From mboxrd@z Thu Jan 1 00:00:00 1970 From: pbonzini@redhat.com (Paolo Bonzini) Date: Fri, 16 Sep 2016 14:54:01 +0200 Subject: [PATCH v3 0/2] KVM: ARM: Enable vtimers with user space gic In-Reply-To: <10C5B047-6A7F-4255-BE56-5358AF88DA5E@suse.de> References: <1474007187-18673-1-git-send-email-agraf@suse.de> <57DBC782.7080305@arm.com> <060ADA14-786E-400E-9B11-61C34B7081B5@suse.de> <20160916122937.GA14140@cbox> <6b92c411-8b27-a4c0-6969-38e32bbf18ab@redhat.com> <10C5B047-6A7F-4255-BE56-5358AF88DA5E@suse.de> Message-ID: <7a781cfd-ed8c-b5d6-d20c-ef3ab9e9434f@redhat.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 16/09/2016 14:44, Alexander Graf wrote: > >> On 16 Sep 2016, at 14:40, Paolo Bonzini >> wrote: >> >> >> >> On 16/09/2016 14:29, Christoffer Dall wrote: >>>> It may be useful for migrating a gicv2 VM to a gicv3 host >>>> without gicv2 emulation as well. >>> >>> I don't see why you'd do this; the VGIC hardware can perfectly >>> well be used for nesting as well, and this works rather well. >> >> Can GICv3 emulate GICv2 in a guest? > > It depends on the gicv3 configuration. As an SOC vendor you can > either enable gicv2 compatibility or disable it. ThunderX for example > is gicv3 only. And QEMU complains on startup and exits, I hope. I am not too optimistic about having migration from kernel GIC to userspace GIC, honestly. But GICv2 emulation on GICv3-only hosts is a very reasonable thing to want, if only for testing/debugging purposes. Paolo