KVM: PPC: Book3S HV: Make HPT reading code notice R/C bit changes

At present, the code that determines whether a HPT entry has changed,
and thus needs to be sent to userspace when it is copying the HPT,
doesn't consider a hardware update to the reference and change bits
(R and C) in the HPT entries to constitute a change that needs to
be sent to userspace.  This adds code to check for changes in R and C
when we are scanning the HPT to find changed entries, and adds code
to set the changed flag for the HPTE when we update the R and C bits
in the guest view of the HPTE.

Since we now need to set the HPTE changed flag in book3s_64_mmu_hv.c
as well as book3s_hv_rm_mmu.c, we move the note_hpte_modification()
function into kvm_book3s_64.h.

Current Linux guest kernels don't use the hardware updates of R and C
in the HPT, so this change won't affect them.  Linux (or other) kernels
might in future want to use the R and C bits and have them correctly
transferred across when a guest is migrated, so it is better to correct
this deficiency.

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

1 files changed, 0 insertions, 11 deletions

diff --git a/arch/powerpc/kvm/book3s_hv_rm_mmu.c b/arch/powerpc/kvm/book3s_hv_rm_mmu.c
index 19c93bae1aea..6dcbb49105a4 100644
--- a/arch/powerpc/kvm/book3s_hv_rm_mmu.c
+++ b/arch/powerpc/kvm/book3s_hv_rm_mmu.c
@@ -97,17 +97,6 @@ void kvmppc_add_revmap_chain(struct kvm *kvm, struct revmap_entry *rev,
 }
 EXPORT_SYMBOL_GPL(kvmppc_add_revmap_chain);
 
-/*
- * Note modification of an HPTE; set the HPTE modified bit
- * if anyone is interested.
- */
-static inline void note_hpte_modification(struct kvm *kvm,
-                                          struct revmap_entry *rev)
-{
-        if (atomic_read(&kvm->arch.hpte_mod_interest))
-                rev->guest_rpte |= HPTE_GR_MODIFIED;
-}
-
 /* Remove this HPTE from the chain for a real page */
 static void remove_revmap_chain(struct kvm *kvm, long pte_index,
                                 struct revmap_entry *rev,