[PATCH v3 1/3] crypto: qat - use pre-allocated buffers in datapath

Giovanni Cabiddu
2022-04-10T19:47:17Z

In order to do DMAs, the QAT device requires that the scatterlist
structures are mapped and translated into a format that the firmware can
understand. This is defined as the composition of a scatter gather list
(SGL) descriptor header, the struct qat_alg_buf_list, plus a variable
number of flat buffer descriptors, the struct qat_alg_buf.

The allocation and mapping of these data structures is done each time a
request is received from the skcipher and aead APIs.
In an OOM situation, this behaviour might lead to a dead-lock if an
allocation fails.

Based on the conversation in [1], increase the size of the aead and
skcipher request contexts to include an SGL descriptor that can handle
a maximum of 4 flat buffers.
If requests exceed 4 entries buffers, memory is allocated dynamically.

In addition, remove the CRYPTO_ALG_ALLOCATES_MEMORY flag from both aead
and skcipher alg structures.

[1] https://lore.kernel.org/linux-crypto/20200722072932.GA27544@gondor.apana.org.au/

Cc: stable@vger.kernel.org
Fixes: d370cec32194 ("crypto: qat - Intel(R) QAT crypto interface")
Reported-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Giovanni Cabiddu <giovanni.cabiddu@intel.com>
Reviewed-by: Marco Chiappero <marco.chiappero@intel.com>
Reviewed-by: Wojciech Ziemba <wojciech.ziemba@intel.com>
---
drivers/crypto/qat/qat_common/qat_algs.c | 77 ++++++++++++----------
drivers/crypto/qat/qat_common/qat_crypto.h | 24 +++++++
2 files changed, 67 insertions(+), 34 deletions(-)

diff --git a/drivers/crypto/qat/qat_common/qat_algs.c b/drivers/crypto/qat/qat_common/qat_algs.c
index f998ed58457c..b9228f3a26de 100644
--- a/drivers/crypto/qat/qat_common/qat_algs.c
+++ b/drivers/crypto/qat/qat_common/qat_algs.c
@@ -46,19 +46,6 @@
static DEFINE_MUTEX(algs_lock);
static unsigned int active_devs;

-struct qat_alg_buf {
- u32 len;
- u32 resrvd;
- u64 addr;
-} __packed;
-
-struct qat_alg_buf_list {
- u64 resrvd;
- u32 num_bufs;
- u32 num_mapped_bufs;
- struct qat_alg_buf bufers[];
-} __packed __aligned(64);
-
/* Common content descriptor */
struct qat_alg_cd {
union {
@@ -693,7 +680,10 @@ static void qat_alg_free_bufl(struct qat_crypto_instance *inst,
bl->bufers[i].len, DMA_BIDIRECTIONAL);

dma_unmap_single(dev, blp, sz, DMA_TO_DEVICE);
- kfree(bl);
+
+ if (!qat_req->buf.sgl_src_valid)
+ kfree(bl);
+
if (blp != blpout) {
/* If out of place operation dma unmap only data */
int bufless = blout->num_bufs - blout->num_mapped_bufs;
@@ -704,7 +694,9 @@ static void qat_alg_free_bufl(struct qat_crypto_instance *inst,
DMA_BIDIRECTIONAL);
}
dma_unmap_single(dev, blpout, sz_out, DMA_TO_DEVICE);
- kfree(blout);
+
+ if (!qat_req->buf.sgl_dst_valid)
+ kfree(blout);
}
}

@@ -721,15 +713,24 @@ static int qat_alg_sgl_to_bufl(struct qat_crypto_instance *inst,
dma_addr_t blp = DMA_MAPPING_ERROR;
dma_addr_t bloutp = DMA_MAPPING_ERROR;
struct scatterlist *sg;
- size_t sz_out, sz = struct_size(bufl, bufers, n + 1);
+ size_t sz_out, sz = struct_size(bufl, bufers, n);
+ int node = dev_to_node(&GET_DEV(inst->accel_dev));

if (unlikely(!n))
return -EINVAL;

- bufl = kzalloc_node(sz, GFP_ATOMIC,
- dev_to_node(&GET_DEV(inst->accel_dev)));
- if (unlikely(!bufl))
- return -ENOMEM;
+ qat_req->buf.sgl_src_valid = false;
+ qat_req->buf.sgl_dst_valid = false;
+
+ if (n > QAT_MAX_BUFF_DESC) {
+ bufl = kzalloc_node(sz, GFP_ATOMIC, node);
+ if (unlikely(!bufl))
+ return -ENOMEM;
+ } else {
+ bufl = &qat_req->buf.sgl_src.sgl_hdr;
+ memset(bufl, 0, sizeof(struct qat_alg_buf_list));
+ qat_req->buf.sgl_src_valid = true;
+ }

for_each_sg(sgl, sg, n, i)
bufl->bufers[i].addr = DMA_MAPPING_ERROR;
@@ -760,12 +761,18 @@ static int qat_alg_sgl_to_bufl(struct qat_crypto_instance *inst,
struct qat_alg_buf *bufers;

n = sg_nents(sglout);
- sz_out = struct_size(buflout, bufers, n + 1);
+ sz_out = struct_size(buflout, bufers, n);
sg_nctr = 0;
- buflout = kzalloc_node(sz_out, GFP_ATOMIC,
- dev_to_node(&GET_DEV(inst->accel_dev)));
- if (unlikely(!buflout))
- goto err_in;
+
+ if (n > QAT_MAX_BUFF_DESC) {
+ buflout = kzalloc_node(sz_out, GFP_ATOMIC, node);
+ if (unlikely(!buflout))
+ goto err_in;
+ } else {
+ buflout = &qat_req->buf.sgl_dst.sgl_hdr;
+ memset(buflout, 0, sizeof(struct qat_alg_buf_list));
+ qat_req->buf.sgl_dst_valid = true;
+ }

bufers = buflout->bufers;
for_each_sg(sglout, sg, n, i)
@@ -810,7 +817,9 @@ static int qat_alg_sgl_to_bufl(struct qat_crypto_instance *inst,
dma_unmap_single(dev, buflout->bufers[i].addr,
buflout->bufers[i].len,
DMA_BIDIRECTIONAL);
- kfree(buflout);
+
+ if (!qat_req->buf.sgl_dst_valid)
+ kfree(buflout);

err_in:
if (!dma_mapping_error(dev, blp))
@@ -823,7 +832,8 @@ static int qat_alg_sgl_to_bufl(struct qat_crypto_instance *inst,
bufl->bufers[i].len,
DMA_BIDIRECTIONAL);

- kfree(bufl);
+ if (!qat_req->buf.sgl_src_valid)
+ kfree(bufl);

dev_err(dev, "Failed to map buf for dma\n");
return -ENOMEM;
@@ -1434,7 +1444,7 @@ static struct aead_alg qat_aeads[] = { {
.cra_name = "authenc(hmac(sha1),cbc(aes))",
.cra_driver_name = "qat_aes_cbc_hmac_sha1",
.cra_priority = 4001,
- .cra_flags = CRYPTO_ALG_ASYNC | CRYPTO_ALG_ALLOCATES_MEMORY,
+ .cra_flags = CRYPTO_ALG_ASYNC,
.cra_blocksize = AES_BLOCK_SIZE,
.cra_ctxsize = sizeof(struct qat_alg_aead_ctx),
.cra_module = THIS_MODULE,
@@ -1451,7 +1461,7 @@ static struct aead_alg qat_aeads[] = { {
.cra_name = "authenc(hmac(sha256),cbc(aes))",
.cra_driver_name = "qat_aes_cbc_hmac_sha256",
.cra_priority = 4001,
- .cra_flags = CRYPTO_ALG_ASYNC | CRYPTO_ALG_ALLOCATES_MEMORY,
+ .cra_flags = CRYPTO_ALG_ASYNC,
.cra_blocksize = AES_BLOCK_SIZE,
.cra_ctxsize = sizeof(struct qat_alg_aead_ctx),
.cra_module = THIS_MODULE,
@@ -1468,7 +1478,7 @@ static struct aead_alg qat_aeads[] = { {
.cra_name = "authenc(hmac(sha512),cbc(aes))",
.cra_driver_name = "qat_aes_cbc_hmac_sha512",
.cra_priority = 4001,
- .cra_flags = CRYPTO_ALG_ASYNC | CRYPTO_ALG_ALLOCATES_MEMORY,
+ .cra_flags = CRYPTO_ALG_ASYNC,
.cra_blocksize = AES_BLOCK_SIZE,
.cra_ctxsize = sizeof(struct qat_alg_aead_ctx),
.cra_module = THIS_MODULE,
@@ -1486,7 +1496,7 @@ static struct skcipher_alg qat_skciphers[] = { {
.base.cra_name = "cbc(aes)",
.base.cra_driver_name = "qat_aes_cbc",
.base.cra_priority = 4001,
- .base.cra_flags = CRYPTO_ALG_ASYNC | CRYPTO_ALG_ALLOCATES_MEMORY,
+ .base.cra_flags = CRYPTO_ALG_ASYNC,
.base.cra_blocksize = AES_BLOCK_SIZE,
.base.cra_ctxsize = sizeof(struct qat_alg_skcipher_ctx),
.base.cra_alignmask = 0,
@@ -1504,7 +1514,7 @@ static struct skcipher_alg qat_skciphers[] = { {
.base.cra_name = "ctr(aes)",
.base.cra_driver_name = "qat_aes_ctr",
.base.cra_priority = 4001,
- .base.cra_flags = CRYPTO_ALG_ASYNC | CRYPTO_ALG_ALLOCATES_MEMORY,
+ .base.cra_flags = CRYPTO_ALG_ASYNC,
.base.cra_blocksize = 1,
.base.cra_ctxsize = sizeof(struct qat_alg_skcipher_ctx),
.base.cra_alignmask = 0,
@@ -1522,8 +1532,7 @@ static struct skcipher_alg qat_skciphers[] = { {
.base.cra_name = "xts(aes)",
.base.cra_driver_name = "qat_aes_xts",
.base.cra_priority = 4001,
- .base.cra_flags = CRYPTO_ALG_ASYNC | CRYPTO_ALG_NEED_FALLBACK |
- CRYPTO_ALG_ALLOCATES_MEMORY,
+ .base.cra_flags = CRYPTO_ALG_ASYNC | CRYPTO_ALG_NEED_FALLBACK,
.base.cra_blocksize = AES_BLOCK_SIZE,
.base.cra_ctxsize = sizeof(struct qat_alg_skcipher_ctx),
.base.cra_alignmask = 0,
diff --git a/drivers/crypto/qat/qat_common/qat_crypto.h b/drivers/crypto/qat/qat_common/qat_crypto.h
index b6a4c95ae003..0928f159ea99 100644
--- a/drivers/crypto/qat/qat_common/qat_crypto.h
+++ b/drivers/crypto/qat/qat_common/qat_crypto.h
@@ -21,6 +21,26 @@ struct qat_crypto_instance {
atomic_t refctr;
};

+#define QAT_MAX_BUFF_DESC 4
+
+struct qat_alg_buf {
+ u32 len;
+ u32 resrvd;
+ u64 addr;
+} __packed;
+
+struct qat_alg_buf_list {
+ u64 resrvd;
+ u32 num_bufs;
+ u32 num_mapped_bufs;
+ struct qat_alg_buf bufers[];
+} __packed;
+
+struct qat_alg_fixed_buf_list {
+ struct qat_alg_buf_list sgl_hdr;
+ struct qat_alg_buf descriptors[QAT_MAX_BUFF_DESC];
+} __packed __aligned(64);
+
struct qat_crypto_request_buffs {
struct qat_alg_buf_list *bl;
dma_addr_t blp;
@@ -28,6 +48,10 @@ struct qat_crypto_request_buffs {
dma_addr_t bloutp;
size_t sz;
size_t sz_out;
+ bool sgl_src_valid;
+ bool sgl_dst_valid;
+ struct qat_alg_fixed_buf_list sgl_src;
+ struct qat_alg_fixed_buf_list sgl_dst;
};

struct qat_crypto_request;
--
2.35.1