ b/arch/x86/kvm/vmx/vmcs_shadow_fields.h
> @@ -74,6 +74,10 @@ SHADOW_FIELD_RW(HOST_GS_BASE, host_gs_base)
>  /* 64-bit */
>  SHADOW_FIELD_RO(GUEST_PHYSICAL_ADDRESS, guest_physical_address)
>  SHADOW_FIELD_RO(GUEST_PHYSICAL_ADDRESS_HIGH, guest_physical_address)
> +SHADOW_FIELD_RO(ORIGINAL_EVENT_DATA, original_event_data)
> +SHADOW_FIELD_RO(ORIGINAL_EVENT_DATA_HIGH, original_event_data)
> +SHADOW_FIELD_RW(INJECTED_EVENT_DATA, injected_event_data)
> +SHADOW_FIELD_RW(INJECTED_EVENT_DATA_HIGH, injected_event_data)

Please add shadow fields in a separate patch, with sufficient explain to justify
why KVM needs to enable VMCS shadowing for the fields (it's purely a performance
optimazation).
Re: [PATCH v9 19/22] KVM: nVMX: Handle FRED VMCS fields in nested VMX context
Posted by Chao Gao 1 week, 5 days ago
>diff --git a/arch/x86/kvm/vmx/capabilities.h b/arch/x86/kvm/vmx/capabilities.h
>index f390f9f883c3..5eba2530ffb4 100644
>--- a/arch/x86/kvm/vmx/capabilities.h
>+++ b/arch/x86/kvm/vmx/capabilities.h
>@@ -80,6 +80,11 @@ static inline bool cpu_has_vmx_basic_no_hw_errcode_cc(void)
> 	return	vmcs_config.basic & VMX_BASIC_NO_HW_ERROR_CODE_CC;
> }
> 
>+static inline bool cpu_has_vmx_nested_exception(void)
>+{
>+	return vmcs_config.basic & VMX_BASIC_NESTED_EXCEPTION;
>+}
>+
> static inline bool cpu_has_virtual_nmis(void)
> {
> 	return vmcs_config.pin_based_exec_ctrl & PIN_BASED_VIRTUAL_NMIS &&
>diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
>index cbb682424a5b..63cdfffba58b 100644
>--- a/arch/x86/kvm/vmx/nested.c
>+++ b/arch/x86/kvm/vmx/nested.c
>@@ -708,6 +708,9 @@ static inline bool nested_vmx_prepare_msr_bitmap(struct kvm_vcpu *vcpu,
> 
> 	nested_vmx_set_intercept_for_msr(vmx, msr_bitmap_l1, msr_bitmap_l0,
> 					 MSR_KERNEL_GS_BASE, MSR_TYPE_RW);
>+
>+	nested_vmx_set_intercept_for_msr(vmx, msr_bitmap_l1, msr_bitmap_l0,
>+					 MSR_IA32_FRED_RSP0, MSR_TYPE_RW);

Why is only this specific MSR handled? What about other FRED MSRs?

> #endif
> 	nested_vmx_set_intercept_for_msr(vmx, msr_bitmap_l1, msr_bitmap_l0,
> 					 MSR_IA32_SPEC_CTRL, MSR_TYPE_RW);
>@@ -1294,9 +1297,11 @@ static int vmx_restore_vmx_basic(struct vcpu_vmx *vmx, u64 data)
> 	const u64 feature_bits = VMX_BASIC_DUAL_MONITOR_TREATMENT |
> 				 VMX_BASIC_INOUT |
> 				 VMX_BASIC_TRUE_CTLS |
>-				 VMX_BASIC_NO_HW_ERROR_CODE_CC;
>+				 VMX_BASIC_NO_HW_ERROR_CODE_CC |
>+				 VMX_BASIC_NESTED_EXCEPTION;
> 
>-	const u64 reserved_bits = GENMASK_ULL(63, 57) |
>+	const u64 reserved_bits = GENMASK_ULL(63, 59) |
>+				  BIT_ULL(57) |
> 				  GENMASK_ULL(47, 45) |
> 				  BIT_ULL(31);
> 
>@@ -2539,6 +2544,8 @@ static void prepare_vmcs02_early(struct vcpu_vmx *vmx, struct loaded_vmcs *vmcs0
> 			     vmcs12->vm_entry_instruction_len);
> 		vmcs_write32(GUEST_INTERRUPTIBILITY_INFO,
> 			     vmcs12->guest_interruptibility_info);
>+		if (cpu_has_vmx_fred())
>+			vmcs_write64(INJECTED_EVENT_DATA, vmcs12->injected_event_data);
> 		vmx->loaded_vmcs->nmi_known_unmasked =
> 			!(vmcs12->guest_interruptibility_info & GUEST_INTR_STATE_NMI);
> 	} else {
>@@ -2693,6 +2700,18 @@ static void prepare_vmcs02_rare(struct vcpu_vmx *vmx, struct vmcs12 *vmcs12)
> 				     vmcs12->guest_ssp, vmcs12->guest_ssp_tbl);
> 
> 	set_cr4_guest_host_mask(vmx);
>+
>+	if (guest_cpu_cap_has(&vmx->vcpu, X86_FEATURE_FRED) &&
>+	    nested_cpu_load_guest_fred_state(vmcs12)) {
>+		vmcs_write64(GUEST_IA32_FRED_CONFIG, vmcs12->guest_ia32_fred_config);
>+		vmcs_write64(GUEST_IA32_FRED_RSP1, vmcs12->guest_ia32_fred_rsp1);
>+		vmcs_write64(GUEST_IA32_FRED_RSP2, vmcs12->guest_ia32_fred_rsp2);
>+		vmcs_write64(GUEST_IA32_FRED_RSP3, vmcs12->guest_ia32_fred_rsp3);
>+		vmcs_write64(GUEST_IA32_FRED_STKLVLS, vmcs12->guest_ia32_fred_stklvls);
>+		vmcs_write64(GUEST_IA32_FRED_SSP1, vmcs12->guest_ia32_fred_ssp1);
>+		vmcs_write64(GUEST_IA32_FRED_SSP2, vmcs12->guest_ia32_fred_ssp2);
>+		vmcs_write64(GUEST_IA32_FRED_SSP3, vmcs12->guest_ia32_fred_ssp3);

...

>+	}
> }
> 
> /*
>@@ -2759,6 +2778,18 @@ static int prepare_vmcs02(struct kvm_vcpu *vcpu, struct vmcs12 *vmcs12,
> 		vmcs_write64(GUEST_IA32_PAT, vcpu->arch.pat);
> 	}
> 
>+	if (guest_cpu_cap_has(vcpu, X86_FEATURE_FRED) &&
>+	    (!vmx->nested.nested_run_pending || !nested_cpu_load_guest_fred_state(vmcs12))) {
>+		vmcs_write64(GUEST_IA32_FRED_CONFIG, vmx->nested.pre_vmenter_fred_config);
>+		vmcs_write64(GUEST_IA32_FRED_RSP1, vmx->nested.pre_vmenter_fred_rsp1);
>+		vmcs_write64(GUEST_IA32_FRED_RSP2, vmx->nested.pre_vmenter_fred_rsp2);
>+		vmcs_write64(GUEST_IA32_FRED_RSP3, vmx->nested.pre_vmenter_fred_rsp3);
>+		vmcs_write64(GUEST_IA32_FRED_STKLVLS, vmx->nested.pre_vmenter_fred_stklvls);
>+		vmcs_write64(GUEST_IA32_FRED_SSP1, vmx->nested.pre_vmenter_fred_ssp1);
>+		vmcs_write64(GUEST_IA32_FRED_SSP2, vmx->nested.pre_vmenter_fred_ssp2);
>+		vmcs_write64(GUEST_IA32_FRED_SSP3, vmx->nested.pre_vmenter_fred_ssp3);

Would it be clearer to add two helpers to read/write FRED VMCS fields? e.g., (compile test only)

diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
index c8edbe9c7e00..b709f4cdcba3 100644
--- a/arch/x86/kvm/vmx/nested.c
+++ b/arch/x86/kvm/vmx/nested.c
@@ -2614,6 +2614,30 @@ static void vmcs_write_cet_state(struct kvm_vcpu *vcpu, u64 s_cet,
	}
 }
 
+static void vmcs_read_fred_msrs(struct fred_msrs *msrs)
+{
+	msrs->fred_config = vmcs_read64(GUEST_IA32_FRED_CONFIG);
+	msrs->fred_rsp1 = vmcs_read64(GUEST_IA32_FRED_RSP1);
+	msrs->fred_rsp2 = vmcs_read64(GUEST_IA32_FRED_RSP2);
+	msrs->fred_rsp3 = vmcs_read64(GUEST_IA32_FRED_RSP3);
+	msrs->fred_stklvls = vmcs_read64(GUEST_IA32_FRED_STKLVLS);
+	msrs->fred_ssp1 = vmcs_read64(GUEST_IA32_FRED_SSP1);
+	msrs->fred_ssp2 = vmcs_read64(GUEST_IA32_FRED_SSP2);
+	msrs->fred_ssp3 = vmcs_read64(GUEST_IA32_FRED_SSP3);
+}
+
+static void vmcs_write_fred_msrs(struct fred_msrs *msrs)
+{
+	vmcs_write64(GUEST_IA32_FRED_CONFIG, msrs->fred_config);
+	vmcs_write64(GUEST_IA32_FRED_RSP1, msrs->fred_rsp1);
+	vmcs_write64(GUEST_IA32_FRED_RSP2, msrs->fred_rsp2);
+	vmcs_write64(GUEST_IA32_FRED_RSP3, msrs->fred_rsp3);
+	vmcs_write64(GUEST_IA32_FRED_STKLVLS, msrs->fred_stklvls);
+	vmcs_write64(GUEST_IA32_FRED_SSP1, msrs->fred_ssp1);
+	vmcs_write64(GUEST_IA32_FRED_SSP2, msrs->fred_ssp2);
+	vmcs_write64(GUEST_IA32_FRED_SSP3, msrs->fred_ssp3);
+}
+
 static void prepare_vmcs02_rare(struct vcpu_vmx *vmx, struct vmcs12 *vmcs12)
 {
	struct hv_enlightened_vmcs *hv_evmcs = nested_vmx_evmcs(vmx);
@@ -2736,16 +2760,8 @@ static void prepare_vmcs02_rare(struct vcpu_vmx *vmx, struct vmcs12 *vmcs12)
 
	set_cr4_guest_host_mask(vmx);
 
-	if (nested_cpu_load_guest_fred_state(vmcs12)) {
-		vmcs_write64(GUEST_IA32_FRED_CONFIG, vmcs12->guest_ia32_fred_config);
-		vmcs_write64(GUEST_IA32_FRED_RSP1, vmcs12->guest_ia32_fred_rsp1);
-		vmcs_write64(GUEST_IA32_FRED_RSP2, vmcs12->guest_ia32_fred_rsp2);
-		vmcs_write64(GUEST_IA32_FRED_RSP3, vmcs12->guest_ia32_fred_rsp3);
-		vmcs_write64(GUEST_IA32_FRED_STKLVLS, vmcs12->guest_ia32_fred_stklvls);
-		vmcs_write64(GUEST_IA32_FRED_SSP1, vmcs12->guest_ia32_fred_ssp1);
-		vmcs_write64(GUEST_IA32_FRED_SSP2, vmcs12->guest_ia32_fred_ssp2);
-		vmcs_write64(GUEST_IA32_FRED_SSP3, vmcs12->guest_ia32_fred_ssp3);
-	}
+	if (nested_cpu_load_guest_fred_state(vmcs12))
+		vmcs_write_fred_msrs((struct fred_msrs *)&vmcs12->guest_ia32_fred_config);
 }
 
 /*
@@ -2813,16 +2829,8 @@ static int prepare_vmcs02(struct kvm_vcpu *vcpu, struct vmcs12 *vmcs12,
	}
 
	if (!vmx->nested.nested_run_pending ||
-	    !nested_cpu_load_guest_fred_state(vmcs12)) {
-		vmcs_write64(GUEST_IA32_FRED_CONFIG, vmx->nested.pre_vmenter_fred_config);
-		vmcs_write64(GUEST_IA32_FRED_RSP1, vmx->nested.pre_vmenter_fred_rsp1);
-		vmcs_write64(GUEST_IA32_FRED_RSP2, vmx->nested.pre_vmenter_fred_rsp2);
-		vmcs_write64(GUEST_IA32_FRED_RSP3, vmx->nested.pre_vmenter_fred_rsp3);
-		vmcs_write64(GUEST_IA32_FRED_STKLVLS, vmx->nested.pre_vmenter_fred_stklvls);
-		vmcs_write64(GUEST_IA32_FRED_SSP1, vmx->nested.pre_vmenter_fred_ssp1);
-		vmcs_write64(GUEST_IA32_FRED_SSP2, vmx->nested.pre_vmenter_fred_ssp2);
-		vmcs_write64(GUEST_IA32_FRED_SSP3, vmx->nested.pre_vmenter_fred_ssp3);
-	}
+	    !nested_cpu_load_guest_fred_state(vmcs12))
+		vmcs_write_fred_msrs(&vmx->nested.fred_msrs_pre_vmenter);
 
	vcpu->arch.tsc_offset = kvm_calc_nested_tsc_offset(
			vcpu->arch.l1_tsc_offset,
@@ -3830,16 +3838,8 @@ enum nvmx_vmentry_status nested_vmx_enter_non_root_mode(struct kvm_vcpu *vcpu,
				    &vmx->nested.pre_vmenter_ssp_tbl);
 
	if (!vmx->nested.nested_run_pending ||
-	    !nested_cpu_load_guest_fred_state(vmcs12)) {
-		vmx->nested.pre_vmenter_fred_config = vmcs_read64(GUEST_IA32_FRED_CONFIG);
-		vmx->nested.pre_vmenter_fred_rsp1 = vmcs_read64(GUEST_IA32_FRED_RSP1);
-		vmx->nested.pre_vmenter_fred_rsp2 = vmcs_read64(GUEST_IA32_FRED_RSP2);
-		vmx->nested.pre_vmenter_fred_rsp3 = vmcs_read64(GUEST_IA32_FRED_RSP3);
-		vmx->nested.pre_vmenter_fred_stklvls = vmcs_read64(GUEST_IA32_FRED_STKLVLS);
-		vmx->nested.pre_vmenter_fred_ssp1 = vmcs_read64(GUEST_IA32_FRED_SSP1);
-		vmx->nested.pre_vmenter_fred_ssp2 = vmcs_read64(GUEST_IA32_FRED_SSP2);
-		vmx->nested.pre_vmenter_fred_ssp3 = vmcs_read64(GUEST_IA32_FRED_SSP3);
-	}
+	    !nested_cpu_load_guest_fred_state(vmcs12))
+		vmcs_read_fred_msrs(&vmx->nested.fred_msrs_pre_vmenter);
 
	/*
	 * Overwrite vmcs01.GUEST_CR3 with L1's CR3 if EPT is disabled *and*
@@ -4938,25 +4938,10 @@ static void sync_vmcs02_to_vmcs12(struct kvm_vcpu *vcpu, struct vmcs12 *vmcs12)
			    &vmcs12->guest_ssp,
			    &vmcs12->guest_ssp_tbl);
 
-	vmx->nested.fred_msr_at_vmexit.fred_config = vmcs_read64(GUEST_IA32_FRED_CONFIG);
-	vmx->nested.fred_msr_at_vmexit.fred_rsp1 = vmcs_read64(GUEST_IA32_FRED_RSP1);
-	vmx->nested.fred_msr_at_vmexit.fred_rsp2 = vmcs_read64(GUEST_IA32_FRED_RSP2);
-	vmx->nested.fred_msr_at_vmexit.fred_rsp3 = vmcs_read64(GUEST_IA32_FRED_RSP3);
-	vmx->nested.fred_msr_at_vmexit.fred_stklvls = vmcs_read64(GUEST_IA32_FRED_STKLVLS);
-	vmx->nested.fred_msr_at_vmexit.fred_ssp1 = vmcs_read64(GUEST_IA32_FRED_SSP1);
-	vmx->nested.fred_msr_at_vmexit.fred_ssp2 = vmcs_read64(GUEST_IA32_FRED_SSP2);
-	vmx->nested.fred_msr_at_vmexit.fred_ssp3 = vmcs_read64(GUEST_IA32_FRED_SSP3);
+	vmcs_read_fred_msrs(&vmx->nested.fred_msrs_at_vmexit);
 
-	if (nested_cpu_save_guest_fred_state(vmcs12)) {
-		vmcs12->guest_ia32_fred_config = vmx->nested.fred_msr_at_vmexit.fred_config;
-		vmcs12->guest_ia32_fred_rsp1 = vmx->nested.fred_msr_at_vmexit.fred_rsp1;
-		vmcs12->guest_ia32_fred_rsp2 = vmx->nested.fred_msr_at_vmexit.fred_rsp2;
-		vmcs12->guest_ia32_fred_rsp3 = vmx->nested.fred_msr_at_vmexit.fred_rsp3;
-		vmcs12->guest_ia32_fred_stklvls = vmx->nested.fred_msr_at_vmexit.fred_stklvls;
-		vmcs12->guest_ia32_fred_ssp1 = vmx->nested.fred_msr_at_vmexit.fred_ssp1;
-		vmcs12->guest_ia32_fred_ssp2 = vmx->nested.fred_msr_at_vmexit.fred_ssp2;
-		vmcs12->guest_ia32_fred_ssp3 = vmx->nested.fred_msr_at_vmexit.fred_ssp3;
-	}
+	if (nested_cpu_save_guest_fred_state(vmcs12))
+		memcpy(&vmcs12->guest_ia32_fred_config, &vmx->nested.fred_msrs_at_vmexit, sizeof(struct fred_msrs));
 }
 
 /*
@@ -5119,25 +5104,10 @@ static void load_vmcs12_host_state(struct kvm_vcpu *vcpu,
		WARN_ON_ONCE(__kvm_emulate_msr_write(vcpu, MSR_CORE_PERF_GLOBAL_CTRL,
						     vmcs12->host_ia32_perf_global_ctrl));
 
-	if (nested_cpu_load_host_fred_state(vmcs12)) {
-		vmcs_write64(GUEST_IA32_FRED_CONFIG, vmcs12->host_ia32_fred_config);
-		vmcs_write64(GUEST_IA32_FRED_RSP1, vmcs12->host_ia32_fred_rsp1);
-		vmcs_write64(GUEST_IA32_FRED_RSP2, vmcs12->host_ia32_fred_rsp2);
-		vmcs_write64(GUEST_IA32_FRED_RSP3, vmcs12->host_ia32_fred_rsp3);
-		vmcs_write64(GUEST_IA32_FRED_STKLVLS, vmcs12->host_ia32_fred_stklvls);
-		vmcs_write64(GUEST_IA32_FRED_SSP1, vmcs12->host_ia32_fred_ssp1);
-		vmcs_write64(GUEST_IA32_FRED_SSP2, vmcs12->host_ia32_fred_ssp2);
-		vmcs_write64(GUEST_IA32_FRED_SSP3, vmcs12->host_ia32_fred_ssp3);
-	} else {
-		vmcs_write64(GUEST_IA32_FRED_CONFIG, vmx->nested.fred_msr_at_vmexit.fred_config);
-		vmcs_write64(GUEST_IA32_FRED_RSP1, vmx->nested.fred_msr_at_vmexit.fred_rsp1);
-		vmcs_write64(GUEST_IA32_FRED_RSP2, vmx->nested.fred_msr_at_vmexit.fred_rsp2);
-		vmcs_write64(GUEST_IA32_FRED_RSP3, vmx->nested.fred_msr_at_vmexit.fred_rsp3);
-		vmcs_write64(GUEST_IA32_FRED_STKLVLS, vmx->nested.fred_msr_at_vmexit.fred_stklvls);
-		vmcs_write64(GUEST_IA32_FRED_SSP1, vmx->nested.fred_msr_at_vmexit.fred_ssp1);
-		vmcs_write64(GUEST_IA32_FRED_SSP2, vmx->nested.fred_msr_at_vmexit.fred_ssp2);
-		vmcs_write64(GUEST_IA32_FRED_SSP3, vmx->nested.fred_msr_at_vmexit.fred_ssp3);
-	}
+	if (nested_cpu_load_host_fred_state(vmcs12))
+		vmcs_write_fred_msrs((struct fred_msrs *)vmcs12->host_ia32_fred_config);
+	else
+		vmcs_write_fred_msrs(&vmx->nested.fred_msrs_at_vmexit);
 
	/* Set L1 segment info according to Intel SDM
	    27.5.2 Loading Host Segment and Descriptor-Table Registers */
diff --git a/arch/x86/kvm/vmx/vmx.h b/arch/x86/kvm/vmx/vmx.h
index 36dcc888e5c6..c1c32e8ae068 100644
--- a/arch/x86/kvm/vmx/vmx.h
+++ b/arch/x86/kvm/vmx/vmx.h
@@ -87,7 +87,7 @@ struct pt_desc {
  * running the L1 VMM if SECONDARY_VM_EXIT_LOAD_IA32_FRED is cleared in
  * vmcs12.
  */
-struct fred_msr_at_vmexit {
+struct fred_msrs {
	u64 fred_config;
	u64 fred_rsp1;
	u64 fred_rsp2;
@@ -215,16 +215,8 @@ struct nested_vmx {
	u64 pre_vmenter_s_cet;
	u64 pre_vmenter_ssp;
	u64 pre_vmenter_ssp_tbl;
-	u64 pre_vmenter_fred_config;
-	u64 pre_vmenter_fred_rsp1;
-	u64 pre_vmenter_fred_rsp2;
-	u64 pre_vmenter_fred_rsp3;
-	u64 pre_vmenter_fred_stklvls;
-	u64 pre_vmenter_fred_ssp1;
-	u64 pre_vmenter_fred_ssp2;
-	u64 pre_vmenter_fred_ssp3;
-
-	struct fred_msr_at_vmexit fred_msr_at_vmexit;
+
+	struct fred_msrs fred_msrs_at_vmexit, fred_msrs_pre_vmenter;
 
	/* to migrate it to L1 if L2 writes to L1's CR8 directly */
	int l1_tpr_threshold;