Re: [PATCH v2 1/3] hw/block/pflash: Remove dynamic field width from trace events

[Eric Blake <eblake@redhat.com>]

On 11/8/19 8:40 AM, Philippe Mathieu-Daudé wrote:
> Since not all trace backends support dynamic field width in
> format (dtrace via stap does not), replace by a static field
> width instead.
> 
> Reported-by: Eric Blake <eblake@redhat.com>
> Buglink: https://bugs.launchpad.net/qemu/+bug/1844817
> Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
> ---
>   hw/block/pflash_cfi01.c | 8 ++++----
>   hw/block/pflash_cfi02.c | 8 ++++----
>   hw/block/trace-events   | 8 ++++----
>   3 files changed, 12 insertions(+), 12 deletions(-)
> 
> diff --git a/hw/block/pflash_cfi01.c b/hw/block/pflash_cfi01.c
> index 566c0acb77..787d1196f2 100644
> --- a/hw/block/pflash_cfi01.c
> +++ b/hw/block/pflash_cfi01.c
> @@ -276,7 +276,7 @@ static uint32_t pflash_data_read(PFlashCFI01 *pfl, hwaddr offset,
>           DPRINTF("BUG in %s\n", __func__);
>           abort();
>       }
> -    trace_pflash_data_read(offset, width << 1, ret);
> +    trace_pflash_data_read(offset, width << 3, ret);

Umm, why is width changing?  That's not mentioned in the commit message.

> @@ -389,7 +389,7 @@ static uint32_t pflash_read(PFlashCFI01 *pfl, hwaddr offset,
>   
>           break;
>       }
> -    trace_pflash_io_read(offset, width, width << 1, ret, pfl->cmd, pfl->wcycle);
> +    trace_pflash_io_read(offset, width << 3, ret, pfl->cmd, pfl->wcycle);

And even this one is odd.  Matching up to the trace messages:


> -pflash_io_read(uint64_t offset, int width, int fmt_width, uint32_t value, uint8_t cmd, uint8_t wcycle) "offset:0x%04"PRIx64" width:%d value:0x%0*x cmd:0x%02x wcycle:%u"

> +pflash_io_read(uint64_t offset, int width, uint32_t value, uint8_t cmd, uint8_t wcycle) "offset:0x%04"PRIx64" width:%d value:0x%04x cmd:0x%02x wcycle:%u"

you are changing from:

"%04"PRIx64" %d %0*x...", offset, width, width << 1, ret,...

(where width<<1, ret matches *x)

into

"%04"PRIx64" %d %04x...", offset, width << 3, ret,...

where you are now printing a different value for width.

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3226
Virtualization:  qemu.org | libvirt.org