From: Dan Williams <dan.j.williams@intel.com>
To: dave.jiang@intel.com
Cc: Kwangjin Ko <kwangjin.ko@sk.com>,
Alison Schofield <alison.schofield@intel.com>,
linux-cxl@vger.kernel.org
Subject: [PATCH] cxl/core: Fix potential payload size confusion in cxl_mem_get_poison()
Date: Fri, 05 Apr 2024 15:00:16 -0700 [thread overview]
Message-ID: <171235441633.2716581.12330082428680958635.stgit@dwillia2-xfh.jf.intel.com> (raw)
A recent change to cxl_mem_get_records_log() [1] highlighted a subtle
nuance of looping calls to cxl_internal_send_cmd(), i.e. that
cxl_internal_send_cmd() modifies the 'size_out' member of the @mbox_cmd
argument. That mechanism is useful for communicating underflow, but it
is unwanted when reusing @mbox_cmd for a subsequent submission. It turns
out that cxl_xfer_log() avoids this scenario by always redefining
@mbox_cmd each iteration.
Update cxl_mem_get_records_log() and cxl_mem_get_poison() to follow the
same style as cxl_xfer_log(), i.e. re-define @mbox_cmd each iteration.
The cxl_mem_get_records_log() change is just a style fixup, but the
cxl_mem_get_poison() change is a potential fix, per Alison [2]:
Poison list retrieval can hit this case if the MORE flag is set and
a follow on read of the list delivers more records than the previous
read. ie. device gives one record, sets the _MORE flag, then gives 5.
Not an urgent fix since this behavior has not been seen in the wild,
but worth tracking as a fix.
Cc: Kwangjin Ko <kwangjin.ko@sk.com>
Cc: Alison Schofield <alison.schofield@intel.com>
Fixes: ed83f7ca398b ("cxl/mbox: Add GET_POISON_LIST mailbox command")
Link: http://lore.kernel.org/r/20240402081404.1106-2-kwangjin.ko@sk.com [1]
Link: http://lore.kernel.org/r/ZhAhAL/GOaWFrauw@aschofie-mobl2 [2]
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
---
drivers/cxl/core/mbox.c | 38 +++++++++++++++++---------------------
1 file changed, 17 insertions(+), 21 deletions(-)
diff --git a/drivers/cxl/core/mbox.c b/drivers/cxl/core/mbox.c
index f0f54aeccc87..65185c9fa001 100644
--- a/drivers/cxl/core/mbox.c
+++ b/drivers/cxl/core/mbox.c
@@ -946,25 +946,22 @@ static void cxl_mem_get_records_log(struct cxl_memdev_state *mds,
struct cxl_memdev *cxlmd = mds->cxlds.cxlmd;
struct device *dev = mds->cxlds.dev;
struct cxl_get_event_payload *payload;
- struct cxl_mbox_cmd mbox_cmd;
u8 log_type = type;
u16 nr_rec;
mutex_lock(&mds->event.log_lock);
payload = mds->event.buf;
- mbox_cmd = (struct cxl_mbox_cmd) {
- .opcode = CXL_MBOX_OP_GET_EVENT_RECORD,
- .payload_in = &log_type,
- .size_in = sizeof(log_type),
- .payload_out = payload,
- .min_out = struct_size(payload, records, 0),
- };
-
do {
int rc, i;
-
- mbox_cmd.size_out = mds->payload_size;
+ struct cxl_mbox_cmd mbox_cmd = (struct cxl_mbox_cmd) {
+ .opcode = CXL_MBOX_OP_GET_EVENT_RECORD,
+ .payload_in = &log_type,
+ .size_in = sizeof(log_type),
+ .payload_out = payload,
+ .size_out = mds->payload_size,
+ .min_out = struct_size(payload, records, 0),
+ };
rc = cxl_internal_send_cmd(mds, &mbox_cmd);
if (rc) {
@@ -1297,7 +1294,6 @@ int cxl_mem_get_poison(struct cxl_memdev *cxlmd, u64 offset, u64 len,
struct cxl_memdev_state *mds = to_cxl_memdev_state(cxlmd->cxlds);
struct cxl_mbox_poison_out *po;
struct cxl_mbox_poison_in pi;
- struct cxl_mbox_cmd mbox_cmd;
int nr_records = 0;
int rc;
@@ -1309,16 +1305,16 @@ int cxl_mem_get_poison(struct cxl_memdev *cxlmd, u64 offset, u64 len,
pi.offset = cpu_to_le64(offset);
pi.length = cpu_to_le64(len / CXL_POISON_LEN_MULT);
- mbox_cmd = (struct cxl_mbox_cmd) {
- .opcode = CXL_MBOX_OP_GET_POISON,
- .size_in = sizeof(pi),
- .payload_in = &pi,
- .size_out = mds->payload_size,
- .payload_out = po,
- .min_out = struct_size(po, record, 0),
- };
-
do {
+ struct cxl_mbox_cmd mbox_cmd = (struct cxl_mbox_cmd){
+ .opcode = CXL_MBOX_OP_GET_POISON,
+ .size_in = sizeof(pi),
+ .payload_in = &pi,
+ .size_out = mds->payload_size,
+ .payload_out = po,
+ .min_out = struct_size(po, record, 0),
+ };
+
rc = cxl_internal_send_cmd(mds, &mbox_cmd);
if (rc)
break;
next reply other threads:[~2024-04-05 22:00 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-04-05 22:00 Dan Williams [this message]
2024-04-05 23:59 ` [PATCH] cxl/core: Fix potential payload size confusion in cxl_mem_get_poison() Alison Schofield
2024-04-20 0:09 ` Ira Weiny
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=171235441633.2716581.12330082428680958635.stgit@dwillia2-xfh.jf.intel.com \
--to=dan.j.williams@intel.com \
--cc=alison.schofield@intel.com \
--cc=dave.jiang@intel.com \
--cc=kwangjin.ko@sk.com \
--cc=linux-cxl@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).