path: root/Documentation/virtual/kvm/api.txt
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authorAnton Arapov <>2012-10-29 11:15:37 +0100
committerAnton Arapov <>2012-10-29 11:15:37 +0100
commit7d558cd9c7b18e4b16953265aa0da45e63f3b968 (patch)
tree7135d5a810768c9c619346282ee9cfdf1765e225 /Documentation/virtual/kvm/api.txt
parent985ef6b2108ed28ffd5f6630e1e0fce2e2a775f2 (diff)
fedora kernel: cd394142aac30b5c751f25b517572e2448695641v3.6.3-2f17
Signed-off-by: Anton Arapov <>
Diffstat (limited to 'Documentation/virtual/kvm/api.txt')
1 files changed, 34 insertions, 0 deletions
diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt
index 2c994837946..bf33aaa4c59 100644
--- a/Documentation/virtual/kvm/api.txt
+++ b/Documentation/virtual/kvm/api.txt
@@ -1946,6 +1946,40 @@ the guest using the specified gsi pin. The irqfd is removed using
the KVM_IRQFD_FLAG_DEASSIGN flag, specifying both kvm_irqfd.fd
and kvm_irqfd.gsi.
+Architectures: powerpc
+Type: vm ioctl
+Parameters: Pointer to u32 containing hash table order (in/out)
+Returns: 0 on success, -1 on error
+This requests the host kernel to allocate an MMU hash table for a
+guest using the PAPR paravirtualization interface. This only does
+anything if the kernel is configured to use the Book 3S HV style of
+virtualization. Otherwise the capability doesn't exist and the ioctl
+returns an ENOTTY error. The rest of this description assumes Book 3S
+There must be no vcpus running when this ioctl is called; if there
+are, it will do nothing and return an EBUSY error.
+The parameter is a pointer to a 32-bit unsigned integer variable
+containing the order (log base 2) of the desired size of the hash
+table, which must be between 18 and 46. On successful return from the
+ioctl, it will have been updated with the order of the hash table that
+was allocated.
+If no hash table has been allocated when any vcpu is asked to run
+(with the KVM_RUN ioctl), the host kernel will allocate a
+default-sized hash table (16 MB).
+If this ioctl is called when a hash table has already been allocated,
+the kernel will clear out the existing hash table (zero all HPTEs) and
+return the hash table order in the parameter. (If the guest is using
+the virtualized real-mode area (VRMA) facility, the kernel will
+re-create the VMRA HPTEs on the next KVM_RUN of any vcpu.)
5. The kvm_run structure