Merge remote-tracking branch 'remotes/armbru/tags/pull-pflash-2019-03-26' into staging

Pflash and firmware configuration patches for 2019-03-26

# gpg: Signature made Tue 26 Mar 2019 07:21:13 GMT
# gpg:                using RSA key 3870B400EB918653
# gpg: Good signature from "Markus Armbruster <armbru@redhat.com>" [full]
# gpg:                 aka "Markus Armbruster <armbru@pond.sub.org>" [full]
# Primary key fingerprint: 354B C8B3 D7EB 2A6B 6867  4E5F 3870 B400 EB91 8653

* remotes/armbru/tags/pull-pflash-2019-03-26:
  pflash: Bury disabled code to limit device sizes
  pflash: Require backend size to match device, improve errors

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

3 files changed, 53 insertions, 23 deletions

diff --git a/hw/block/block.c b/hw/block/block.c
index cf0eb82..bf56c76 100644
--- a/hw/block/block.c
+++ b/hw/block/block.c
@@ -13,7 +13,53 @@
 #include "hw/block/block.h"
 #include "qapi/error.h"
 #include "qapi/qapi-types-block.h"
-#include "qemu/error-report.h"
+
+/*
+ * Read the entire contents of @blk into @buf.
+ * @blk's contents must be @size bytes, and @size must be at most
+ * BDRV_REQUEST_MAX_BYTES.
+ * On success, return true.
+ * On failure, store an error through @errp and return false.
+ * Note that the error messages do not identify the block backend.
+ * TODO Since callers don't either, this can result in confusing
+ * errors.
+ * This function not intended for actual block devices, which read on
+ * demand.  It's for things like memory devices that (ab)use a block
+ * backend to provide persistence.
+ */
+bool blk_check_size_and_read_all(BlockBackend *blk, void *buf, hwaddr size,
+                                 Error **errp)
+{
+    int64_t blk_len;
+    int ret;
+
+    blk_len = blk_getlength(blk);
+    if (blk_len < 0) {
+        error_setg_errno(errp, -blk_len,
+                         "can't get size of block backend");
+        return false;
+    }
+    if (blk_len != size) {
+        error_setg(errp, "device requires %" HWADDR_PRIu " bytes, "
+                   "block backend provides %" PRIu64 " bytes",
+                   size, blk_len);
+        return false;
+    }
+
+    /*
+     * We could loop for @size > BDRV_REQUEST_MAX_BYTES, but if we
+     * ever get to the point we want to read *gigabytes* here, we
+     * should probably rework the device to be more like an actual
+     * block device and read only on demand.
+     */
+    assert(size <= BDRV_REQUEST_MAX_BYTES);
+    ret = blk_pread(blk, 0, buf, size);
+    if (ret < 0) {
+        error_setg_errno(errp, -ret, "can't read block backend");
+        return false;
+    }
+    return true;
+}
 
 void blkconf_blocksizes(BlockConf *conf)
 {
diff --git a/hw/block/pflash_cfi01.c b/hw/block/pflash_cfi01.c
index 125f70b..16dfae1 100644
--- a/hw/block/pflash_cfi01.c
+++ b/hw/block/pflash_cfi01.c
@@ -38,6 +38,7 @@
 
 #include "qemu/osdep.h"
 #include "hw/hw.h"
+#include "hw/block/block.h"
 #include "hw/block/flash.h"
 #include "sysemu/block-backend.h"
 #include "qapi/error.h"
@@ -730,13 +731,6 @@ static void pflash_cfi01_realize(DeviceState *dev, Error **errp)
     }
     device_len = sector_len_per_device * blocks_per_device;
 
-    /* XXX: to be fixed */
-#if 0
-    if (total_len != (8 * 1024 * 1024) && total_len != (16 * 1024 * 1024) &&
-        total_len != (32 * 1024 * 1024) && total_len != (64 * 1024 * 1024))
-        return NULL;
-#endif
-
     memory_region_init_rom_device(
         &pfl->mem, OBJECT(dev),
         &pflash_cfi01_ops,
@@ -763,12 +757,9 @@ static void pflash_cfi01_realize(DeviceState *dev, Error **errp)
     }
 
     if (pfl->blk) {
-        /* read the initial flash content */
-        ret = blk_pread(pfl->blk, 0, pfl->storage, total_len);
-
-        if (ret < 0) {
+        if (!blk_check_size_and_read_all(pfl->blk, pfl->storage, total_len,
+                                         errp)) {
             vmstate_unregister_ram(&pfl->mem, DEVICE(pfl));
-            error_setg(errp, "failed to read the initial flash content");
             return;
         }
     }
diff --git a/hw/block/pflash_cfi02.c b/hw/block/pflash_cfi02.c
index c9db430..f2c6201 100644
--- a/hw/block/pflash_cfi02.c
+++ b/hw/block/pflash_cfi02.c
@@ -37,6 +37,7 @@
 
 #include "qemu/osdep.h"
 #include "hw/hw.h"
+#include "hw/block/block.h"
 #include "hw/block/flash.h"
 #include "qapi/error.h"
 #include "qemu/timer.h"
@@ -550,12 +551,6 @@ static void pflash_cfi02_realize(DeviceState *dev, Error **errp)
     }
 
     chip_len = pfl->sector_len * pfl->nb_blocs;
-    /* XXX: to be fixed */
-#if 0
-    if (total_len != (8 * 1024 * 1024) && total_len != (16 * 1024 * 1024) &&
-        total_len != (32 * 1024 * 1024) && total_len != (64 * 1024 * 1024))
-        return NULL;
-#endif
 
     memory_region_init_rom_device(&pfl->orig_mem, OBJECT(pfl), pfl->be ?
                                   &pflash_cfi02_ops_be : &pflash_cfi02_ops_le,
@@ -581,11 +576,9 @@ static void pflash_cfi02_realize(DeviceState *dev, Error **errp)
     }
 
     if (pfl->blk) {
-        /* read the initial flash content */
-        ret = blk_pread(pfl->blk, 0, pfl->storage, chip_len);
-        if (ret < 0) {
+        if (!blk_check_size_and_read_all(pfl->blk, pfl->storage, chip_len,
+                                         errp)) {
             vmstate_unregister_ram(&pfl->orig_mem, DEVICE(pfl));
-            error_setg(errp, "failed to read the initial flash content");
             return;
         }
     }