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

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

[nifan.cxl]

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

[Philippe Mathieu-Daudé]

Hi,

On 21/2/24 19:53, 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/latest/source/hw/cxl/cxl-device-utils.c#L204

Since "latest" isn't stable, this link won't be accurate in 6 months.

Please use the current release:
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(-)

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

[fan]

On Wed, Feb 21, 2024 at 09:59:49PM +0100, Philippe Mathieu-Daudé wrote:
> Hi,
> 
> On 21/2/24 19:53, 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/latest/source/hw/cxl/cxl-device-utils.c#L204
> 
> Since "latest" isn't stable, this link won't be accurate in 6 months.
> 
> Please use the current release:
> https://elixir.bootlin.com/qemu/v8.2.1/source/hw/cxl/cxl-device-utils.c#L204
> 

Thanks, Philippe. 

Just sent out v2 as you suggested.
https://lore.kernel.org/linux-cxl/20240221221824.1092966-1-nifan.cxl@gmail.com/T/#u

Fan

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