Re: [PATCH v2 3/3] hw/cxl/cxl-mailbox-utils: Add support for Media operations Sanitize and Write Zeros commands (8.2.9.9.5.3)

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

On Thu, 13 Feb 2025 14:45:58 +0530
Vinayak Holikatti <vinayak.kh@samsung.com> wrote:

> CXL spec 3.1 section 8.2.9.9.5.3 describes media operations commands.
As in previous - please update to the r3.2 spec.

A few comments inline.

Thanks,

Jonathan

> CXL devices supports media operations Sanitize and Write zero command.
> 
> Signed-off-by: Vinayak Holikatti <vinayak.kh@samsung.com>
> ---
>  hw/cxl/cxl-mailbox-utils.c  | 217 +++++++++++++++++++++++++++++++++++-
>  include/hw/cxl/cxl_device.h |   4 +
>  2 files changed, 216 insertions(+), 5 deletions(-)
> 
> diff --git a/hw/cxl/cxl-mailbox-utils.c b/hw/cxl/cxl-mailbox-utils.c
> index d58c20842f..2d8d1171b4 100644
> --- a/hw/cxl/cxl-mailbox-utils.c
> +++ b/hw/cxl/cxl-mailbox-utils.c
> @@ -1732,6 +1732,130 @@ static CXLRetCode cmd_sanitize_overwrite(const struct cxl_cmd *cmd,
>  }
>  
>  #define CXL_CACHELINE_SIZE 64
> +struct CXLSanitizeInfo {
> +    uint32_t dpa_range_count;
> +    uint8_t fill_value;
> +    struct {
> +            uint64_t starting_dpa;
> +            uint64_t length;
> +    } dpa_range_list[];
> +};
> +
> +struct dpa_range_list_entry {
> +    uint64_t starting_dpa;
> +    uint64_t length;
> +};

Declare it above and use in CXLSanitizeInfo

> +
> +static uint64_t get_vmr_size(CXLType3Dev *ct3d, MemoryRegion **vmr)
> +{
> +    uint64_t vmr_size = 0;
> +    if (ct3d->hostvmem) {
> +        *vmr = host_memory_backend_get_memory(ct3d->hostvmem);
> +        vmr_size = memory_region_size(*vmr);
> +    }
> +    return vmr_size;
> +}
> +

I would write as

static uint64_t get_pmr_size(CXLTYpe3Dev *ct3d, MemoryRegion **pmr)
{
    MemoryRegion *mr;
    if (ct3d->hostpmem) {
        mr = host_memory_region_backend_get_memory(ct3d->hostpmem);
        if (pmr) {
            *pmr = mr;
        }
	return memory_region_size(mr);
    }
    return 0;
}

Making the pmr argument optional for when you don't need it.

> +static uint64_t get_pmr_size(CXLType3Dev *ct3d, MemoryRegion **pmr)
> +{
> +    uint64_t pmr_size = 0;
> +    if (ct3d->hostpmem) {
> +        *pmr = host_memory_backend_get_memory(ct3d->hostpmem);
> +        pmr_size = memory_region_size(*pmr);
> +    }
> +    return pmr_size;
> +}
> +
> +static uint64_t get_dc_size(CXLType3Dev *ct3d, MemoryRegion **dc_mr)
> +{
> +    uint64_t dc_size = 0;
> +    if (ct3d->dc.host_dc) {
> +        *dc_mr = host_memory_backend_get_memory(ct3d->dc.host_dc);
> +        dc_size = memory_region_size(*dc_mr);
> +    }
> +    return dc_size;
> +}
> +
> +static int validate_dpa_addr(CXLType3Dev *ct3d, uint64_t dpa_addr,
> +                             size_t length)
> +{
> +    MemoryRegion *vmr = NULL, *pmr = NULL, *dc_mr = NULL;
> +    uint64_t vmr_size = 0, pmr_size = 0, dc_size = 0;

overwritten in all paths were we use them. So don't assign initial values.

> +
> +    if ((dpa_addr % CXL_CACHELINE_SIZE) ||
> +         (length % CXL_CACHELINE_SIZE)  ||
> +         (length <= 0)) {
Align as
    if ((dpa_addr % CXL_CACHELINE_SIZE) ||
        (length % CXL_CACHELINE_SIZE) ||
        (length <= 0)) {

> +        return -EINVAL;
> +    }
> +
> +    vmr_size = get_vmr_size(ct3d, &vmr);
> +    pmr_size = get_pmr_size(ct3d, &pmr);
> +    dc_size = get_dc_size(ct3d, &dc_mr);
> +
> +    if (!vmr && !pmr && !dc_mr) {

That's a bit late given you used them to get the sizes.
Do this before filling sizes.

> +        return -ENODEV;
> +    }
> +
> +    if ((dpa_addr + length) > vmr_size + pmr_size + dc_size) {
Skip inner brackets.

> +        return -EINVAL;
> +    }
> +
> +    if (dpa_addr > vmr_size + pmr_size) {
> +        if (!ct3_test_region_block_backed(ct3d, dpa_addr, length)) {
> +            return -ENODEV;
> +        }
> +    }
> +
> +    return 0;
> +}
> +
> +static int sanitize_range(CXLType3Dev *ct3d, uint64_t dpa_addr, size_t length,
> +                          uint8_t fill_value)
> +{
> +
> +    MemoryRegion *vmr = NULL, *pmr = NULL;
> +    uint64_t vmr_size = 0, pmr_size = 0;
> +    AddressSpace *as = NULL;
> +    MemTxAttrs mem_attrs = {0};
> +
> +    vmr_size = get_vmr_size(ct3d, &vmr);
> +    pmr_size = get_pmr_size(ct3d, &pmr);
> +
> +    if (dpa_addr < vmr_size) {
> +        as = &ct3d->hostvmem_as;
> +    } else if (dpa_addr < vmr_size + pmr_size) {
> +        as = &ct3d->hostpmem_as;
> +    } else {
> +        if (!ct3_test_region_block_backed(ct3d, dpa_addr, length)) {
> +            return -ENODEV;
> +        }
> +        as = &ct3d->dc.host_dc_as;
> +    }
> +
> +    return address_space_set(as, dpa_addr,
> +                              fill_value, length, mem_attrs);

Odd wrap.  Put as much as fits on line under 80 chars on first line
then align next line to just after (

> +}
> +
> +/* Perform the actual device zeroing */
> +static void __do_sanitize(CXLType3Dev *ct3d)
> +{
> +    struct CXLSanitizeInfo  *san_info = ct3d->media_op_sanitize;
> +    int dpa_range_count = san_info->dpa_range_count;
> +    int rc = 0;
> +
> +    for (int i = 0; i < dpa_range_count; i++) {

Declare i outside loop (match local style).

> +        rc = sanitize_range(ct3d, san_info->dpa_range_list[i].starting_dpa,
> +                san_info->dpa_range_list[i].length, san_info->fill_value);

Either align 4 spaces after start of line above, or immediately after (

> +        if (rc) {
> +            goto exit;
> +        }
> +    }
> +exit:
> +    g_free(ct3d->media_op_sanitize);
> +    ct3d->media_op_sanitize = NULL;
> +    return;
> +}
> +
>  enum {
>      MEDIA_OP_CLASS_GENERAL  = 0x0,
>          #define MEDIA_OP_GEN_SUBC_DISCOVERY 0x0
> @@ -1760,9 +1884,9 @@ static const struct media_op_supported_list_entry media_op_matrix[] = {
>  };
>  
>  static CXLRetCode media_operations_discovery(uint8_t *payload_in,
> -                                                size_t len_in,
> -                                                uint8_t *payload_out,
> -                                                size_t *len_out)
> +                                             size_t len_in,
> +                                             uint8_t *payload_out,
> +                                             size_t *len_out)

Ah. Drag this to earlier patch.

>  {
>      struct {
>          uint8_t media_operation_class;
> @@ -1811,6 +1935,66 @@ static CXLRetCode media_operations_discovery(uint8_t *payload_in,
>      return CXL_MBOX_SUCCESS;
>  }
>  
> +static CXLRetCode media_operations_sanitize(CXLType3Dev *ct3d,
> +                                            uint8_t *payload_in,
> +                                            size_t len_in,
> +                                            uint8_t *payload_out,
> +                                            size_t *len_out,
> +                                            uint8_t fill_value,
> +                                            CXLCCI *cci)
> +{
> +    struct media_operations_sanitize {
> +        uint8_t media_operation_class;
> +        uint8_t media_operation_subclass;
> +        uint8_t rsvd[2];
> +        uint32_t dpa_range_count;
> +        struct {
> +            uint64_t starting_dpa;
> +            uint64_t length;
> +        } dpa_range_list[];
> +    } QEMU_PACKED *media_op_in_sanitize_pl = (void *)payload_in;
> +    uint32_t dpa_range_count = media_op_in_sanitize_pl->dpa_range_count;
> +    uint64_t total_mem = 0;
> +    int secs = 0;
> +
> +    if (len_in < (sizeof(*media_op_in_sanitize_pl) +
> +           (dpa_range_count * sizeof(struct dpa_range_list_entry)))) {
> +        return CXL_MBOX_INVALID_PAYLOAD_LENGTH;
> +    }
> +
> +    for (int i = 0; i < dpa_range_count; i++) {

Declare outside of there (to match local style)

> +        if (validate_dpa_addr(ct3d,
> +            media_op_in_sanitize_pl->dpa_range_list[i].starting_dpa,

Hmm. This is tricky to read because of alignment.  I'd have local
start_dpa nad length variables.

    for (i = 0; i < dpa_range_count; i++) {
        uint64_t start_dpa = media_op_in_sanitize_pl->dpa_range_list[i].starting_dpa;
        uint64_t length = media_op_in_sanitize_pl->dpa_range_list[i].length;

	if (validate_dpa_addr(ct3d, dpa_start, length)) {

> +            media_op_in_sanitize_pl->dpa_range_list[i].length)) {
> +            return CXL_MBOX_INVALID_INPUT;
> +        }
> +        total_mem += media_op_in_sanitize_pl->dpa_range_list[i].length;
> +    }
> +    ct3d->media_op_sanitize = g_malloc0(sizeof(struct CXLSanitizeInfo) +
> +                                  (dpa_range_count *
> +                                  sizeof(struct dpa_range_list_entry)));
> +
> +    if (ct3d->media_op_sanitize) {
> +        ct3d->media_op_sanitize->dpa_range_count = dpa_range_count;
> +        ct3d->media_op_sanitize->fill_value = fill_value;
> +        memcpy(ct3d->media_op_sanitize->dpa_range_list,
> +                  media_op_in_sanitize_pl->dpa_range_list,
> +                  (dpa_range_count *
> +                  sizeof(struct dpa_range_list_entry)));
> +        secs = get_sanitize_duration(total_mem >> 20);
> +    }
> +
> +    /* EBUSY other bg cmds as of now */
> +    cci->bg.runtime = secs * 1000UL;
> +    *len_out = 0;
> +    /*
> +     * media op sanitize is targeted so no need to disable media or
> +     * clear event logs
> +     */
> +    return CXL_MBOX_BG_STARTED;
> +

No blank line here.

> +}
> +
>  static CXLRetCode cmd_media_operations(const struct cxl_cmd *cmd,
>                                           uint8_t *payload_in,
>                                           size_t len_in,
> @@ -1825,6 +2009,9 @@ static CXLRetCode cmd_media_operations(const struct cxl_cmd *cmd,
>          uint32_t dpa_range_count;
>      } QEMU_PACKED *media_op_in_common_pl = (void *)payload_in;
>  
> +    CXLType3Dev *ct3d = CXL_TYPE3(cci->d);
> +    uint8_t fill_value = 0;

Maybe just put this value in directly into where it is used?

> +
>      if (len_in < sizeof(*media_op_in_common_pl)) {
>          return CXL_MBOX_INVALID_PAYLOAD_LENGTH;
>      }
> @@ -1851,15 +2038,29 @@ static CXLRetCode cmd_media_operations(const struct cxl_cmd *cmd,
>          return media_operations_discovery(payload_in, len_in, payload_out,
>                                               len_out);
>      case MEDIA_OP_CLASS_SANITIZE:
> +        if (dpa_range_count == 0) {
> +            return CXL_MBOX_SUCCESS;
> +        }
>          switch (media_op_subclass) {
> +        case MEDIA_OP_SAN_SUBC_SANITIZE:
> +            fill_value = 0xF;
> +            return media_operations_sanitize(ct3d, payload_in, len_in,
> +                                             payload_out, len_out, fill_value,
> +                                             cci);
> +            break;

Can reach this break so remove it.

> +        case MEDIA_OP_SAN_SUBC_ZERO:
> +            fill_value = 0;
> +            return media_operations_sanitize(ct3d, payload_in, len_in,
> +                                             payload_out, len_out, fill_value,
> +                                             cci);
> +            break;

Can't reach this break either.

>          default:
>              return CXL_MBOX_UNSUPPORTED;
>          }
> +        break;
>      default:
>          return CXL_MBOX_UNSUPPORTED;
>      }
> -
> -    return CXL_MBOX_SUCCESS;

This removal belongs in patch 1

>  }

> diff --git a/include/hw/cxl/cxl_device.h b/include/hw/cxl/cxl_device.h
> index a64739be25..b391a293a8 100644
> --- a/include/hw/cxl/cxl_device.h
> +++ b/include/hw/cxl/cxl_device.h
> @@ -581,6 +581,8 @@ typedef struct CXLSetFeatureInfo {
>      size_t data_size;
>  } CXLSetFeatureInfo;
>  
> +struct CXLSanitizeInfo;
> +
>  struct CXLType3Dev {
>      /* Private */
>      PCIDevice parent_obj;
> @@ -651,6 +653,8 @@ struct CXLType3Dev {
>          uint8_t num_regions; /* 0-8 regions */
>          CXLDCRegion regions[DCD_MAX_NUM_REGION];
>      } dc;
> +
> +    struct CXLSanitizeInfo  *media_op_sanitize;

Only one place before *

>  };
>  
>  #define TYPE_CXL_TYPE3 "cxl-type3"