On 5/1/19 8:49 AM, Waiman Long wrote: > On Wed, Apr 03, 2019 at 11:34:04AM -0600, Khalid Aziz wrote: >> diff --git a/Documentation/admin-guide/kernel-parameters.txt > b/Documentation/admin-guide/kernel-parameters.txt > >> index 858b6c0b9a15..9b36da94760e 100644 >> --- a/Documentation/admin-guide/kernel-parameters.txt >> +++ b/Documentation/admin-guide/kernel-parameters.txt >> @@ -2997,6 +2997,12 @@ >> >> nox2apic [X86-64,APIC] Do not enable x2APIC mode. >> >> + noxpfo [XPFO] Disable eXclusive Page Frame Ownership (XPFO) >> + when CONFIG_XPFO is on. Physical pages mapped into >> + user applications will also be mapped in the >> + kernel's address space as if CONFIG_XPFO was not >> + enabled. >> + >> cpu0_hotplug [X86] Turn on CPU0 hotplug feature when >> CONFIG_BO OTPARAM_HOTPLUG_CPU0 is off. >> Some features depend on CPU0. Known dependencies are: > > Given the big performance impact that XPFO can have. It should be off by > default when configured. Instead, the xpfo option should be used to > enable it.
Agreed. I plan to disable it by default in the next version of the patch. This is likely to end up being a feature for extreme security conscious folks only, unless I or someone else comes up with further significant performance boost. Thanks, Khalid _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu
