Re: [RFC PATCH v9 03/13] mm: Add support for eXclusive Page Frame Ownership (XPFO)
From: Khalid Aziz <hidden>
Date: 2019-05-01 15:22:15
Also in:
linux-arm-kernel, linux-doc, linux-iommu, linux-mm, lkml
On 5/1/19 8:49 AM, Waiman Long wrote:
On Wed, Apr 03, 2019 at 11:34:04AM -0600, Khalid Aziz wrote:quoted
diff --git a/Documentation/admin-guide/kernel-parameters.txtb/Documentation/admin-guide/kernel-parameters.txtquoted
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