hw/misc/aspeed_hace: Extract direct mode hash buffer setup into helper function

To improve code readability and maintainability of do_hash_operation(), this
commit introduces a new helper function: hash_prepare_direct_iov().
This function encapsulates the logic for setting up the I/O vector (iov)
in direct mode (non-scatter-gather).

No functional changes are introduced.

Signed-off-by: Jamin Lin <jamin_lin@aspeedtech.com>
Reviewed-by: Cédric Le Goater <clg@redhat.com>
Link: https://lore.kernel.org/qemu-devel/20250515081008.583578-5-jamin_lin@aspeedtech.com
Signed-off-by: Cédric Le Goater <clg@redhat.com>

hw/misc/aspeed_hace.c

@@ -142,6 +142,31 @@ static bool has_padding(AspeedHACEState *s, struct iovec *iov,
     return false;
 }
 
+static int hash_prepare_direct_iov(AspeedHACEState *s, struct iovec *iov)
+{
+    uint32_t src;
+    void *haddr;
+    hwaddr plen;
+    int iov_idx;
+
+    plen = s->regs[R_HASH_SRC_LEN];
+    src = s->regs[R_HASH_SRC];
+    haddr = address_space_map(&s->dram_as, src, &plen, false,
+                              MEMTXATTRS_UNSPECIFIED);
+    if (haddr == NULL) {
+        qemu_log_mask(LOG_GUEST_ERROR,
+                      "%s: Unable to map address, addr=0x%x, "
+                      "plen=0x%" HWADDR_PRIx "\n",
+                      __func__, src, plen);
+        return -1;
+    }
+
+    iov[0].iov_base = haddr;
+    iov[0].iov_len = plen;
+    iov_idx = 1;
+
+    return iov_idx;
+}
 static void do_hash_operation(AspeedHACEState *s, int algo, bool sg_mode,
                               bool acc_mode)
 {
@@ -169,6 +194,7 @@ static void do_hash_operation(AspeedHACEState *s, int algo, bool sg_mode,
         }
     }
 
+    /* Prepares the iov for hashing operations based on the selected mode */
     if (sg_mode) {
         for (iov_idx = 0; !(len & SG_LIST_LEN_LAST); iov_idx++) {
             if (iov_idx == ASPEED_HACE_MAX_SG) {
@@ -211,17 +237,13 @@ static void do_hash_operation(AspeedHACEState *s, int algo, bool sg_mode,
             }
         }
     } else {
-        plen = s->regs[R_HASH_SRC_LEN];
+        iov_idx = hash_prepare_direct_iov(s, iov);
+    }
 
-        haddr = address_space_map(&s->dram_as, s->regs[R_HASH_SRC],
-                                  &plen, false, MEMTXATTRS_UNSPECIFIED);
-        if (haddr == NULL) {
-            qemu_log_mask(LOG_GUEST_ERROR, "%s: qcrypto failed\n", __func__);
-            return;
-        }
-        iov[0].iov_base = haddr;
-        iov[0].iov_len = plen;
-        iov_idx = 1;
+    if (iov_idx <= 0) {
+        qemu_log_mask(LOG_GUEST_ERROR,
+                      "%s: Failed to prepare iov\n", __func__);
+         return;
     }
 
     if (acc_mode) {