From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from us-smtp-1.mimecast.com ([205.139.110.61]:50837 "EHLO us-smtp-delivery-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1730235AbfJXN1r (ORCPT ); Thu, 24 Oct 2019 09:27:47 -0400 Subject: Re: [RFC 02/37] s390/protvirt: introduce host side setup From: David Hildenbrand References: <20191024114059.102802-1-frankja@linux.ibm.com> <20191024114059.102802-3-frankja@linux.ibm.com> Message-ID: Date: Thu, 24 Oct 2019 15:27:37 +0200 MIME-Version: 1.0 In-Reply-To: Content-Language: en-US Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: quoted-printable Sender: linux-s390-owner@vger.kernel.org List-ID: To: Janosch Frank , kvm@vger.kernel.org Cc: linux-s390@vger.kernel.org, thuth@redhat.com, borntraeger@de.ibm.com, imbrenda@linux.ibm.com, mihajlov@linux.ibm.com, mimu@linux.ibm.com, cohuck@redhat.com, gor@linux.ibm.com On 24.10.19 15:25, David Hildenbrand wrote: > On 24.10.19 13:40, Janosch Frank wrote: >> From: Vasily Gorbik >> >> Introduce KVM_S390_PROTECTED_VIRTUALIZATION_HOST kbuild option for >> protected virtual machines hosting support code. >> >> Add "prot_virt" command line option which controls if the kernel >> protected VMs support is enabled at runtime. >> >> Extend ultravisor info definitions and expose it via uv_info struct >> filled in during startup. >> >> Signed-off-by: Vasily Gorbik >> --- >> .../admin-guide/kernel-parameters.txt | 5 ++ >> arch/s390/boot/Makefile | 2 +- >> arch/s390/boot/uv.c | 20 +++++++- >> arch/s390/include/asm/uv.h | 46 ++++++++++++++++-- >> arch/s390/kernel/Makefile | 1 + >> arch/s390/kernel/setup.c | 4 -- >> arch/s390/kernel/uv.c | 48 ++++++++++++++++++= + >> arch/s390/kvm/Kconfig | 9 ++++ >> 8 files changed, 126 insertions(+), 9 deletions(-) >> create mode 100644 arch/s390/kernel/uv.c >> >> diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documenta= tion/admin-guide/kernel-parameters.txt >> index c7ac2f3ac99f..aa22e36b3105 100644 >> --- a/Documentation/admin-guide/kernel-parameters.txt >> +++ b/Documentation/admin-guide/kernel-parameters.txt >> @@ -3693,6 +3693,11 @@ >> =09=09=09before loading. >> =09=09=09See Documentation/admin-guide/blockdev/ramdisk.rst. >> =20 >> +=09prot_virt=3D=09[S390] enable hosting protected virtual machines >> +=09=09=09isolated from the hypervisor (if hardware supports >> +=09=09=09that). >> +=09=09=09Format: >=20 > Isn't that a virt driver detail that should come in via KVM module > parameters? I don't see quite yet why this has to be a kernel parameter > (that can be changed at runtime). >=20 I was confused by "runtime" in "which controls if the kernel protected=20 VMs support is enabled at runtime" So this can't be changed at runtime. Can you clarify why kvm can't=20 initialize that when loaded and why we need a kernel parameter? --=20 Thanks, David / dhildenb