From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752642AbdHVTuL (ORCPT ); Tue, 22 Aug 2017 15:50:11 -0400 Received: from mail-wr0-f181.google.com ([209.85.128.181]:36766 "EHLO mail-wr0-f181.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751739AbdHVTuJ (ORCPT ); Tue, 22 Aug 2017 15:50:09 -0400 MIME-Version: 1.0 In-Reply-To: References: <1501684690-211093-1-git-send-email-dplotnikov@virtuozzo.com> From: John Stultz Date: Tue, 22 Aug 2017 12:50:06 -0700 Message-ID: Subject: Re: [PATCH v4 00/10] make L2's kvm-clock stable, get rid of pvclock_gtod_copy in KVM To: Denis Plotnikov Cc: Paolo Bonzini , Radim Krcmar , kvm list , Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , lkml , "x86@kernel.org" , rkagan@virtuozzo.com, den@virtuozzo.com, Marcelo Tosatti Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Aug 21, 2017 at 1:40 AM, Denis Plotnikov wrote: > ping! > I still don't feel my questions have been well answered. Its really not clear to me why, in order to allow the level-2 guest to use a vdso that the answer is to export more data through the entire stack rather then to make the kvmclock to be usable from the vsyscall. So far for a problem statement, all I've got is: "However, when using nested virtualization you have L0: bare-metal hypervisor (uses TSC) L1: nested hypervisor (uses kvmclock, can use vsyscall) L2: nested guest and L2 cannot use vsyscall because it is not using the TSC." Which is a start but doesn't really make it clear why the proposed solution is best/necessary. thanks -john