[PATCH] KVM: PPC: E500: Support hugetlbfs

[Alexander Graf <agraf@xxxxxxx>]

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@xxxxxxx>
---
 arch/powerpc/kvm/e500_tlb.c |   22 ++++++++++++++++++++++
 1 files changed, 22 insertions(+), 0 deletions(-)

diff --git a/arch/powerpc/kvm/e500_tlb.c b/arch/powerpc/kvm/e500_tlb.c
index ec17148..64f75eb 100644
--- a/arch/powerpc/kvm/e500_tlb.c
+++ b/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>
 
@@ -673,13 +674,34 @@ 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);
+			int lz;
+
+			tsize = (gtlbe->mas1 & MAS1_TSIZE_MASK) >>
+				MAS1_TSIZE_SHIFT;
+
+			/*
+			 * e500 doesn't implement the lowest tsize bit,
+			 * or 1K pages.
+			 */
+			tsize = max(BOOK3E_PAGESZ_4K, tsize & ~1);
+
+			/* take the smallest page size that satisfies host and
+			   guest mapping */
+			asm (PPC_CNTLZL "%0,%1" : "=r" (lz) : "r" (psize));
+			tsize = min(21 - lz, tsize);
 		}
 
 		up_read(&current->mm->mmap_sem);
 	}
 
 	if (likely(!pfnmap)) {
+		unsigned long tsize_pages = 1 << (tsize - 2);
 		pfn = gfn_to_pfn_memslot(vcpu_e500->vcpu.kvm, slot, gfn);
+		pfn &= ~(tsize_pages - 1);
+		gvaddr &= ~((tsize_pages << PAGE_SHIFT) - 1);
 		if (is_error_pfn(pfn)) {
 			printk(KERN_ERR "Couldn't get real page for gfn %lx!\n",
 					(long)gfn);
-- 
1.6.0.2

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