linux-kernel - Re: [PATCH v5 11/11] KVM: x86: Disable Intel Processor Trace when VMXON in L1 guest

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Date:   Mon, 19 Mar 2018 10:05:15 +0100
From:   Paolo Bonzini <pbonzini@...hat.com>
To:     "Kang, Luwei" <luwei.kang@...el.com>,
        "kvm@...r.kernel.org" <kvm@...r.kernel.org>
Cc:     "tglx@...utronix.de" <tglx@...utronix.de>,
        "mingo@...hat.com" <mingo@...hat.com>,
        "hpa@...or.com" <hpa@...or.com>, "x86@...nel.org" <x86@...nel.org>,
        "rkrcmar@...hat.com" <rkrcmar@...hat.com>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "joro@...tes.org" <joro@...tes.org>
Subject: Re: [PATCH v5 11/11] KVM: x86: Disable Intel Processor Trace when
 VMXON in L1 guest

On 19/03/2018 08:31, Kang, Luwei wrote:
>>> +	if (pt_mode == PT_MODE_HOST_GUEST) {
>> This would be vmx_pt_supported(), but I think it's better to remove that function and just test pt_mode ==
>> PT_MODE_HOST_GUEST everywhere (or !=).
> Hi Paolo,
>     There have so many vmx_pt_supported() invoked in MSRs read/write (patch 9) patch and I think it can be replaced by  pt_mode check.
>     But I think this function need to be reserved in patch 5(cpuid emulation). What is your opinion?

Yes, the function pointer needs to stay.

Paolo