From mboxrd@z Thu Jan 1 00:00:00 1970 From: Zachary Amsden Subject: Re: [patch] paravirt: VDSO page is essential Date: Mon, 05 Mar 2007 12:42:25 -0800 Message-ID: <45EC80B1.8030901@vmware.com> References: <20070305120631.GA14105@elte.hu> <1173101297.26165.39.camel@localhost.localdomain> <20070305143437.GF22829@bingen.suse.de> <45EC796D.5050705@vmware.com> <20070305201957.GA733@elte.hu> Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Return-path: In-Reply-To: <20070305201957.GA733@elte.hu> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: virtualization-bounces@lists.osdl.org Errors-To: virtualization-bounces@lists.osdl.org To: Ingo Molnar Cc: virtualization , Andrew Morton , Roland McGrath , linux-kernel@vger.kernel.org List-Id: virtualization@lists.linuxfoundation.org Ingo Molnar wrote: > there's no need to disable the VDSO for old userspace ... > = Well, apart from the obvious question to which nobody actually knows the = answer, (how many people run old user space that required = CONFIG_COMPAT_VDSO), what do you think of reversing the boot option? vdso=3Denabled (default - turn on VDSO on normal boots) vdso=3Ddisabled (turn off VDSO unconditionally) [vdso=3Dcompat] (default for COMPAT_VDSO - keep VDSO only when mapped at = compat location. Note the option is not required to be implemented = because it is logically implied from vdso=3Denabled && COMPAT_VDSO and the = default boot behavior) vdso=3Dforce (keep VDSO even when moved to a new location and COMPAT_VDSO = is enabled). In our case, installing VMware tools in the guest would then detect if = userspace supports VDSO or if it requires COMPAT_VDSO and would then set = boot parameters for the kernel appropriately. And the native boot and = kvm paravirt-ops boot are completely unaffected. Zach