[v2] hw/cxl/cxl-mailbox-utils: remove unneeded mailbox output payload space zeroing

[PATCH v2] hw/cxl/cxl-mailbox-utils: remove unneeded mailbox output payload space zeroing

Posted by nifan.cxl@gmail.com 9 months, 1 week ago

From: Fan Ni <fan.ni@samsung.com>

The whole mailbox output payload space is already zeroed after copying
out the input payload, which happens before processing the specific mailbox
command:
https://elixir.bootlin.com/qemu/v8.2.1/source/hw/cxl/cxl-device-utils.c#L204

Signed-off-by: Fan Ni <fan.ni@samsung.com>
---
 hw/cxl/cxl-mailbox-utils.c | 7 -------
 1 file changed, 7 deletions(-)

diff --git a/hw/cxl/cxl-mailbox-utils.c b/hw/cxl/cxl-mailbox-utils.c
index e5eb97cb91..fda88470a3 100644
--- a/hw/cxl/cxl-mailbox-utils.c
+++ b/hw/cxl/cxl-mailbox-utils.c
@@ -226,7 +226,6 @@ static CXLRetCode cmd_events_get_records(const struct cxl_cmd *cmd,
     log_type = payload_in[0];
 
     pl = (CXLGetEventPayload *)payload_out;
-    memset(pl, 0, sizeof(*pl));
 
     max_recs = (cxlds->payload_size - CXL_EVENT_PAYLOAD_HDR_SIZE) /
                 CXL_EVENT_RECORD_SIZE;
@@ -264,7 +263,6 @@ static CXLRetCode cmd_events_get_interrupt_policy(const struct cxl_cmd *cmd,
     CXLEventLog *log;
 
     policy = (CXLEventInterruptPolicy *)payload_out;
-    memset(policy, 0, sizeof(*policy));
 
     log = &cxlds->event_logs[CXL_EVENT_TYPE_INFO];
     if (log->irq_enabled) {
@@ -363,7 +361,6 @@ static CXLRetCode cmd_infostat_identify(const struct cxl_cmd *cmd,
     QEMU_BUILD_BUG_ON(sizeof(*is_identify) != 18);
 
     is_identify = (void *)payload_out;
-    memset(is_identify, 0, sizeof(*is_identify));
     is_identify->pcie_vid = class->vendor_id;
     is_identify->pcie_did = class->device_id;
     if (object_dynamic_cast(OBJECT(cci->d), TYPE_CXL_USP)) {
@@ -597,7 +594,6 @@ static CXLRetCode cmd_infostat_bg_op_sts(const struct cxl_cmd *cmd,
     QEMU_BUILD_BUG_ON(sizeof(*bg_op_status) != 8);
 
     bg_op_status = (void *)payload_out;
-    memset(bg_op_status, 0, sizeof(*bg_op_status));
     bg_op_status->status = cci->bg.complete_pct << 1;
     if (cci->bg.runtime > 0) {
         bg_op_status->status |= 1U << 0;
@@ -636,7 +632,6 @@ static CXLRetCode cmd_firmware_update_get_info(const struct cxl_cmd *cmd,
     }
 
     fw_info = (void *)payload_out;
-    memset(fw_info, 0, sizeof(*fw_info));
 
     fw_info->slots_supported = 2;
     fw_info->slot_info = BIT(0) | BIT(3);
@@ -792,7 +787,6 @@ static CXLRetCode cmd_identify_memory_device(const struct cxl_cmd *cmd,
     }
 
     id = (void *)payload_out;
-    memset(id, 0, sizeof(*id));
 
     snprintf(id->fw_revision, 0x10, "BWFW VERSION %02d", 0);
 
@@ -1079,7 +1073,6 @@ static CXLRetCode cmd_media_get_poison_list(const struct cxl_cmd *cmd,
     out_pl_len = sizeof(*out) + record_count * sizeof(out->records[0]);
     assert(out_pl_len <= CXL_MAILBOX_MAX_PAYLOAD_SIZE);
 
-    memset(out, 0, out_pl_len);
     QLIST_FOREACH(ent, poison_list, node) {
         uint64_t start, stop;
 
-- 
2.43.0

Re: [PATCH v2] hw/cxl/cxl-mailbox-utils: remove unneeded mailbox output payload space zeroing

Posted by Jonathan Cameron via 8 months, 3 weeks ago

On Wed, 21 Feb 2024 14:18:11 -0800
nifan.cxl@gmail.com wrote:

> From: Fan Ni <fan.ni@samsung.com>
> 
> The whole mailbox output payload space is already zeroed after copying
> out the input payload, which happens before processing the specific mailbox
> command:
> https://elixir.bootlin.com/qemu/v8.2.1/source/hw/cxl/cxl-device-utils.c#L204
> 
> Signed-off-by: Fan Ni <fan.ni@samsung.com>
Good point.

I've applied this to my local tree - not rushing on this one.

Jonathan

> ---
>  hw/cxl/cxl-mailbox-utils.c | 7 -------
>  1 file changed, 7 deletions(-)
> 
> diff --git a/hw/cxl/cxl-mailbox-utils.c b/hw/cxl/cxl-mailbox-utils.c
> index e5eb97cb91..fda88470a3 100644
> --- a/hw/cxl/cxl-mailbox-utils.c
> +++ b/hw/cxl/cxl-mailbox-utils.c
> @@ -226,7 +226,6 @@ static CXLRetCode cmd_events_get_records(const struct cxl_cmd *cmd,
>      log_type = payload_in[0];
>  
>      pl = (CXLGetEventPayload *)payload_out;
> -    memset(pl, 0, sizeof(*pl));
>  
>      max_recs = (cxlds->payload_size - CXL_EVENT_PAYLOAD_HDR_SIZE) /
>                  CXL_EVENT_RECORD_SIZE;
> @@ -264,7 +263,6 @@ static CXLRetCode cmd_events_get_interrupt_policy(const struct cxl_cmd *cmd,
>      CXLEventLog *log;
>  
>      policy = (CXLEventInterruptPolicy *)payload_out;
> -    memset(policy, 0, sizeof(*policy));
>  
>      log = &cxlds->event_logs[CXL_EVENT_TYPE_INFO];
>      if (log->irq_enabled) {
> @@ -363,7 +361,6 @@ static CXLRetCode cmd_infostat_identify(const struct cxl_cmd *cmd,
>      QEMU_BUILD_BUG_ON(sizeof(*is_identify) != 18);
>  
>      is_identify = (void *)payload_out;
> -    memset(is_identify, 0, sizeof(*is_identify));
>      is_identify->pcie_vid = class->vendor_id;
>      is_identify->pcie_did = class->device_id;
>      if (object_dynamic_cast(OBJECT(cci->d), TYPE_CXL_USP)) {
> @@ -597,7 +594,6 @@ static CXLRetCode cmd_infostat_bg_op_sts(const struct cxl_cmd *cmd,
>      QEMU_BUILD_BUG_ON(sizeof(*bg_op_status) != 8);
>  
>      bg_op_status = (void *)payload_out;
> -    memset(bg_op_status, 0, sizeof(*bg_op_status));
>      bg_op_status->status = cci->bg.complete_pct << 1;
>      if (cci->bg.runtime > 0) {
>          bg_op_status->status |= 1U << 0;
> @@ -636,7 +632,6 @@ static CXLRetCode cmd_firmware_update_get_info(const struct cxl_cmd *cmd,
>      }
>  
>      fw_info = (void *)payload_out;
> -    memset(fw_info, 0, sizeof(*fw_info));
>  
>      fw_info->slots_supported = 2;
>      fw_info->slot_info = BIT(0) | BIT(3);
> @@ -792,7 +787,6 @@ static CXLRetCode cmd_identify_memory_device(const struct cxl_cmd *cmd,
>      }
>  
>      id = (void *)payload_out;
> -    memset(id, 0, sizeof(*id));
>  
>      snprintf(id->fw_revision, 0x10, "BWFW VERSION %02d", 0);
>  
> @@ -1079,7 +1073,6 @@ static CXLRetCode cmd_media_get_poison_list(const struct cxl_cmd *cmd,
>      out_pl_len = sizeof(*out) + record_count * sizeof(out->records[0]);
>      assert(out_pl_len <= CXL_MAILBOX_MAX_PAYLOAD_SIZE);
>  
> -    memset(out, 0, out_pl_len);
>      QLIST_FOREACH(ent, poison_list, node) {
>          uint64_t start, stop;
>