Re: [PATCH v8 RESEND 27/38] iommu/amd: Allow the AMD IOMMU to work with memory encryption

[Tom Lendacky]

On 6/28/2017 4:36 AM, Joerg Roedel wrote:
> Hi Tom,

Hi Joerg,

> On Tue, Jun 27, 2017 at 10:12:30AM -0500, Tom Lendacky wrote:
> > ---
> >   drivers/iommu/amd_iommu.c       |   30 ++++++++++++++++--------------
> >   drivers/iommu/amd_iommu_init.c  |   34 ++++++++++++++++++++++++++++------
> >   drivers/iommu/amd_iommu_proto.h |   10 ++++++++++
> >   drivers/iommu/amd_iommu_types.h |    2 +-
> >   4 files changed, 55 insertions(+), 21 deletions(-)
>
> Looks like a straightforward change. Just one nit below.
>
> > +static bool amd_iommu_supports_sme(void)
> > +{
> > +	if (!sme_active() || (boot_cpu_data.x86 != 0x17))
> > +		return true;
> > +
> > +	/* For Fam17h, a specific level of support is required */
> > +	if (boot_cpu_data.microcode >= 0x08001205)
> > +		return true;
> > +
> > +	if ((boot_cpu_data.microcode >= 0x08001126) &&
> > +	    (boot_cpu_data.microcode <= 0x080011ff))
> > +		return true;
> > +
> > +	pr_notice("AMD-Vi: IOMMU not currently supported when SME is active\n");
> > +
> > +	return false;
> > +}
>
> The name of the function is misleading. It checks whether the IOMMU can
> be enabled when SME is active. But the name suggests that it checks
> whether the iommu hardware supports SME.
>
> How about renaming it to amd_iommu_sme_check()?

Can do.

Thanks,
Tom

> With that change the patch is:
>
> 	Acked-by: Joerg Roedel <jroedel@xxxxxxx>