Re: [PATCH v5 02/13] hw/cxl/cxl-mailbox-utils: Add dynamic capacity region representative and mailbox command support

[Jonathan Cameron via <qemu-devel@nongnu.org>]

On Mon,  4 Mar 2024 11:33:57 -0800
nifan.cxl@gmail.com wrote:

> From: Fan Ni <fan.ni@samsung.com>
> 
> Per cxl spec r3.1, add dynamic capacity region representative based on
> Table 8-165 and extend the cxl type3 device definition to include dc region
> information. Also, based on info in 8.2.9.9.9.1, add 'Get Dynamic Capacity
> Configuration' mailbox support.
> 
> Note: we store region decode length as byte-wise length on the device, which
> should be divided by 256 * MiB before being returned to the host
> for "Get Dynamic Capacity Configuration" mailbox command per
> specification.
> 
> Signed-off-by: Fan Ni <fan.ni@samsung.com>

Really minor nice to have type comments inline.
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

> ---
>  hw/cxl/cxl-mailbox-utils.c  | 99 +++++++++++++++++++++++++++++++++++++
>  include/hw/cxl/cxl_device.h | 16 ++++++
>  2 files changed, 115 insertions(+)
> 
> diff --git a/hw/cxl/cxl-mailbox-utils.c b/hw/cxl/cxl-mailbox-utils.c
> index ba1d9901df..5792010c12 100644
> --- a/hw/cxl/cxl-mailbox-utils.c
> +++ b/hw/cxl/cxl-mailbox-utils.c
> @@ -22,6 +22,8 @@
>  
>  #define CXL_CAPACITY_MULTIPLIER   (256 * MiB)
>  #define CXL_DC_EVENT_LOG_SIZE 8
> +#define CXL_NUM_EXTENTS_SUPPORTED 512
> +#define CXL_NUM_TAGS_SUPPORTED 0
>  
>  /*
>   * How to add a new command, example. The command set FOO, with cmd BAR.
> @@ -80,6 +82,8 @@ enum {
>          #define GET_POISON_LIST        0x0
>          #define INJECT_POISON          0x1
>          #define CLEAR_POISON           0x2
> +    DCD_CONFIG  = 0x48,
> +        #define GET_DC_CONFIG          0x0
>      PHYSICAL_SWITCH = 0x51,
>          #define IDENTIFY_SWITCH_DEVICE      0x0
>          #define GET_PHYSICAL_PORT_STATE     0x1
> @@ -1238,6 +1242,91 @@ static CXLRetCode cmd_media_clear_poison(const struct cxl_cmd *cmd,
>      return CXL_MBOX_SUCCESS;
>  }
>  
> +/*
> + * CXL r3.1 section 8.2.9.9.9.1: Get Dynamic Capacity Configuration
> + * (Opcode: 4800h)
> + */
> +static CXLRetCode cmd_dcd_get_dyn_cap_config(const struct cxl_cmd *cmd,
> +                                             uint8_t *payload_in,
> +                                             size_t len_in,
> +                                             uint8_t *payload_out,
> +                                             size_t *len_out,
> +                                             CXLCCI *cci)
> +{
> +    CXLType3Dev *ct3d = CXL_TYPE3(cci->d);
> +    struct {
> +        uint8_t region_cnt;
> +        uint8_t start_region_id;
> +    } QEMU_PACKED *in;

If you respin a few line breaks might help on readability.
I'd stick one after each struct.

> +    struct {
> +        uint8_t num_regions;
> +        uint8_t regions_returned;
> +        uint8_t rsvd1[6];
> +        struct {
> +            uint64_t base;
> +            uint64_t decode_len;
> +            uint64_t region_len;
> +            uint64_t block_size;
> +            uint32_t dsmadhandle;
> +            uint8_t flags;
> +            uint8_t rsvd2[3];
> +        } QEMU_PACKED records[];
> +    } QEMU_PACKED *out;
    } QEMU_PACKED *out = (void *)payload_out;
(see below)

> +    struct {
> +        uint32_t num_extents_supported;
> +        uint32_t num_extents_available;
> +        uint32_t num_tags_supported;
> +        uint32_t num_tags_available;
> +    } QEMU_PACKED *extra_out;

> +    uint16_t record_count;
> +    uint16_t i;
> +    uint16_t out_pl_len;
> +    uint8_t start_region_id;
> +
> +    in = (void *)payload_in;
> +    out = (void *)payload_out;

These are a bit uninteresting so could just assign them at the definitions above?


> +    start_region_id = in->start_region_id;

Perhaps something shorter like start_rid for the local variable?

> +    if (start_region_id >= ct3d->dc.num_regions) {
> +        return CXL_MBOX_INVALID_INPUT;
> +    }
> +
> +    record_count = MIN(ct3d->dc.num_regions - in->start_region_id,
> +            in->region_cnt);
I'd align with just after opening bracket.

> +
> +    out_pl_len = sizeof(*out) + record_count * sizeof(out->records[0]);
> +    extra_out = (void *)(payload_out + out_pl_len);
> +    out_pl_len += sizeof(*extra_out);
> +    assert(out_pl_len <= CXL_MAILBOX_MAX_PAYLOAD_SIZE);
> +
> +    out->num_regions = ct3d->dc.num_regions;
> +    out->regions_returned = record_count;
> +    for (i = 0; i < record_count; i++) {
> +        stq_le_p(&out->records[i].base,
> +                 ct3d->dc.regions[start_region_id + i].base);
> +        stq_le_p(&out->records[i].decode_len,
> +                 ct3d->dc.regions[start_region_id + i].decode_len /
> +                 CXL_CAPACITY_MULTIPLIER);
> +        stq_le_p(&out->records[i].region_len,
> +                 ct3d->dc.regions[start_region_id + i].len);
> +        stq_le_p(&out->records[i].block_size,
> +                 ct3d->dc.regions[start_region_id + i].block_size);
> +        stl_le_p(&out->records[i].dsmadhandle,
> +                 ct3d->dc.regions[start_region_id + i].dsmadhandle);
> +        out->records[i].flags = ct3d->dc.regions[start_region_id + i].flags;
> +    }
> +    /*
> +     * TODO: will assign proper values when extents and tags are introduced
> +     * to use.
Drop the to use
	* TODO: Assign values once extents and tags are introduced.

> +     */
> +    stl_le_p(&extra_out->num_extents_supported, CXL_NUM_EXTENTS_SUPPORTED);
> +    stl_le_p(&extra_out->num_extents_available, CXL_NUM_EXTENTS_SUPPORTED);
> +    stl_le_p(&extra_out->num_tags_supported, CXL_NUM_TAGS_SUPPORTED);
> +    stl_le_p(&extra_out->num_tags_available, CXL_NUM_TAGS_SUPPORTED);
> +
> +    *len_out = out_pl_len;
> +    return CXL_MBOX_SUCCESS;
> +}