KVM: PPC: Book3S HV: Move kvmppc_svm_page_out up

kvmppc_svm_page_out() will need to be called by kvmppc_uvmem_drop_pages()
so move it up earlier in this file.

Furthermore it will be interesting to call this function when already
holding the kvm->arch.uvmem_lock, so prefix the original function with __
and remove the locking in it, and introduce a wrapper which call that
function with the lock held.

There is no functional change.
Reviewed-by: Bharata B Rao <bharata@linux.ibm.com>
Signed-off-by: Laurent Dufour <ldufour@linux.ibm.com>
Signed-off-by: Ram Pai <linuxram@us.ibm.com>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>

arch/powerpc/kvm/book3s_hv_uvmem.c

@@ -496,6 +496,96 @@ unsigned long kvmppc_h_svm_init_start(struct kvm *kvm)
 	return ret;
 }
 
+/*
+ * Provision a new page on HV side and copy over the contents
+ * from secure memory using UV_PAGE_OUT uvcall.
+ * Caller must held kvm->arch.uvmem_lock.
+ */
+static int __kvmppc_svm_page_out(struct vm_area_struct *vma,
+		unsigned long start,
+		unsigned long end, unsigned long page_shift,
+		struct kvm *kvm, unsigned long gpa)
+{
+	unsigned long src_pfn, dst_pfn = 0;
+	struct migrate_vma mig;
+	struct page *dpage, *spage;
+	struct kvmppc_uvmem_page_pvt *pvt;
+	unsigned long pfn;
+	int ret = U_SUCCESS;
+
+	memset(&mig, 0, sizeof(mig));
+	mig.vma = vma;
+	mig.start = start;
+	mig.end = end;
+	mig.src = &src_pfn;
+	mig.dst = &dst_pfn;
+	mig.src_owner = &kvmppc_uvmem_pgmap;
+
+	/* The requested page is already paged-out, nothing to do */
+	if (!kvmppc_gfn_is_uvmem_pfn(gpa >> page_shift, kvm, NULL))
+		return ret;
+
+	ret = migrate_vma_setup(&mig);
+	if (ret)
+		return -1;
+
+	spage = migrate_pfn_to_page(*mig.src);
+	if (!spage || !(*mig.src & MIGRATE_PFN_MIGRATE))
+		goto out_finalize;
+
+	if (!is_zone_device_page(spage))
+		goto out_finalize;
+
+	dpage = alloc_page_vma(GFP_HIGHUSER, vma, start);
+	if (!dpage) {
+		ret = -1;
+		goto out_finalize;
+	}
+
+	lock_page(dpage);
+	pvt = spage->zone_device_data;
+	pfn = page_to_pfn(dpage);
+
+	/*
+	 * This function is used in two cases:
+	 * - When HV touches a secure page, for which we do UV_PAGE_OUT
+	 * - When a secure page is converted to shared page, we *get*
+	 *   the page to essentially unmap the device page. In this
+	 *   case we skip page-out.
+	 */
+	if (!pvt->skip_page_out)
+		ret = uv_page_out(kvm->arch.lpid, pfn << page_shift,
+				  gpa, 0, page_shift);
+
+	if (ret == U_SUCCESS)
+		*mig.dst = migrate_pfn(pfn) | MIGRATE_PFN_LOCKED;
+	else {
+		unlock_page(dpage);
+		__free_page(dpage);
+		goto out_finalize;
+	}
+
+	migrate_vma_pages(&mig);
+
+out_finalize:
+	migrate_vma_finalize(&mig);
+	return ret;
+}
+
+static inline int kvmppc_svm_page_out(struct vm_area_struct *vma,
+				      unsigned long start, unsigned long end,
+				      unsigned long page_shift,
+				      struct kvm *kvm, unsigned long gpa)
+{
+	int ret;
+
+	mutex_lock(&kvm->arch.uvmem_lock);
+	ret = __kvmppc_svm_page_out(vma, start, end, page_shift, kvm, gpa);
+	mutex_unlock(&kvm->arch.uvmem_lock);
+
+	return ret;
+}
+
 /*
  * Drop device pages that we maintain for the secure guest
  *
@@ -866,82 +956,6 @@ unsigned long kvmppc_h_svm_page_in(struct kvm *kvm, unsigned long gpa,
 	return ret;
 }
 
-/*
- * Provision a new page on HV side and copy over the contents
- * from secure memory using UV_PAGE_OUT uvcall.
- */
-static int kvmppc_svm_page_out(struct vm_area_struct *vma,
-		unsigned long start,
-		unsigned long end, unsigned long page_shift,
-		struct kvm *kvm, unsigned long gpa)
-{
-	unsigned long src_pfn, dst_pfn = 0;
-	struct migrate_vma mig;
-	struct page *dpage, *spage;
-	struct kvmppc_uvmem_page_pvt *pvt;
-	unsigned long pfn;
-	int ret = U_SUCCESS;
-
-	memset(&mig, 0, sizeof(mig));
-	mig.vma = vma;
-	mig.start = start;
-	mig.end = end;
-	mig.src = &src_pfn;
-	mig.dst = &dst_pfn;
-	mig.src_owner = &kvmppc_uvmem_pgmap;
-
-	mutex_lock(&kvm->arch.uvmem_lock);
-	/* The requested page is already paged-out, nothing to do */
-	if (!kvmppc_gfn_is_uvmem_pfn(gpa >> page_shift, kvm, NULL))
-		goto out;
-
-	ret = migrate_vma_setup(&mig);
-	if (ret)
-		goto out;
-
-	spage = migrate_pfn_to_page(*mig.src);
-	if (!spage || !(*mig.src & MIGRATE_PFN_MIGRATE))
-		goto out_finalize;
-
-	if (!is_zone_device_page(spage))
-		goto out_finalize;
-
-	dpage = alloc_page_vma(GFP_HIGHUSER, vma, start);
-	if (!dpage) {
-		ret = -1;
-		goto out_finalize;
-	}
-
-	lock_page(dpage);
-	pvt = spage->zone_device_data;
-	pfn = page_to_pfn(dpage);
-
-	/*
-	 * This function is used in two cases:
-	 * - When HV touches a secure page, for which we do UV_PAGE_OUT
-	 * - When a secure page is converted to shared page, we *get*
-	 *   the page to essentially unmap the device page. In this
-	 *   case we skip page-out.
-	 */
-	if (!pvt->skip_page_out)
-		ret = uv_page_out(kvm->arch.lpid, pfn << page_shift,
-				  gpa, 0, page_shift);
-
-	if (ret == U_SUCCESS)
-		*mig.dst = migrate_pfn(pfn) | MIGRATE_PFN_LOCKED;
-	else {
-		unlock_page(dpage);
-		__free_page(dpage);
-		goto out_finalize;
-	}
-
-	migrate_vma_pages(&mig);
-out_finalize:
-	migrate_vma_finalize(&mig);
-out:
-	mutex_unlock(&kvm->arch.uvmem_lock);
-	return ret;
-}
 
 /*
  * Fault handler callback that gets called when HV touches any page that