linux-kernel - Re: [patch 0/3] kvm tool: Serial emulation overhaul

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:	Mon, 12 Dec 2011 11:02:36 +0000
From:	Alan Cox <alan@...rguk.ukuu.org.uk>
To:	Sasha Levin <levinsasha928@...il.com>
Cc:	Thomas Gleixner <tglx@...utronix.de>, Ingo Molnar <mingo@...e.hu>,
	Pekka Enberg <penberg@...nel.org>,
	LKML <linux-kernel@...r.kernel.org>
Subject: Re: [patch 0/3] kvm tool: Serial emulation overhaul

> > You can emulate a chip with a 64byte or so FIFO. You can do I/O cycle
> > prediction in the kernel part and you can use the empty bit as a clue
> > (which is what most serial<->ethernet widgetry does).
> 
> The performance problems here aren't the same performance problems you
> have on real hardware. The problem here is that it costs 40k cycles for
> the guest to access the emulated chip.

How much of that 40K cycles is bouncing back and forth into emulation
layers and how much of it is the kernel trap ?
 
--
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/