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authorPaul Mackerras <paulus@samba.org>2012-09-26 00:33:06 +0400
committerAlexander Graf <agraf@suse.de>2012-10-06 01:38:55 +0400
commit55b665b0263ae88a776071306ef1eee4b769016b (patch)
treec83b5a0f8961ecac8a708cbdeb01f41d5b685d9e /Documentation/virtual
parenta8bd19ef4dd49f0eef86a4a8eb43d60f967236b8 (diff)
downloadlinux-55b665b0263ae88a776071306ef1eee4b769016b.tar.xz
KVM: PPC: Book3S HV: Provide a way for userspace to get/set per-vCPU areas
The PAPR paravirtualization interface lets guests register three different types of per-vCPU buffer areas in its memory for communication with the hypervisor. These are called virtual processor areas (VPAs). Currently the hypercalls to register and unregister VPAs are handled by KVM in the kernel, and userspace has no way to know about or save and restore these registrations across a migration. This adds "register" codes for these three areas that userspace can use with the KVM_GET/SET_ONE_REG ioctls to see what addresses have been registered, and to register or unregister them. This will be needed for guest hibernation and migration, and is also needed so that userspace can unregister them on reset (otherwise we corrupt guest memory after reboot by writing to the VPAs registered by the previous kernel). The "register" for the VPA is a 64-bit value containing the address, since the length of the VPA is fixed. The "registers" for the SLB shadow buffer and dispatch trace log (DTL) are 128 bits long, consisting of the guest physical address in the high (first) 64 bits and the length in the low 64 bits. This also fixes a bug where we were calling init_vpa unconditionally, leading to an oops when unregistering the VPA. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
Diffstat (limited to 'Documentation/virtual')
-rw-r--r--Documentation/virtual/kvm/api.txt3
1 files changed, 3 insertions, 0 deletions
diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt
index 71dc7e2ec8eb..e726d76eeebb 100644
--- a/Documentation/virtual/kvm/api.txt
+++ b/Documentation/virtual/kvm/api.txt
@@ -1770,6 +1770,9 @@ registers, find a list below:
PPC | KVM_REG_PPC_VSR31 | 128
PPC | KVM_REG_PPC_FPSCR | 64
PPC | KVM_REG_PPC_VSCR | 32
+ PPC | KVM_REG_PPC_VPA_ADDR | 64
+ PPC | KVM_REG_PPC_VPA_SLB | 128
+ PPC | KVM_REG_PPC_VPA_DTL | 128
4.69 KVM_GET_ONE_REG