[Qemu-devel] [5060] Ignore IDE command if issued while IDE is busy (Gleb Natapov)

[Qemu-devel] [5060] Ignore IDE command if issued while IDE is busy (Gleb Natapov)

[Anthony Liguori]

Revision: 5060
          http://svn.sv.gnu.org/viewvc/?view=rev&root=qemu&revision=5060
Author:   aliguori
Date:     2008-08-21 22:40:00 +0000 (Thu, 21 Aug 2008)

Log Message:
-----------
Ignore IDE command if issued while IDE is busy (Gleb Natapov)

Feature, Sector Count, LBA Low/Mid/High and Device registers should be
written only when both BSY and DRQ are cleared to zero.
Command register shall only be written when BSY and DRQ are set to zero
for all commands except DEVICE RESET.
Data Port register shall be accessed for host PIO data transfer only when
DRQ is set to one.

Signed-off-by: Gleb Natapov <gleb@qumranet.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>

Modified Paths:
--------------
    trunk/hw/ide.c

Modified: trunk/hw/ide.c
===================================================================
--- trunk/hw/ide.c	2008-08-21 22:24:32 UTC (rev 5059)
+++ trunk/hw/ide.c	2008-08-21 22:40:00 UTC (rev 5060)
@@ -1981,6 +1981,11 @@
 #endif
 
     addr &= 7;
+
+    /* ignore writes to command block while busy with previous command */
+    if (addr != 7 && (ide_if->cur_drive->status & (BUSY_STAT|DRQ_STAT)))
+        return;
+
     switch(addr) {
     case 0:
         break;
@@ -2040,6 +2045,10 @@
         if (s != ide_if && !s->bs)
             break;
 
+        /* Only DEVICE RESET is allowed while BSY or/and DRQ are set */
+        if ((s->status & (BUSY_STAT|DRQ_STAT)) && val != WIN_DEVICE_RESET)
+            break;
+
         switch(val) {
         case WIN_IDENTIFY:
             if (s->bs && !s->is_cdrom) {
@@ -2498,6 +2507,10 @@
     IDEState *s = ((IDEState *)opaque)->cur_drive;
     uint8_t *p;
 
+    /* PIO data access allowed only when DRQ bit is set */
+    if (!(s->status & DRQ_STAT))
+        return;
+
     p = s->data_ptr;
     *(uint16_t *)p = le16_to_cpu(val);
     p += 2;
@@ -2511,6 +2524,11 @@
     IDEState *s = ((IDEState *)opaque)->cur_drive;
     uint8_t *p;
     int ret;
+
+    /* PIO data access allowed only when DRQ bit is set */
+    if (!(s->status & DRQ_STAT))
+        return 0;
+
     p = s->data_ptr;
     ret = cpu_to_le16(*(uint16_t *)p);
     p += 2;
@@ -2525,6 +2543,10 @@
     IDEState *s = ((IDEState *)opaque)->cur_drive;
     uint8_t *p;
 
+    /* PIO data access allowed only when DRQ bit is set */
+    if (!(s->status & DRQ_STAT))
+        return;
+
     p = s->data_ptr;
     *(uint32_t *)p = le32_to_cpu(val);
     p += 4;
@@ -2539,6 +2561,10 @@
     uint8_t *p;
     int ret;
 
+    /* PIO data access allowed only when DRQ bit is set */
+    if (!(s->status & DRQ_STAT))
+        return 0;
+
     p = s->data_ptr;
     ret = cpu_to_le32(*(uint32_t *)p);
     p += 4;