Re: [patch V2 04/14] x86/pkru: Make the fpinit state update work

On Sun, Jun 06, 2021 at 01:47:46AM +0200, Thomas Gleixner wrote:

@@ -120,6 +121,8 @@ void __init check_bugs(void) arch_smt_update();

• pkru_propagate_default();

I guess this fits better at the end of identify_boot_cpu(), which is pretty close to here, in the boot order.

Regardless, that function check_bugs() needs cleaning up as it has collected a lot more stuff than just checking the bugs nasty.

+void pkru_propagate_default(void) {

• u32 init_pkru_value_snapshot = READ_ONCE(init_pkru_value);

• struct pkru_state *pk;
• if (!boot_cpu_has(X86_FEATURE_OSPKE))

cpu_feature_enabled()

• return;
  

  /*

• * Override the PKRU state that came from 'init_fpstate'
  

• * with the baseline from the process.
  

• * Force XFEATURE_PKRU to be set in the header otherwise
  

• * get_xsave_addr() does not work and it needs to be set
  

• * to make XRSTOR(S) load it.
  

  */

• write_pkru(init_pkru_value_snapshot);

• init_fpstate.xsave.header.xfeatures |= XFEATURE_MASK_PKRU;
• pk = get_xsave_addr(&init_fpstate.xsave, XFEATURE_PKRU);
• pk->pkru = READ_ONCE(init_pkru_value);

}