From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from us-smtp-delivery-1.mimecast.com ([207.211.31.120]:42479 "EHLO us-smtp-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1728066AbgBQOYs (ORCPT ); Mon, 17 Feb 2020 09:24:48 -0500 Subject: Re: [PATCH v2 23/42] KVM: s390: protvirt: Write sthyi data to instruction data area References: <20200214222658.12946-1-borntraeger@de.ibm.com> <20200214222658.12946-24-borntraeger@de.ibm.com> From: David Hildenbrand Message-ID: <0054ceb5-a1ab-5129-cc34-b785ee8ad782@redhat.com> Date: Mon, 17 Feb 2020 15:24:35 +0100 MIME-Version: 1.0 In-Reply-To: <20200214222658.12946-24-borntraeger@de.ibm.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-s390-owner@vger.kernel.org List-ID: To: Christian Borntraeger , Janosch Frank Cc: KVM , Cornelia Huck , Thomas Huth , Ulrich Weigand , Claudio Imbrenda , linux-s390 , Michael Mueller , Vasily Gorbik , Janosch Frank On 14.02.20 23:26, Christian Borntraeger wrote: > From: Janosch Frank > > STHYI data has to go through the bounce buffer. > > Signed-off-by: Janosch Frank > Reviewed-by: Thomas Huth > Reviewed-by: Cornelia Huck > [borntraeger@de.ibm.com: patch merging, splitting, fixing] > Signed-off-by: Christian Borntraeger > --- > arch/s390/kvm/intercept.c | 15 ++++++++++----- > 1 file changed, 10 insertions(+), 5 deletions(-) > > diff --git a/arch/s390/kvm/intercept.c b/arch/s390/kvm/intercept.c > index 1e231058e4b3..cfabeecbb777 100644 > --- a/arch/s390/kvm/intercept.c > +++ b/arch/s390/kvm/intercept.c > @@ -392,7 +392,7 @@ int handle_sthyi(struct kvm_vcpu *vcpu) > goto out; > } > > - if (addr & ~PAGE_MASK) > + if (!kvm_s390_pv_is_protected(vcpu->kvm) && (addr & ~PAGE_MASK)) > return kvm_s390_inject_program_int(vcpu, PGM_SPECIFICATION); > > sctns = (void *)get_zeroed_page(GFP_KERNEL); > @@ -403,10 +403,15 @@ int handle_sthyi(struct kvm_vcpu *vcpu) > > out: > if (!cc) { > - r = write_guest(vcpu, addr, reg2, sctns, PAGE_SIZE); > - if (r) { > - free_page((unsigned long)sctns); > - return kvm_s390_inject_prog_cond(vcpu, r); > + if (kvm_s390_pv_is_protected(vcpu->kvm)) { I have the feeling that we might have to think about proper locking for kvm_s390_pv_is_protected(). We have to make sure there cannot be any races with user space. Smells like a new r/w lock maybe. -- Thanks, David / dhildenb