1 files changed, 27 insertions, 15 deletions

diff --git a/arch/powerpc/kvm/book3s_64_mmu_radix.c b/arch/powerpc/kvm/book3s_64_mmu_radix.c
index 5cb4e4687107..ed62164f8474 100644
--- a/arch/powerpc/kvm/book3s_64_mmu_radix.c
+++ b/arch/powerpc/kvm/book3s_64_mmu_radix.c
@@ -160,6 +160,17 @@ static void kvmppc_radix_tlbie_page(struct kvm *kvm, unsigned long addr,
         asm volatile("ptesync": : :"memory");
 }
 
+static void kvmppc_radix_flush_pwc(struct kvm *kvm, unsigned long addr)
+{
+        unsigned long rb = 0x2 << PPC_BITLSHIFT(53); /* IS = 2 */
+
+        asm volatile("ptesync": : :"memory");
+        /* RIC=1 PRS=0 R=1 IS=2 */
+        asm volatile(PPC_TLBIE_5(%0, %1, 1, 0, 1)
+                     : : "r" (rb), "r" (kvm->arch.lpid) : "memory");
+        asm volatile("ptesync": : :"memory");
+}
+
 unsigned long kvmppc_radix_update_pte(struct kvm *kvm, pte_t *ptep,
                                       unsigned long clr, unsigned long set,
                                       unsigned long addr, unsigned int shift)
@@ -261,6 +272,11 @@ static int kvmppc_create_pte(struct kvm *kvm, pte_t pte, unsigned long gpa,
                         ret = -EAGAIN;
                         goto out_unlock;
                 }
+                /* Check if we raced and someone else has set the same thing */
+                if (level == 1 && pmd_raw(*pmd) == pte_raw(pte)) {
+                        ret = 0;
+                        goto out_unlock;
+                }
                 /* Valid 2MB page here already, remove it */
                 old = kvmppc_radix_update_pte(kvm, pmdp_ptep(pmd),
                                               ~0UL, 0, lgpa, PMD_SHIFT);
@@ -275,12 +291,13 @@ static int kvmppc_create_pte(struct kvm *kvm, pte_t pte, unsigned long gpa,
                 }
         } else if (level == 1 && !pmd_none(*pmd)) {
                 /*
-                 * There's a page table page here, but we wanted
-                 * to install a large page.  Tell the caller and let
-                 * it try installing a normal page if it wants.
+                 * There's a page table page here, but we wanted to
+                 * install a large page, so remove and free the page
+                 * table page.  new_ptep will be NULL since level == 1.
                  */
-                ret = -EBUSY;
-                goto out_unlock;
+                new_ptep = pte_offset_kernel(pmd, 0);
+                pmd_clear(pmd);
+                kvmppc_radix_flush_pwc(kvm, gpa);
         }
         if (level == 0) {
                 if (pmd_none(*pmd)) {
@@ -291,6 +308,11 @@ static int kvmppc_create_pte(struct kvm *kvm, pte_t pte, unsigned long gpa,
                 }
                 ptep = pte_offset_kernel(pmd, gpa);
                 if (pte_present(*ptep)) {
+                        /* Check if someone else set the same thing */
+                        if (pte_raw(*ptep) == pte_raw(pte)) {
+                                ret = 0;
+                                goto out_unlock;
+                        }
                         /* PTE was previously valid, so invalidate it */
                         old = kvmppc_radix_update_pte(kvm, ptep, _PAGE_PRESENT,
                                                       0, gpa, 0);
@@ -469,16 +491,6 @@ int kvmppc_book3s_radix_page_fault(struct kvm_run *run, struct kvm_vcpu *vcpu,
 
         /* Allocate space in the tree and write the PTE */
         ret = kvmppc_create_pte(kvm, pte, gpa, level, mmu_seq);
-        if (ret == -EBUSY) {
-                /*
-                 * There's already a PMD where wanted to install a large page;
-                 * for now, fall back to installing a small page.
-                 */
-                level = 0;
-                pfn |= gfn & ((PMD_SIZE >> PAGE_SHIFT) - 1);
-                pte = pfn_pte(pfn, __pgprot(pgflags));
-                ret = kvmppc_create_pte(kvm, pte, gpa, level, mmu_seq);
-        }
 
         if (page) {
                 if (!ret && (pgflags & _PAGE_WRITE))