Re: [Qemu PATCH v2 1/9] hw/cxl/cxl-mailbox-utils: Add dc_event_log_size field to output payload of identify memory device command

[Jonathan Cameron <Jonathan.Cameron@Huawei.com>]

On Tue, 25 Jul 2023 18:39:55 +0000
Fan Ni <fan.ni@samsung.com> wrote:

> From: Fan Ni <nifan@outlook.com>
> 
> Based on CXL spec 3.0 Table 8-94 (Identify Memory Device Output
> Payload), dynamic capacity event log size should be part of
> output of the Identify command.
> Add dc_event_log_size to the output payload for the host to get the info.
> 
> Signed-off-by: Fan Ni <fan.ni@samsung.com>
> ---
>  hw/cxl/cxl-mailbox-utils.c | 6 +++++-
>  1 file changed, 5 insertions(+), 1 deletion(-)
> 
> diff --git a/hw/cxl/cxl-mailbox-utils.c b/hw/cxl/cxl-mailbox-utils.c
> index ad7a6116e4..b013e30314 100644
> --- a/hw/cxl/cxl-mailbox-utils.c
> +++ b/hw/cxl/cxl-mailbox-utils.c
> @@ -21,6 +21,8 @@
>  #include "sysemu/hostmem.h"
>  
>  #define CXL_CAPACITY_MULTIPLIER   (256 * MiB)
> +/* Experimental value: dynamic capacity event log size */

It's got to have some value.  Not sure why this is 'experimental'.
As such I would drop the comment as not helpful.

> +#define CXL_DC_EVENT_LOG_SIZE 8
>  
>  /*
>   * How to add a new command, example. The command set FOO, with cmd BAR.
> @@ -519,8 +521,9 @@ static CXLRetCode cmd_identify_memory_device(struct cxl_cmd *cmd,
>          uint16_t inject_poison_limit;
>          uint8_t poison_caps;
>          uint8_t qos_telemetry_caps;
> +        uint16_t dc_event_log_size;
>      } QEMU_PACKED *id;
> -    QEMU_BUILD_BUG_ON(sizeof(*id) != 0x43);
> +    QEMU_BUILD_BUG_ON(sizeof(*id) != 0x45);
>  
>      CXLType3Dev *ct3d = container_of(cxl_dstate, CXLType3Dev, cxl_dstate);
>      CXLType3Class *cvc = CXL_TYPE3_GET_CLASS(ct3d);
> @@ -543,6 +546,7 @@ static CXLRetCode cmd_identify_memory_device(struct cxl_cmd *cmd,
>      st24_le_p(id->poison_list_max_mer, 256);
>      /* No limit - so limited by main poison record limit */
>      stw_le_p(&id->inject_poison_limit, 0);
> +    stw_le_p(&id->dc_event_log_size, CXL_DC_EVENT_LOG_SIZE);
>  
>      *len = sizeof(*id);
>      return CXL_MBOX_SUCCESS;