From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: [RFC PATCH v3 0/3] Add segment limit checks to emulator Date: Sun, 25 Jul 2010 11:55:47 +0300 Message-ID: <4C4BFC13.8080907@redhat.com> References: <1278888970-2936-1-git-send-email-m.gamal005@gmail.com> <4C3AB59B.60705@redhat.com> <4C3B14E2.8050404@redhat.com> <20100724154522.GA13246@morn.localdomain> <20100724161630.GA15361@morn.localdomain> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: Mohammed Gamal , kvm@vger.kernel.org, seabios@seabios.org To: "Kevin O'Connor" Return-path: Received: from mx1.redhat.com ([209.132.183.28]:12805 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751504Ab0GYI4L (ORCPT ); Sun, 25 Jul 2010 04:56:11 -0400 In-Reply-To: <20100724161630.GA15361@morn.localdomain> Sender: kvm-owner@vger.kernel.org List-ID: On 07/24/2010 07:16 PM, Kevin O'Connor wrote: > On Sat, Jul 24, 2010 at 11:45:22AM -0400, Kevin O'Connor wrote: >> On Mon, Jul 12, 2010 at 04:13:06PM +0300, Avi Kivity wrote: >>> Does SeaBIOS use big real mode now? >> SeaBIOS calls option roms in big real mode. This is required by the >> relevant specs. >> >> See the transition16big function in src/romlayout.S. It briefly jumps >> to an address at 0xffxxx during the transition to real-mode. At a >> quick glance, it looks like it could probably be changed to not use a >> code address>64K. > I put together a SeaBIOS patch so it does not use code addresses>64K > in big real mode - in case anyone wants to test it. Note, this only > reduces the use of code addresses>64K - SeaBIOS will still try to use > data addresses>64K (eg, in option rom PMM code). > What conditions are needed to trigger this path? This can't occur under normal operation, since it will fail badly with kvm on Intel. > -Kevin > > > diff --git a/src/misc.c b/src/misc.c > index 354df87..108c332 100644 > --- a/src/misc.c > +++ b/src/misc.c > @@ -156,8 +156,8 @@ u64 rombios32_gdt[] VAR16VISIBLE __aligned(8) = { > GDT_LIMIT(BUILD_BIOS_SIZE-1) | GDT_CODE | GDT_BASE(BUILD_BIOS_ADDR), > // 16 bit data segment base=0x0 limit=0xffff (SEG32_MODE16_DS) > GDT_LIMIT(0x0ffff) | GDT_DATA, > - // 16 bit code segment base=0 limit=0xffffffff (SEG32_MODE16BIG_CS) > - GDT_LIMIT(0xfffff) | GDT_CODE | GDT_G, > + // 16 bit code segment base=0xf0000 limit=0xffffffff (SEG32_MODE16BIG_CS) > + GDT_LIMIT(0xfffff) | GDT_CODE | GDT_G | GDT_BASE(BUILD_BIOS_ADDR), > // 16 bit data segment base=0 limit=0xffffffff (SEG32_MODE16BIG_DS) > GDT_LIMIT(0xfffff) | GDT_DATA | GDT_G, > }; > diff --git a/src/romlayout.S b/src/romlayout.S > index 54e5a4d..a469596 100644 > --- a/src/romlayout.S > +++ b/src/romlayout.S > @@ -105,7 +105,7 @@ transition16big: > movw %ax, %fs > movw %ax, %gs > > - ljmpl $SEG32_MODE16BIG_CS, $(BUILD_BIOS_ADDR + 1f) > + ljmpw $SEG32_MODE16BIG_CS, $1f > > .code16gcc > 1: > -- > 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 -- error compiling committee.c: too many arguments to function