From mboxrd@z Thu Jan 1 00:00:00 1970 From: marc.zyngier@arm.com (Marc Zyngier) Date: Mon, 07 Oct 2013 09:07:56 +0100 Subject: [PATCH 3/3] KVM: ARM: Add support for Cortex-A7 In-Reply-To: References: <1380210568-23175-1-git-send-email-jonathan.austin@arm.com> <1380210568-23175-4-git-send-email-jonathan.austin@arm.com> <20130926161743.GD1389@cbox> <52446A48.9070501@arm.com> Message-ID: <52526BDC.3050305@arm.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 07/10/13 07:16, Gavin Guo wrote: > On Sun, Oct 6, 2013 at 10:56 PM, Peter Maydell > wrote: > > On 6 October 2013 23:03, Gavin Guo > wrote: > > Does it mean the currently qemu can't support A15 vcpu running on > host A7? > > No, that's a kernel restriction. That is why the patch description > reads: > # This patch adds support for running Cortex-A7 guests on Cortex-A7 > hosts. > > (What QEMU is currently missing is A7 support, so you can't ask it to > run an A7 guest CPU.) > > -- PMM > > > Thanks, I saw the checking in the kvm_vcpu_set_target(). I'm confused > that what is the concern to run the same cpu type? Does it matter to run > A15 on A7 or inverse? It does. MIDR registers are different. Cache size is different. It may work, or it may not. And at the very least, you should present a consistent view of the underlying system to the unsuspecting OS. M. -- Jazz is not dead. It just smells funny...