From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from us-smtp-delivery-1.mimecast.com ([207.211.31.120]:28481 "EHLO us-smtp-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1727922AbgBJRcM (ORCPT ); Mon, 10 Feb 2020 12:32:12 -0500 Date: Mon, 10 Feb 2020 18:31:52 +0100 From: Cornelia Huck Subject: Re: [PATCH 1/1] s390/uv: Fix handling of length extensions Message-ID: <20200210183152.40bfae24.cohuck@redhat.com> In-Reply-To: <20200210165439.3767-2-borntraeger@de.ibm.com> References: <20200210165439.3767-1-borntraeger@de.ibm.com> <20200210165439.3767-2-borntraeger@de.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-s390-owner@vger.kernel.org List-ID: To: Christian Borntraeger Cc: Janosch Frank , KVM , David Hildenbrand , Thomas Huth , linux-s390 , Vasily Gorbik On Mon, 10 Feb 2020 11:54:39 -0500 Christian Borntraeger wrote: > The query parameter block might contain additional information and can > be extended in the future. If the size of the block does not suffice we > get an error code of rc=0x100. The buffer will contain all information > up to the specified size and the hypervisor/guest simply do not need the > additional information as they do not know about the new data. That > means that we can (and must) accept rc=0x100 as success. > > Cc: stable@vger.kernel.org > Fixes: 5abb9351dfd9 ("s390/uv: introduce guest side ultravisor code") > Signed-off-by: Christian Borntraeger > --- > arch/s390/boot/uv.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/arch/s390/boot/uv.c b/arch/s390/boot/uv.c > index af9e1cc93c68..c003593664cd 100644 > --- a/arch/s390/boot/uv.c > +++ b/arch/s390/boot/uv.c > @@ -21,7 +21,7 @@ void uv_query_info(void) > if (!test_facility(158)) > return; > > - if (uv_call(0, (uint64_t)&uvcb)) > + if (uv_call(0, (uint64_t)&uvcb) && uvcb.header.rc != 0x100) Add a comment like /* rc==0x100 means that there is additional data we do not process */ to avoid headscratching in the future? > return; > > if (IS_ENABLED(CONFIG_KVM)) { Reviewed-by: Cornelia Huck