linux-kernel - Re: [PATCH v5 4/8] KVM: VMX: dump_vmcs() reports tertiary_exec

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Date:   Fri, 14 Jan 2022 12:19:53 +0800
From:   Zeng Guang <guang.zeng@...el.com>
To:     Sean Christopherson <seanjc@...gle.com>
Cc:     Paolo Bonzini <pbonzini@...hat.com>,
        Vitaly Kuznetsov <vkuznets@...hat.com>,
        Wanpeng Li <wanpengli@...cent.com>,
        Jim Mattson <jmattson@...gle.com>,
        Joerg Roedel <joro@...tes.org>,
        "kvm@...r.kernel.org" <kvm@...r.kernel.org>,
        Dave Hansen <dave.hansen@...ux.intel.com>,
        "Luck, Tony" <tony.luck@...el.com>,
        Kan Liang <kan.liang@...ux.intel.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        "H. Peter Anvin" <hpa@...or.com>,
        Kim Phillips <kim.phillips@....com>,
        Jarkko Sakkinen <jarkko@...nel.org>,
        Jethro Beekman <jethro@...tanix.com>,
        "Huang, Kai" <kai.huang@...el.com>,
        "x86@...nel.org" <x86@...nel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "Hu, Robert" <robert.hu@...el.com>,
        "Gao, Chao" <chao.gao@...el.com>,
        Robert Hoo <robert.hu@...ux.intel.com>
Subject: Re: [PATCH v5 4/8] KVM: VMX: dump_vmcs() reports
 tertiary_exec_control field as well

On 1/14/2022 5:03 AM, Sean Christopherson wrote:
> On Fri, Dec 31, 2021, Zeng Guang wrote:
>> From: Robert Hoo <robert.hu@...ux.intel.com>
>>
>> Add tertiary_exec_control field report in dump_vmcs()
>>
>> Signed-off-by: Robert Hoo <robert.hu@...ux.intel.com>
>> Signed-off-by: Zeng Guang <guang.zeng@...el.com>
>> ---
>>   arch/x86/kvm/vmx/vmx.c | 9 +++++++--
>>   1 file changed, 7 insertions(+), 2 deletions(-)
>>
>> diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
>> index fb0f600368c6..5716db9704c0 100644
>> --- a/arch/x86/kvm/vmx/vmx.c
>> +++ b/arch/x86/kvm/vmx/vmx.c
>> @@ -5729,6 +5729,7 @@ 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 = 0;
>>   	unsigned long cr4;
>>   	int efer_slot;
>>   
>> @@ -5746,6 +5747,9 @@ void dump_vmcs(struct kvm_vcpu *vcpu)
>>   	if (cpu_has_secondary_exec_ctrls())
>>   		secondary_exec_control = vmcs_read32(SECONDARY_VM_EXEC_CONTROL);
> Gah, this (not your) code is silly.  I had to go look at the full source to see
> that secondary_exec_control isn't accessed uninitialized...
>
> Can you opportunistically tweak it to the below, and use the same patter for the
> tertiary controls?
>
> 	if (cpu_has_secondary_exec_ctrls())
> 		secondary_exec_control = vmcs_read32(SECONDARY_VM_EXEC_CONTROL);
> 	else
> 		secondary_exec_control = 0;
Actually secondary_exec_control did zero initialization ahead .
yah, it's better to unify the code for both.
>>   
>> +	if (cpu_has_tertiary_exec_ctrls())
>> +		tertiary_exec_control = vmcs_read64(TERTIARY_VM_EXEC_CONTROL);
>> +
>>   	pr_err("VMCS %p, last attempted VM-entry on CPU %d\n",
>>   	       vmx->loaded_vmcs->vmcs, vcpu->arch.last_vmentry_cpu);
>>   	pr_err("*** Guest State ***\n");
>> @@ -5844,8 +5848,9 @@ void dump_vmcs(struct kvm_vcpu *vcpu)
>>   		vmx_dump_msrs("host autoload", &vmx->msr_autoload.host);
>>   
>>   	pr_err("*** Control State ***\n");
>> -	pr_err("PinBased=%08x CPUBased=%08x SecondaryExec=%08x\n",
>> -	       pin_based_exec_ctrl, cpu_based_exec_ctrl, secondary_exec_control);
>> +	pr_err("PinBased=0x%08x CPUBased=0x%08x SecondaryExec=0x%08x TertiaryExec=0x%016llx\n",
>> +	       pin_based_exec_ctrl, cpu_based_exec_ctrl, secondary_exec_control,
>> +	       tertiary_exec_control);
> Can you provide a sample dump?  It's hard to visualize the output, e.g. I'm worried
> this will be overly log and harder to read than putting tertiary controls on their
> own line.

Sample dump here.
  
*** Control State ***

  PinBased=0x000000ff CPUBased=0xb5a26dfa SecondaryExec=0x061037eb 
TertiaryExec=0x0000000000000010
  EntryControls=0000d1ff ExitControls=002befff
  ExceptionBitmap=00060042 PFECmask=00000000 PFECmatch=00000000
  VMEntry: intr_info=00000000 errcode=00000000 ilen=00000000
  VMExit: intr_info=00000000 errcode=00000000 ilen=00000003
          reason=00000030 qualification=0000000000000784
>>   	pr_err("EntryControls=%08x ExitControls=%08x\n", vmentry_ctl, vmexit_ctl);
>>   	pr_err("ExceptionBitmap=%08x PFECmask=%08x PFECmatch=%08x\n",
>>   	       vmcs_read32(EXCEPTION_BITMAP),
>> -- 
>> 2.27.0
>>