KVM: PPC: Allow use of small pages to back Book3S HV guests

This relaxes the requirement that the guest memory be provided as
16MB huge pages, allowing it to be provided as normal memory, i.e.
in pages of PAGE_SIZE bytes (4k or 64k).  To allow this, we index
the kvm->arch.slot_phys[] arrays with a small page index, even if
huge pages are being used, and use the low-order 5 bits of each
entry to store the order of the enclosing page with respect to
normal pages, i.e. log_2(enclosing_page_size / PAGE_SIZE).

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

4 files changed, 13 insertions, 3 deletions

diff --git a/arch/powerpc/include/asm/kvm_book3s_64.h b/arch/powerpc/include/asm/kvm_book3s_64.h
index 7e6f2ede44ac..10920f7a2b8d 100644
--- a/arch/powerpc/include/asm/kvm_book3s_64.h
+++ b/arch/powerpc/include/asm/kvm_book3s_64.h
@@ -113,4 +113,14 @@ static inline unsigned long hpte_page_size(unsigned long h, unsigned long l)
         return 0;                               /* error */
 }
 
+static inline bool slot_is_aligned(struct kvm_memory_slot *memslot,
+                                   unsigned long pagesize)
+{
+        unsigned long mask = (pagesize >> PAGE_SHIFT) - 1;
+
+        if (pagesize <= PAGE_SIZE)
+                return 1;
+        return !(memslot->base_gfn & mask) && !(memslot->npages & mask);
+}
+
 #endif /* __ASM_KVM_BOOK3S_64_H__ */
diff --git a/arch/powerpc/include/asm/kvm_host.h b/arch/powerpc/include/asm/kvm_host.h
index beb22ba71e26..9252d5e3758d 100644
--- a/arch/powerpc/include/asm/kvm_host.h
+++ b/arch/powerpc/include/asm/kvm_host.h
@@ -177,14 +177,13 @@ struct revmap_entry {
 };
 
 /* Low-order bits in kvm->arch.slot_phys[][] */
+#define KVMPPC_PAGE_ORDER_MASK  0x1f
 #define KVMPPC_GOT_PAGE         0x80
 
 struct kvm_arch {
 #ifdef CONFIG_KVM_BOOK3S_64_HV
         unsigned long hpt_virt;
         struct revmap_entry *revmap;
-        unsigned long ram_psize;
-        unsigned long ram_porder;
         unsigned int lpid;
         unsigned int host_lpid;
         unsigned long host_lpcr;
diff --git a/arch/powerpc/include/asm/kvm_ppc.h b/arch/powerpc/include/asm/kvm_ppc.h
index 1458c6740ea3..fb70414db90c 100644
--- a/arch/powerpc/include/asm/kvm_ppc.h
+++ b/arch/powerpc/include/asm/kvm_ppc.h
@@ -122,7 +122,7 @@ extern void kvmppc_free_hpt(struct kvm *kvm);
 extern long kvmppc_prepare_vrma(struct kvm *kvm,
                                 struct kvm_userspace_memory_region *mem);
 extern void kvmppc_map_vrma(struct kvm_vcpu *vcpu,
-                            struct kvm_memory_slot *memslot);
+                        struct kvm_memory_slot *memslot, unsigned long porder);
 extern int kvmppc_pseries_do_hcall(struct kvm_vcpu *vcpu);
 extern long kvm_vm_ioctl_create_spapr_tce(struct kvm *kvm,
                                 struct kvm_create_spapr_tce *args);
diff --git a/arch/powerpc/include/asm/reg.h b/arch/powerpc/include/asm/reg.h
index 7fdc2c0b7fa0..64447f6c049a 100644
--- a/arch/powerpc/include/asm/reg.h
+++ b/arch/powerpc/include/asm/reg.h
@@ -237,6 +237,7 @@
 #define   LPCR_ISL      (1ul << (63-2))
 #define   LPCR_VC_SH    (63-2)
 #define   LPCR_DPFD_SH  (63-11)
+#define   LPCR_VRMASD   (0x1ful << (63-16))
 #define   LPCR_VRMA_L   (1ul << (63-12))
 #define   LPCR_VRMA_LP0 (1ul << (63-15))
 #define   LPCR_VRMA_LP1 (1ul << (63-16))