From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:35841) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ey0gE-0002fR-4X for qemu-devel@nongnu.org; Mon, 19 Mar 2018 15:42:51 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ey0gA-00081O-6a for qemu-devel@nongnu.org; Mon, 19 Mar 2018 15:42:50 -0400 Received: from mx1.redhat.com ([209.132.183.28]:47432) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1ey0gA-000802-17 for qemu-devel@nongnu.org; Mon, 19 Mar 2018 15:42:46 -0400 Date: Mon, 19 Mar 2018 19:42:42 +0000 From: "Richard W.M. Jones" Message-ID: <20180319194242.GQ2787@redhat.com> References: <1521221171-47213-1-git-send-email-mjc@sifive.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Subject: Re: [Qemu-devel] [PATCH v3] RISC-V: Fix riscv_isa_string memory size bug List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Michael Clark Cc: Philippe =?iso-8859-1?Q?Mathieu-Daud=E9?= , QEMU Developers , Palmer Dabbelt , Peter Maydell On Mon, Mar 19, 2018 at 11:35:51AM -0700, Michael Clark wrote: > The RISC-V post-merge spec conformance and cleanup series has had a lot of > testing. I've been using it to compile QEMU inside of QEMU using the RISC-V > Fedora Image and its native RISC-V GCC toolchain running inside SMP Linux > 4.16-rc2. It appears to be pretty rock-solid. The rcu lock fix would likely > only affect users who are ballooning memory while a guest is under load. > The page walker changes have also been tested under load (including > performance tests). Did you see the problem with restoring floating point registers on context switch? The test case is quite simple: http://oirase.annexia.org/tmp/sched.c Note you must compile it with gcc -O2 to manifest the bug. (We originally thought it was a problem with gcc's optimization, but it isn't.) In Fedora's qemu tree are carrying the following patch which is just a workaround: https://github.com/rwmjones/fedora-riscv-bootstrap/blob/master/stage1-riscv-qemu/force-float-save.patch Rich. -- Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones Read my programming and virtualization blog: http://rwmj.wordpress.com libguestfs lets you edit virtual machines. Supports shell scripting, bindings from many languages. http://libguestfs.org