From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from us-smtp-delivery-1.mimecast.com ([205.139.110.120]:37720 "EHLO us-smtp-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S2388711AbfKESET (ORCPT ); Tue, 5 Nov 2019 13:04:19 -0500 Date: Tue, 5 Nov 2019 19:04:07 +0100 From: Cornelia Huck Subject: Re: [RFC 12/37] KVM: s390: protvirt: Handle SE notification interceptions Message-ID: <20191105190407.68992d92.cohuck@redhat.com> In-Reply-To: <20191024114059.102802-13-frankja@linux.ibm.com> References: <20191024114059.102802-1-frankja@linux.ibm.com> <20191024114059.102802-13-frankja@linux.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=WINDOWS-1252 Content-Transfer-Encoding: quoted-printable Sender: linux-s390-owner@vger.kernel.org List-ID: To: Janosch Frank Cc: kvm@vger.kernel.org, linux-s390@vger.kernel.org, thuth@redhat.com, david@redhat.com, borntraeger@de.ibm.com, imbrenda@linux.ibm.com, mihajlov@linux.ibm.com, mimu@linux.ibm.com, gor@linux.ibm.com On Thu, 24 Oct 2019 07:40:34 -0400 Janosch Frank wrote: > Since KVM doesn't emulate any form of load control and load psw > instructions anymore, we wouldn't get an interception if PSWs or CRs > are changed in the guest. That means we can't inject IRQs right after > the guest is enabled for them. >=20 > The new interception codes solve that problem by being a notification > for changes to IRQ enablement relevant bits in CRs 0, 6 and 14, as > well a the machine check mask bit in the PSW. >=20 > No special handling is needed for these interception codes, the KVM > pre-run code will consult all necessary CRs and PSW bits and inject > IRQs the guest is enabled for. Just to clarify: The hypervisor can still access the relevant bits for pv guests, this is only about the notification, right? >=20 > Signed-off-by: Janosch Frank > --- > arch/s390/include/asm/kvm_host.h | 2 ++ > arch/s390/kvm/intercept.c | 18 ++++++++++++++++++ > 2 files changed, 20 insertions(+)