Re: [PATCH 02/30] x86, tlb: make CR4-based TLB flushes more robust

From: Thomas Gleixner
Date: Thu Nov 09 2017 - 05:51:18 EST


On Thu, 9 Nov 2017, Borislav Petkov wrote:
> On Wed, Nov 08, 2017 at 11:46:49AM -0800, Dave Hansen wrote:
> > + /* Put original CR4 value back: */
> > native_write_cr4(cr4);
> > }
>
> Btw, Andy, we read the CR4 shadow in that function but we don't update
> it. Why?

Because its the same as before.

> > + /* Put original CR4 value back: */
> > native_write_cr4(cr4);

Thanks,

tglx