From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([140.186.70.92]:39117) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1R9Xrs-0000IO-Dh for qemu-devel@nongnu.org; Fri, 30 Sep 2011 03:50:51 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1R9Xrr-0006p9-Fp for qemu-devel@nongnu.org; Fri, 30 Sep 2011 03:50:48 -0400 Received: from ozlabs.org ([203.10.76.45]:54475) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1R9Xrr-0006ov-30 for qemu-devel@nongnu.org; Fri, 30 Sep 2011 03:50:47 -0400 From: David Gibson Date: Fri, 30 Sep 2011 17:50:37 +1000 Message-Id: <1317369040-30437-1-git-send-email-david@gibson.dropbear.id.au> Subject: [Qemu-devel] [0/3] pseries: RFC: Advertise host CPU capabilties to guest List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: agraf@suse.de Cc: qemu-devel@nongnu.org This series contains some patches which, when using KVM, gather information about the capabilities of the host CPU and advertise them to the guest system when using the pseries machine. Specifically it does this for whether the CPU supports VMX, VSX and/or DFP instructions, and for the CPUs supported page sizes. The VSX and DFP portions of this were posted earlier, and I've fixed the minor comments which people made. This leaves one objection from Alex Graf, that whether the features are advertised should also depend on the target CPU selected in qemu. A similar objection may apply to the pagesizes patch. I guess the idea is to "clamp" the advertised capabilities to those permitted by the selected target CPU, but I'm not entirely sure what the logic here should be. Frankly, particularly in the case of KVM Book3S-HV, I'm not terribly convinced that attempting to make the guest CPU appear different from the host CPU is terribly meaningful. These patches as they stand have the advantage that future, roughly compatible CPUs should Just Work with these capabilities advertised in the correct cases. Alex, can you advise what sort of logic you'd like here.