From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Date: Fri, 12 Aug 2011 13:33:43 +1000 From: David Gibson To: Alexander Graf Subject: Re: [PATCH 09/10] KVM: PPC: Support SC1 hypercalls for PAPR in PR mode Message-ID: <20110812033343.GR30552@yookeroo.fritz.box> References: <1312907508-14599-1-git-send-email-agraf@suse.de> <1312907508-14599-10-git-send-email-agraf@suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <1312907508-14599-10-git-send-email-agraf@suse.de> Cc: linuxppc-dev@ozlabs.org, paulus@samba.org, kvm@vger.kernel.org, kvm-ppc@vger.kernel.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Tue, Aug 09, 2011 at 06:31:47PM +0200, Alexander Graf wrote: > PAPR defines hypercalls as SC1 instructions. Using these, the guest modifies > page tables and does other privileged operations that it wouldn't be allowed > to do in supervisor mode. > > This patch adds support for PR KVM to trap these instructions and route them > through the same PAPR hypercall interface that we already use for HV style > KVM. This will work on a powermac or bare metal host. Unfortunately, it's not enough on a pSeries LPAR host - the sc 1 instruction from the guest problem state will go direct to the hypervisor, which will return an error rather than trapping to the guest kernel. The only way around this I can see is for qemu to search for and patch up sc 1 instructions to something else. Obviously that would also need some kernel support, and probably a capability to let it know if it's necessary. -- David Gibson | I'll have my music baroque, and my code david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_ | _way_ _around_! http://www.ozlabs.org/~dgibson