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authorJunaid Shahid <junaids@google.com>2019-11-04 20:26:00 +0100
committerThomas Gleixner <tglx@linutronix.de>2019-11-04 20:26:00 +0100
commit1aa9b9572b10529c2e64e2b8f44025d86e124308 (patch)
tree8986b81fe6ccb070a657d3f37b1963a790890c21 /Documentation/admin-guide/kernel-parameters.txt
parentc57c80467f90e5504c8df9ad3555d2c78800bf94 (diff)
kvm: x86: mmu: Recovery of shattered NX large pages
The page table pages corresponding to broken down large pages are zapped in FIFO order, so that the large page can potentially be recovered, if it is not longer being used for execution. This removes the performance penalty for walking deeper EPT page tables. By default, one large page will last about one hour once the guest reaches a steady state. Signed-off-by: Junaid Shahid <junaids@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'Documentation/admin-guide/kernel-parameters.txt')
-rw-r--r--Documentation/admin-guide/kernel-parameters.txt6
1 files changed, 6 insertions, 0 deletions
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 9d5f123cc218..8dee8f68fe15 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -2068,6 +2068,12 @@
If the software workaround is enabled for the host,
guests do need not to enable it for nested guests.
+ kvm.nx_huge_pages_recovery_ratio=
+ [KVM] Controls how many 4KiB pages are periodically zapped
+ back to huge pages. 0 disables the recovery, otherwise if
+ the value is N KVM will zap 1/Nth of the 4KiB pages every
+ minute. The default is 60.
+
kvm-amd.nested= [KVM,AMD] Allow nested virtualization in KVM/SVM.
Default is 1 (enabled)