[PATCH v8 15/21] KVM: VMX: Dump FRED context in dump_vmcs()

Xin Li (Intel)
2025-10-14T01:11:11Z

Add FRED related VMCS fields to dump_vmcs() to dump FRED context.

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 v5:
* Read guest FRED RSP0 with vmx_read_guest_fred_rsp0() (Sean).
* Add TB from Xuelian Guo.

Change in v3:
* Use (vmentry_ctrl & VM_ENTRY_LOAD_IA32_FRED) instead of is_fred_enabled()
(Chao Gao).

Changes in v2:
* Use kvm_cpu_cap_has() instead of cpu_feature_enabled() (Chao Gao).
* Dump guest FRED states only if guest has FRED enabled (Nikolay Borisov).
---
arch/x86/kvm/vmx/vmx.c | 43 +++++++++++++++++++++++++++++++++++-------
1 file changed, 36 insertions(+), 7 deletions(-)

diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 2379a0433816..b92fc81af5c4 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -1398,6 +1398,9 @@ static void vmx_write_guest_fred_rsp0(struct vcpu_vmx *vmx, u64 data)
vmx_write_guest_host_msr(vmx, MSR_IA32_FRED_RSP0, data,
&vmx->msr_guest_fred_rsp0);
}
+#else
+/* Make sure it builds on 32-bit */
+static u64 vmx_read_guest_fred_rsp0(struct vcpu_vmx *vmx) { return 0; }
#endif

static void grow_ple_window(struct kvm_vcpu *vcpu)
@@ -6441,7 +6444,7 @@ void dump_vmcs(struct kvm_vcpu *vcpu)
struct vcpu_vmx *vmx = to_vmx(vcpu);
u32 vmentry_ctl, vmexit_ctl;
u32 cpu_based_exec_ctrl, pin_based_exec_ctrl, secondary_exec_control;
- u64 tertiary_exec_control;
+ u64 tertiary_exec_control, secondary_vmexit_ctl;
unsigned long cr4;
int efer_slot;

@@ -6452,6 +6455,8 @@ void dump_vmcs(struct kvm_vcpu *vcpu)

vmentry_ctl = vmcs_read32(VM_ENTRY_CONTROLS);
vmexit_ctl = vmcs_read32(VM_EXIT_CONTROLS);
+ secondary_vmexit_ctl = cpu_has_secondary_vmexit_ctrls() ?
+ vmcs_read64(SECONDARY_VM_EXIT_CONTROLS) : 0;
cpu_based_exec_ctrl = vmcs_read32(CPU_BASED_VM_EXEC_CONTROL);
pin_based_exec_ctrl = vmcs_read32(PIN_BASED_VM_EXEC_CONTROL);
cr4 = vmcs_readl(GUEST_CR4);
@@ -6498,6 +6503,16 @@ void dump_vmcs(struct kvm_vcpu *vcpu)
vmx_dump_sel("LDTR:", GUEST_LDTR_SELECTOR);
vmx_dump_dtsel("IDTR:", GUEST_IDTR_LIMIT);
vmx_dump_sel("TR: ", GUEST_TR_SELECTOR);
+ if (vmentry_ctl & VM_ENTRY_LOAD_IA32_FRED)
+ pr_err("FRED guest: config=0x%016llx, stack_levels=0x%016llx\n"
+ "RSP0=0x%016llx, RSP1=0x%016llx\n"
+ "RSP2=0x%016llx, RSP3=0x%016llx\n",
+ vmcs_read64(GUEST_IA32_FRED_CONFIG),
+ vmcs_read64(GUEST_IA32_FRED_STKLVLS),
+ vmx_read_guest_fred_rsp0(vmx),
+ vmcs_read64(GUEST_IA32_FRED_RSP1),
+ vmcs_read64(GUEST_IA32_FRED_RSP2),
+ vmcs_read64(GUEST_IA32_FRED_RSP3));
efer_slot = vmx_find_loadstore_msr_slot(&vmx->msr_autoload.guest, MSR_EFER);
if (vmentry_ctl & VM_ENTRY_LOAD_IA32_EFER)
pr_err("EFER= 0x%016llx\n", vmcs_read64(GUEST_IA32_EFER));
@@ -6549,6 +6564,16 @@ void dump_vmcs(struct kvm_vcpu *vcpu)
vmcs_readl(HOST_TR_BASE));
pr_err("GDTBase=%016lx IDTBase=%016lx\n",
vmcs_readl(HOST_GDTR_BASE), vmcs_readl(HOST_IDTR_BASE));
+ if (vmexit_ctl & SECONDARY_VM_EXIT_LOAD_IA32_FRED)
+ pr_err("FRED host: config=0x%016llx, stack_levels=0x%016llx\n"
+ "RSP0=0x%016lx, RSP1=0x%016llx\n"
+ "RSP2=0x%016llx, RSP3=0x%016llx\n",
+ vmcs_read64(HOST_IA32_FRED_CONFIG),
+ vmcs_read64(HOST_IA32_FRED_STKLVLS),
+ (unsigned long)task_stack_page(current) + THREAD_SIZE,
+ vmcs_read64(HOST_IA32_FRED_RSP1),
+ vmcs_read64(HOST_IA32_FRED_RSP2),
+ vmcs_read64(HOST_IA32_FRED_RSP3));
pr_err("CR0=%016lx CR3=%016lx CR4=%016lx\n",
vmcs_readl(HOST_CR0), vmcs_readl(HOST_CR3),
vmcs_readl(HOST_CR4));
@@ -6574,25 +6599,29 @@ void dump_vmcs(struct kvm_vcpu *vcpu)
pr_err("*** Control State ***\n");
pr_err("CPUBased=0x%08x SecondaryExec=0x%08x TertiaryExec=0x%016llx\n",
cpu_based_exec_ctrl, secondary_exec_control, tertiary_exec_control);
- pr_err("PinBased=0x%08x EntryControls=%08x ExitControls=%08x\n",
- pin_based_exec_ctrl, vmentry_ctl, vmexit_ctl);
+ pr_err("PinBased=0x%08x EntryControls=0x%08x\n",
+ pin_based_exec_ctrl, vmentry_ctl);
+ pr_err("ExitControls=0x%08x SecondaryExitControls=0x%016llx\n",
+ vmexit_ctl, secondary_vmexit_ctl);
pr_err("ExceptionBitmap=%08x PFECmask=%08x PFECmatch=%08x\n",
vmcs_read32(EXCEPTION_BITMAP),
vmcs_read32(PAGE_FAULT_ERROR_CODE_MASK),
vmcs_read32(PAGE_FAULT_ERROR_CODE_MATCH));
- pr_err("VMEntry: intr_info=%08x errcode=%08x ilen=%08x\n",
+ pr_err("VMEntry: intr_info=%08x errcode=%08x ilen=%08x event_data=%016llx\n",
vmcs_read32(VM_ENTRY_INTR_INFO_FIELD),
vmcs_read32(VM_ENTRY_EXCEPTION_ERROR_CODE),
- vmcs_read32(VM_ENTRY_INSTRUCTION_LEN));
+ vmcs_read32(VM_ENTRY_INSTRUCTION_LEN),
+ kvm_cpu_cap_has(X86_FEATURE_FRED) ? vmcs_read64(INJECTED_EVENT_DATA) : 0);
pr_err("VMExit: intr_info=%08x errcode=%08x ilen=%08x\n",
vmcs_read32(VM_EXIT_INTR_INFO),
vmcs_read32(VM_EXIT_INTR_ERROR_CODE),
vmcs_read32(VM_EXIT_INSTRUCTION_LEN));
pr_err(" reason=%08x qualification=%016lx\n",
vmcs_read32(VM_EXIT_REASON), vmcs_readl(EXIT_QUALIFICATION));
- pr_err("IDTVectoring: info=%08x errcode=%08x\n",
+ pr_err("IDTVectoring: info=%08x errcode=%08x event_data=%016llx\n",
vmcs_read32(IDT_VECTORING_INFO_FIELD),
- vmcs_read32(IDT_VECTORING_ERROR_CODE));
+ vmcs_read32(IDT_VECTORING_ERROR_CODE),
+ kvm_cpu_cap_has(X86_FEATURE_FRED) ? vmcs_read64(ORIGINAL_EVENT_DATA) : 0);
pr_err("TSC Offset = 0x%016llx\n", vmcs_read64(TSC_OFFSET));
if (secondary_exec_control & SECONDARY_EXEC_TSC_SCALING)
pr_err("TSC Multiplier = 0x%016llx\n",
--
2.51.0