KVM: PPC: Implement MMU notifiers for Book3S HV guests

This adds the infrastructure to enable us to page out pages underneath
a Book3S HV guest, on processors that support virtualized partition
memory, that is, POWER7.  Instead of pinning all the guest's pages,
we now look in the host userspace Linux page tables to find the
mapping for a given guest page.  Then, if the userspace Linux PTE
gets invalidated, kvm_unmap_hva() gets called for that address, and
we replace all the guest HPTEs that refer to that page with absent
HPTEs, i.e. ones with the valid bit clear and the HPTE_V_ABSENT bit
set, which will cause an HDSI when the guest tries to access them.
Finally, the page fault handler is extended to reinstantiate the
guest HPTE when the guest tries to access a page which has been paged
out.

Since we can't intercept the guest DSI and ISI interrupts on PPC970,
we still have to pin all the guest pages on PPC970.  We have a new flag,
kvm->arch.using_mmu_notifiers, that indicates whether we can page
guest pages out.  If it is not set, the MMU notifier callbacks do
nothing and everything operates as before.

Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>

1 files changed, 16 insertions, 0 deletions

diff --git a/arch/powerpc/include/asm/kvm_host.h b/arch/powerpc/include/asm/kvm_host.h
index 937cacaaf236..968f3aa61cd1 100644
--- a/arch/powerpc/include/asm/kvm_host.h
+++ b/arch/powerpc/include/asm/kvm_host.h
@@ -32,6 +32,7 @@
 #include <linux/atomic.h>
 #include <asm/kvm_asm.h>
 #include <asm/processor.h>
+#include <asm/page.h>
 
 #define KVM_MAX_VCPUS           NR_CPUS
 #define KVM_MAX_VCORES          NR_CPUS
@@ -44,6 +45,19 @@
 #define KVM_COALESCED_MMIO_PAGE_OFFSET 1
 #endif
 
+#ifdef CONFIG_KVM_BOOK3S_64_HV
+#include <linux/mmu_notifier.h>
+
+#define KVM_ARCH_WANT_MMU_NOTIFIER
+
+struct kvm;
+extern int kvm_unmap_hva(struct kvm *kvm, unsigned long hva);
+extern int kvm_age_hva(struct kvm *kvm, unsigned long hva);
+extern int kvm_test_age_hva(struct kvm *kvm, unsigned long hva);
+extern void kvm_set_spte_hva(struct kvm *kvm, unsigned long hva, pte_t pte);
+
+#endif
+
 /* We don't currently support large pages. */
 #define KVM_HPAGE_GFN_SHIFT(x)  0
 #define KVM_NR_PAGE_SIZES       1
@@ -212,6 +226,7 @@ struct kvm_arch {
         struct kvmppc_rma_info *rma;
         unsigned long vrma_slb_v;
         int rma_setup_done;
+        int using_mmu_notifiers;
         struct list_head spapr_tce_tables;
         spinlock_t slot_phys_lock;
         unsigned long *slot_phys[KVM_MEM_SLOTS_NUM];
@@ -460,6 +475,7 @@ struct kvm_vcpu_arch {
         struct list_head run_list;
         struct task_struct *run_task;
         struct kvm_run *kvm_run;
+        pgd_t *pgdir;
 #endif
 };