Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Date:   Wed, 13 Jan 2021 19:27:48 +0100
From:   Peter Zijlstra <peterz@infradead.org>
To:     Like Xu <like.xu@linux.intel.com>
Cc:     Paolo Bonzini <pbonzini@redhat.com>, eranian@google.com,
        kvm@vger.kernel.org, Ingo Molnar <mingo@redhat.com>,
        Sean Christopherson <seanjc@google.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        Vitaly Kuznetsov <vkuznets@redhat.com>,
        Wanpeng Li <wanpengli@tencent.com>,
        Jim Mattson <jmattson@google.com>,
        Joerg Roedel <joro@8bytes.org>,
        Andi Kleen <andi@firstfloor.org>,
        Kan Liang <kan.liang@linux.intel.com>, wei.w.wang@intel.com,
        luwei.kang@intel.com, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v3 04/17] perf: x86/ds: Handle guest PEBS overflow PMI
 and inject it to guest
Message-ID: <X/87pChioUE7hsK/@hirez.programming.kicks-ass.net>
References: <20210104131542.495413-1-like.xu@linux.intel.com>
 <20210104131542.495413-5-like.xu@linux.intel.com>
 <X/86UWuV/9yt14hQ@hirez.programming.kicks-ass.net>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <X/86UWuV/9yt14hQ@hirez.programming.kicks-ass.net>
Precedence: bulk

On Wed, Jan 13, 2021 at 07:22:09PM +0100, Peter Zijlstra wrote:
> Again; for the virt illiterate people here (me); why is it expensive to
> check guest DS?

Remember, you're trying to get someone that thinks virt is the devil's
work (me) to review virt patches. You get to spell things out in detail.