From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:38323) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1eqM6A-0004JC-9r for qemu-devel@nongnu.org; Mon, 26 Feb 2018 11:57:59 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1eqM66-00006x-Tm for qemu-devel@nongnu.org; Mon, 26 Feb 2018 11:57:58 -0500 Date: Mon, 26 Feb 2018 17:57:51 +0100 From: Cornelia Huck Message-ID: <20180226175751.2d8e5f05.cohuck@redhat.com> In-Reply-To: <1519407778-23095-4-git-send-email-imbrenda@linux.vnet.ibm.com> References: <1519407778-23095-1-git-send-email-imbrenda@linux.vnet.ibm.com> <1519407778-23095-4-git-send-email-imbrenda@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH v4 3/3] s390x/sclp: extend SCLP event masks to 64 bits List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Claudio Imbrenda Cc: qemu-s390x@nongnu.org, qemu-devel@nongnu.org, borntraeger@de.ibm.com On Fri, 23 Feb 2018 18:42:58 +0100 Claudio Imbrenda wrote: > Extend the SCLP event masks to 64 bits. > > Notice that using any of the new bits results in a state that cannot be > migrated to an older version. > > Signed-off-by: Claudio Imbrenda > --- > hw/s390x/event-facility.c | 56 ++++++++++++++++++++++++++++++--------- > include/hw/s390x/event-facility.h | 2 +- > 2 files changed, 45 insertions(+), 13 deletions(-) > > diff --git a/hw/s390x/event-facility.c b/hw/s390x/event-facility.c > index e04ed9f..c3e39ee 100644 > --- a/hw/s390x/event-facility.c > +++ b/hw/s390x/event-facility.c > @@ -30,7 +30,7 @@ struct SCLPEventFacility { > SysBusDevice parent_obj; > SCLPEventsBus sbus; > /* guest's receive mask */ > - sccb_mask_t receive_mask; > + uint32_t receive_mask_pieces[2]; > /* > * when false, we keep the same broken, backwards compatible behaviour as > * before, allowing only masks of size exactly 4; when true, we implement > @@ -42,6 +42,18 @@ struct SCLPEventFacility { > uint16_t mask_length; > }; > > +static inline sccb_mask_t make_receive_mask(SCLPEventFacility *ef) > +{ > + return ((sccb_mask_t)ef->receive_mask_pieces[0]) << 32 | > + ef->receive_mask_pieces[1]; > +} > + > +static inline void store_receive_mask(SCLPEventFacility *ef, sccb_mask_t val) > +{ > + ef->receive_mask_pieces[1] = val; > + ef->receive_mask_pieces[0] = val >> 32; > +} > + Hm... how are all those values actually defined in the architecture? You pass around some values internally (which are supposedly in host endian) and then and/or them with the receive mask here. Are they compared byte-for-byte? 32-bit-for-32-bit? I'm also not a fan of the _pieces suffix - reminds me of Dwarf pieces :)