From mboxrd@z Thu Jan 1 00:00:00 1970 From: Konrad Rzeszutek Wilk Subject: Re: [PATCH 2/2] KVM: VMX: Add Force Emulation Prefix for "emulate the next instruction" Date: Tue, 27 Mar 2018 01:18:40 -0400 Message-ID: <20180327051840.GF16974@char.us.oracle.com> References: <1522116735-4861-1-git-send-email-wanpengli@tencent.com> <1522116735-4861-3-git-send-email-wanpengli@tencent.com> <20180327044020.GB16974@char.us.oracle.com> <20180327045558.GC16974@char.us.oracle.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: LKML , kvm , Paolo Bonzini , Radim =?utf-8?B?S3LEjW3DocWZ?= , Andrew Cooper To: Wanpeng Li Return-path: Content-Disposition: inline In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org List-Id: kvm.vger.kernel.org On Tue, Mar 27, 2018 at 01:03:15PM +0800, Wanpeng Li wrote: > 2018-03-27 12:55 GMT+08:00 Konrad Rzeszutek Wilk : > > On Tue, Mar 27, 2018 at 12:40:20AM -0400, Konrad Rzeszutek Wilk wrote: > >> On Mon, Mar 26, 2018 at 07:12:15PM -0700, Wanpeng Li wrote: > >> > From: Wanpeng Li > >> > > >> > This patch introduces a Force Emulation Prefix (ud2a; .ascii "kvm") for > >> > "emulate the next instruction", the codes will be executed by emulator > >> > instead of processor, for testing purposes. > >> > >> Can you expand a bit ? Why do you want this in KVM in the first place? > > Please refer to the original discussion(Force Emulation Prefix part). > https://lkml.org/lkml/2018/3/22/220 That really should be part massaged in this patch as part of the description. > > >> Should this be controlled by a boolean parameter? > > > > .. per guest. That is instead of a global one, have a per guest one? > > As Paolo pointed out offline: > > Testing without the hacks being done by emulator.flat (TLB mismatch between instructions and data). And also this above. > I think a global module is enough for testing. If so, perhaps have it wrapped with #ifdef DEBUG? No need to put code gadgets that won't be utilized 99% of time. > > Regards, > Wanpeng Li