This is a note to let you know that I've just added the patch titled
RDMA/irdma: Add missing read barriers
to the 5.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
rdma-irdma-add-missing-read-barriers.patch
and it can be found in the queue-5.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 7faeeb29116796bc154b40d070f2cef173274f31
Author: Shiraz Saleem <shiraz.saleem@xxxxxxxxx>
Date: Tue Jul 11 12:52:51 2023 -0500
RDMA/irdma: Add missing read barriers
[ Upstream commit 4984eb51453ff7eddee9e5ce816145be39c0ec5c ]
On code inspection, there are many instances in the driver where
CEQE and AEQE fields written to by HW are read without guaranteeing
that the polarity bit has been read and checked first.
Add a read barrier to avoid reordering of loads on the CEQE/AEQE fields
prior to checking the polarity bit.
Fixes: 3f49d6842569 ("RDMA/irdma: Implement HW Admin Queue OPs")
Signed-off-by: Shiraz Saleem <shiraz.saleem@xxxxxxxxx>
Link: https://lore.kernel.org/r/20230711175253.1289-2-shiraz.saleem@xxxxxxxxx
Signed-off-by: Leon Romanovsky <leon@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/infiniband/hw/irdma/ctrl.c b/drivers/infiniband/hw/irdma/ctrl.c
index 1ac7067e21be1..ab195ae089cfd 100644
--- a/drivers/infiniband/hw/irdma/ctrl.c
+++ b/drivers/infiniband/hw/irdma/ctrl.c
@@ -3395,6 +3395,9 @@ enum irdma_status_code irdma_sc_ccq_get_cqe_info(struct irdma_sc_cq *ccq,
if (polarity != ccq->cq_uk.polarity)
return IRDMA_ERR_Q_EMPTY;
+ /* Ensure CEQE contents are read after valid bit is checked */
+ dma_rmb();
+
get_64bit_val(cqe, 8, &qp_ctx);
cqp = (struct irdma_sc_cqp *)(unsigned long)qp_ctx;
info->error = (bool)FIELD_GET(IRDMA_CQ_ERROR, temp);
@@ -4046,13 +4049,17 @@ enum irdma_status_code irdma_sc_get_next_aeqe(struct irdma_sc_aeq *aeq,
u8 polarity;
aeqe = IRDMA_GET_CURRENT_AEQ_ELEM(aeq);
- get_64bit_val(aeqe, 0, &compl_ctx);
get_64bit_val(aeqe, 8, &temp);
polarity = (u8)FIELD_GET(IRDMA_AEQE_VALID, temp);
if (aeq->polarity != polarity)
return IRDMA_ERR_Q_EMPTY;
+ /* Ensure AEQE contents are read after valid bit is checked */
+ dma_rmb();
+
+ get_64bit_val(aeqe, 0, &compl_ctx);
+
print_hex_dump_debug("WQE: AEQ_ENTRY WQE", DUMP_PREFIX_OFFSET, 16, 8,
aeqe, 16, false);
diff --git a/drivers/infiniband/hw/irdma/puda.c b/drivers/infiniband/hw/irdma/puda.c
index 58e7d875643b8..197eba5eb78fa 100644
--- a/drivers/infiniband/hw/irdma/puda.c
+++ b/drivers/infiniband/hw/irdma/puda.c
@@ -235,6 +235,9 @@ irdma_puda_poll_info(struct irdma_sc_cq *cq, struct irdma_puda_cmpl_info *info)
if (valid_bit != cq_uk->polarity)
return IRDMA_ERR_Q_EMPTY;
+ /* Ensure CQE contents are read after valid bit is checked */
+ dma_rmb();
+
if (cq->dev->hw_attrs.uk_attrs.hw_rev >= IRDMA_GEN_2)
ext_valid = (bool)FIELD_GET(IRDMA_CQ_EXTCQE, qword3);
@@ -248,6 +251,9 @@ irdma_puda_poll_info(struct irdma_sc_cq *cq, struct irdma_puda_cmpl_info *info)
if (polarity != cq_uk->polarity)
return IRDMA_ERR_Q_EMPTY;
+ /* Ensure ext CQE contents are read after ext valid bit is checked */
+ dma_rmb();
+
IRDMA_RING_MOVE_HEAD_NOCHECK(cq_uk->cq_ring);
if (!IRDMA_RING_CURRENT_HEAD(cq_uk->cq_ring))
cq_uk->polarity = !cq_uk->polarity;
diff --git a/drivers/infiniband/hw/irdma/uk.c b/drivers/infiniband/hw/irdma/uk.c
index a348f0c010ab3..4b00a9adbe3a5 100644
--- a/drivers/infiniband/hw/irdma/uk.c
+++ b/drivers/infiniband/hw/irdma/uk.c
@@ -1549,6 +1549,9 @@ void irdma_uk_clean_cq(void *q, struct irdma_cq_uk *cq)
if (polarity != temp)
break;
+ /* Ensure CQE contents are read after valid bit is checked */
+ dma_rmb();
+
get_64bit_val(cqe, 8, &comp_ctx);
if ((void *)(unsigned long)comp_ctx == q)
set_64bit_val(cqe, 8, 0);
