[PATCH v2 7/7] hw/ide/core.c: Implement ATA INITIALIZE_DEVICE_PARAMETERS command

[Lev Kujawski]

CHS-based disk utilities and operating systems may adjust the logical
geometry of a hard drive to cope with the expectations or limitations
of software using the ATA INITIALIZE_DEVICE_PARAMETERS command.

Prior to this patch, INITIALIZE_DEVICE_PARAMETERS was a nop that
always returned success, raising the possibility of data loss or
corruption if the CHS<->LBA translation redirected a write to the
wrong sector.

* hw/ide/core.c
ide_reset():
  Reset the logical CHS geometry of the hard disk when the power-on
  defaults feature is enabled.
cmd_specify():
  a) New function implementing INITIALIZE_DEVICE_PARAMETERS.
  b) Ignore calls for empty or ATAPI devices.
cmd_set_features():
  Implement the power-on defaults enable and disable features.
struct ide_cmd_table:
  Switch WIN_SPECIFY from cmd_nop() to cmd_specify().
ide_init_drive():
  Set new fields 'drive_heads' and 'drive_sectors' based upon the
  actual disk geometry.

* include/hw/ide/internal.h
struct IDEState:
a) Store the actual drive CHS values within the new fields
   'drive_heads' and 'drive_sectors.'
b) Track whether a soft IDE reset should also reset the logical CHS
   geometry of the hard disk within the new field 'reset_reverts'.

Signed-off-by: Lev Kujawski <lkujaw@member.fsf.org>
---
 hw/ide/core.c             | 29 ++++++++++++++++++++++++++---
 include/hw/ide/internal.h |  3 +++
 2 files changed, 29 insertions(+), 3 deletions(-)

diff --git a/hw/ide/core.c b/hw/ide/core.c
index b747191ebf..39afdc0006 100644
--- a/hw/ide/core.c
+++ b/hw/ide/core.c
@@ -1340,6 +1340,11 @@ static void ide_reset(IDEState *s)
         s->pio_aiocb = NULL;
     }
 
+    if (s->reset_reverts) {
+        s->reset_reverts = false;
+        s->heads         = s->drive_heads;
+        s->sectors       = s->drive_sectors;
+    }
     if (s->drive_kind == IDE_CFATA)
         s->mult_sectors = 0;
     else
@@ -1618,6 +1623,20 @@ static bool cmd_check_power_mode(IDEState *s, uint8_t 
cmd)
     return true;
 }
 
+/* INITIALIZE DEVICE PARAMETERS */
+static bool cmd_specify(IDEState *s, uint8_t cmd)
+{
+    if (s->blk && s->drive_kind != IDE_CD) {
+        s->heads = (s->select & (ATA_DEV_HS)) + 1;
+        s->sectors = s->nsector;
+        ide_set_irq(s->bus);
+    } else {
+        ide_abort_command(s);
+    }
+
+    return true;
+}
+
 static bool cmd_set_features(IDEState *s, uint8_t cmd)
 {
     uint16_t *identify_data;
@@ -1641,7 +1660,11 @@ static bool cmd_set_features(IDEState *s, uint8_t cmd)
         ide_flush_cache(s);
         return false;
     case 0xcc: /* reverting to power-on defaults enable */
+        s->reset_reverts = true;
+        return true;
     case 0x66: /* reverting to power-on defaults disable */
+        s->reset_reverts = false;
+        return true;
     case 0xaa: /* read look-ahead enable */
     case 0x55: /* read look-ahead disable */
     case 0x05: /* set advanced power management mode */
@@ -2051,7 +2074,7 @@ static const struct {
     [WIN_SEEK]                    = { cmd_seek, HD_CFA_OK | SET_DSC },
     [CFA_TRANSLATE_SECTOR]        = { cmd_cfa_translate_sector, CFA_OK },
     [WIN_DIAGNOSE]                = { cmd_exec_dev_diagnostic, ALL_OK },
-    [WIN_SPECIFY]                 = { cmd_nop, HD_CFA_OK | SET_DSC },
+    [WIN_SPECIFY]                 = { cmd_specify, HD_CFA_OK | SET_DSC },
     [WIN_STANDBYNOW2]             = { cmd_nop, HD_CFA_OK },
     [WIN_IDLEIMMEDIATE2]          = { cmd_nop, HD_CFA_OK },
     [WIN_STANDBY2]                = { cmd_nop, HD_CFA_OK },
@@ -2541,8 +2564,8 @@ int ide_init_drive(IDEState *s, BlockBackend *blk, 
IDEDriveKind kind,
 
     blk_get_geometry(blk, &nb_sectors);
     s->cylinders = cylinders;
-    s->heads = heads;
-    s->sectors = secs;
+    s->heads = s->drive_heads = heads;
+    s->sectors = s->drive_sectors = secs;
     s->chs_trans = chs_trans;
     s->nb_sectors = nb_sectors;
     s->wwn = wwn;
diff --git a/include/hw/ide/internal.h b/include/hw/ide/internal.h
index 97e7e59dc5..b17f36df95 100644
--- a/include/hw/ide/internal.h
+++ b/include/hw/ide/internal.h
@@ -375,6 +375,7 @@ struct IDEState {
     uint8_t unit;
     /* ide config */
     IDEDriveKind drive_kind;
+    int drive_heads, drive_sectors;
     int cylinders, heads, sectors, chs_trans;
     int64_t nb_sectors;
     int mult_sectors;
@@ -401,6 +402,8 @@ struct IDEState {
     uint8_t select;
     uint8_t status;
 
+    bool reset_reverts;
+
     /* set for lba48 access */
     uint8_t lba48;
     BlockBackend *blk;
-- 
2.34.1