[PATCH v3 22/27] KVM: nVMX: Add support for the secondary VM exit controls
From: Xin Li (Intel)
Date: Tue Oct 01 2024 - 01:06:10 EST
From: Xin Li <xin3.li@xxxxxxxxx>
Enable the secondary VM exit controls to prepare for nested FRED.
Signed-off-by: Xin Li <xin3.li@xxxxxxxxx>
Signed-off-by: Xin Li (Intel) <xin@xxxxxxxxx>
Tested-by: Shan Kang <shan.kang@xxxxxxxxx>
---
Change since v2:
* Read secondary VM exit controls from vmcs_conf insteasd of the hardware
MSR MSR_IA32_VMX_EXIT_CTLS2 to avoid advertising features to L1 that KVM
itself doesn't support, e.g. because the expected entry+exit pairs aren't
supported. (Sean Christopherson)
---
Documentation/virt/kvm/x86/nested-vmx.rst | 1 +
arch/x86/kvm/vmx/capabilities.h | 1 +
arch/x86/kvm/vmx/nested.c | 21 ++++++++++++++++++++-
arch/x86/kvm/vmx/vmcs12.c | 1 +
arch/x86/kvm/vmx/vmcs12.h | 2 ++
arch/x86/kvm/x86.h | 2 +-
6 files changed, 26 insertions(+), 2 deletions(-)
diff --git a/Documentation/virt/kvm/x86/nested-vmx.rst b/Documentation/virt/kvm/x86/nested-vmx.rst
index ac2095d41f02..e64ef231f310 100644
--- a/Documentation/virt/kvm/x86/nested-vmx.rst
+++ b/Documentation/virt/kvm/x86/nested-vmx.rst
@@ -217,6 +217,7 @@ struct shadow_vmcs is ever changed.
u16 host_fs_selector;
u16 host_gs_selector;
u16 host_tr_selector;
+ u64 secondary_vm_exit_controls;
};
diff --git a/arch/x86/kvm/vmx/capabilities.h b/arch/x86/kvm/vmx/capabilities.h
index 2962a3bb9747..c96e6cb18c9a 100644
--- a/arch/x86/kvm/vmx/capabilities.h
+++ b/arch/x86/kvm/vmx/capabilities.h
@@ -38,6 +38,7 @@ struct nested_vmx_msrs {
u32 pinbased_ctls_high;
u32 exit_ctls_low;
u32 exit_ctls_high;
+ u64 secondary_exit_ctls;
u32 entry_ctls_low;
u32 entry_ctls_high;
u32 misc_low;
diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
index a8e7bc04d9bf..42e43eb7561f 100644
--- a/arch/x86/kvm/vmx/nested.c
+++ b/arch/x86/kvm/vmx/nested.c
@@ -1454,6 +1454,7 @@ int vmx_set_vmx_msr(struct kvm_vcpu *vcpu, u32 msr_index, u64 data)
case MSR_IA32_VMX_PINBASED_CTLS:
case MSR_IA32_VMX_PROCBASED_CTLS:
case MSR_IA32_VMX_EXIT_CTLS:
+ case MSR_IA32_VMX_EXIT_CTLS2:
case MSR_IA32_VMX_ENTRY_CTLS:
/*
* The "non-true" VMX capability MSRs are generated from the
@@ -1532,6 +1533,9 @@ int vmx_get_vmx_msr(struct nested_vmx_msrs *msrs, u32 msr_index, u64 *pdata)
if (msr_index == MSR_IA32_VMX_EXIT_CTLS)
*pdata |= VM_EXIT_ALWAYSON_WITHOUT_TRUE_MSR;
break;
+ case MSR_IA32_VMX_EXIT_CTLS2:
+ *pdata = msrs->secondary_exit_ctls;
+ break;
case MSR_IA32_VMX_TRUE_ENTRY_CTLS:
case MSR_IA32_VMX_ENTRY_CTLS:
*pdata = vmx_control_msr(
@@ -2471,6 +2475,11 @@ static void prepare_vmcs02_early(struct vcpu_vmx *vmx, struct loaded_vmcs *vmcs0
exec_control &= ~VM_EXIT_LOAD_IA32_EFER;
vm_exit_controls_set(vmx, exec_control);
+ if (exec_control & VM_EXIT_ACTIVATE_SECONDARY_CONTROLS) {
+ exec_control = __secondary_vm_exit_controls_get(vmcs01);
+ secondary_vm_exit_controls_set(vmx, exec_control);
+ }
+
/*
* Interrupt/Exception Fields
*/
@@ -6956,7 +6965,7 @@ static void nested_vmx_setup_exit_ctls(struct vmcs_config *vmcs_conf,
VM_EXIT_HOST_ADDR_SPACE_SIZE |
#endif
VM_EXIT_LOAD_IA32_PAT | VM_EXIT_SAVE_IA32_PAT |
- VM_EXIT_CLEAR_BNDCFGS;
+ VM_EXIT_CLEAR_BNDCFGS | VM_EXIT_ACTIVATE_SECONDARY_CONTROLS;
msrs->exit_ctls_high |=
VM_EXIT_ALWAYSON_WITHOUT_TRUE_MSR |
VM_EXIT_LOAD_IA32_EFER | VM_EXIT_SAVE_IA32_EFER |
@@ -6965,6 +6974,16 @@ static void nested_vmx_setup_exit_ctls(struct vmcs_config *vmcs_conf,
/* We support free control of debug control saving. */
msrs->exit_ctls_low &= ~VM_EXIT_SAVE_DEBUG_CONTROLS;
+
+ if (msrs->exit_ctls_high & VM_EXIT_ACTIVATE_SECONDARY_CONTROLS) {
+ msrs->secondary_exit_ctls = vmcs_conf->secondary_vmexit_ctrl;
+ /*
+ * As the secondary VM exit control is always loaded, do not
+ * advertise any feature in it to nVMX until its nVMX support
+ * is ready.
+ */
+ msrs->secondary_exit_ctls &= 0;
+ }
}
static void nested_vmx_setup_entry_ctls(struct vmcs_config *vmcs_conf,
diff --git a/arch/x86/kvm/vmx/vmcs12.c b/arch/x86/kvm/vmx/vmcs12.c
index 106a72c923ca..98457d7b2b23 100644
--- a/arch/x86/kvm/vmx/vmcs12.c
+++ b/arch/x86/kvm/vmx/vmcs12.c
@@ -73,6 +73,7 @@ const unsigned short vmcs12_field_offsets[] = {
FIELD(PAGE_FAULT_ERROR_CODE_MATCH, page_fault_error_code_match),
FIELD(CR3_TARGET_COUNT, cr3_target_count),
FIELD(VM_EXIT_CONTROLS, vm_exit_controls),
+ FIELD(SECONDARY_VM_EXIT_CONTROLS, secondary_vm_exit_controls),
FIELD(VM_EXIT_MSR_STORE_COUNT, vm_exit_msr_store_count),
FIELD(VM_EXIT_MSR_LOAD_COUNT, vm_exit_msr_load_count),
FIELD(VM_ENTRY_CONTROLS, vm_entry_controls),
diff --git a/arch/x86/kvm/vmx/vmcs12.h b/arch/x86/kvm/vmx/vmcs12.h
index 56fd150a6f24..1fe3ed9108aa 100644
--- a/arch/x86/kvm/vmx/vmcs12.h
+++ b/arch/x86/kvm/vmx/vmcs12.h
@@ -185,6 +185,7 @@ struct __packed vmcs12 {
u16 host_gs_selector;
u16 host_tr_selector;
u16 guest_pml_index;
+ u64 secondary_vm_exit_controls;
};
/*
@@ -360,6 +361,7 @@ 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(secondary_vm_exit_controls, 998);
}
extern const unsigned short vmcs12_field_offsets[];
diff --git a/arch/x86/kvm/x86.h b/arch/x86/kvm/x86.h
index 0ed91512b757..890b7a6554d5 100644
--- a/arch/x86/kvm/x86.h
+++ b/arch/x86/kvm/x86.h
@@ -66,7 +66,7 @@ void kvm_spurious_fault(void);
* associated feature that KVM supports for nested virtualization.
*/
#define KVM_FIRST_EMULATED_VMX_MSR MSR_IA32_VMX_BASIC
-#define KVM_LAST_EMULATED_VMX_MSR MSR_IA32_VMX_VMFUNC
+#define KVM_LAST_EMULATED_VMX_MSR MSR_IA32_VMX_EXIT_CTLS2
#define KVM_DEFAULT_PLE_GAP 128
#define KVM_VMX_DEFAULT_PLE_WINDOW 4096
--
2.46.2