Changeset 47036 in vbox for trunk/src/VBox/Devices/PC

Timestamp:

Jul 8, 2013 12:26:47 PM (12 years ago)

Author:

vboxsync

svn:sync-xref-src-repo-rev:

87069

Message:

BIOS,DevFdc,DrvBlock: The floppy controller should query the block/host driver for the drive type, or it'll all go real bad if the guest code trusts CMOS/BIOS drive info. Changed the block driver to automatically upgrade the drive type (for fdc and bios/cmos setup only) if the image is larger than the configured drive capacity. Introduced two fake drive types with max capacities, 15.6 MB and 63.5 MB, the first is the max that INT13 can officially access, the second is reinterpreting CL as holding an 8-bit wide sector number and no cylinder bits (which actually seems to be how real bioses work with floppies).

Location:

trunk/src/VBox/Devices/PC

Files:

• BIOS/floppy.c (modified) (4 diffs)
• DevPcBios.cpp (modified) (3 diffs)

trunk/src/VBox/Devices/PC/BIOS/floppy.c

@@ -392 +392 @@
         retval = 1;
     }
+    else if ( drive_type == 14 || drive_type == 15 ) {
+        // 15.6 MB 3.5" (fake) || 63.5 MB 3.5" (fake) - report same as 2.88 MB.
+        config_data = 0xCC; // 1100 1100
+        media_state = 0xD7; // 1101 0111
+        retval = 1;
+    }
     else {
         // not recognized
@@ -1026 +1032 @@
         SET_AL(0);
         SET_DL(num_floppies);
+        SET_DH(1);      // max head #
         
         switch (drive_type) {
@@ -1035 +1042 @@
         case 1: // 360KB, 5.25"
             CX = 0x2709;    // 40 tracks, 9 sectors
-            SET_DH(1);      // max head #
             break;
         
         case 2: // 1.2MB, 5.25"
             CX = 0x4f0f;    // 80 tracks, 15 sectors
-            SET_DH(1);      // max head #
             break;
         
         case 3: // 720KB, 3.5"
             CX = 0x4f09;    // 80 tracks, 9 sectors
-            SET_DH(1);      // max head #
             break;
         
         case 4: // 1.44MB, 3.5"
             CX = 0x4f12;    // 80 tracks, 18 sectors
-            SET_DH(1);      // max head #
             break;
         
         case 5: // 2.88MB, 3.5"
             CX = 0x4f24;    // 80 tracks, 36 sectors
-            SET_DH(1);      // max head #
             break;
         
@@ -1070 +1072 @@
         case 8: // 320k, 5.25"
             CX = 0x2708;    // 40 tracks, 8 sectors
-            SET_DH(1);      // max head #
-            break;
-        
+            break;
+        
+        case 14: // 15.6 MB 3.5" (fake)
+            CX = 0xfe3f;    // 255 tracks, 63 sectors
+            break;
+
+        case 15: // 63.5 MB 3.5" (fake)
+            CX = 0xfeff;    // 255 tracks, 255 sectors - This works because the cylinder
+            break;          // and sectors limits/encoding aren't checked by the BIOS
+                            // due to copy protection schemes and such stuff.
+
         default: // ?
             BX_PANIC("%s: bad floppy type\n", __func__);

trunk/src/VBox/Devices/PC/DevPcBios.cpp

@@ -502 +502 @@
     PUVM            pUVM = PDMDevHlpGetUVM(pDevIns); AssertRelease(pUVM);
     PPDMIBLOCKBIOS  apHDs[4] = {0};
-    PPDMIBLOCKBIOS  apFDs[2] = {0};
     LogFlow(("pcbiosInitComplete:\n"));
 
@@ -587 +586 @@
      * Floppy drive type.
      */
-    for (i = 0; i < RT_ELEMENTS(apFDs); i++)
+    uint32_t cFDs = 0;
+    u32 = 0;
+    for (i = 0; i < 2; i++)
     {
         PPDMIBASE pBase;
         int rc = PDMR3QueryLun(pUVM, pThis->pszFDDevice, 0, i, &pBase);
         if (RT_SUCCESS(rc))
-            apFDs[i] = PDMIBASE_QUERY_INTERFACE(pBase, PDMIBLOCKBIOS);
-    }
-    u32 = 0;
-    if (apFDs[0])
-        switch (apFDs[0]->pfnGetType(apFDs[0]))
-        {
-            case PDMBLOCKTYPE_FLOPPY_360:   u32 |= 1 << 4; break;
-            case PDMBLOCKTYPE_FLOPPY_1_20:  u32 |= 2 << 4; break;
-            case PDMBLOCKTYPE_FLOPPY_720:   u32 |= 3 << 4; break;
-            case PDMBLOCKTYPE_FLOPPY_1_44:  u32 |= 4 << 4; break;
-            case PDMBLOCKTYPE_FLOPPY_2_88:  u32 |= 5 << 4; break;
-            default:                        AssertFailed(); break;
-        }
-    if (apFDs[1])
-        switch (apFDs[1]->pfnGetType(apFDs[1]))
-        {
-            case PDMBLOCKTYPE_FLOPPY_360:   u32 |= 1; break;
-            case PDMBLOCKTYPE_FLOPPY_1_20:  u32 |= 2; break;
-            case PDMBLOCKTYPE_FLOPPY_720:   u32 |= 3; break;
-            case PDMBLOCKTYPE_FLOPPY_1_44:  u32 |= 4; break;
-            case PDMBLOCKTYPE_FLOPPY_2_88:  u32 |= 5; break;
-            default:                        AssertFailed(); break;
-        }
+        {
+            PPDMIBLOCKBIOS pFD = PDMIBASE_QUERY_INTERFACE(pBase, PDMIBLOCKBIOS);
+            if (pFD)
+            {
+                cFDs++;
+                unsigned cShift = i == 0 ? 4 : 0;
+                switch (pFD->pfnGetType(pFD))
+                {
+                    case PDMBLOCKTYPE_FLOPPY_360:       u32 |= 1  << cShift; break;
+                    case PDMBLOCKTYPE_FLOPPY_1_20:      u32 |= 2  << cShift; break;
+                    case PDMBLOCKTYPE_FLOPPY_720:       u32 |= 3  << cShift; break;
+                    case PDMBLOCKTYPE_FLOPPY_1_44:      u32 |= 4  << cShift; break;
+                    case PDMBLOCKTYPE_FLOPPY_2_88:      u32 |= 5  << cShift; break;
+                    case PDMBLOCKTYPE_FLOPPY_FAKE_15_6: u32 |= 14 << cShift; break;
+                    case PDMBLOCKTYPE_FLOPPY_FAKE_63_5: u32 |= 15 << cShift; break;
+                    default:                        AssertFailed(); break;
+                }
+            }
+        }
+    }
     pcbiosCmosWrite(pDevIns, 0x10, u32);                                        /* 10h - Floppy Drive Type */
 
@@ -620 +618 @@
      * Equipment byte.
      */
-    u32 = !!apFDs[0] + !!apFDs[1];
-    switch (u32)
-    {
-        case 1: u32 = 0x01; break;      /* floppy installed, 2 drives. */
-        default:u32 = 0;    break;      /* floppy not installed. */
-    }
+    if (cFDs > 0)
+        u32 = 0x01;                        /* floppy installed, 2 drives. */
+    else
+        u32 = 0x00;                        /* floppy not installed. */
     u32 |= RT_BIT(1);                      /* math coprocessor installed  */
     u32 |= RT_BIT(2);                      /* keyboard enabled (or mouse?) */