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From: Pierre Morel <pmorel@linux.vnet.ibm.com>
To: Halil Pasic <pasic@linux.vnet.ibm.com>,
	Cornelia Huck <cohuck@redhat.com>
Cc: Dong Jia Shi <bjsdjshi@linux.vnet.ibm.com>, qemu-devel@nongnu.org
Subject: Re: [Qemu-devel] [PATCH v2 1/4] s390x/css: introduce css data stream
Date: Tue, 19 Sep 2017 11:11:27 +0200	[thread overview]
Message-ID: <63eabac3-0646-92ff-dede-d16391124061@linux.vnet.ibm.com> (raw)
In-Reply-To: <20170913115029.47626-2-pasic@linux.vnet.ibm.com>

On 13/09/2017 13:50, 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 the basic scheme (no IDA or MIDA).
> 
> Signed-off-by: Halil Pasic <pasic@linux.vnet.ibm.com>
> ---
>   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 901dc6a0f3..e8d2016563 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)
> + */
> +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;
> +        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.
> +     */
> +    g_assert(!(orb->ctrl1 & ORB_CTRL1_MASK_MIDAW));
> +    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);
> +    }
> +}
> 
>   static int css_interpret_ccw(SubchDev *sch, hwaddr ccw_addr,
>                                bool suspend_allowed)
> diff --git a/include/hw/s390x/css.h b/include/hw/s390x/css.h
> index 0653d3c9be..79acaf99b7 100644
> --- a/include/hw/s390x/css.h
> +++ b/include/hw/s390x/css.h
> @@ -75,6 +75,29 @@ typedef struct CMBE {
>       uint32_t reserved[7];
>   } QEMU_PACKED CMBE;
> 
> +typedef enum CcwDataStreamOp {
> +    CDS_OP_R = 0,
> +    CDS_OP_W = 1,
> +    CDS_OP_A = 2
> +} CcwDataStreamOp;
> +
> +/** normal usage is via SuchchDev.cds instead of instantiating */
> +typedef struct CcwDataStream {
> +#define CDS_F_IDA   0x01
> +#define CDS_F_MIDA  0x02
> +#define CDS_F_I2K   0x04
> +#define CDS_F_C64   0x08
> +#define CDS_F_STREAM_BROKEN  0x80
> +    uint8_t flags;
> +    uint8_t at_idaw;
> +    uint16_t at_byte;
> +    uint16_t count;
> +    uint32_t cda_orig;
> +    int (*op_handler)(struct CcwDataStream *cds, void *buff, int len,
> +                      CcwDataStreamOp op);

I would have prefer one handler per operation instead of a operation 
parameter.

Is it possible to change the name of the "buf" argument to "arg".
I just think of the foollowing:
If one day we do not want to gather all IDAs into a single buffer but 
keep them split, we can have something like an array of buffers as argument.



> +    hwaddr cda;
> +} CcwDataStream;
> +
>   typedef struct SubchDev SubchDev;
>   struct SubchDev {
>       /* channel-subsystem related things: */
> @@ -92,6 +115,7 @@ struct SubchDev {
>       uint8_t ccw_no_data_cnt;
>       uint16_t migrated_schid; /* used for missmatch detection */
>       ORB orb;
> +    CcwDataStream cds;
>       /* transport-provided data: */
>       int (*ccw_cb) (SubchDev *, CCW1);
>       void (*disable_cb)(SubchDev *);
> @@ -240,4 +264,47 @@ SubchDev *css_create_sch(CssDevId bus_id, bool is_virtual, bool squash_mcss,
>   /** Turn on css migration */
>   void css_register_vmstate(void);
> 
> +
> +void ccw_dstream_init(CcwDataStream *cds, CCW1 const *ccw, ORB const *orb);
> +
> +static inline void ccw_dstream_rewind(CcwDataStream *cds)
> +{
> +    cds->at_byte = 0;
> +    cds->at_idaw = 0;
> +    cds->cda = cds->cda_orig;
> +}
> +
> +static inline bool ccw_dstream_good(CcwDataStream *cds)
> +{
> +    return !(cds->flags & CDS_F_STREAM_BROKEN);
> +}
> +
> +static inline uint16_t ccw_dstream_residual_count(CcwDataStream *cds)
> +{
> +    return cds->count - cds->at_byte;
> +}
> +
> +static inline uint16_t ccw_dstream_avail(CcwDataStream *cds)
> +{
> +    return ccw_dstream_good(cds) ?  ccw_dstream_residual_count(cds) : 0;
> +}
> +
> +static inline int ccw_dstream_advance(CcwDataStream *cds, int len)
> +{
> +    return cds->op_handler(cds, NULL, len, CDS_OP_A);
> +}
> +
> +static inline int ccw_dstream_write_buf(CcwDataStream *cds, void *buff, int len)
> +{
> +    return cds->op_handler(cds, buff, len, CDS_OP_W);
> +}
> +
> +static inline int ccw_dstream_read_buf(CcwDataStream *cds, void *buff, int len)
> +{
> +    return cds->op_handler(cds, buff, len, CDS_OP_R);
> +}
> +
> +#define ccw_dstream_read(cds, v) ccw_dstream_read_buf((cds), &(v), sizeof(v))
> +#define ccw_dstream_write(cds, v) ccw_dstream_write_buf((cds), &(v), sizeof(v))
> +
>   #endif
> 

otherwise, LGTM

-- 
Pierre Morel
Linux/KVM/QEMU in Böblingen - Germany

  parent reply	other threads:[~2017-09-19  9:11 UTC|newest]

Thread overview: 39+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-09-13 11:50 [Qemu-devel] [PATCH v2 0/4] add CCW indirect data access support Halil Pasic
2017-09-13 11:50 ` [Qemu-devel] [PATCH v2 1/4] s390x/css: introduce css data stream Halil Pasic
2017-09-14  9:08   ` Cornelia Huck
2017-09-19  2:21   ` Dong Jia Shi
2017-09-19  8:38     ` Cornelia Huck
2017-09-19  9:11   ` Pierre Morel [this message]
2017-09-19  9:53     ` Cornelia Huck
2017-09-19 11:41       ` Pierre Morel
2017-09-19 12:16         ` Halil Pasic
2017-09-19 13:55       ` Pierre Morel
2017-09-13 11:50 ` [Qemu-devel] [PATCH v2 2/4] s390x/css: use ccw " Halil Pasic
2017-09-19  2:45   ` Dong Jia Shi
2017-09-19 13:57   ` Pierre Morel
2017-09-13 11:50 ` [Qemu-devel] [PATCH v2 3/4] virtio-ccw: " Halil Pasic
2017-09-14  8:47   ` Cornelia Huck
2017-09-19  3:37   ` Dong Jia Shi
2017-09-19  9:06     ` Cornelia Huck
2017-09-19 13:30       ` Halil Pasic
2017-09-20  1:16         ` Dong Jia Shi
2017-09-19 14:07   ` Pierre Morel
2017-09-13 11:50 ` [Qemu-devel] [PATCH v2 4/4] s390x/css: support ccw IDA Halil Pasic
2017-09-14  9:14   ` Cornelia Huck
2017-09-19  5:50   ` Dong Jia Shi
2017-09-19  9:48     ` Cornelia Huck
2017-09-19 10:36       ` Halil Pasic
2017-09-19 10:57         ` Cornelia Huck
2017-09-19 12:04           ` Halil Pasic
2017-09-19 12:23             ` Cornelia Huck
2017-09-19 12:32               ` Halil Pasic
2017-09-19 14:34                 ` Cornelia Huck
2017-09-19 18:05               ` Halil Pasic
2017-09-20  1:37                 ` Dong Jia Shi
2017-09-20  6:40             ` Dong Jia Shi
2017-09-19 13:46           ` Pierre Morel
2017-09-19 16:49             ` Halil Pasic
2017-09-14  9:15 ` [Qemu-devel] [PATCH v2 0/4] add CCW indirect data access support Cornelia Huck
2017-09-14 11:02   ` Halil Pasic
2017-09-14 11:19     ` Cornelia Huck
2017-09-14 14:16 ` Cornelia Huck

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