From mboxrd@z Thu Jan 1 00:00:00 1970 From: Glauber Costa Subject: Re: [PATCH] Fix up pxe boot Date: Wed, 3 Sep 2008 16:27:00 -0300 Message-ID: <20080903192700.GA8000@poweredge.glommer> References: <1220303503-19413-1-git-send-email-glommer@redhat.com> <48BCFBB1.4090109@qumranet.com> <5d6222a80809020407l68f7ab87i6d2520c57c7ddeb3@mail.gmail.com> <48BD59D7.7000702@qumranet.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Glauber Costa , qemu-devel@nongnu.org, kvm@vger.kernel.org, aliguori@us.ibm.com, apevec@redhat.com, chrisw@sous-sol.org, Eduardo Habkost To: Avi Kivity Return-path: Received: from mx2.redhat.com ([66.187.237.31]:33947 "EHLO mx2.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752048AbYICTcD (ORCPT ); Wed, 3 Sep 2008 15:32:03 -0400 Content-Disposition: inline In-Reply-To: <48BD59D7.7000702@qumranet.com> Sender: kvm-owner@vger.kernel.org List-ID: On Tue, Sep 02, 2008 at 06:20:55PM +0300, Avi Kivity wrote: > Glauber Costa wrote: >> On Tue, Sep 2, 2008 at 5:39 AM, Avi Kivity wrote: >> >>> Glauber Costa wrote: >>> >>>> diff --git a/target-i386/op_helper.c b/target-i386/op_helper.c >>>> index 0b5fdc0..433aa3f 100644 >>>> --- a/target-i386/op_helper.c >>>> +++ b/target-i386/op_helper.c >>>> @@ -600,7 +600,7 @@ do {\ >>>> #define PUSHL(ssp, sp, sp_mask, val)\ >>>> {\ >>>> sp -= 4;\ >>>> - stl_kernel((ssp) + (sp & (sp_mask)), (val));\ >>>> + stl_kernel((uint32_t)((ssp) + (sp & (sp_mask))), (uint32_t)(val));\ >>>> } >>>> >>>> >>> Surly it is better to push this into the underlying virtual->physical >>> translation functions, so it applies everywhere? >>> >>> btw, the cast is wrong for x86-64, so it must be qualified for 32-bit >>> operating modes. >>> >> The tests were all done with x86_64. This is a PUSHL macro, so it's >> 32-bit anyway. >> A x86_64-only PUSHQ seems to do the right thing. >> >> > > Right. > > It's still odd to see this in an op helper rather than in somewhere generic. After a second look, here's what it seems to me: It's not in a generic place, such as ldl, because in general, we may want to grab a 32-bit value from a 64-bit address. This is perfectly valid. It's a specifity that the pop instruction, when not in long mode (manual says that in 64-bit mode no 32-bit operand is valid, but then again, qemu should use the POPQ macro), that ssp:sp may overflow, but we don't want it. It would be possible to do something more generic if we had a segment_to_linear() function, that returned the linear address, but we don't. Does it make more sense to you? > > -- > error compiling committee.c: too many arguments to function >