From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:43231) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fst9T-0002B0-F5 for qemu-devel@nongnu.org; Thu, 23 Aug 2018 13:12:10 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1fst9P-0007Vm-GZ for qemu-devel@nongnu.org; Thu, 23 Aug 2018 13:12:07 -0400 Received: from mx1.redhat.com ([209.132.183.28]:54674) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1fst9P-0007VT-8j for qemu-devel@nongnu.org; Thu, 23 Aug 2018 13:12:03 -0400 Date: Thu, 23 Aug 2018 14:11:58 -0300 From: Eduardo Habkost Message-ID: <20180823171158.GI3778@localhost.localdomain> References: <1533909989-56115-1-git-send-email-robert.hu@linux.intel.com> <1533909989-56115-3-git-send-email-robert.hu@linux.intel.com> <20180817131810.GA15372@localhost.localdomain> <1534577221.4104.20.camel@linux.intel.com> <20180818150548.GN15372@localhost.localdomain> <1535005708.4104.34.camel@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1535005708.4104.34.camel@linux.intel.com> Subject: Re: [Qemu-devel] [PATCH v3 2/3] kvm: Add support to KVM_GET_MSR_FEATURE_INDEX_LIST and KVM_GET_MSRS system ioctl List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Robert Hoo Cc: robert.hu@intel.com, pbonzini@redhat.com, rth@twiddle.net, thomas.lendacky@amd.com, qemu-devel@nongnu.org, jingqi.liu@intel.com On Thu, Aug 23, 2018 at 02:28:28PM +0800, Robert Hoo wrote: > On Sat, 2018-08-18 at 12:05 -0300, Eduardo Habkost wrote: [...] > > We don't want QEMU to refuse to run if the kernel doesn't have > > KVM_CAP_GET_MSR_FEATURES. We can treat missing capability as > > equivalent to returning an empty list of MSRs. > Yes. I'll let caller (kvm_arch_init) ignore the return value but a > simple warning. Warnings tend to be ignored and are generally a sign that QEMU isn't doing the right thing. Sometimes we have no choice, but I don't think that's the case here. As far as I can see, we have only two possibilities here: 1) The host can run a VM that behaves exactly as requested on the command-line (no warning required). 2) The host can't run the requested configuration (fatal error, not a warning). -- Eduardo