Re: [PATCH v2 1/4] iommu/vt-d: Enable write protect for supervisor SVM

[Jacob Pan]

Hi Guenter,

On Mon, 22 Mar 2021 10:53:38 -0700, Guenter Roeck <linux@xxxxxxxxxxxx>
wrote:

> On Tue, Mar 02, 2021 at 02:13:57AM -0800, Jacob Pan wrote:
> > Write protect bit, when set, inhibits supervisor writes to the read-only
> > pages. In supervisor shared virtual addressing (SVA), where page tables
> > are shared between CPU and DMA, IOMMU PASID entry WPE bit should match
> > CR0.WP bit in the CPU.
> > This patch sets WPE bit for supervisor PASIDs if CR0.WP is set.
> > 
> > Signed-off-by: Sanjay Kumar <sanjay.k.kumar@xxxxxxxxx>
> > Signed-off-by: Jacob Pan <jacob.jun.pan@xxxxxxxxxxxxxxx>
> > ---  
> 
> ia64:defconfig:
> 
> drivers/iommu/intel/pasid.c: In function 'pasid_enable_wpe':
> drivers/iommu/intel/pasid.c:536:22: error: implicit declaration of
> function 'read_cr0' drivers/iommu/intel/pasid.c:539:23: error:
> 'X86_CR0_WP' undeclared
> 
> Maybe it _is_ time to retire ia64 ?

Good catch, sorry for the late reply. I guess otherwise I will have to do
some #ifdef?

There are many basic x86 helpers are missing in ia64.

+Tony

Thanks,

Jacob