linux-kernel - Re: [PATCH 2/3] KVM: improve trace events of vmexit/mmio/ioport

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Tue, 17 Jan 2012 09:55:58 -0200
From:	Marcelo Tosatti <mtosatti@...hat.com>
To:	Xiao Guangrong <xiaoguangrong@...ux.vnet.ibm.com>
Cc:	Avi Kivity <avi@...hat.com>, LKML <linux-kernel@...r.kernel.org>,
	KVM <kvm@...r.kernel.org>
Subject: Re: [PATCH 2/3] KVM: improve trace events of vmexit/mmio/ioport

On Tue, Jan 17, 2012 at 10:28:11AM +0800, Xiao Guangrong wrote:
> On 01/16/2012 05:38 PM, Avi Kivity wrote:
> 
> > On 01/16/2012 11:32 AM, Xiao Guangrong wrote:
> >> - trace vcpu_id for these events
> > 
> > We can infer the vcpu id from the kvm_entry tracepoints, no?
> > 
> 
> 
> Thanks for your review, Avi!
> 
> Hmm. i think it is hard to do since the vcpu thread can be scheduled
> anytime, one example is as follow:
> 
> CPU 0
> 
> kvm_entry vcpu 0
> ......
> kvm_entry vcpu 1
> ......
> event1 occurs
> ......
> event2 occurs
> 
> It is hard to know the event belong to which kvm_entry?
> 
> >> - add kvm_mmio_done to trace the time when mmio/ioport emulation is completed
> > 
> > ditto?
> > 
> 
> 
> I think is ok to get the event end time by using kvm_entry.
> 
> > 
> > Relying on the existing tracepoints will make the tool work on older
> > kernels.
> > 
> 
> 
> We can drop all new events, but unfortunately, the information of the origin
> tracepoints is not enough, at least vcpu_id need be traced in theses events
> to match its events. Yes?

Yes, and if you don't add completed events, you'll have to use kvm_entry 
whose collection adds a lot of overhead.

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/