Add support for Xen dedicated CMA and page allocators

Signed-off-by: Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com>

arch/arm/xen/enlighten.c

@@ -36,6 +36,10 @@
 
 #include <linux/mm.h>
 
+#if defined(CONFIG_XT_CMA_HELPER)
+#include <xen/xt_cma_helper.h>
+#endif
+
 struct start_info _xen_start_info;
 struct start_info *xen_start_info = &_xen_start_info;
 EXPORT_SYMBOL(xen_start_info);
@@ -353,7 +357,11 @@ static int __init xen_guest_init(void)
 	if (efi_enabled(EFI_RUNTIME_SERVICES))
 		xen_efi_runtime_setup();
 
+#if defined(CONFIG_XT_CMA_HELPER)
+	shared_info_page = (struct shared_info *)xt_cma_get_zeroed_page(GFP_KERNEL);
+#else
 	shared_info_page = (struct shared_info *)get_zeroed_page(GFP_KERNEL);
+#endif
 
 	if (!shared_info_page) {
 		pr_err("not enough memory\n");

arch/arm/xen/xt_cma_helper.c

@@ -0,0 +1,270 @@
+#include <linux/genalloc.h>
+#include <linux/memblock.h>
+#include <linux/slab.h>
+
+#include <xen/xen.h>
+#include <xen/xt_cma_helper.h>
+#include <xen/mem-reservation.h>
+#include <xen/grant_table.h>
+
+/* The size of the boot memory in MiB for page allocator. */
+static int xt_cma_helper_bootmem_page_pool_sz __initdata = SZ_64M;
+
+/* The size of the boot memory in MiB for CMA allocator. */
+static int xt_cma_helper_bootmem_cma_pool_sz __initdata = SZ_128M;
+
+/* Memory pool for non-CMA allocations (page pool). */
+static phys_addr_t xt_cma_helper_bootmem_page_pool_phys;
+static struct gen_pool *xt_cma_helper_bootmem_page_pool;
+
+/* Memory pool for CMA allocations. */
+static phys_addr_t xt_cma_helper_bootmem_cma_pool_phys;
+static struct gen_pool *xt_cma_helper_bootmem_cma_pool;
+
+static int __init xt_cma_helper_bootmem_page_setup(char *p)
+{
+	xt_cma_helper_bootmem_page_pool_sz = memparse(p, &p);
+	return 0;
+}
+early_param("xt_page_pool", xt_cma_helper_bootmem_page_setup);
+
+static int __init xt_cma_helper_bootmem_cma_setup(char *p)
+{
+	xt_cma_helper_bootmem_cma_pool_sz = memparse(p, &p);
+	return 0;
+}
+early_param("xt_cma", xt_cma_helper_bootmem_cma_setup);
+
+void __init xt_cma_helper_init(void)
+{
+	if (!xen_domain())
+		return;
+
+	xt_cma_helper_bootmem_page_pool_phys =
+		memblock_alloc_base(xt_cma_helper_bootmem_page_pool_sz,
+				    SZ_2M, MEMBLOCK_ALLOC_ANYWHERE);
+
+	xt_cma_helper_bootmem_cma_pool_phys =
+		memblock_alloc_base(xt_cma_helper_bootmem_cma_pool_sz,
+				    SZ_2M, MEMBLOCK_ALLOC_ANYWHERE);
+
+	printk("Allocated %d bytes for Xen page allocator at 0x%llx",
+	       xt_cma_helper_bootmem_page_pool_sz,
+	       xt_cma_helper_bootmem_page_pool_phys);
+
+	printk("Allocated %d bytes for Xen CMA allocator at 0x%llx",
+	       xt_cma_helper_bootmem_cma_pool_sz,
+	       xt_cma_helper_bootmem_cma_pool_phys);
+}
+
+static void create_page_alloc_pools(void)
+{
+	void *vaddr = phys_to_virt(xt_cma_helper_bootmem_page_pool_phys);
+	int ret;
+
+	/* Page pool. */
+	xt_cma_helper_bootmem_page_pool =
+		gen_pool_create(PAGE_SHIFT, -1);
+	BUG_ON(!xt_cma_helper_bootmem_page_pool);
+
+	gen_pool_set_algo(xt_cma_helper_bootmem_page_pool,
+			  gen_pool_best_fit, NULL);
+	ret = gen_pool_add_virt(xt_cma_helper_bootmem_page_pool,
+				(unsigned long)vaddr,
+				xt_cma_helper_bootmem_page_pool_phys,
+				xt_cma_helper_bootmem_page_pool_sz, -1);
+	BUG_ON(ret);
+
+	/* CMA pool. */
+	vaddr = phys_to_virt(xt_cma_helper_bootmem_cma_pool_phys);
+
+	xt_cma_helper_bootmem_cma_pool =
+		gen_pool_create(PAGE_SHIFT, -1);
+	BUG_ON(!xt_cma_helper_bootmem_cma_pool);
+
+	gen_pool_set_algo(xt_cma_helper_bootmem_cma_pool,
+			  gen_pool_best_fit, NULL);
+	ret = gen_pool_add_virt(xt_cma_helper_bootmem_cma_pool,
+				(unsigned long)vaddr,
+				xt_cma_helper_bootmem_cma_pool_phys,
+				xt_cma_helper_bootmem_cma_pool_sz, -1);
+	BUG_ON(ret);
+}
+
+struct page *xt_cma_alloc_page(gfp_t gfp_mask)
+{
+	void *va;
+
+	/*
+	 * FIXME: this is first called from xen_guest_init which is
+	 * an early_init call. We can also install an early_init
+	 * for the pool creation below, but cannot guarantee it runs
+	 * before xen_guest_init.
+	 */
+	if (unlikely(!xt_cma_helper_bootmem_page_pool))
+		create_page_alloc_pools();
+
+	va = (void *)gen_pool_alloc(xt_cma_helper_bootmem_page_pool,
+				    PAGE_SIZE);
+	if (IS_ERR(va))
+		return va;
+
+	return virt_to_page(va);
+}
+
+unsigned long xt_cma_get_zeroed_page(gfp_t gfp_mask)
+{
+	void *va = page_to_virt(xt_cma_alloc_page(gfp_mask));
+
+	memset(va, 0, PAGE_SIZE);
+	return (unsigned long)va;
+}
+
+void xt_cma_free_page(unsigned long addr)
+{
+	gen_pool_free(xt_cma_helper_bootmem_page_pool,
+		      addr, PAGE_SIZE);
+}
+
+static int xt_cma_alloc_pages(gfp_t gfp_mask, int count,
+			      struct page **pages)
+{
+	int i;
+
+	/*
+	 * Alocate pages one by one - mimic what balloon driver does:
+	 * this gives a possibilyty then to free individual pages which
+	 * is a problem if we allocate all pages at once from the pool.
+	 */
+	for (i = 0; i < count; i++) {
+		pages[i] = xt_cma_alloc_page(gfp_mask);
+		if (IS_ERR(pages[i]))
+			goto fail;
+	}
+	return 0;
+
+fail:
+	for (; i >=0; i--)
+		xt_cma_free_page((unsigned long)page_to_virt(pages[i]));
+	return -ENOMEM;
+}
+
+static void xt_cma_free_pages(struct page **pages, int count)
+{
+	int i;
+
+	for (i = 0; i < count; i++)
+		xt_cma_free_page((unsigned long)page_to_virt(pages[i]));
+}
+
+void *xt_cma_dma_alloc_coherent(struct device *dev, size_t size,
+				dma_addr_t *dma_handle, gfp_t gfp_mask)
+{
+	void *va;
+
+	va = (void *)gen_pool_alloc(xt_cma_helper_bootmem_cma_pool,
+				    ALIGN(size, PAGE_SIZE));
+	if (IS_ERR(va))
+		return va;
+
+	*dma_handle = virt_to_phys(va);
+	return va;
+}
+EXPORT_SYMBOL(xt_cma_dma_alloc_coherent);
+
+void *xt_cma_dma_alloc_wc(struct device *dev, size_t size,
+			  dma_addr_t *dma_handle, gfp_t gfp_mask)
+{
+	return xt_cma_dma_alloc_coherent(dev, size, dma_handle, gfp_mask);
+}
+EXPORT_SYMBOL(xt_cma_dma_alloc_wc);
+
+void xt_cma_dma_free_coherent(struct device *dev, size_t size,
+			      void *cpu_addr, dma_addr_t dma_handle)
+{
+	gen_pool_free(xt_cma_helper_bootmem_cma_pool,
+		      (unsigned long)cpu_addr, ALIGN(size, PAGE_SIZE));
+}
+EXPORT_SYMBOL(xt_cma_dma_free_coherent);
+
+void xt_cma_dma_free_wc(struct device *dev, size_t size,
+			void *cpu_addr, dma_addr_t dma_handle)
+{
+	xt_cma_dma_free_coherent(dev, size, cpu_addr, dma_handle);
+}
+EXPORT_SYMBOL(xt_cma_dma_free_wc);
+
+int alloc_xenballooned_pages(int nr_pages, struct page **pages)
+{
+	xen_pfn_t *frames;
+	int i, ret;
+
+	ret = xt_cma_alloc_pages(GFP_KERNEL, nr_pages, pages);
+	if (ret < 0)
+		return ret;
+
+	frames = kcalloc(nr_pages, sizeof(*frames), GFP_KERNEL);
+	if (!frames) {
+		pr_debug("Failed to allocate frames to decrease reservation\n");
+		ret = -ENOMEM;
+		goto fail;
+	}
+
+	for (i = 0; i < nr_pages; i++) {
+		struct page *page = pages[i];
+
+		frames[i] = xen_page_to_gfn(page);
+		xenmem_reservation_scrub_page(page);
+	}
+
+	xenmem_reservation_va_mapping_reset(nr_pages, pages);
+
+	ret = xenmem_reservation_decrease(nr_pages, frames);
+	if (ret != nr_pages) {
+		pr_debug("Failed to decrease reservation for pages\n");
+		ret = -EFAULT;
+		goto fail;
+	}
+
+	ret = gnttab_pages_set_private(nr_pages, pages);
+	if (ret < 0)
+		goto fail;
+
+	kfree(frames);
+	return 0;
+
+fail:
+	xt_cma_free_pages(pages, nr_pages);
+	kfree(frames);
+	return ret;
+}
+EXPORT_SYMBOL(alloc_xenballooned_pages);
+
+void free_xenballooned_pages(int nr_pages, struct page **pages)
+{
+	xen_pfn_t *frames;
+	int i, ret;
+
+	gnttab_pages_clear_private(nr_pages, pages);
+
+	frames = kcalloc(nr_pages, sizeof(*frames), GFP_KERNEL);
+	if (!frames) {
+		pr_debug("Failed to allocate frames to increase reservation\n");
+		return;
+	}
+
+	for (i = 0; i < nr_pages; i++)
+		frames[i] = xen_page_to_gfn(pages[i]);
+
+	ret = xenmem_reservation_increase(nr_pages, frames);
+	if (ret != nr_pages)
+		pr_debug("Failed to increase reservation for pages\n");
+
+	xenmem_reservation_va_mapping_update(nr_pages, pages, frames);
+
+	xt_cma_free_pages(pages, nr_pages);
+
+	kfree(frames);
+}
+EXPORT_SYMBOL(free_xenballooned_pages);
+

arch/arm64/mm/init.c

@@ -53,6 +53,10 @@
 #include <asm/tlb.h>
 #include <asm/alternative.h>
 
+#if defined(CONFIG_XT_CMA_HELPER)
+#include <xen/xt_cma_helper.h>
+#endif
+
 /*
  * We need to be able to catch inadvertent references to memstart_addr
  * that occur (potentially in generic code) before arm64_memblock_init()
@@ -478,6 +482,10 @@ void __init arm64_memblock_init(void)
 
 	high_memory = __va(memblock_end_of_DRAM() - 1) + 1;
 
+#if defined(CONFIG_XT_CMA_HELPER)
+	xt_cma_helper_init();
+#endif
+
 	dma_contiguous_reserve(arm64_dma_phys_limit);
 
 	memblock_allow_resize();

arch/arm64/xen/Makefile

@@ -1,3 +1,4 @@
 xen-arm-y	+= $(addprefix ../../arm/xen/, enlighten.o grant-table.o p2m.o mm.o)
 obj-y		:= xen-arm.o hypercall.o
-obj-$(CONFIG_XEN_EFI) += $(addprefix ../../arm/xen/, efi.o)
+obj-$(CONFIG_XEN_EFI)       += $(addprefix ../../arm/xen/, efi.o)
+obj-$(CONFIG_XT_CMA_HELPER) += $(addprefix ../../arm/xen/, xt_cma_helper.o)

drivers/xen/balloon.c

@@ -73,7 +73,9 @@
 #include <xen/page.h>
 #include <xen/mem-reservation.h>
 
+#if !defined(CONFIG_XT_CMA_HELPER)
 static int xen_hotplug_unpopulated;
+#endif
 
 #ifdef CONFIG_XEN_BALLOON_MEMORY_HOTPLUG
 
@@ -597,6 +599,7 @@ void balloon_set_new_target(unsigned long target)
 }
 EXPORT_SYMBOL_GPL(balloon_set_new_target);
 
+#if !defined(CONFIG_XT_CMA_HELPER)
 static int add_ballooned_pages(int nr_pages)
 {
 	enum bp_state st;
@@ -692,6 +695,7 @@ void free_xenballooned_pages(int nr_pages, struct page **pages)
 	mutex_unlock(&balloon_mutex);
 }
 EXPORT_SYMBOL(free_xenballooned_pages);
+#endif
 
 #ifdef CONFIG_XEN_PV
 static void __init balloon_add_region(unsigned long start_pfn,