(dropping netdev and the visws list) On Thu, 2011-04-07 at 11:07 -0700, Jeremy Fitzhardinge wrote: > On 04/06/2011 11:58 PM, Ian Campbell wrote: > > On Wed, 2011-04-06 at 22:45 +0100, David Miller wrote: > >> From: Ian Campbell <Ian.Campbell@xxxxxxxxxxxxx> > >> Date: Mon, 4 Apr 2011 10:55:55 +0100 > >> > >>> You mean the "!X86_VISWS" I presume? It doesn't make sense to me either. > >> No, I think 32-bit x86 allmodconfig elides XEN because of it's X86_TSC dependency. > > TSC is a real dependency of the Xen interfaces. > > Not really. The TSC register is a requirement, but that's going to be > present on any CPU which can boot Xen. We don't need any of the > kernel's TSC machinery though. So why the Kconfig dependency then? In principal a kernel compiled for a non-TSC processor (which meets the other requirements for Xen, such as PAE support) will run just fine under Xen on a newer piece of hardware. Is there any downside to this patch (is X86_CMPXCHG in the same sort of boat?) 8<---------------------------------- >From 7204945696a927d281366f2a57baee37e2b43ca3 Mon Sep 17 00:00:00 2001 From: Ian Campbell <ijc@xxxxxxxxxxxxxx> Date: Fri, 8 Apr 2011 07:33:21 +0100 Subject: [PATCH] xen: remove Kconfig dependency on X86_TSC The TSC register is a requirement when running under Xen, but that's going to be present on any CPU which can boot Xen. We don't need any of the kernel's TSC machinery, since the usage is contained within the Xen interfaces, and therefore XEN does not need to depend on CONFIG_X86_TSC. Signed-off-by: Ian Campbell <ian.campbell@xxxxxxxxxx> --- arch/x86/xen/Kconfig | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-) diff --git a/arch/x86/xen/Kconfig b/arch/x86/xen/Kconfig index 1c7121b..ac69c5b 100644 --- a/arch/x86/xen/Kconfig +++ b/arch/x86/xen/Kconfig @@ -7,7 +7,7 @@ config XEN select PARAVIRT select PARAVIRT_CLOCK depends on X86_64 || (X86_32 && X86_PAE && !X86_VISWS) - depends on X86_CMPXCHG && X86_TSC + depends on X86_CMPXCHG help This is the Linux Xen port. Enabling this will allow the kernel to boot in a paravirtualized environment under the -- 1.7.4.1 _______________________________________________ Virtualization mailing list Virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/virtualization
