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Date:   Thu, 3 May 2018 15:13:01 +0300
From:   Alexander Shishkin <alexander.shishkin@linux.intel.com>
To:     "Kang, Luwei" <luwei.kang@intel.com>
Cc:     Alexander Shishkin <alexander.shishkin@linux.intel.com>,
        "kvm@vger.kernel.org" <kvm@vger.kernel.org>,
        "tglx@linutronix.de" <tglx@linutronix.de>,
        "mingo@redhat.com" <mingo@redhat.com>,
        "hpa@zytor.com" <hpa@zytor.com>, "x86@kernel.org" <x86@kernel.org>,
        "pbonzini@redhat.com" <pbonzini@redhat.com>,
        "rkrcmar@redhat.com" <rkrcmar@redhat.com>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "joro@8bytes.org" <joro@8bytes.org>,
        "peterz@infradead.org" <peterz@infradead.org>,
        "chao.p.peng@linux.intel.com" <chao.p.peng@linux.intel.com>
Subject: Re: [PATCH v7 05/13] perf/x86/intel/pt: Introduce a new function to
 get capability of Intel PT
Message-ID: <20180503121301.nlbm4cotbv26tc7l@um.fi.intel.com>
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On Thu, May 03, 2018 at 11:04:52AM +0000, Kang, Luwei wrote:
> > > New function __pt_cap_get() will be invoked in KVM to check if a
> > > specific capability is availiable in KVM guest.
> > > Another function pt_cap_get() can only check the hardware capabilities
> > > but this may different with KVM guest because some features may not be
> > > exposed to guest.
> > 
> > Do we really need both in KVM?
> 
> Yes, KVM need get host capability to estimate if can expose this feature
> to guest

Can you elaborate on this, what information do we need besides
MSR_IA32_VMX_MISC[14]?

Thanks,
--
Alex