Re: [patch] paravirt: VDSO page is essential

Andi Kleen
2007-03-05T13:27:52Z

On Mon, Mar 05, 2007 at 01:06:31PM +0100, Ingo Molnar wrote:
> Subject: [patch] paravirt: VDSO page is essential
> From: Ingo Molnar <mingo@elte.hu>
>
> commit 3bbf54725467d604698721384d858b5983b87e8f disables the VDSO for
> CONFIG_PARAVIRT kernels. This #ifdeffery was a bad change: the VDSO is

Well it was the change that made my test machine (with SUSE 9.0 userland)
work with CONFIG_PARAVIRT on. If you have a better solution please post
it.

> an essential component of Linux, and this change forces all of them to
> use int $0x80 - including sane ones like KVM. (If a hypervisor does not
> handle the VDSO properly then it can work things around via the vdso=0

No hypervisor involved, just CONFIG_PARAVIRT=y on bare hardware.

> boot option. Or CONFIG_PARAVIRT should not have been merged. But in any
> case, it is a basic taste issue: we DO NOT #ifdef around core features
> like this!)

We set sensible defaults for full backwards compatibility.

-Andi