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Re: [Qemu-block] [Qemu-devel] [RFC PATCH v6 1/4] hw/block: better report
From: |
Markus Armbruster |
Subject: |
Re: [Qemu-block] [Qemu-devel] [RFC PATCH v6 1/4] hw/block: better reporting on pflash backing file mismatch |
Date: |
Thu, 07 Mar 2019 18:14:33 +0100 |
User-agent: |
Gnus/5.13 (Gnus v5.13) Emacs/26.1 (gnu/linux) |
Alex Bennée <address@hidden> writes:
> Markus Armbruster <address@hidden> writes:
>
>> From: Alex Bennée <address@hidden>
>>
>> It looks like there was going to be code to check we had some sort of
>> alignment so let's replace it with an actual check. Reject undersized
>> images with "device needs N bytes, backing file provides only M
>> bytes". This is a bit more useful than the enigmatic "failed to read
>> the initial flash content" when we attempt to read the number of bytes
>> the device should have. Continue to accept oversized images, but warn
>> "device needs N bytes, rest ignored".
>>
>> Signed-off-by: Alex Bennée <address@hidden>
>> Reviewed-by: Laszlo Ersek <address@hidden>
>> Signed-off-by: Markus Armbruster <address@hidden>
>> ---
>> hw/block/pflash_cfi01.c | 29 ++++++++++++++++++++++-------
>> 1 file changed, 22 insertions(+), 7 deletions(-)
>>
>> diff --git a/hw/block/pflash_cfi01.c b/hw/block/pflash_cfi01.c
>> index 9d1c356eb6..75ce8ef489 100644
>> --- a/hw/block/pflash_cfi01.c
>> +++ b/hw/block/pflash_cfi01.c
>> @@ -45,6 +45,7 @@
>> #include "qemu/bitops.h"
>> #include "qemu/host-utils.h"
>> #include "qemu/log.h"
>> +#include "qemu/error-report.h"
>> #include "hw/sysbus.h"
>> #include "sysemu/sysemu.h"
>> #include "trace.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,
>> @@ -763,6 +757,27 @@ 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.
>> + */
>> + int64_t backing_len = blk_getlength(pfl->blk);
>> + if (backing_len < 0) {
>> + error_setg(errp, "unable to check size of backing file");
>> + return;
>> + }
>> +
>> + if (backing_len < total_len) {
>> + error_setg(errp, "device needs %" PRIu64 " bytes, "
>> + "backing file provides only %" PRIu64 " bytes",
>> + total_len, backing_len);
>> + return;
>> + } else if (backing_len > total_len) {
>> + warn_report("device needs %" PRIu64 " bytes, rest ignored",
>> + total_len);
>> + }
>
> As discussed elsewhere I'm happy for this just to error out with a
> useful error message.
I'll do that in the next spin. Thanks!
>> +
>> /* read the initial flash content */
>> ret = blk_pread(pfl->blk, 0, pfl->storage, total_len);
>
>
> --
> Alex Bennée