[Qemu-devel] [PATCH 12/13] hw/block/pflash_cfi02: Fix command address comparison

["Philippe Mathieu-Daudé" <philmd@redhat.com>]

From: Stephen Checkoway <stephen.checkoway@oberlin.edu>

Most AMD commands only examine 11 bits of the address. This masks the
addresses used in the comparison to 11 bits. The exceptions are word or
sector addresses which use offset directly rather than the shifted
offset, boff.

Signed-off-by: Stephen Checkoway <stephen.checkoway@oberlin.edu>
Acked-by: Thomas Huth <thuth@redhat.com>
Message-Id: <20190426162624.55977-4-stephen.checkoway@oberlin.edu>
[PMD: Prepend 'hw/' in patch subject]
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
---
 hw/block/pflash_cfi02.c   |  8 +++++++-
 tests/pflash-cfi02-test.c | 12 ++++++++++--
 2 files changed, 17 insertions(+), 3 deletions(-)

diff --git a/hw/block/pflash_cfi02.c b/hw/block/pflash_cfi02.c
index 59daade2ee6..4c17dbf99f4 100644
--- a/hw/block/pflash_cfi02.c
+++ b/hw/block/pflash_cfi02.c
@@ -297,11 +297,13 @@ static void pflash_write(void *opaque, hwaddr offset, uint64_t value,
 
     DPRINTF("%s: offset " TARGET_FMT_plx " %08" PRIx64 " %d\n", __func__,
             offset, value, width);
-    boff = offset & (pfl->sector_len - 1);
+    boff = offset;
     if (pfl->width == 2)
         boff = boff >> 1;
     else if (pfl->width == 4)
         boff = boff >> 2;
+    /* Only the least-significant 11 bits are used in most cases. */
+    boff &= 0x7FF;
     switch (pfl->wcycle) {
     case 0:
         /* Set the device in I/O access mode if required */
@@ -520,6 +522,10 @@ static void pflash_cfi02_realize(DeviceState *dev, Error **errp)
         return;
     }
 
+    /* Only 11 bits are used in the comparison. */
+    pfl->unlock_addr0 &= 0x7FF;
+    pfl->unlock_addr1 &= 0x7FF;
+
     chip_len = pfl->sector_len * pfl->nb_blocs;
 
     memory_region_init_rom_device(&pfl->orig_mem, OBJECT(pfl),
diff --git a/tests/pflash-cfi02-test.c b/tests/pflash-cfi02-test.c
index 3c37465499a..1e5d9124b71 100644
--- a/tests/pflash-cfi02-test.c
+++ b/tests/pflash-cfi02-test.c
@@ -22,8 +22,8 @@
 
 #define FLASH_WIDTH 2
 #define CFI_ADDR (FLASH_WIDTH * 0x55)
-#define UNLOCK0_ADDR (FLASH_WIDTH * 0x5555)
-#define UNLOCK1_ADDR (FLASH_WIDTH * 0x2AAA)
+#define UNLOCK0_ADDR (FLASH_WIDTH * 0x555)
+#define UNLOCK1_ADDR (FLASH_WIDTH * 0x2AA)
 
 #define CFI_CMD 0x98
 #define UNLOCK0_CMD 0xAA
@@ -190,6 +190,14 @@ static void test_flash(const void *opaque)
     g_assert_cmpint(flash_read(6), ==, 0xCDEF);
     g_assert_cmpint(flash_read(8), ==, 0xFFFF);
 
+    /* Test ignored high order bits of address. */
+    flash_write(FLASH_WIDTH * 0x5555, UNLOCK0_CMD);
+    flash_write(FLASH_WIDTH * 0x2AAA, UNLOCK1_CMD);
+    flash_write(FLASH_WIDTH * 0x5555, AUTOSELECT_CMD);
+    g_assert_cmpint(flash_read(FLASH_WIDTH * 0x0000), ==, 0x00BF);
+    g_assert_cmpint(flash_read(FLASH_WIDTH * 0x0001), ==, 0x236D);
+    reset();
+
     qtest_quit(global_qtest);
 }
 
-- 
2.20.1