ide: Cap LBA28 capacity announcement to 2^28-1

The LBA28 capacity (at offsets 60/61 of identification) is supposed to
express the maximum size supported by LBA28 commands. If the device is
larger than this, we have to cap it to 2^28-1.

At least NetBSD happens to be using this value to determine whether to use
LBA28 or LBA48 for its commands, using LBA28 for sectors that don't need
LBA48. This commit thus fixes NetBSD access to disks larger than 128GiB.

Signed-off-by: Samuel Thibault <samuel.thibault@ens-lyon.org>
Message-Id: <20210824104344.3878849-1-samuel.thibault@ens-lyon.org>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

diff --git a/hw/ide/core.c b/hw/ide/core.c
index fd69ca3167d97d45046e98b978bce40be5ad7bd2..e28f8aad6111f080b1aa9fec16c7b8d1d3d93cd0 100644 (file)
--- a/hw/ide/core.c
+++ b/hw/ide/core.c
@@ -98,8 +98,12 @@ static void put_le16(uint16_t *p, unsigned int v)
 static void ide_identify_size(IDEState *s)
 {
     uint16_t *p = (uint16_t *)s->identify_data;
-    put_le16(p + 60, s->nb_sectors);
-    put_le16(p + 61, s->nb_sectors >> 16);
+    int64_t nb_sectors_lba28 = s->nb_sectors;
+    if (nb_sectors_lba28 >= 1 << 28) {
+        nb_sectors_lba28 = (1 << 28) - 1;
+    }
+    put_le16(p + 60, nb_sectors_lba28);
+    put_le16(p + 61, nb_sectors_lba28 >> 16);
     put_le16(p + 100, s->nb_sectors);
     put_le16(p + 101, s->nb_sectors >> 16);
     put_le16(p + 102, s->nb_sectors >> 32);