[PATCH v1 05/23] KVM: VMX: Initialize FRED VM entry/exit controls in vmcs_config

Xin Li
2023-11-08T19:00:28Z

Setup the global vmcs_config for FRED:
1) Add VM_ENTRY_LOAD_IA32_FRED to KVM_OPTIONAL_VMX_VM_ENTRY_CONTROLS to
have a FRED CPU load guest FRED MSRs from VMCS upon VM entry.
2) Add SECONDARY_VM_EXIT_SAVE_IA32_FRED to
KVM_OPTIONAL_VMX_SECONDARY_VM_EXIT_CONTROLS to have a FRED CPU save
guest FRED MSRs to VMCS during VM exit.
3) add SECONDARY_VM_EXIT_LOAD_IA32_FRED to
KVM_OPTIONAL_VMX_SECONDARY_VM_EXIT_CONTROLS to have a FRED CPU load
host FRED MSRs from VMCS during VM exit.

Also add sanity checks to make sure FRED VM entry/exit controls can be
set on a FRED CPU.

Tested-by: Shan Kang <shan.kang@intel.com>
Signed-off-by: Xin Li <xin3.li@intel.com>
---
arch/x86/include/asm/vmx.h | 3 +++
arch/x86/kvm/vmx/vmx.c | 19 ++++++++++++++++++-
arch/x86/kvm/vmx/vmx.h | 7 +++++--
3 files changed, 26 insertions(+), 3 deletions(-)

diff --git a/arch/x86/include/asm/vmx.h b/arch/x86/include/asm/vmx.h
index 4d4177ec802c..41796a733bc9 100644
--- a/arch/x86/include/asm/vmx.h
+++ b/arch/x86/include/asm/vmx.h
@@ -106,6 +106,8 @@
#define VM_EXIT_PT_CONCEAL_PIP 0x01000000
#define VM_EXIT_CLEAR_IA32_RTIT_CTL 0x02000000
#define VM_EXIT_ACTIVATE_SECONDARY_CONTROLS 0x80000000
+#define SECONDARY_VM_EXIT_SAVE_IA32_FRED 0x00000001
+#define SECONDARY_VM_EXIT_LOAD_IA32_FRED 0x00000002

#define VM_EXIT_ALWAYSON_WITHOUT_TRUE_MSR 0x00036dff

@@ -119,6 +121,7 @@
#define VM_ENTRY_LOAD_BNDCFGS 0x00010000
#define VM_ENTRY_PT_CONCEAL_PIP 0x00020000
#define VM_ENTRY_LOAD_IA32_RTIT_CTL 0x00040000
+#define VM_ENTRY_LOAD_IA32_FRED 0x00800000

#define VM_ENTRY_ALWAYSON_WITHOUT_TRUE_MSR 0x000011ff

diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index df769207cbe0..9186f41974ab 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -2694,10 +2694,27 @@ static int setup_vmcs_config(struct vmcs_config *vmcs_conf,
_vmexit_control &= ~x_ctrl;
}

- if (_vmexit_control & VM_EXIT_ACTIVATE_SECONDARY_CONTROLS)
+ if (_vmexit_control & VM_EXIT_ACTIVATE_SECONDARY_CONTROLS) {
_secondary_vmexit_control =
adjust_vmx_controls64(KVM_OPTIONAL_VMX_SECONDARY_VM_EXIT_CONTROLS,
MSR_IA32_VMX_EXIT_CTLS2);
+ if (cpu_feature_enabled(X86_FEATURE_FRED) &&
+ !(_secondary_vmexit_control & SECONDARY_VM_EXIT_SAVE_IA32_FRED &&
+ _secondary_vmexit_control & SECONDARY_VM_EXIT_LOAD_IA32_FRED)) {
+ pr_warn_once("FRED enabled but no VMX VM-Exit {SAVE,LOAD}_IA32_FRED controls: %llx\n",
+ _secondary_vmexit_control);
+ if (error_on_inconsistent_vmcs_config)
+ return -EIO;
+ }
+ }
+
+ if (cpu_feature_enabled(X86_FEATURE_FRED) &&
+ !(_vmentry_control & VM_ENTRY_LOAD_IA32_FRED)) {
+ pr_warn_once("FRED enabled but no VMX VM-Entry LOAD_IA32_FRED control: %x\n",
+ _vmentry_control);
+ if (error_on_inconsistent_vmcs_config)
+ return -EIO;
+ }

rdmsrl(MSR_IA32_VMX_BASIC, basic_msr);

diff --git a/arch/x86/kvm/vmx/vmx.h b/arch/x86/kvm/vmx/vmx.h
index 99a0f6783085..f8c02bd37069 100644
--- a/arch/x86/kvm/vmx/vmx.h
+++ b/arch/x86/kvm/vmx/vmx.h
@@ -480,7 +480,8 @@ static inline u8 vmx_get_rvi(void)
VM_ENTRY_LOAD_IA32_EFER | \
VM_ENTRY_LOAD_BNDCFGS | \
VM_ENTRY_PT_CONCEAL_PIP | \
- VM_ENTRY_LOAD_IA32_RTIT_CTL)
+ VM_ENTRY_LOAD_IA32_RTIT_CTL | \
+ VM_ENTRY_LOAD_IA32_FRED)

#define __KVM_REQUIRED_VMX_VM_EXIT_CONTROLS \
(VM_EXIT_SAVE_DEBUG_CONTROLS | \
@@ -506,7 +507,9 @@ static inline u8 vmx_get_rvi(void)
VM_EXIT_ACTIVATE_SECONDARY_CONTROLS)

#define KVM_REQUIRED_VMX_SECONDARY_VM_EXIT_CONTROLS (0)
-#define KVM_OPTIONAL_VMX_SECONDARY_VM_EXIT_CONTROLS (0)
+#define KVM_OPTIONAL_VMX_SECONDARY_VM_EXIT_CONTROLS \
+ (SECONDARY_VM_EXIT_SAVE_IA32_FRED | \
+ SECONDARY_VM_EXIT_LOAD_IA32_FRED)

#define KVM_REQUIRED_VMX_PIN_BASED_VM_EXEC_CONTROL \
(PIN_BASED_EXT_INTR_MASK | \
--
2.42.0