From mboxrd@z Thu Jan  1 00:00:00 1970
From: Avi Kivity <avi@redhat.com>
Subject: Re: [PATCH v1 0/5] KVM in-guest performance monitoring
Date: Thu, 12 May 2011 17:45:59 +0300
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Cc: Jan Kiszka <jan.kiszka@siemens.com>, linux-kernel@vger.kernel.org,
	kvm@vger.kernel.org, Ingo Molnar <mingo@elte.hu>,
	Peter Zijlstra <a.p.zijlstra@chello.nl>,
	Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
To: Joerg Roedel <joro@8bytes.org>
Return-path: <linux-kernel-owner@vger.kernel.org>
In-Reply-To: <4DCBF0B7.7080102@redhat.com>
Sender: linux-kernel-owner@vger.kernel.org
List-Id: kvm.vger.kernel.org

On 05/12/2011 05:37 PM, Avi Kivity wrote:
>
> I've considered something similar for mmio - use hypercalls for 
> ordinary mmio to avoid calling into the emulator - but virtio uses pio 
> which isn't emulated and we don't have massive consumers of mmio 
> (except perhaps hpet).

Say,

enum {
    KVM_OP_MMIO_READ = 1,
    KVM_OP_MMIO_WRITE = 2,
    KVM_OP_PIO_READ = 3,
    KVM_OP_PIO_WRITE = 4,
    KVM_OP_MSR_READ = 5,
    KVM_OP_MSR_WRITE = 6,
    KVM_OP_HLT = 7, /* so we can program the apic timer and sleep */
}

struct kvm_batch_op {
     u8 op;
     u8 result;
     u8 size;
     u8 reserved[5];
     u64 address;
     u64 data;
};

int kvm_batch(int nr, u64 kvm_batch_op_phys);

This is really repeating Xen PV though (different ops), not sure it's 
worth the intrusiveness.

-- 
error compiling committee.c: too many arguments to function