KVM: PPC: Maintain a doubly-linked list of guest HPTEs for each gfn

[deliverable/linux.git] / arch / powerpc / include / asm / kvm_host.h

diff --git a/arch/powerpc/include/asm/kvm_host.h b/arch/powerpc/include/asm/kvm_host.h
index 243bc8038572dd73aedb0b45d7f2eb845534a3c7..97cb2d7865f3ad583e1169386aa3bc86a431e879 100644 (file)
--- a/arch/powerpc/include/asm/kvm_host.h
+++ b/arch/powerpc/include/asm/kvm_host.h
@@ -170,12 +170,27 @@ struct kvmppc_rma_info {
 /*
  * The reverse mapping array has one entry for each HPTE,
  * which stores the guest's view of the second word of the HPTE
- * (including the guest physical address of the mapping).
+ * (including the guest physical address of the mapping),
+ * plus forward and backward pointers in a doubly-linked ring
+ * of HPTEs that map the same host page.  The pointers in this
+ * ring are 32-bit HPTE indexes, to save space.
  */
 struct revmap_entry {
        unsigned long guest_rpte;
+       unsigned int forw, back;
 };
 
+/*
+ * We use the top bit of each memslot->rmap entry as a lock bit,
+ * and bit 32 as a present flag.  The bottom 32 bits are the
+ * index in the guest HPT of a HPTE that points to the page.
+ */
+#define KVMPPC_RMAP_LOCK_BIT   63
+#define KVMPPC_RMAP_REF_BIT    33
+#define KVMPPC_RMAP_REFERENCED (1ul << KVMPPC_RMAP_REF_BIT)
+#define KVMPPC_RMAP_PRESENT    0x100000000ul
+#define KVMPPC_RMAP_INDEX      0xfffffffful
+
 /* Low-order bits in kvm->arch.slot_phys[][] */
 #define KVMPPC_PAGE_ORDER_MASK 0x1f
 #define KVMPPC_PAGE_NO_CACHE   HPTE_R_I        /* 0x20 */