KVM: PPC: Book3S HV: Save/restore XER in checkpointed register state
commit 0d808df06a44200f52262b6eb72bcb6042f5a7c5 upstream.
When switching from/to a guest that has a transaction in progress,
we need to save/restore the checkpointed register state. Although
XER is part of the CPU state that gets checkpointed, the code that
does this saving and restoring doesn't save/restore XER.
This fixes it by saving and restoring the XER. To allow userspace
to read/write the checkpointed XER value, we also add a new ONE_REG
specifier.
The visible effect of this bug is that the guest may see its XER
value being corrupted when it uses transactions.
Fixes: e4e38121507a ("KVM: PPC: Book3S HV: Add transactional memory support")
Fixes: 0a8eccefcb34 ("KVM: PPC: Book3S HV: Add missing code for transaction reclaim on guest exit")
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt
index 6bbceb9..1f5eab4 100644
--- a/Documentation/virtual/kvm/api.txt
+++ b/Documentation/virtual/kvm/api.txt
@@ -2050,6 +2050,7 @@
PPC | KVM_REG_PPC_TM_VSCR | 32
PPC | KVM_REG_PPC_TM_DSCR | 64
PPC | KVM_REG_PPC_TM_TAR | 64
+ PPC | KVM_REG_PPC_TM_XER | 64
| |
MIPS | KVM_REG_MIPS_R0 | 64
...