aspeed/hace: Support AST2600 HACE

The aspeed ast2600 accumulative mode is described in datasheet
ast2600v10.pdf section 25.6.4:
 1. Allocating and initiating accumulative hash digest write buffer
    with initial state.
    * Since QEMU crypto/hash api doesn't provide the API to set initial
      state of hash library, and the initial state is already set by
      crypto library (gcrypt/glib/...), so skip this step.
 2. Calculating accumulative hash digest.
    (a) When receiving the last accumulative data, software need to add
        padding message at the end of the accumulative data. Padding
        message described in specific of MD5, SHA-1, SHA224, SHA256,
        SHA512, SHA512/224, SHA512/256.
        * Since the crypto library (gcrypt/glib) already pad the
          padding message internally.
        * This patch is to remove the padding message which fed byguest
          machine driver.

Signed-off-by: Troy Lee <troy_lee@aspeedtech.com>
Signed-off-by: Steven Lee <steven_lee@aspeedtech.com>
Reviewed-by: Cédric Le Goater <clg@kaod.org>
Message-Id: <20220426021120.28255-3-steven_lee@aspeedtech.com>
Signed-off-by: Cédric Le Goater <clg@kaod.org>

1 files changed, 127 insertions, 5 deletions

diff --git a/hw/misc/aspeed_hace.c b/hw/misc/aspeed_hace.c
index 59fe5bfca2..0f4059e6df 100644
--- a/hw/misc/aspeed_hace.c
+++ b/hw/misc/aspeed_hace.c
@@ -65,7 +65,6 @@
 #define SG_LIST_ADDR_SIZE               4
 #define SG_LIST_ADDR_MASK               0x7FFFFFFF
 #define SG_LIST_ENTRY_SIZE              (SG_LIST_LEN_SIZE + SG_LIST_ADDR_SIZE)
-#define ASPEED_HACE_MAX_SG              256        /* max number of entries */
 
 static const struct {
     uint32_t mask;
@@ -95,11 +94,104 @@ static int hash_algo_lookup(uint32_t reg)
     return -1;
 }
 
-static void do_hash_operation(AspeedHACEState *s, int algo, bool sg_mode)
+/**
+ * Check whether the request contains padding message.
+ *
+ * @param s             aspeed hace state object
+ * @param iov           iov of current request
+ * @param req_len       length of the current request
+ * @param total_msg_len length of all acc_mode requests(excluding padding msg)
+ * @param pad_offset    start offset of padding message
+ */
+static bool has_padding(AspeedHACEState *s, struct iovec *iov,
+                        hwaddr req_len, uint32_t *total_msg_len,
+                        uint32_t *pad_offset)
+{
+    *total_msg_len = (uint32_t)(ldq_be_p(iov->iov_base + req_len - 8) / 8);
+    /*
+     * SG_LIST_LEN_LAST asserted in the request length doesn't mean it is the
+     * last request. The last request should contain padding message.
+     * We check whether message contains padding by
+     *   1. Get total message length. If the current message contains
+     *      padding, the last 8 bytes are total message length.
+     *   2. Check whether the total message length is valid.
+     *      If it is valid, the value should less than or equal to
+     *      total_req_len.
+     *   3. Current request len - padding_size to get padding offset.
+     *      The padding message's first byte should be 0x80
+     */
+    if (*total_msg_len <= s->total_req_len) {
+        uint32_t padding_size = s->total_req_len - *total_msg_len;
+        uint8_t *padding = iov->iov_base;
+        *pad_offset = req_len - padding_size;
+        if (padding[*pad_offset] == 0x80) {
+            return true;
+        }
+    }
+
+    return false;
+}
+
+static int reconstruct_iov(AspeedHACEState *s, struct iovec *iov, int id,
+                           uint32_t *pad_offset)
+{
+    int i, iov_count;
+    if (*pad_offset != 0) {
+        s->iov_cache[s->iov_count].iov_base = iov[id].iov_base;
+        s->iov_cache[s->iov_count].iov_len = *pad_offset;
+        ++s->iov_count;
+    }
+    for (i = 0; i < s->iov_count; i++) {
+        iov[i].iov_base = s->iov_cache[i].iov_base;
+        iov[i].iov_len = s->iov_cache[i].iov_len;
+    }
+    iov_count = s->iov_count;
+    s->iov_count = 0;
+    s->total_req_len = 0;
+    return iov_count;
+}
+
+/**
+ * Generate iov for accumulative mode.
+ *
+ * @param s             aspeed hace state object
+ * @param iov           iov of the current request
+ * @param id            index of the current iov
+ * @param req_len       length of the current request
+ *
+ * @return count of iov
+ */
+static int gen_acc_mode_iov(AspeedHACEState *s, struct iovec *iov, int id,
+                            hwaddr *req_len)
+{
+    uint32_t pad_offset;
+    uint32_t total_msg_len;
+    s->total_req_len += *req_len;
+
+    if (has_padding(s, &iov[id], *req_len, &total_msg_len, &pad_offset)) {
+        if (s->iov_count) {
+            return reconstruct_iov(s, iov, id, &pad_offset);
+        }
+
+        *req_len -= s->total_req_len - total_msg_len;
+        s->total_req_len = 0;
+        iov[id].iov_len = *req_len;
+    } else {
+        s->iov_cache[s->iov_count].iov_base = iov->iov_base;
+        s->iov_cache[s->iov_count].iov_len = *req_len;
+        ++s->iov_count;
+    }
+
+    return id + 1;
+}
+
+static void do_hash_operation(AspeedHACEState *s, int algo, bool sg_mode,
+                              bool acc_mode)
 {
     struct iovec iov[ASPEED_HACE_MAX_SG];
     g_autofree uint8_t *digest_buf;
     size_t digest_len = 0;
+    int niov = 0;
     int i;
 
     if (sg_mode) {
@@ -124,10 +216,16 @@ static void do_hash_operation(AspeedHACEState *s, int algo, bool sg_mode)
                                         MEMTXATTRS_UNSPECIFIED, NULL);
             addr &= SG_LIST_ADDR_MASK;
 
-            iov[i].iov_len = len & SG_LIST_LEN_MASK;
-            plen = iov[i].iov_len;
+            plen = len & SG_LIST_LEN_MASK;
             iov[i].iov_base = address_space_map(&s->dram_as, addr, &plen, false,
                                                 MEMTXATTRS_UNSPECIFIED);
+
+            if (acc_mode) {
+                niov = gen_acc_mode_iov(s, iov, i, &plen);
+
+            } else {
+                iov[i].iov_len = plen;
+            }
         }
     } else {
         hwaddr len = s->regs[R_HASH_SRC_LEN];
@@ -137,6 +235,25 @@ static void do_hash_operation(AspeedHACEState *s, int algo, bool sg_mode)
                                             &len, false,
                                             MEMTXATTRS_UNSPECIFIED);
         i = 1;
+
+        if (s->iov_count) {
+            /*
+             * In aspeed sdk kernel driver, sg_mode is disabled in hash_final().
+             * Thus if we received a request with sg_mode disabled, it is
+             * required to check whether cache is empty. If no, we should
+             * combine cached iov and the current iov.
+             */
+            uint32_t total_msg_len;
+            uint32_t pad_offset;
+            s->total_req_len += len;
+            if (has_padding(s, iov, len, &total_msg_len, &pad_offset)) {
+                niov = reconstruct_iov(s, iov, 0, &pad_offset);
+            }
+        }
+    }
+
+    if (niov) {
+        i = niov;
     }
 
     if (qcrypto_hash_bytesv(algo, iov, i, &digest_buf, &digest_len, NULL) < 0) {
@@ -238,7 +355,8 @@ static void aspeed_hace_write(void *opaque, hwaddr addr, uint64_t data,
                         __func__, data & ahc->hash_mask);
                 break;
         }
-        do_hash_operation(s, algo, data & HASH_SG_EN);
+        do_hash_operation(s, algo, data & HASH_SG_EN,
+                ((data & HASH_HMAC_MASK) == HASH_DIGEST_ACCUM));
 
         if (data & HASH_IRQ_EN) {
             qemu_irq_raise(s->irq);
@@ -271,6 +389,8 @@ static void aspeed_hace_reset(DeviceState *dev)
     struct AspeedHACEState *s = ASPEED_HACE(dev);
 
     memset(s->regs, 0, sizeof(s->regs));
+    s->iov_count = 0;
+    s->total_req_len = 0;
 }
 
 static void aspeed_hace_realize(DeviceState *dev, Error **errp)
@@ -306,6 +426,8 @@ static const VMStateDescription vmstate_aspeed_hace = {
     .minimum_version_id = 1,
     .fields = (VMStateField[]) {
         VMSTATE_UINT32_ARRAY(regs, AspeedHACEState, ASPEED_HACE_NR_REGS),
+        VMSTATE_UINT32(total_req_len, AspeedHACEState),
+        VMSTATE_UINT32(iov_count, AspeedHACEState),
         VMSTATE_END_OF_LIST(),
     }
 };