KVM: PPC: Implement correct SID mapping on Book3s_32

Up until now we were doing segment mappings wrong on Book3s_32. For Book3s_64
we were using a trick where we know that a single mmu_context gives us 16 bits
of context ids.

The mm system on Book3s_32 instead uses a clever algorithm to distribute VSIDs
across the available range, so a context id really only gives us 16 available
VSIDs.

To keep at least a few guest processes in the SID shadow, let's map a number of
contexts that we can use as VSID pool. This makes the code be actually correct
and shouldn't hurt performance too much.

Signed-off-by: Alexander Graf <agraf@suse.de>

1 files changed, 13 insertions, 2 deletions

diff --git a/arch/powerpc/include/asm/kvm_book3s.h b/arch/powerpc/include/asm/kvm_book3s.h
index be8aac24ba8..d62e703f121 100644
--- a/arch/powerpc/include/asm/kvm_book3s.h
+++ b/arch/powerpc/include/asm/kvm_book3s.h
@@ -60,6 +60,13 @@ struct kvmppc_sid_map {
 #define SID_MAP_NUM     (1 << SID_MAP_BITS)
 #define SID_MAP_MASK    (SID_MAP_NUM - 1)
 
+#ifdef CONFIG_PPC_BOOK3S_64
+#define SID_CONTEXTS	1
+#else
+#define SID_CONTEXTS	128
+#define VSID_POOL_SIZE	(SID_CONTEXTS * 16)
+#endif
+
 struct kvmppc_vcpu_book3s {
 	struct kvm_vcpu vcpu;
 	struct kvmppc_book3s_shadow_vcpu *shadow_vcpu;
@@ -78,10 +85,14 @@ struct kvmppc_vcpu_book3s {
 	u64 sdr1;
 	u64 hior;
 	u64 msr_mask;
-	u64 vsid_first;
 	u64 vsid_next;
+#ifdef CONFIG_PPC_BOOK3S_32
+	u32 vsid_pool[VSID_POOL_SIZE];
+#else
+	u64 vsid_first;
 	u64 vsid_max;
-	int context_id;
+#endif
+	int context_id[SID_CONTEXTS];
 	ulong prog_flags; /* flags to inject when giving a 700 trap */
 };