KVM: PPC: Split host-state fields out of kvmppc_book3s_shadow_vcpu

There are several fields in struct kvmppc_book3s_shadow_vcpu that
temporarily store bits of host state while a guest is running,
rather than anything relating to the particular guest or vcpu.
This splits them out into a new kvmppc_host_state structure and
modifies the definitions in asm-offsets.c to suit.

On 32-bit, we have a kvmppc_host_state structure inside the
kvmppc_book3s_shadow_vcpu since the assembly code needs to be able
to get to them both with one pointer.  On 64-bit they are separate
fields in the PACA.  This means that on 64-bit we don't need to
copy the kvmppc_host_state in and out on vcpu load/unload, and
in future will mean that the book3s_hv code doesn't need a
shadow_vcpu struct in the PACA at all.  That does mean that we
have to be careful not to rely on any values persisting in the
hstate field of the paca across any point where we could block
or get preempted.

Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>

1 files changed, 19 insertions, 8 deletions

diff --git a/arch/powerpc/include/asm/kvm_book3s_asm.h b/arch/powerpc/include/asm/kvm_book3s_asm.h
index d5a8a3861635..312617529864 100644
--- a/arch/powerpc/include/asm/kvm_book3s_asm.h
+++ b/arch/powerpc/include/asm/kvm_book3s_asm.h
@@ -60,6 +60,22 @@ kvmppc_resume_\intno:
 
 #else  /*__ASSEMBLY__ */
 
+/*
+ * This struct goes in the PACA on 64-bit processors.  It is used
+ * to store host state that needs to be saved when we enter a guest
+ * and restored when we exit, but isn't specific to any particular
+ * guest or vcpu.  It also has some scratch fields used by the guest
+ * exit code.
+ */
+struct kvmppc_host_state {
+	ulong host_r1;
+	ulong host_r2;
+	ulong vmhandler;
+	ulong scratch0;
+	ulong scratch1;
+	u8 in_guest;
+};
+
 struct kvmppc_book3s_shadow_vcpu {
 	ulong gpr[14];
 	u32 cr;
@@ -73,17 +89,12 @@ struct kvmppc_book3s_shadow_vcpu {
 	ulong shadow_srr1;
 	ulong fault_dar;
 
-	ulong host_r1;
-	ulong host_r2;
-	ulong handler;
-	ulong scratch0;
-	ulong scratch1;
-	ulong vmhandler;
-	u8 in_guest;
-
 #ifdef CONFIG_PPC_BOOK3S_32
 	u32     sr[16];			/* Guest SRs */
+
+	struct kvmppc_host_state hstate;
 #endif
+
 #ifdef CONFIG_PPC_BOOK3S_64
 	u8 slb_max;			/* highest used guest slb entry */
 	struct  {