Re: [Qemu-devel] [PATCH 1/2] nvram: Add TPM NVRAM implementation

[Corey Bryant <coreyb@linux.vnet.ibm.com>]

On 06/05/2013 09:42 AM, Kevin Wolf wrote:
> Am 05.06.2013 um 15:28 hat Corey Bryant geschrieben:
>>>> +
>>>> +    if (rwr->rc == 0) {
>>>> +        rwr->rc = rwr->num_sectors;
>>>> +        *rwr->blob_r = g_malloc(rwr->size);
>>>> +        memcpy(*rwr->blob_r, buf, rwr->size);
>>>
>>> Use bdrv_pread()/bdrv_pwrite() for byte-granularity I/O instead of
>>> duplicating the buffering yourself.
>>>
>>
>> Aren't bdrv_pread()/bdrv_pwrite() synchronous?  Wouldn't using them
>> block the main QEMU thread?  That is why I switched to using the
>> coroutine versions.
>
> You need to call them from coroutine context to avoid that they invoke
> their on coroutine on which they wait in this this while (!done)
> { qemu_aio_wait(); } loop that blocks everything. Called from coroutine
> context, they do the Right Thing, though.
>
> Kevin
>
>
>

Ah, thanks for explaining.  Now I can work in bytes rather than sectors.  :)

-- 
Regards,
Corey Bryant