From aaa076ff1d68545085fb85ee24d5410b60a123bd Mon Sep 17 00:00:00 2001
From: Ian Moffett <ian@osmora.org>
Date: Tue, 14 Oct 2025 20:23:19 -0400
Subject: kern: dms: Make DMS block size aware

In order to safely copy between disk and host memory through a
programming interface, DMS must be aware of the hardware disk block size

Signed-off-by: Ian Moffett <ian@osmora.org>
---
 src/sys/dms/dms_subr.c    | 35 +++++++++++++++++++++++++++++++++--
 src/sys/include/dms/dms.h |  7 ++++++-
 src/sys/io/ic/ahci.c      |  1 +
 3 files changed, 40 insertions(+), 3 deletions(-)

(limited to 'src/sys')

diff --git a/src/sys/dms/dms_subr.c b/src/sys/dms/dms_subr.c
index 240449a..085633b 100644
--- a/src/sys/dms/dms_subr.c
+++ b/src/sys/dms/dms_subr.c
@@ -30,6 +30,7 @@
 #include <sys/types.h>
 #include <sys/errno.h>
 #include <sys/queue.h>
+#include <sys/param.h>
 #include <os/kalloc.h>
 #include <dms/dms.h>
 #include <string.h>
@@ -100,6 +101,9 @@ dms_get(disk_id_t disk_id)
 ssize_t
 dms_write(struct dms_disk *dp, void *p, off_t off, size_t len)
 {
+    void *buf;
+    size_t real_len;
+    int error;
     struct dms_ops *ops;
 
     if (dp == NULL || p == NULL) {
@@ -114,13 +118,25 @@ dms_write(struct dms_disk *dp, void *p, off_t off, size_t len)
         return -ENOTSUP;
     }
 
-    return ops->write(dp, p, off, len);
+    real_len = ALIGN_UP(len, dp->bsize);
+    if ((buf = kalloc(real_len)) == NULL) {
+        return -ENOMEM;
+    }
+
+    memset(buf, 0, real_len);
+    memcpy(buf, p, len);
+    error = ops->write(dp, buf, off, real_len);
+    kfree(buf);
+    return error;
 }
 
 ssize_t
 dms_read(struct dms_disk *dp, void *p, off_t off, size_t len)
 {
+    void *buf;
     struct dms_ops *ops;
+    size_t real_len;
+    int error;
 
     if (dp == NULL || p == NULL) {
         return -EINVAL;
@@ -134,5 +150,20 @@ dms_read(struct dms_disk *dp, void *p, off_t off, size_t len)
         return -ENOTSUP;
     }
 
-    return ops->read(dp, p, off, len);
+    /* Allocate a real sized buffer */
+    real_len = ALIGN_UP(len, dp->bsize);
+    if ((buf = kalloc(real_len)) == NULL) {
+        return -ENOMEM;
+    }
+
+    memset(buf, 0, real_len);
+    error =  ops->read(dp, buf, off, real_len);
+    if (error < 0) {
+        kfree(buf);
+        return error;
+    }
+
+    memcpy(p, buf, len);
+    kfree(buf);
+    return 0;
 }
diff --git a/src/sys/include/dms/dms.h b/src/sys/include/dms/dms.h
index fca40b4..06e78ac 100644
--- a/src/sys/include/dms/dms.h
+++ b/src/sys/include/dms/dms.h
@@ -74,14 +74,19 @@ struct dms_ops {
  *
  * @name: Name of this device
  * @ops: Operations that can be performed
- * @data: Driver specific data
+ * @data: Driver specific data  [set by driver]
+ * @bsize: Disk block size      [set by driver]
  * @id: ID of the disk
  * @link: Internal queue link
+ *
+ * XXX: The `data' and `bsize' fields must be set by
+ *      the driver
  */
 struct dms_disk {
     char name[DISKNAME_MAX];
     struct dms_ops *ops;
     void *data;
+    uint16_t bsize;
     disk_id_t id;
     TAILQ_ENTRY(dms_disk) link;
 };
diff --git a/src/sys/io/ic/ahci.c b/src/sys/io/ic/ahci.c
index 9aa19b4..48560a8 100644
--- a/src/sys/io/ic/ahci.c
+++ b/src/sys/io/ic/ahci.c
@@ -236,6 +236,7 @@ ahci_register(struct ata_identity *identity, struct ahci_port *port)
         return error;
     }
 
+    dp->bsize = port->bsize;
     dp->data = (void *)port;
     return 0;
 }
-- 
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