Re: [PATCH v2 15/25] KVM: VMX: Dump FRED context in dump_vmcs()

[Chao Gao]

On Thu, Feb 08, 2024 at 01:26:35AM +0800, Xin Li wrote:
>Add FRED related VMCS fields to dump_vmcs() to have it dump FRED context.
>
>Signed-off-by: Xin Li <xin3.li@xxxxxxxxx>
>Tested-by: Shan Kang <shan.kang@xxxxxxxxx>
>---
>
>Change since v1:
>* 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 | 46 +++++++++++++++++++++++++++++++++++-------
> 1 file changed, 39 insertions(+), 7 deletions(-)
>
>diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
>index a484b9ac2400..e3409607122d 100644
>--- a/arch/x86/kvm/vmx/vmx.c
>+++ b/arch/x86/kvm/vmx/vmx.c
>@@ -6392,7 +6392,7 @@ 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;
>
>@@ -6403,6 +6403,8 @@ 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);
>@@ -6449,6 +6451,19 @@ 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);
>+#ifdef CONFIG_X86_64
>+       if (kvm_is_fred_enabled(vcpu)) {

FRED MSRs are accessible even if CR4.FRED isn't set and #ifdef is ugly, I think
you can simply do:

	if (vmentry_ctrl & VM_ENTRY_LOAD_IA32_FRED)

just like below handling for EFER/PAT etc.

>+               pr_err("FRED guest: config=0x%016llx, stack levels=0x%016llx\n"
>+                      "RSP0=0x%016lx, RSP1=0x%016llx\n"
>+                      "RSP2=0x%016llx, RSP3=0x%016llx\n",
>+                      vmcs_read64(GUEST_IA32_FRED_CONFIG),
>+                      vmcs_read64(GUEST_IA32_FRED_STKLVLS),
>+                      read_msr(MSR_IA32_FRED_RSP0),
>+                      vmcs_read64(GUEST_IA32_FRED_RSP1),
>+                      vmcs_read64(GUEST_IA32_FRED_RSP2),
>+                      vmcs_read64(GUEST_IA32_FRED_RSP3));
>+       }
>+#endif
>        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));
>@@ -6496,6 +6511,19 @@ 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));
>+#ifdef CONFIG_X86_64
>+       if (kvm_cpu_cap_has(X86_FEATURE_FRED)) {

ditto

>+               pr_err("FRED host: config=0x%016llx, stack levels=0x%016llx\n"
>+                      "RSP0=0x%016llx, RSP1=0x%016llx\n"
>+                      "RSP2=0x%016llx, RSP3=0x%016llx\n",
>+                      vmcs_read64(HOST_IA32_FRED_CONFIG),
>+                      vmcs_read64(HOST_IA32_FRED_STKLVLS),
>+                      vmx->msr_host_fred_rsp0,
>+                      vmcs_read64(HOST_IA32_FRED_RSP1),
>+                      vmcs_read64(HOST_IA32_FRED_RSP2),
>+                      vmcs_read64(HOST_IA32_FRED_RSP3));
>+       }
>+#endif
>        pr_err("CR0=%016lx CR3=%016lx CR4=%016lx\n",
>               vmcs_readl(HOST_CR0), vmcs_readl(HOST_CR3),
>               vmcs_readl(HOST_CR4));
>@@ -6517,25 +6545,29 @@ 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",

s/event data/event_data/

>               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);

again, it is better to check some vmexit/vmentry ctrl bit.

>        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",

s/event data/event_data/

>               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);

ditto