From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Date: Sun, 27 Jun 2010 08:21:08 +0000 Subject: Re: [PATCH 08/26] KVM: PPC: Add PV guest critical sections Message-Id: <4C2709F4.10805@redhat.com> List-Id: References: <1277508314-915-1-git-send-email-agraf@suse.de> <1277508314-915-9-git-send-email-agraf@suse.de> In-Reply-To: <1277508314-915-9-git-send-email-agraf-l3A5Bk7waGM@public.gmane.org> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Alexander Graf Cc: kvm-ppc-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, KVM list , linuxppc-dev On 06/26/2010 02:24 AM, Alexander Graf wrote: > When running in hooked code we need a way to disable interrupts without > clobbering any interrupts or exiting out to the hypervisor. > > To achieve this, we have an additional critical field in the shared page. If > that field is equal to the r1 register of the guest, it tells the hypervisor > that we're in such a critical section and thus may not receive any interrupts. > Is r1 reserved for this purpose? Can't it match accidentally? Why won't zero/nonzero work for this? -- error compiling committee.c: too many arguments to function