Re: [libvirt] [PATCH v3 05/18] blockjob: hoist bandwidth scaling out of monitor code

On 08/31/14 06:02, Eric Blake wrote: > qemu treats blockjob bandwidth as a 64-bit number, in the units > of bytes/second. But we stupidly modeled block job bandwidth > after migration bandwidth, which in turn was an 'unsigned long' > and therefore subject to 32-bit vs. 64-bit interpretations, and > with a scale of MiB/s. Our code already has to convert between > the two scales, and report overflow as appropriate; although > this conversion currently lives in the monitor code. >

> > - /* Convert bandwidth MiB to bytes - unfortunately the JSON QMP protocol is > - * limited to LLONG_MAX also for unsigned values */ > - speed = bandwidth; > - if (speed > LLONG_MAX >> 20) { > - virReportError(VIR_ERR_OVERFLOW, > - _("bandwidth must be less than %llu"), > - LLONG_MAX >> 20); I'd keep the check for if (speed > LLONG_MAX) here to be sure that we don't pass something between LLONG_MAX and ULLONG_MAX to qemu as it would be converted to signed by the monitor code.

Possibly we could add a new conversion option to qemuMonitorJSONMakeCommand that would check and reject numbers between LLONG_MAX and ULLONG_MAX rather than converting them to signed silently...