Re: [Xen-devel] [PATCH] x86: introduce and use setup_force_cpu_cap()

2017-09-06 Thread Jan Beulich
>>> Sarah Newman 09/07/17 3:55 AM >>> >On 09/05/2017 06:22 AM, Jan Beulich wrote: >> For XEN_SMEP and XEN_SMAP to not be cleared while bringing up APs we'd >> need to clone the respective hack used for CPUID_FAULTING. Introduce an >> inverse of setup_clear_cpu_cap() instead, but let clearing of fe

Re: [Xen-devel] [PATCH] x86: introduce and use setup_force_cpu_cap()

2017-09-06 Thread Sarah Newman
On 09/05/2017 06:22 AM, Jan Beulich wrote: > For XEN_SMEP and XEN_SMAP to not be cleared while bringing up APs we'd > need to clone the respective hack used for CPUID_FAULTING. Introduce an > inverse of setup_clear_cpu_cap() instead, but let clearing of features > overrule forced setting of them. >

Re: [Xen-devel] [PATCH] x86: introduce and use setup_force_cpu_cap()

2017-09-05 Thread Andrew Cooper
On 05/09/17 14:22, Jan Beulich wrote: > For XEN_SMEP and XEN_SMAP to not be cleared while bringing up APs we'd > need to clone the respective hack used for CPUID_FAULTING. Introduce an > inverse of setup_clear_cpu_cap() instead, but let clearing of features > overrule forced setting of them. > > XE

[Xen-devel] [PATCH] x86: introduce and use setup_force_cpu_cap()

2017-09-05 Thread Jan Beulich
For XEN_SMEP and XEN_SMAP to not be cleared while bringing up APs we'd need to clone the respective hack used for CPUID_FAULTING. Introduce an inverse of setup_clear_cpu_cap() instead, but let clearing of features overrule forced setting of them. XEN_SMAP being wrong post-boot is a problem specifi