From patchwork Wed Oct 19 00:20:14 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kevin O'Connor X-Patchwork-Id: 9383375 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 2CC73607D0 for ; Wed, 19 Oct 2016 00:20:43 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 1A4BC29757 for ; Wed, 19 Oct 2016 00:20:43 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 097D729760; Wed, 19 Oct 2016 00:20:43 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.8 required=2.0 tests=BAYES_00,DKIM_SIGNED, RCVD_IN_DNSWL_HI,T_DKIM_INVALID autolearn=ham version=3.3.1 Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 81691296BE for ; Wed, 19 Oct 2016 00:20:42 +0000 (UTC) Received: from localhost ([::1]:44587 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bweca-0000xv-2h for patchwork-qemu-devel@patchwork.kernel.org; Tue, 18 Oct 2016 20:20:40 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:39266) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bwecI-0000xo-Lb for qemu-devel@nongnu.org; Tue, 18 Oct 2016 20:20:23 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1bwecD-0002SN-84 for qemu-devel@nongnu.org; Tue, 18 Oct 2016 20:20:22 -0400 Received: from mail-qk0-x243.google.com ([2607:f8b0:400d:c09::243]:35840) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1bwecD-0002RV-2d for qemu-devel@nongnu.org; Tue, 18 Oct 2016 20:20:17 -0400 Received: by mail-qk0-x243.google.com with SMTP id z190so725259qkc.3 for ; Tue, 18 Oct 2016 17:20:16 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=koconnor-net.20150623.gappssmtp.com; s=20150623; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=U+p525YWABryG+bBf73FqTBHe5a2GjjjRgX/prfX3D4=; b=hiBFNih99LxzAgLHz5zFUQrWpOgSyfQE590AX28fKloGm5lnHGMJmVi6NesLy+C4Dv aTjNYa0BAA+N0JXTIVK2HKHKgOAmD1gybCO2RPWa5dYD2FbohyNsbDMJ7SrC4w5nlCwO IajfrpR/2Uft3pPQ6SshELHMH8K13xl23OPVuTyHcfirZgVDz4iHi8H+z5Px39fS3JlJ 1oR9M7+6AUB7GIDceVRuZbv6tt8HQ6JzUyIKZgctqJJJbzJhcnwDvMtfYMvPZ/+jufeJ xyrXHSYdMfAl1O4kSqpYo/2bD8o3S42Zwg23Wmdsj/3Y9KCeyopH3eV8H+Qkif02awHP VUAg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=U+p525YWABryG+bBf73FqTBHe5a2GjjjRgX/prfX3D4=; b=Bc7oYSNnyI0M/aBTUw2Ey1BGtvvhQiEgM6xsbsrzeLsqcJLU4EV+VhrWzkbBTS1UlG 4dFhhhcw+OaOC2yXkZnSKJK0nLKdtSFvaCQ7dGC8T7bgYCk+fF4oT9v4lXfcEYWf2ySz rqcAPNj3c3hCNGuasK8MTe135Xhpv6uBGjNwKKOtK+iGZns3ImOV09bL3u2rhmzD8vVl DpwxgHMa2mTSPhCG1esvrIeHkRwwPh/2pTsWotAmRB5F3zuU6mJ+4PjqpGmq3/6ZjeJa F8KGJjLuO5Q0Vb/E8NQx3FXW/9L32t9iswPtkMBM2nTBXR9Pt6GXZogwe6BqT61SyfKL 1cHg== X-Gm-Message-State: AA6/9RkDJ2FTlqHtZpL8/QIp/ct0frAJxtPyE7L4oq/6e/ZOF7gUhu/mh/4ilspb9gAs/Q== X-Received: by 10.55.156.85 with SMTP id f82mr3298555qke.177.1476836416156; Tue, 18 Oct 2016 17:20:16 -0700 (PDT) Received: from localhost ([64.9.249.129]) by smtp.gmail.com with ESMTPSA id a20sm19321387qkj.39.2016.10.18.17.20.15 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Tue, 18 Oct 2016 17:20:15 -0700 (PDT) Date: Tue, 18 Oct 2016 20:20:14 -0400 From: Kevin O'Connor To: Gerd Hoffmann Message-ID: <20161019002014.GA18055@morn.lan> References: <1475053640-30483-1-git-send-email-kraxel@redhat.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <1475053640-30483-1-git-send-email-kraxel@redhat.com> User-Agent: Mutt/1.7.0 (2016-08-17) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 2607:f8b0:400d:c09::243 Subject: Re: [Qemu-devel] [SeaBIOS] [PATCH 0/7] serial console support X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: seabios@seabios.org, qemu-devel@nongnu.org Errors-To: qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Sender: "Qemu-devel" X-Virus-Scanned: ClamAV using ClamSMTP On Wed, Sep 28, 2016 at 11:07:13AM +0200, Gerd Hoffmann wrote: > Hi, > > After a looong break finally the next round > of the seabios serial console patches. Hi Gerd, Sorry for the delay in responding. I ran some tests on your series and it looks like it causes issues with some systems that are picky about the vgabios. It looks like it tickles the skifree bug. Test case is windows vista running the ancient dos program skifree. When we last investigated this, it looked like anything in the vgabios path that tries to write to memory above 0xc0000 causes problems. The SeaBIOS extra stack is in that range by default. It originally looked like old versions of x86emu were working. But when I apply a trivial debugging patch (see below) I then find I can't start X. Test case is an old fedora13 image. I suspect that random code movement could cause x86emu to sometimes hit a problematic instruction and sometimes not. I don't see these issues with sgabios. -Kevin --- a/src/sercon.c +++ b/src/sercon.c @@ -483,6 +483,7 @@ sercon_10_splitmode(struct bregs *regs) return; if (!GET_LOW(sercon_port)) return; + dprintf(1, "here\n"); switch (regs->ah) { case 0x01: