KVM: PPC: Make shared struct aka magic page guest endian
The shared (magic) page is a data structure that contains often used
supervisor privileged SPRs accessible via memory to the user to reduce
the number of exits we have to take to read/write them.
When we actually share this structure with the guest we have to maintain
it in guest endianness, because some of the patch tricks only work with
native endian load/store operations.
Since we only share the structure with either host or guest in little
endian on book3s_64 pr mode, we don't have to worry about booke or book3s hv.
For booke, the shared struct stays big endian. For book3s_64 hv we maintain
the struct in host native endian, since it never gets shared with the guest.
For book3s_64 pr we introduce a variable that tells us which endianness the
shared struct is in and route every access to it through helper inline
functions that evaluate this variable.
Signed-off-by: Alexander Graf <agraf@suse.de>
diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c
index 8227dba..030821a 100644
--- a/arch/powerpc/kvm/book3s_hv.c
+++ b/arch/powerpc/kvm/book3s_hv.c
@@ -1280,6 +1280,17 @@
goto free_vcpu;
vcpu->arch.shared = &vcpu->arch.shregs;
+#ifdef CONFIG_KVM_BOOK3S_PR_POSSIBLE
+ /*
+ * The shared struct is never shared on HV,
+ * so we can always use host endianness
+ */
+#ifdef __BIG_ENDIAN__
+ vcpu->arch.shared_big_endian = true;
+#else
+ vcpu->arch.shared_big_endian = false;
+#endif
+#endif
vcpu->arch.mmcr[0] = MMCR0_FC;
vcpu->arch.ctrl = CTRL_RUNLATCH;
/* default to host PVR, since we can't spoof it */