From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:44221) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1cS238-00022v-2H for qemu-devel@nongnu.org; Fri, 13 Jan 2017 08:37:47 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1cS235-0000vS-02 for qemu-devel@nongnu.org; Fri, 13 Jan 2017 08:37:46 -0500 Received: from mga02.intel.com ([134.134.136.20]:61174) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1cS234-0000vA-Mn for qemu-devel@nongnu.org; Fri, 13 Jan 2017 08:37:42 -0500 Date: Fri, 13 Jan 2017 21:37:38 +0800 From: Haozhong Zhang Message-ID: <20170113133738.k3vyvysehcz2gppc@hz-desktop> References: <20170113115651.17607-1-haozhong.zhang@intel.com> <20170113131727.GA10706@stefanha-x1.localdomain> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Disposition: inline In-Reply-To: <20170113131727.GA10706@stefanha-x1.localdomain> Subject: Re: [Qemu-devel] [PATCH] hw/i386: check if nvdimm is enabled before plugging List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Stefan Hajnoczi , Xiao Guangrong Cc: qemu-devel@nongnu.org, Paolo Bonzini , Richard Henderson , Eduardo Habkost , "Michael S . Tsirkin" , imammedo@redhat.com On 01/13/17 13:17 +0000, Stefan Hajnoczi wrote: >On Fri, Jan 13, 2017 at 07:56:51PM +0800, Haozhong Zhang wrote: >> The missing of 'nvdimm' in the machine type option '-M' means NVDIMM >> is disabled. QEMU should refuse to plug any NVDIMM device in this case >> and report the misconfiguration. >> >> Reported-by: Stefan Hajnoczi >> Signed-off-by: Haozhong Zhang >> Message-Id: 20170112110928.GF4621@stefanha-x1.localdomain >> Message-Id: 20170111093630.2088-1-stefanha@redhat.com >> --- >> hw/i386/pc.c | 5 +++++ >> 1 file changed, 5 insertions(+) >> >> diff --git a/hw/i386/pc.c b/hw/i386/pc.c >> index 25e8586..3907609 100644 >> --- a/hw/i386/pc.c >> +++ b/hw/i386/pc.c >> @@ -1715,6 +1715,11 @@ static void pc_dimm_plug(HotplugHandler *hotplug_dev, >> } >> >> if (object_dynamic_cast(OBJECT(dev), TYPE_NVDIMM)) { >> + if (!pcms->acpi_nvdimm_state.is_enabled) { >> + error_setg(&local_err, >> + "nvdimm is not enabled: missing 'nvdimm' in '-M'"); >> + goto out; >> + } > >A warning is definitely useful to notify users of a possible >configuration error. If NVDIMM is plugged at boot time, QEMU with this patch will stop and report a message like qemu-system-x86_64: -device nvdimm,...: nvdimm is not enabled: missing 'nvdimm' in '-M' If NVDIMM is plugged via 'device_add' command, QEMU with this patch will report a warning message nvdimm is not enabled: missing 'nvdimm' in '-M' and continue to run w/o plugging this device. > >I wonder what happens when you plug an NVDIMM into a motherboard where >the firmware lacks support. Does it: > * Refuse to boot? > * Treat the DIMM as regular RAM? > * Boot but the DIMM will not be used by firmware and kernel? Good question. Guangrong, any idea? Thanks, Haozhong > >QEMU should act the same way as real hardware. > >Stefan