Re: [PATCH kvm-unit-tests 01/17] x86: intel-iommu: add vt-d init test

[Peter Xu <peterx@redhat.com>]

On Fri, Nov 04, 2016 at 05:12:04PM +0100, Andrew Jones wrote:

[...]

> > +#include "intel-iommu.h"
> > +
> > +#define ONE_BIT_ONLY(x) ((x) && !((x) & ((x) - 1)))
> 
> How about instead adding
> 
>  static inline bool is_power_of_2(unsigned long n)
>  {
>      return (n && !(n & (n - 1)));
>  }
> 
> to libcflat.h, because there's a few other places I've needed
> this check myself.

Sure. Will do. 

[...]

> > +static void vtd_gcmd_or(uint32_t cmd)
> > +{
> > +	uint32_t status;
> > +
> > +	/* We only allow set one bit for each time */
> > +	assert(ONE_BIT_ONLY(cmd));
> > +
> > +	status = vtd_readl(DMAR_GSTS_REG);
> > +	vtd_writel(DMAR_GCMD_REG, status | cmd);
> > +
> > +	if (cmd & VTD_GCMD_ONE_SHOT_BITS)
> > +		/* One-shot bits are taking effect immediately */
> > +		return;
> 
> Please use {} when adding comments between an if and its one line.

Will fix.

Thanks!

-- peterx