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Message-ID: <aFrTAT-xTLmlwO5V@google.com>
Date: Tue, 24 Jun 2025 09:32:01 -0700
From: Sean Christopherson <seanjc@...gle.com>
To: "Xin Li (Intel)" <xin@...or.com>
Cc: pbonzini@...hat.com, kvm@...r.kernel.org, linux-doc@...r.kernel.org,
linux-kernel@...r.kernel.org, corbet@....net, tglx@...utronix.de,
mingo@...hat.com, bp@...en8.de, dave.hansen@...ux.intel.com, x86@...nel.org,
hpa@...or.com, andrew.cooper3@...rix.com, luto@...nel.org,
peterz@...radead.org, chao.gao@...el.com, xin3.li@...el.com
Subject: Re: [PATCH v4 14/19] KVM: VMX: Dump FRED context in dump_vmcs()
On Fri, Mar 28, 2025, Xin Li (Intel) wrote:
> From: Xin Li <xin3.li@...el.com>
>
> Add FRED related VMCS fields to dump_vmcs() to dump FRED context.
>
> Signed-off-by: Xin Li <xin3.li@...el.com>
> Signed-off-by: Xin Li (Intel) <xin@...or.com>
> Tested-by: Shan Kang <shan.kang@...el.com>
> ---
>
> 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 | 40 +++++++++++++++++++++++++++++++++-------
> 1 file changed, 33 insertions(+), 7 deletions(-)
>
> diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
> index c76015e1e3f8..03855d6690b2 100644
> --- a/arch/x86/kvm/vmx/vmx.c
> +++ b/arch/x86/kvm/vmx/vmx.c
> @@ -6462,7 +6462,7 @@ 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;
>
> @@ -6473,6 +6473,8 @@ 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);
> @@ -6519,6 +6521,16 @@ 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),
> + __rdmsr(MSR_IA32_FRED_RSP0),
There is no guarantee the vCPU's FRED_RSP is loaded in hardware at this point.
I think you need to use vmx_read_guest_fred_rsp0().
> + 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));
> @@ -6566,6 +6578,16 @@ 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,
Maybe add a helper in arch/x86/include/asm/fred.h to generate the desired RSP0?
Not sure it's worth doing that just for this code.
> + 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));
> @@ -6587,25 +6609,29 @@ 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",
> --
> 2.48.1
>
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