* Re: [Qemu-devel] [PATCH] hw/block: report when pflash backing file isn't aligned
2019-02-14 22:38 ` Alex Bennée
@ 2019-02-15 6:23 ` Geert Stappers
2019-02-15 9:12 ` Markus Armbruster
2019-02-15 13:57 ` Laszlo Ersek
2 siblings, 0 replies; 6+ messages in thread
From: Geert Stappers @ 2019-02-15 6:23 UTC (permalink / raw)
To: Alex Bennée; +Cc: Laszlo Ersek, pkg-qemu-devel, qemu-devel, ard.biesheuvel
On Thu, Feb 14, 2019 at 10:38:35PM +0000, Alex Bennée wrote:
> Laszlo Ersek <lersek@redhat.com> writes:
> > On 02/14/19 16:57, Alex Bennée wrote:
> >> + /*
> >> + * Validate the backing store is the right size for pflash
> >> + * devices. It has to be padded to a multiple of the flash block
> >> + * size.
> >> + */
> >> + if (pfl->blk) {
> >> + uint64_t backing_len = blk_getlength(pfl->blk);
> >> + if (device_len != backing_len) {
> >> + error_setg(errp, "backing file wrong size "
> >> + "(%" PRId64 " != %" PRId64")", backing_len, device_len);
> >> + return;
> >> + }
> >> + }
> >>
> >> memory_region_init_rom_device(
> >> &pfl->mem, OBJECT(dev),
> >>
>
> > - from a user POV, I find it more useful if the error message also shows
> > which quantity is which, not just two inequal numbers.
>
> How about:
>
> "backing file size (%) not enough for whole device (%)"
>
> ?
>
from a user POV, I find it more useful if the error messsage
resembles the actual test in the source. Above is test !=
How about
"backing file size (%) not equal to whole device size (%)"
?
Groeten
Geert Stappers
--
Leven en laten leven
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [Qemu-devel] [PATCH] hw/block: report when pflash backing file isn't aligned
2019-02-14 22:38 ` Alex Bennée
2019-02-15 6:23 ` Geert Stappers
@ 2019-02-15 9:12 ` Markus Armbruster
2019-02-15 13:57 ` Laszlo Ersek
2 siblings, 0 replies; 6+ messages in thread
From: Markus Armbruster @ 2019-02-15 9:12 UTC (permalink / raw)
To: Alex Bennée; +Cc: Laszlo Ersek, pkg-qemu-devel, qemu-devel, ard.biesheuvel
Alex Bennée <alex.bennee@linaro.org> writes:
> Laszlo Ersek <lersek@redhat.com> writes:
>
>> On 02/14/19 16:57, Alex Bennée wrote:
>>> It looks like there was going to be code to check we had some sort of
>>> alignment so lets replace it with an actual check. 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.
>>>
>>> This is a potential confusing stumbling block when you move from using
>>> -bios to using -drive if=pflash,file=blob,format=raw,readonly for
>>> loading your firmware code.
>>>
>>> Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
>>> ---
>>> hw/block/pflash_cfi01.c | 19 +++++++++++++------
>>> 1 file changed, 13 insertions(+), 6 deletions(-)
>>>
>>> diff --git a/hw/block/pflash_cfi01.c b/hw/block/pflash_cfi01.c
>>> index bffb4c40e7..f3251b236c 100644
>>> --- a/hw/block/pflash_cfi01.c
>>> +++ b/hw/block/pflash_cfi01.c
>>> @@ -722,12 +722,19 @@ 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
>>> + /*
>>> + * Validate the backing store is the right size for pflash
>>> + * devices. It has to be padded to a multiple of the flash block
>>> + * size.
>>> + */
>>> + if (pfl->blk) {
>>> + uint64_t backing_len = blk_getlength(pfl->blk);
>>> + if (device_len != backing_len) {
>>> + error_setg(errp, "backing file wrong size "
>>> + "(%" PRId64 " != %" PRId64")", backing_len, device_len);
>>> + return;
>>> + }
>>> + }
>>>
>>> memory_region_init_rom_device(
>>> &pfl->mem, OBJECT(dev),
>>>
>>
>> I have two suggestions:
>> - backing_len and device_len are both uint64_t; we should print them
>> with PRIu64
>
> blk_getlength actually returns int64_t for some reason (do signed
> lengths even make sense? maybe it's for error handling?). But sure I can
> make it PRIu64
Use of signed integers for file offsets is pervasive in the block layer.
It's convenient when we return either a non-negative offset or a
negative error code. It's admittedly sloppy anywhere else.
>> - from a user POV, I find it more useful if the error message also shows
>> which quantity is which, not just two inequal numbers.
>
> How about:
>
> "backing file size (%) not enough for whole device (%)"
>
> ?
Not bad. Another one, avoiding parentheses:
"device needs DDD bytes, backing file provides only BBB bytes"
>
>>
>> I don't feel too strongly about this, so up to you.
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [Qemu-devel] [PATCH] hw/block: report when pflash backing file isn't aligned
2019-02-14 22:38 ` Alex Bennée
2019-02-15 6:23 ` Geert Stappers
2019-02-15 9:12 ` Markus Armbruster
@ 2019-02-15 13:57 ` Laszlo Ersek
2 siblings, 0 replies; 6+ messages in thread
From: Laszlo Ersek @ 2019-02-15 13:57 UTC (permalink / raw)
To: Alex Bennée; +Cc: qemu-devel, pkg-qemu-devel, ard.biesheuvel
On 02/14/19 23:38, Alex Bennée wrote:
>
> Laszlo Ersek <lersek@redhat.com> writes:
>
>> On 02/14/19 16:57, Alex Bennée wrote:
>>> It looks like there was going to be code to check we had some sort of
>>> alignment so lets replace it with an actual check. 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.
>>>
>>> This is a potential confusing stumbling block when you move from using
>>> -bios to using -drive if=pflash,file=blob,format=raw,readonly for
>>> loading your firmware code.
>>>
>>> Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
>>> ---
>>> hw/block/pflash_cfi01.c | 19 +++++++++++++------
>>> 1 file changed, 13 insertions(+), 6 deletions(-)
>>>
>>> diff --git a/hw/block/pflash_cfi01.c b/hw/block/pflash_cfi01.c
>>> index bffb4c40e7..f3251b236c 100644
>>> --- a/hw/block/pflash_cfi01.c
>>> +++ b/hw/block/pflash_cfi01.c
>>> @@ -722,12 +722,19 @@ 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
>>> + /*
>>> + * Validate the backing store is the right size for pflash
>>> + * devices. It has to be padded to a multiple of the flash block
>>> + * size.
>>> + */
>>> + if (pfl->blk) {
>>> + uint64_t backing_len = blk_getlength(pfl->blk);
>>> + if (device_len != backing_len) {
>>> + error_setg(errp, "backing file wrong size "
>>> + "(%" PRId64 " != %" PRId64")", backing_len, device_len);
>>> + return;
>>> + }
>>> + }
>>>
>>> memory_region_init_rom_device(
>>> &pfl->mem, OBJECT(dev),
>>>
>>
>> I have two suggestions:
>> - backing_len and device_len are both uint64_t; we should print them
>> with PRIu64
>
> blk_getlength actually returns int64_t for some reason (do signed
> lengths even make sense? maybe it's for error handling?).
Ah, sorry, I didn't realize. I guess we should cover negative values
then explicitly? Not sure.
> But sure I can
> make it PRIu64
>
>> - from a user POV, I find it more useful if the error message also shows
>> which quantity is which, not just two inequal numbers.
>
> How about:
>
> "backing file size (%) not enough for whole device (%)"
"not enough" means "<", but the C expression uses "!=". How about
"backing file size (...) does not match device size (...)"?
Or "does not equal", whichever sounds more palatable.
Thanks!
Laszlo
^ permalink raw reply [flat|nested] 6+ messages in thread