From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Date: Wed, 8 Aug 2018 14:47:33 +0200 From: Cornelia Huck Subject: Re: [PATCH RFC 2/2] KVM: s390: introduce and use KVM_REQ_VSIE_RESTART Message-ID: <20180808144733.507ba955.cohuck@redhat.com> In-Reply-To: <20180807125131.3606-3-david@redhat.com> References: <20180807125131.3606-1-david@redhat.com> <20180807125131.3606-3-david@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-Archive: List-Post: To: David Hildenbrand Cc: linux-kernel@vger.kernel.org, linux-s390@vger.kernel.org, Heiko Carstens , Martin Schwidefsky , Janosch Frank , Christian Borntraeger , Pierre Morel List-ID: On Tue, 7 Aug 2018 14:51:31 +0200 David Hildenbrand wrote: > When we change the crycb (or execution controls), we also have to make sure > that the vSIE shadow datastructures properly consider the changed > values before rerunning the vSIE. We can achieve that by simply using a > VCPU request now. Is this actually a concrete problem right now, or does this only become a real concern with vfio-ap? > > This has to be a synchronous request (== handled before entering the > (v)SIE again). > > The request will make sure that the vSIE handler is left, and that the > request will be processed (NOP), therefore forcing a reload of all > vSIE data (including rebuilding the crycb) when re-entering the vSIE > interception handler the next time. > > Signed-off-by: David Hildenbrand > --- > arch/s390/include/asm/kvm_host.h | 1 + > arch/s390/kvm/kvm-s390.c | 7 ++++++- > 2 files changed, 7 insertions(+), 1 deletion(-) Reviewed-by: Cornelia Huck