On Thu, Sep 14, 2017 at 11:48:34AM +1000, Balbir Singh wrote: > On Fri, 8 Sep 2017 15:44:45 -0700 > Ram Pai <linux...@us.ibm.com> wrote: > > > We need PTE bits 3 ,4, 5, 6 and 57 to support protection-keys, > > because these are the bits we want to consolidate on across all > > configuration to support protection keys. > > > > Bit 3,4,5 and 6 are currently used on 4K-pte kernels. But bit 9 > > and 10 are available. Hence we use the two available bits and > > free up bit 5 and 6. We will still not be able to free up bit 3 > > and 4. In the absence of any other free bits, we will have to > > stay satisfied with what we have :-(. This means we will not > > be able to support 32 protection keys, but only 8. The bit > > numbers are big-endian as defined in the ISA3.0 > > > > Any chance for 4k PTE's we can do slot searching for the PTE? > I guess thats add additional complexity
Aneesh, i think, is working on moving slot information out of the PTE. If that happens, we will have leg-space to support more keys. RP
