From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:34259) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dpa6J-0002qF-7O for qemu-devel@nongnu.org; Wed, 06 Sep 2017 09:10:45 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1dpa6D-00070x-03 for qemu-devel@nongnu.org; Wed, 06 Sep 2017 09:10:39 -0400 Received: from mx1.redhat.com ([209.132.183.28]:60004) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1dpa6C-00070G-NJ for qemu-devel@nongnu.org; Wed, 06 Sep 2017 09:10:32 -0400 Date: Wed, 6 Sep 2017 15:10:28 +0200 From: Cornelia Huck Message-ID: <20170906151028.545f208e.cohuck@redhat.com> In-Reply-To: <20170905111645.18068-5-pasic@linux.vnet.ibm.com> References: <20170905111645.18068-1-pasic@linux.vnet.ibm.com> <20170905111645.18068-5-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 4/5] s390x/css: support ccw IDA 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 13:16:44 +0200 Halil Pasic wrote: > Let's add indirect data addressing support for our virtual channel > subsystem. This implementation does no prefetching, but steps > trough the idal as we go. > > Signed-off-by: Halil Pasic > --- > hw/s390x/css.c | 110 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++- > 1 file changed, 109 insertions(+), 1 deletion(-) > > diff --git a/hw/s390x/css.c b/hw/s390x/css.c > index c1bc9944e6..9d8f9fd7ea 100644 > --- a/hw/s390x/css.c > +++ b/hw/s390x/css.c > @@ -819,6 +819,114 @@ incr: > return 0; > } > > +/* retuns values between 1 and bs, where bs is a power of 2 */ 'bs' is 'block size'? > +static inline uint16_t ida_continuous_left(hwaddr cda, uint64_t bs) > +{ > + return bs - (cda & (bs - 1)); > +} > + > +static inline uint64_t ccw_ida_block_size(uint8_t flags) > +{ > + return 1ULL << (((flags ^ CDS_F_C64) & (CDS_F_C64 | CDS_F_I2K)) ? 11 : 12); > +} > + > +static inline int ida_read_next_idaw(CcwDataStream *cds) > +{ > + union {uint64_t fmt2; uint32_t fmt1; } idaw; > + bool is_fmt2 = cds->flags & CDS_F_C64; > + int ret; > + hwaddr idaw_addr; > + > + if (is_fmt2) { > + idaw_addr = cds->cda_orig + sizeof(idaw.fmt2) * cds->at_idaw; > + if (idaw_addr & 0x07) { > + return -EINVAL; /* chanel program check */ How fashionable ;) [s/chanel/channel/ :D] > + } > + ret = address_space_rw(&address_space_memory, idaw_addr, > + MEMTXATTRS_UNSPECIFIED, (void *) &idaw.fmt2, > + sizeof(idaw.fmt2), false); > + cds->cda = be64_to_cpu(idaw.fmt2); > + } else { > + idaw_addr = cds->cda_orig + sizeof(idaw.fmt1) * cds->at_idaw; > + if (idaw_addr & 0x03) { > + return -EINVAL; /* chanel program check */ > + > + } > + ret = address_space_rw(&address_space_memory, idaw_addr, > + MEMTXATTRS_UNSPECIFIED, (void *) &idaw.fmt1, > + sizeof(idaw.fmt1), false); > + cds->cda = be64_to_cpu(idaw.fmt1); > + } > + ++(cds->at_idaw); > + if (ret != MEMTX_OK) { > + /* assume inaccessible address */ > + return -EINVAL; /* chanel program check */ > + > + } > + return 0; > +} > + > +static int ccw_dstream_rw_ida(CcwDataStream *cds, void *buff, int len, > + CcwDataStreamOp op) > +{ > + uint64_t bs = ccw_ida_block_size(cds->flags); > + int ret = 0; > + uint16_t cont_left, iter_len; > + > + ret = cds_check_len(cds, len); > + if (ret <= 0) { > + return ret; > + } > + if (!cds->at_idaw) { > + /* read first idaw */ > + ret = ida_read_next_idaw(cds); > + if (ret) { > + goto err; > + } > + cont_left = ida_continuous_left(cds->cda, bs); > + } else { > + cont_left = ida_continuous_left(cds->cda, bs); > + if (cont_left == bs) { > + ret = ida_read_next_idaw(cds); > + if (ret) { > + goto err; > + } > + if (cds->cda & (bs - 1)) { > + ret = -EINVAL; /* chanel program check */ > + goto err; > + } > + } > + } > +do_iter_len: > + iter_len = MIN(len, cont_left); > + if (op == CDS_OP_A) { > + goto incr; > + } > + ret = address_space_rw(&address_space_memory, cds->cda, > + MEMTXATTRS_UNSPECIFIED, buff, iter_len, op); > + if (ret != MEMTX_OK) { > + /* assume inaccessible address */ > + ret = -EINVAL; /* chanel program check */ > + goto err; > + } > +incr: > + cds->at_byte += iter_len; > + cds->cda += iter_len; > + len -= iter_len; > + if (len) { > + ret = ida_read_next_idaw(cds); > + if (ret) { > + goto err; > + } > + cont_left = bs; > + goto do_iter_len; > + } > + return ret; > +err: > + cds->flags |= CDS_F_STREAM_BROKEN; > + return ret; > +} I'm not so happy about the many gotos (excepting the err ones). Any chance to get around these? > + > void ccw_dstream_init(CcwDataStream *cds, CCW1 const *ccw, ORB const *orb) > { > /* > @@ -835,7 +943,7 @@ void ccw_dstream_init(CcwDataStream *cds, CCW1 const *ccw, ORB const *orb) > if (!(cds->flags & CDS_F_IDA)) { > cds->op_handler = ccw_dstream_rw_noflags; > } else { > - assert(false); > + cds->op_handler = ccw_dstream_rw_ida; > } > } >