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Re: [Qemu-devel] [PATCH v7] pflash: Require backend size to match device
From: |
Alex Bennée |
Subject: |
Re: [Qemu-devel] [PATCH v7] pflash: Require backend size to match device, improve errors |
Date: |
Fri, 08 Mar 2019 10:00:39 +0000 |
User-agent: |
mu4e 1.1.0; emacs 26.1 |
Markus Armbruster <address@hidden> writes:
> From: Alex Bennée <address@hidden>
>
> We reject undersized backends with a rather enigmatic "failed to read
> the initial flash content" error.
>
> We happily accept oversized images, ignoring their tail. Throwing
> away parts of firmware that way is pretty much certain to end in an
> even more enigmatic failure to boot.
>
> Require the backend's size to match the device's size exactly. Report
> mismatch as "device requires N bytes, block backend 'NAME' provides M
> bytes".
>
> Improve the error for actual read failures to "can't read initial
> flash content from block backend 'NAME'.
>
> We disabled code to limit device sizes to 8, 16, 32 or 64MiB more than
> a decade ago in commit 95d1f3edd5e and c8b153d7949, v0.9.1. Bury.
>
> Signed-off-by: Alex Bennée <address@hidden>
> Signed-off-by: Markus Armbruster <address@hidden>
> ---
> hw/block/pflash_cfi01.c | 31 ++++++++++++++++++++++---------
> hw/block/pflash_cfi02.c | 31 +++++++++++++++++++++++--------
> 2 files changed, 45 insertions(+), 17 deletions(-)
>
> diff --git a/hw/block/pflash_cfi01.c b/hw/block/pflash_cfi01.c
> index 9d1c356eb6..2e3a05c0b3 100644
> --- a/hw/block/pflash_cfi01.c
> +++ b/hw/block/pflash_cfi01.c
> @@ -730,13 +730,6 @@ 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 +756,32 @@ static void pflash_cfi01_realize(DeviceState *dev,
> Error **errp)
> }
>
> if (pfl->blk) {
> + /*
> + * Validate the backing store is the right size for pflash
> + * devices. If the user supplies a larger file we ignore the
> + * tail.
> + */
We need to drop the last sentence...
> + int64_t backing_len = blk_getlength(pfl->blk);
> +
> + if (backing_len < 0) {
> + error_setg(errp, "can't get size of block backend '%s'",
> + blk_name(pfl->blk));
> + return;
> + }
> + if (backing_len != total_len) {
> + error_setg(errp, "device requires %" PRIu64 " bytes, "
> + "block backend '%s' provides %" PRIu64 " bytes",
> + total_len, blk_name(pfl->blk), backing_len);
> + return;
> + }
> +
> /* read the initial flash content */
> ret = blk_pread(pfl->blk, 0, pfl->storage, total_len);
> -
> if (ret < 0) {
> vmstate_unregister_ram(&pfl->mem, DEVICE(pfl));
> - error_setg(errp, "failed to read the initial flash content");
> + error_setg(errp, "can't read initial flash content"
> + " from block backend '%s'",
> + blk_name(pfl->blk));
> return;
> }
> }
> diff --git a/hw/block/pflash_cfi02.c b/hw/block/pflash_cfi02.c
> index 33779ce807..45b88d65d8 100644
> --- a/hw/block/pflash_cfi02.c
> +++ b/hw/block/pflash_cfi02.c
> @@ -550,12 +550,6 @@ 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 +575,32 @@ static void pflash_cfi02_realize(DeviceState *dev,
> Error **errp)
> }
>
> if (pfl->blk) {
> + /*
> + * Validate the backing store is the right size for pflash
> + * devices. If the user supplies a larger file we ignore the
> + * tail.
> + */
And here.
> + int64_t backing_len = blk_getlength(pfl->blk);
> +
> + if (backing_len < 0) {
> + error_setg(errp, "can't get size of block backend '%s'",
> + blk_name(pfl->blk));
> + return;
> + }
> + if (backing_len != chip_len) {
> + error_setg(errp, "device requires %" PRIu32 " bytes, "
> + "block backend '%s' provides %" PRIu64 " bytes",
> + chip_len, blk_name(pfl->blk), backing_len);
> + return;
> + }
> +
> /* read the initial flash content */
> ret = blk_pread(pfl->blk, 0, pfl->storage, chip_len);
> if (ret < 0) {
> - vmstate_unregister_ram(&pfl->orig_mem, DEVICE(pfl));
> - error_setg(errp, "failed to read the initial flash content");
> + vmstate_unregister_ram(&pfl->mem, DEVICE(pfl));
> + error_setg(errp, "can't read initial flash content"
> + " from block backend '%s'",
> + blk_name(pfl->blk));
> return;
> }
> }
Otherwise all good... not that a r-b means anything from me ;-)
--
Alex Bennée
- [Qemu-devel] [PATCH v7] pflash: Require backend size to match device, improve errors, Markus Armbruster, 2019/03/08
- Re: [Qemu-devel] [PATCH v7] pflash: Require backend size to match device, improve errors,
Alex Bennée <=
- Re: [Qemu-devel] [PATCH v7] pflash: Require backend size to match device, improve errors, Laszlo Ersek, 2019/03/08
- Re: [Qemu-devel] [PATCH v7] pflash: Require backend size to match device, improve errors, Markus Armbruster, 2019/03/08
- Re: [Qemu-devel] [PATCH v7] pflash: Require backend size to match device, improve errors, Kevin Wolf, 2019/03/08
- Re: [Qemu-devel] [PATCH v7] pflash: Require backend size to match device, improve errors, Laszlo Ersek, 2019/03/08
- Re: [Qemu-devel] [PATCH v7] pflash: Require backend size to match device, improve errors, Philippe Mathieu-Daudé, 2019/03/08
- Re: [Qemu-devel] [PATCH v7] pflash: Require backend size to match device, improve errors, Markus Armbruster, 2019/03/08
- Re: [Qemu-devel] [PATCH v7] pflash: Require backend size to match device, improve errors, Kevin Wolf, 2019/03/08
- Re: [Qemu-devel] [PATCH v7] pflash: Require backend size to match device, improve errors, Philippe Mathieu-Daudé, 2019/03/08
- Re: [Qemu-devel] [PATCH v7] pflash: Require backend size to match device, improve errors, Markus Armbruster, 2019/03/08