KVM: PPC: E500: Support hugetlbfs

With hugetlbfs support emerging on e500, we should also support KVM
backing its guest memory by it.

This patch adds support for hugetlbfs into the e500 shadow mmu code.
Signed-off-by: Alexander Graf <agraf@suse.de>
Acked-by: Scott Wood <scottwood@freescale.com>
Signed-off-by: Avi Kivity <avi@redhat.com>

arch/powerpc/kvm/e500_tlb.c

@@ -24,6 +24,7 @@
 #include <linux/sched.h>
 #include <linux/rwsem.h>
 #include <linux/vmalloc.h>
+#include <linux/hugetlb.h>
 #include <asm/kvm_ppc.h>
 #include <asm/kvm_e500.h>
 
@@ -673,12 +674,31 @@ static inline void kvmppc_e500_shadow_map(struct kvmppc_vcpu_e500 *vcpu_e500,
 				pfn &= ~(tsize_pages - 1);
 				break;
 			}
+		} else if (vma && hva >= vma->vm_start &&
+			   (vma->vm_flags & VM_HUGETLB)) {
+			unsigned long psize = vma_kernel_pagesize(vma);
+
+			tsize = (gtlbe->mas1 & MAS1_TSIZE_MASK) >>
+				MAS1_TSIZE_SHIFT;
+
+			/*
+			 * Take the largest page size that satisfies both host
+			 * and guest mapping
+			 */
+			tsize = min(__ilog2(psize) - 10, tsize);
+
+			/*
+			 * e500 doesn't implement the lowest tsize bit,
+			 * or 1K pages.
+			 */
+			tsize = max(BOOK3E_PAGESZ_4K, tsize & ~1);
 		}
 
 		up_read(&current->mm->mmap_sem);
 	}
 
 	if (likely(!pfnmap)) {
+		unsigned long tsize_pages = 1 << (tsize + 10 - PAGE_SHIFT);
 		pfn = gfn_to_pfn_memslot(vcpu_e500->vcpu.kvm, slot, gfn);
 		if (is_error_pfn(pfn)) {
 			printk(KERN_ERR "Couldn't get real page for gfn %lx!\n",
@@ -686,6 +706,10 @@ static inline void kvmppc_e500_shadow_map(struct kvmppc_vcpu_e500 *vcpu_e500,
 			kvm_release_pfn_clean(pfn);
 			return;
 		}
+
+		/* Align guest and physical address to page map boundaries */
+		pfn &= ~(tsize_pages - 1);
+		gvaddr &= ~((tsize_pages << PAGE_SHIFT) - 1);
 	}
 
 	/* Drop old ref and setup new one. */