From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Yang, Sheng" Subject: Re: [PATCH] kvm: bios: end AP boot code execution in rombios Date: Mon, 18 Aug 2008 10:45:30 +0800 Message-ID: <200808181045.30451.sheng.yang@intel.com> References: <200807311043.20880.sheng.yang@intel.com> <1219012543$2777@local> <48A8DF67.90600@codemonkey.ws> Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Cc: Sebastian Herbszt , Avi Kivity , kvm@vger.kernel.org To: Anthony Liguori Return-path: Received: from mga09.intel.com ([134.134.136.24]:16713 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750858AbYHRCni (ORCPT ); Sun, 17 Aug 2008 22:43:38 -0400 In-Reply-To: <48A8DF67.90600@codemonkey.ws> Content-Disposition: inline Sender: kvm-owner@vger.kernel.org List-ID: On Monday 18 August 2008 10:33:11 Anthony Liguori wrote: > Sebastian Herbszt wrote: > > Jump to rombios before executing the halt loop. > > Why? More importantly, why is this specific to KVM? The bios copy AP boot up code to 0x10000 now in KVM, so it can be overwrite by userspace program like grub. I found it caused stop/cont/info cpus in grub corrupt AP. Please refer to " KVM: Fix exiting from HLT emulation with MP_STATE_HALTED" (well, I found the patch duplicated with Marcelo's patch later, then drop it...) Yeah, I am agree this should not be a specific issue to KVM. -- regards Yang, Sheng > > Regards, > > Anthony Liguori > > > Signed-off-by: Sebastian Herbszt > > > > diff -uNrp a/bios/rombios32start.S b/bios/rombios32start.S > > --- a/bios/rombios32start.S 2008-08-17 23:30:42.000000000 +0200 > > +++ b/bios/rombios32start.S 2008-08-17 23:38:42.000000000 +0200 > > @@ -40,6 +40,7 @@ _start: > > > > .code16 > > smp_ap_boot_code_start: > > + cli > > xor %ax, %ax > > mov %ax, %ds > > xor %eax, %eax > > @@ -60,6 +61,7 @@ smp_ap_boot_code_start: > > 12: > > > > incw CPU_COUNT_ADDR > > + ljmp $0xe000, $(1f-_start) > > 1: > > hlt > > jmp 1b > > > > -- > > To unsubscribe from this list: send the line "unsubscribe kvm" in > > the body of a message to majordomo@vger.kernel.org > > More majordomo info at > > http://vger.kernel.org/majordomo-info.html > > -- > To unsubscribe from this list: send the line "unsubscribe kvm" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html