From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:41564) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dpZIE-00081p-0u for qemu-devel@nongnu.org; Wed, 06 Sep 2017 08:18:58 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1dpZIA-00058V-LB for qemu-devel@nongnu.org; Wed, 06 Sep 2017 08:18:53 -0400 Received: from mx1.redhat.com ([209.132.183.28]:36508) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1dpZIA-00057u-Cv for qemu-devel@nongnu.org; Wed, 06 Sep 2017 08:18:50 -0400 Date: Wed, 6 Sep 2017 14:18:46 +0200 From: Cornelia Huck Message-ID: <20170906141846.0be413fb.cohuck@redhat.com> In-Reply-To: <20170905111645.18068-2-pasic@linux.vnet.ibm.com> References: <20170905111645.18068-1-pasic@linux.vnet.ibm.com> <20170905111645.18068-2-pasic@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH 1/5] s390x/css: introduce css data stream List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Halil Pasic Cc: Dong Jia Shi , Pierre Morel , qemu-devel@nongnu.org On Tue, 5 Sep 2017 13:16:41 +0200 Halil Pasic wrote: > This is a preparation for introducing handling for indirect data > addressing and modified indirect data addressing (CCW). Here we introduce > an interface which should make the addressing scheme transparent for the > client code. Here we implement only basic scheme (no IDA or MIDA). s/basic scheme/the basic scheme/ > > Signed-off-by: Halil Pasic > --- > hw/s390x/css.c | 55 +++++++++++++++++++++++++++++++++++++++++ > include/hw/s390x/css.h | 67 ++++++++++++++++++++++++++++++++++++++++++++++++++ > 2 files changed, 122 insertions(+) > > diff --git a/hw/s390x/css.c b/hw/s390x/css.c > index 1880b1a0ff..87d913f81c 100644 > --- a/hw/s390x/css.c > +++ b/hw/s390x/css.c > @@ -783,6 +783,61 @@ static CCW1 copy_ccw_from_guest(hwaddr addr, bool fmt1) > } > return ret; > } > +/** > + * If out of bounds marks the stream broken. If broken returns -EINVAL, > + * otherwise the requested length (may be zero) s/requested length/requested length/ > + */ > +static inline int cds_check_len(CcwDataStream *cds, int len) > +{ > + if (cds->at_byte + len > cds->count) { > + cds->flags |= CDS_F_STREAM_BROKEN; > + } > + return cds->flags & CDS_F_STREAM_BROKEN ? -EINVAL : len; > +} > + > +static int ccw_dstream_rw_noflags(CcwDataStream *cds, void *buff, int len, > + CcwDataStreamOp op) > +{ > + int ret; > + > + ret = cds_check_len(cds, len); > + if (ret <= 0) { > + return ret; > + } > + if (op == CDS_OP_A) { > + goto incr; > + } > + ret = address_space_rw(&address_space_memory, cds->cda, > + MEMTXATTRS_UNSPECIFIED, buff, len, op); > + if (ret != MEMTX_OK) { > + cds->flags |= CDS_F_STREAM_BROKEN; Do we want to distinguish between different reasons for the stream being broken? I.e, is there a case where we want to signal different errors back to the caller? > + return -EINVAL; > + } > +incr: > + cds->at_byte += len; > + cds->cda += len; > + return 0; > +} > + > +void ccw_dstream_init(CcwDataStream *cds, CCW1 const *ccw, ORB const *orb) > +{ > + /* > + * We don't support MIDA (an optional facility) yet and we > + * catch this earlier. Just for expressing the precondition. > + */ > + assert(!(orb->ctrl1 & ORB_CTRL1_MASK_MIDAW)); I don't know, this is infrastructure, should it trust its callers? If you keep the assert, please make it g_assert(). > + cds->flags = (orb->ctrl0 & ORB_CTRL0_MASK_I2K ? CDS_F_I2K : 0) | > + (orb->ctrl0 & ORB_CTRL0_MASK_C64 ? CDS_F_C64 : 0) | > + (ccw->flags & CCW_FLAG_IDA ? CDS_F_IDA : 0); > + cds->count = ccw->count; > + cds->cda_orig = ccw->cda; > + ccw_dstream_rewind(cds); > + if (!(cds->flags & CDS_F_IDA)) { > + cds->op_handler = ccw_dstream_rw_noflags; > + } else { > + assert(false); Same here. Or should we make this return an error and have the callers deal with that? (I still need to look at the users.) > + } > +} > > static int css_interpret_ccw(SubchDev *sch, hwaddr ccw_addr, > bool suspend_allowed)