From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:36741) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XMYMH-0001cN-Kd for qemu-devel@nongnu.org; Wed, 27 Aug 2014 04:13:38 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1XMYMC-0004JI-Q6 for qemu-devel@nongnu.org; Wed, 27 Aug 2014 04:13:33 -0400 Received: from [59.151.112.132] (port=10117 helo=heian.cn.fujitsu.com) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XMYMC-0004JE-Cy for qemu-devel@nongnu.org; Wed, 27 Aug 2014 04:13:28 -0400 Message-ID: <53FD9362.8090404@cn.fujitsu.com> Date: Wed, 27 Aug 2014 16:14:26 +0800 From: tangchen MIME-Version: 1.0 References: <1409126988-22287-1-git-send-email-tangchen@cn.fujitsu.com> In-Reply-To: <1409126988-22287-1-git-send-email-tangchen@cn.fujitsu.com> Content-Type: text/plain; charset="ISO-8859-1"; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [RFC PATCH v1 0/4] Handle memory hotplug errors from guest OS. List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org, imammedo@redhat.com, mst@redhat.com, pbonzini@redhat.com Cc: hutao@cn.fujitsu.com, isimatu.yasuaki@jp.fujitsu.com, zhugh.fnst@cn.fujitsu.com, tangchen@cn.fujitsu.com Forgot to mention, this patch-set is based on the following patch-set: [RESEND PATCH v3 0/8] QEmu memory hot unplug support. https://www.mail-archive.com/qemu-devel@nongnu.org/msg253018.html Thanks. On 08/27/2014 04:09 PM, Tang Chen wrote: > When doing memory hotplug, QEmu is not aware of guest OS error when hotplugging > memory devices. Even if guest OS failed to hot-add memory, the pc-dimm > device will be added to QEmu. Even if guest OS failed to hot-remove memory, > QEmu will remove the pc-dimm device. > > An example is: for a Linux guest, the Linux kernel limited that the size of > hot-added memory should be mutiple of memory section (128MB by default). > If we add 130MB memory, the Linux kernel won't add it. We are not able > to handle the size check in QEmu commmand line because different OS may > have different limits. > > And also, QEmu outputs nothing but guest OS failed to hot-add memory will > confuse users. We should at least report an error. > > So, we should report the error to users, and cancel the memory hotplug > progress in QEmu. > > QEmu thread sends a SCI to guest OS and return immediately. The vcpu thread > will emulate ACPI hardware operations. So this patch-set introduces a wait > condition variable to synchronize these two threads. > > Tang Chen (4): > Use macro to define ACPI notification event. > Add event handling for memory device insertion. > Introduce wait condition to catch guest OS memory hotplug error. > Handle memory hotplug error from guest OS in QEmu. > > hw/acpi/memory_hotplug.c | 146 +++++++++++++++++++++++++++++++++++++++++++++-- > include/hw/acpi/acpi.h | 15 ++++- > 2 files changed, 153 insertions(+), 8 deletions(-) >