[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [RFC PATCH 1/2] xen/unpopulated-alloc: Introduce helpers for DMA allocations
On 04.06.22 00:52, Stefano Stabellini wrote: Hello Stefano Thank you for having a look and sorry for the late response. On Tue, 17 May 2022, Oleksandr Tyshchenko wrote:From: Oleksandr Tyshchenko <oleksandr_tyshchenko@xxxxxxxx> Add ability to allocate unpopulated DMAable (contiguous) pages suitable for grant mapping into. This is going to be used by gnttab code (see gnttab_dma_alloc_pages()). TODO: There is a code duplication in fill_dma_pool(). Also pool oparations likely need to be protected by the lock. Signed-off-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@xxxxxxxx> --- drivers/xen/unpopulated-alloc.c | 167 ++++++++++++++++++++++++++++++++++++++++ include/xen/xen.h | 15 ++++ 2 files changed, 182 insertions(+) diff --git a/drivers/xen/unpopulated-alloc.c b/drivers/xen/unpopulated-alloc.c index a39f2d3..bca0198 100644 --- a/drivers/xen/unpopulated-alloc.c +++ b/drivers/xen/unpopulated-alloc.c @@ -1,5 +1,6 @@ // SPDX-License-Identifier: GPL-2.0 #include <linux/errno.h> +#include <linux/genalloc.h> #include <linux/gfp.h> #include <linux/kernel.h> #include <linux/mm.h> @@ -16,6 +17,8 @@ static DEFINE_MUTEX(list_lock); static struct page *page_list; static unsigned int list_count;+static struct gen_pool *dma_pool;+ static struct resource *target_resource;/*@@ -230,6 +233,161 @@ void xen_free_unpopulated_pages(unsigned int nr_pages, struct page **pages) } EXPORT_SYMBOL(xen_free_unpopulated_pages);+static int fill_dma_pool(unsigned int nr_pages)+{I think we shouldn't need to add this function at all as we should be able to reuse fill_list even for contiguous pages. fill_list could always call gen_pool_add_virt before returning. First of all, I agree that fill_dma_pool() has a lot in common with fill_list(), so we indeed can avoid code duplication (this was mentioned in TODO). I am not quite sure regarding "to always call gen_pool_add_virt before returning" (does this mean that the same pages will be in the "page_list" and "dma_pool" simultaneously?), but I completely agree that we can reuse fill_list() for contiguous pages as well slightly updating it. Please see below. + struct dev_pagemap *pgmap; + struct resource *res, *tmp_res = NULL; + void *vaddr; + unsigned int alloc_pages = round_up(nr_pages, PAGES_PER_SECTION); + struct range mhp_range; + int ret; + + res = kzalloc(sizeof(*res), GFP_KERNEL); + if (!res) + return -ENOMEM; + + res->name = "Xen DMA pool"; + res->flags = IORESOURCE_MEM | IORESOURCE_BUSY; + + mhp_range = mhp_get_pluggable_range(true); + + ret = allocate_resource(target_resource, res, + alloc_pages * PAGE_SIZE, mhp_range.start, mhp_range.end, + PAGES_PER_SECTION * PAGE_SIZE, NULL, NULL); + if (ret < 0) { + pr_err("Cannot allocate new IOMEM resource\n"); + goto err_resource; + } + + /* + * Reserve the region previously allocated from Xen resource to avoid + * re-using it by someone else. + */ + if (target_resource != &iomem_resource) { + tmp_res = kzalloc(sizeof(*tmp_res), GFP_KERNEL); + if (!res) { + ret = -ENOMEM; + goto err_insert; + } + + tmp_res->name = res->name; + tmp_res->start = res->start; + tmp_res->end = res->end; + tmp_res->flags = res->flags; + + ret = request_resource(&iomem_resource, tmp_res); + if (ret < 0) { + pr_err("Cannot request resource %pR (%d)\n", tmp_res, ret); + kfree(tmp_res); + goto err_insert; + } + } + + pgmap = kzalloc(sizeof(*pgmap), GFP_KERNEL); + if (!pgmap) { + ret = -ENOMEM; + goto err_pgmap; + } + + pgmap->type = MEMORY_DEVICE_GENERIC; + pgmap->range = (struct range) { + .start = res->start, + .end = res->end, + }; + pgmap->nr_range = 1; + pgmap->owner = res; + + vaddr = memremap_pages(pgmap, NUMA_NO_NODE); + if (IS_ERR(vaddr)) { + pr_err("Cannot remap memory range\n"); + ret = PTR_ERR(vaddr); + goto err_memremap; + } + + ret = gen_pool_add_virt(dma_pool, (unsigned long)vaddr, res->start, + alloc_pages * PAGE_SIZE, NUMA_NO_NODE); + if (ret) + goto err_pool; + + return 0; + +err_pool: + memunmap_pages(pgmap); +err_memremap: + kfree(pgmap); +err_pgmap: + if (tmp_res) { + release_resource(tmp_res); + kfree(tmp_res); + } +err_insert: + release_resource(res); +err_resource: + kfree(res); + return ret; +} + +/** + * xen_alloc_unpopulated_dma_pages - alloc unpopulated DMAable pages + * @dev: valid struct device pointer + * @nr_pages: Number of pages + * @pages: pages returned + * @return 0 on success, error otherwise + */ +int xen_alloc_unpopulated_dma_pages(struct device *dev, unsigned int nr_pages, + struct page **pages) +{ + void *vaddr; + bool filled = false; + unsigned int i; + int ret;Also probably it might be better if xen_alloc_unpopulated_pages and xen_alloc_unpopulated_dma_pages shared the implementation. Something along these lines: int xen_alloc_unpopulated_pages(unsigned int nr_pages, struct page **pages) { return _xen_alloc_unpopulated_pages(nr_pages, pages, false); } int xen_alloc_unpopulated_dma_pages(struct device *dev, unsigned int nr_pages, struct page **pages) { return _xen_alloc_unpopulated_pages(nr_pages, pages, true); } I think, this makes sense, although it depends on how the resulting _xen_alloc_unpopulated_pages() will look like. I'd s/_xen_alloc_unpopulated_pages/alloc_unpopulated_pages Please see below. static int _xen_alloc_unpopulated_pages(unsigned int nr_pages, struct page **pages, bool contiguous) { unsigned int i; int ret = 0; if (contiguous && !xen_feature(XENFEAT_auto_translated_physmap)) return -EINVAL; /* * Fallback to default behavior if we do not have any suitable resource * to allocate required region from and as the result we won't be able to * construct pages. */ if (!target_resource) { if (contiguous) return -EINVAL; return xen_alloc_ballooned_pages(nr_pages, pages); } mutex_lock(&list_lock); if (list_count < nr_pages) { ret = fill_list(nr_pages - list_count); As I understand, this might not work if we need contiguous pages. The check might not be precise as "list_count" is a number of available pages in the list, which are not guaranteed to be contiguous, also the amount of pages to be added to the pool here "nr_pages - list_count" might not be enough to allocate contiguous region with "nr_pages" size. if (ret) goto out; } if (contiguous) { vaddr = (void *)gen_pool_alloc(dma_pool, nr_pages * PAGE_SIZE); for (i = 0; i < nr_pages; i++) pages[i] = virt_to_page(vaddr + PAGE_SIZE * i); } else { for (i = 0; i < nr_pages; i++) { struct page *pg = page_list; BUG_ON(!pg); page_list = pg->zone_device_data; list_count--; pages[i] = pg; I think, if we keep the same pages in the "page_list" and "dma_pool" simultaneously we will need to reflect that here, otherwise we might end up reusing already allocated pages. What I mean is if we allocate pages from "dma_pool" we will need to remove them from the "page_list" as well and vice versa, so this might add a complexity to the code. I or missed something? According to the suggestions I see two options, both follow suggestion where xen_alloc(free)_unpopulated_pages() and xen_alloc(free)_unpopulated_dma_pages() share the implementation. 1. Keep "page_list" and "dma_pool" separately. So they don't share pages. Like how it was implemented in current patch but with eliminating both TODOs. This doesn't change behavior for all users of xen_alloc_unpopulated_pages(). Below the diff for unpopulated-alloc.c. The patch is also available at: https://github.com/otyshchenko1/linux/commit/1c629abc37478c108a5f4c37ae8076b766c4d5ccdiff --git a/drivers/xen/unpopulated-alloc.c b/drivers/xen/unpopulated-alloc.c index a39f2d3..c3a86c09 100644 --- a/drivers/xen/unpopulated-alloc.c +++ b/drivers/xen/unpopulated-alloc.c @@ -1,5 +1,7 @@ // SPDX-License-Identifier: GPL-2.0 +#include <linux/dma-mapping.h> #include <linux/errno.h> +#include <linux/genalloc.h> #include <linux/gfp.h> #include <linux/kernel.h> #include <linux/mm.h> @@ -16,6 +18,8 @@ static DEFINE_MUTEX(list_lock); static struct page *page_list; static unsigned int list_count; +static struct gen_pool *dma_pool; + static struct resource *target_resource; /*@@ -31,7 +35,7 @@ int __weak __init arch_xen_unpopulated_init(struct resource **res) return 0; } -static int fill_list(unsigned int nr_pages) +static int fill_list(unsigned int nr_pages, bool use_pool) { struct dev_pagemap *pgmap; struct resource *res, *tmp_res = NULL; @@ -125,12 +129,21 @@ static int fill_list(unsigned int nr_pages) goto err_memremap; } - for (i = 0; i < alloc_pages; i++) { - struct page *pg = virt_to_page(vaddr + PAGE_SIZE * i); + if (use_pool) {+ ret = gen_pool_add_virt(dma_pool, (unsigned long)vaddr, res->start, + alloc_pages * PAGE_SIZE, NUMA_NO_NODE); + if (ret) { + memunmap_pages(pgmap); + goto err_memremap; + } + } else { + for (i = 0; i < alloc_pages; i++) {+ struct page *pg = virt_to_page(vaddr + PAGE_SIZE * i); - pg->zone_device_data = page_list; - page_list = pg; - list_count++; + pg->zone_device_data = page_list; + page_list = pg; + list_count++; + } } return 0; @@ -149,13 +162,8 @@ static int fill_list(unsigned int nr_pages) return ret; } -/** - * xen_alloc_unpopulated_pages - alloc unpopulated pages - * @nr_pages: Number of pages - * @pages: pages returned - * @return 0 on success, error otherwise - */ -int xen_alloc_unpopulated_pages(unsigned int nr_pages, struct page **pages)+static int alloc_unpopulated_pages(unsigned int nr_pages, struct page **pages, + bool contiguous) { unsigned int i; int ret = 0;@@ -165,71 +173,167 @@ int xen_alloc_unpopulated_pages(unsigned int nr_pages, struct page **pages) * to allocate required region from and as the result we won't be able to * construct pages. */ - if (!target_resource) + if (!target_resource) { + if (contiguous) + return -ENODEV; + return xen_alloc_ballooned_pages(nr_pages, pages); + } mutex_lock(&list_lock); - if (list_count < nr_pages) { - ret = fill_list(nr_pages - list_count); - if (ret) - goto out; - } - for (i = 0; i < nr_pages; i++) { - struct page *pg = page_list; + if (contiguous) { + void *vaddr; + bool filled = false; ++ while (!(vaddr = (void *)gen_pool_alloc(dma_pool, nr_pages * PAGE_SIZE))) { + if (filled) + ret = -ENOMEM; + else { + ret = fill_list(nr_pages, true); + filled = true; + } + if (ret) + goto out; + } - BUG_ON(!pg); - page_list = pg->zone_device_data; - list_count--; - pages[i] = pg; + for (i = 0; i < nr_pages; i++) { + pages[i] = virt_to_page(vaddr + PAGE_SIZE * i); #ifdef CONFIG_XEN_HAVE_PVMMU - if (!xen_feature(XENFEAT_auto_translated_physmap)) { - ret = xen_alloc_p2m_entry(page_to_pfn(pg)); - if (ret < 0) { - unsigned int j; - - for (j = 0; j <= i; j++) { - pages[j]->zone_device_data = page_list; - page_list = pages[j]; - list_count++; + if (!xen_feature(XENFEAT_auto_translated_physmap)) {+ ret = xen_alloc_p2m_entry(page_to_pfn(pages[i])); + if (ret < 0) {+ /* XXX Do we need to zeroed pages[i]? */ + gen_pool_free(dma_pool, (unsigned long)vaddr, + nr_pages * PAGE_SIZE); + goto out; } - goto out; } +#endif + } + } else { + if (list_count < nr_pages) { + ret = fill_list(nr_pages - list_count, false); + if (ret) + goto out; } + + for (i = 0; i < nr_pages; i++) { + struct page *pg = page_list; + + BUG_ON(!pg); + page_list = pg->zone_device_data; + list_count--; + pages[i] = pg; + +#ifdef CONFIG_XEN_HAVE_PVMMU + if (!xen_feature(XENFEAT_auto_translated_physmap)) { + ret = xen_alloc_p2m_entry(page_to_pfn(pg)); + if (ret < 0) { + unsigned int j; + + for (j = 0; j <= i; j++) { + pages[j]->zone_device_data = page_list; + page_list = pages[j]; + list_count++; + } + goto out; + } + } #endif + } } out: mutex_unlock(&list_lock); return ret; } -EXPORT_SYMBOL(xen_alloc_unpopulated_pages); -/** - * xen_free_unpopulated_pages - return unpopulated pages - * @nr_pages: Number of pages - * @pages: pages to return - */ -void xen_free_unpopulated_pages(unsigned int nr_pages, struct page **pages)+static void free_unpopulated_pages(unsigned int nr_pages, struct page **pages, + bool contiguous) { - unsigned int i; - if (!target_resource) { + if (contiguous) + return; + xen_free_ballooned_pages(nr_pages, pages); return; } mutex_lock(&list_lock); - for (i = 0; i < nr_pages; i++) { - pages[i]->zone_device_data = page_list; - page_list = pages[i]; - list_count++; + + /* XXX Do we need to check the range (gen_pool_has_addr)? */ + if (contiguous)+ gen_pool_free(dma_pool, (unsigned long)page_to_virt(pages[0]), + nr_pages * PAGE_SIZE); + else { + unsigned int i; + + for (i = 0; i < nr_pages; i++) { + pages[i]->zone_device_data = page_list; + page_list = pages[i]; + list_count++; + } } + mutex_unlock(&list_lock); } + +/** + * xen_alloc_unpopulated_pages - alloc unpopulated pages + * @nr_pages: Number of pages + * @pages: pages returned + * @return 0 on success, error otherwise + */ +int xen_alloc_unpopulated_pages(unsigned int nr_pages, struct page **pages) +{ + return alloc_unpopulated_pages(nr_pages, pages, false); +} +EXPORT_SYMBOL(xen_alloc_unpopulated_pages); + +/** + * xen_free_unpopulated_pages - return unpopulated pages + * @nr_pages: Number of pages + * @pages: pages to return + */ +void xen_free_unpopulated_pages(unsigned int nr_pages, struct page **pages) +{ + free_unpopulated_pages(nr_pages, pages, false); +} EXPORT_SYMBOL(xen_free_unpopulated_pages); +/** + * xen_alloc_unpopulated_dma_pages - alloc unpopulated DMAable pages + * @dev: valid struct device pointer + * @nr_pages: Number of pages + * @pages: pages returned + * @return 0 on success, error otherwise + */+int xen_alloc_unpopulated_dma_pages(struct device *dev, unsigned int nr_pages, + struct page **pages) +{+ /* XXX Handle devices which support 64-bit DMA address only for now */ + if (dma_get_mask(dev) != DMA_BIT_MASK(64)) + return -EINVAL; + + return alloc_unpopulated_pages(nr_pages, pages, true); +} +EXPORT_SYMBOL(xen_alloc_unpopulated_dma_pages); + +/** + * xen_free_unpopulated_dma_pages - return unpopulated DMAable pages + * @dev: valid struct device pointer + * @nr_pages: Number of pages + * @pages: pages to return + */+void xen_free_unpopulated_dma_pages(struct device *dev, unsigned int nr_pages, + struct page **pages) +{ + free_unpopulated_pages(nr_pages, pages, true); +} +EXPORT_SYMBOL(xen_free_unpopulated_dma_pages); + static int __init unpopulated_init(void) { int ret; @@ -237,9 +341,19 @@ static int __init unpopulated_init(void) if (!xen_domain()) return -ENODEV; + dma_pool = gen_pool_create(PAGE_SHIFT, NUMA_NO_NODE); + if (!dma_pool) { + pr_err("xen:unpopulated: Cannot create DMA pool\n"); + return -ENOMEM; + } + + gen_pool_set_algo(dma_pool, gen_pool_best_fit, NULL); + ret = arch_xen_unpopulated_init(&target_resource); if (ret) {pr_err("xen:unpopulated: Cannot initialize target resource\n"); + gen_pool_destroy(dma_pool); + dma_pool = NULL; target_resource = NULL; } [snip]2. Drop the "page_list" entirely and use "dma_pool" for all (contiguous and non-contiguous) allocations. After all, all pages are initially contiguous in fill_list() as they are built from the resource. This changes behavior for all users of xen_alloc_unpopulated_pages() Below the diff for unpopulated-alloc.c. The patch is also available at: https://github.com/otyshchenko1/linux/commit/7be569f113a4acbdc4bcb9b20cb3995b3151387adiff --git a/drivers/xen/unpopulated-alloc.c b/drivers/xen/unpopulated-alloc.c index a39f2d3..ab5c7bd 100644 --- a/drivers/xen/unpopulated-alloc.c +++ b/drivers/xen/unpopulated-alloc.c @@ -1,5 +1,7 @@ // SPDX-License-Identifier: GPL-2.0 +#include <linux/dma-mapping.h> #include <linux/errno.h> +#include <linux/genalloc.h> #include <linux/gfp.h> #include <linux/kernel.h> #include <linux/mm.h> @@ -13,8 +15,8 @@ #include <xen/xen.h> static DEFINE_MUTEX(list_lock); -static struct page *page_list; -static unsigned int list_count; + +static struct gen_pool *dma_pool; static struct resource *target_resource; @@ -36,7 +38,7 @@ static int fill_list(unsigned int nr_pages) struct dev_pagemap *pgmap; struct resource *res, *tmp_res = NULL; void *vaddr; - unsigned int i, alloc_pages = round_up(nr_pages, PAGES_PER_SECTION); + unsigned int alloc_pages = round_up(nr_pages, PAGES_PER_SECTION); struct range mhp_range; int ret; @@ -106,6 +108,7 @@ static int fill_list(unsigned int nr_pages) * conflict with any devices. */ if (!xen_feature(XENFEAT_auto_translated_physmap)) { + unsigned int i; xen_pfn_t pfn = PFN_DOWN(res->start); for (i = 0; i < alloc_pages; i++) { @@ -125,16 +128,17 @@ static int fill_list(unsigned int nr_pages) goto err_memremap; } - for (i = 0; i < alloc_pages; i++) { - struct page *pg = virt_to_page(vaddr + PAGE_SIZE * i); - - pg->zone_device_data = page_list; - page_list = pg; - list_count++; + ret = gen_pool_add_virt(dma_pool, (unsigned long)vaddr, res->start, + alloc_pages * PAGE_SIZE, NUMA_NO_NODE); + if (ret) { + pr_err("Cannot add memory range to the pool\n"); + goto err_pool; } return 0; +err_pool: + memunmap_pages(pgmap); err_memremap: kfree(pgmap); err_pgmap: @@ -149,51 +153,49 @@ static int fill_list(unsigned int nr_pages) return ret; } -/** - * xen_alloc_unpopulated_pages - alloc unpopulated pages - * @nr_pages: Number of pages - * @pages: pages returned - * @return 0 on success, error otherwise - */ -int xen_alloc_unpopulated_pages(unsigned int nr_pages, struct page **pages)+static int alloc_unpopulated_pages(unsigned int nr_pages, struct page **pages, + bool contiguous) { unsigned int i; int ret = 0; + void *vaddr; + bool filled = false; /** Fallback to default behavior if we do not have any suitable resource * to allocate required region from and as the result we won't be able to * construct pages. */ - if (!target_resource) + if (!target_resource) { + if (contiguous) + return -ENODEV; + return xen_alloc_ballooned_pages(nr_pages, pages); + } mutex_lock(&list_lock); - if (list_count < nr_pages) { - ret = fill_list(nr_pages - list_count); ++ while (!(vaddr = (void *)gen_pool_alloc(dma_pool, nr_pages * PAGE_SIZE))) { + if (filled) + ret = -ENOMEM; + else { + ret = fill_list(nr_pages); + filled = true; + } if (ret) goto out; } for (i = 0; i < nr_pages; i++) { - struct page *pg = page_list; - - BUG_ON(!pg); - page_list = pg->zone_device_data; - list_count--; - pages[i] = pg; + pages[i] = virt_to_page(vaddr + PAGE_SIZE * i); #ifdef CONFIG_XEN_HAVE_PVMMU if (!xen_feature(XENFEAT_auto_translated_physmap)) { - ret = xen_alloc_p2m_entry(page_to_pfn(pg)); + ret = xen_alloc_p2m_entry(page_to_pfn(pages[i])); if (ret < 0) { - unsigned int j; - - for (j = 0; j <= i; j++) { - pages[j]->zone_device_data = page_list; - page_list = pages[j]; - list_count++; - } + /* XXX Do we need to zeroed pages[i]? */+ gen_pool_free(dma_pool, (unsigned long)vaddr, + nr_pages * PAGE_SIZE); goto out; } }@@ -204,32 +206,89 @@ int xen_alloc_unpopulated_pages(unsigned int nr_pages, struct page **pages) mutex_unlock(&list_lock); return ret; } -EXPORT_SYMBOL(xen_alloc_unpopulated_pages); -/** - * xen_free_unpopulated_pages - return unpopulated pages - * @nr_pages: Number of pages - * @pages: pages to return - */ -void xen_free_unpopulated_pages(unsigned int nr_pages, struct page **pages)+static void free_unpopulated_pages(unsigned int nr_pages, struct page **pages, + bool contiguous) { - unsigned int i; - if (!target_resource) { + if (contiguous) + return; + xen_free_ballooned_pages(nr_pages, pages); return; } mutex_lock(&list_lock); - for (i = 0; i < nr_pages; i++) { - pages[i]->zone_device_data = page_list; - page_list = pages[i]; - list_count++; + + /* XXX Do we need to check the range (gen_pool_has_addr)? */ + if (contiguous)+ gen_pool_free(dma_pool, (unsigned long)page_to_virt(pages[0]), + nr_pages * PAGE_SIZE); + else { + unsigned int i; + + for (i = 0; i < nr_pages; i++)+ gen_pool_free(dma_pool, (unsigned long)page_to_virt(pages[i]), + PAGE_SIZE); } + mutex_unlock(&list_lock); } + +/** + * xen_alloc_unpopulated_pages - alloc unpopulated pages + * @nr_pages: Number of pages + * @pages: pages returned + * @return 0 on success, error otherwise + */ +int xen_alloc_unpopulated_pages(unsigned int nr_pages, struct page **pages) +{ + return alloc_unpopulated_pages(nr_pages, pages, false); +} +EXPORT_SYMBOL(xen_alloc_unpopulated_pages); + +/** + * xen_free_unpopulated_pages - return unpopulated pages + * @nr_pages: Number of pages + * @pages: pages to return + */ +void xen_free_unpopulated_pages(unsigned int nr_pages, struct page **pages) +{ + free_unpopulated_pages(nr_pages, pages, false); +} EXPORT_SYMBOL(xen_free_unpopulated_pages); +/** + * xen_alloc_unpopulated_dma_pages - alloc unpopulated DMAable pages + * @dev: valid struct device pointer + * @nr_pages: Number of pages + * @pages: pages returned + * @return 0 on success, error otherwise + */+int xen_alloc_unpopulated_dma_pages(struct device *dev, unsigned int nr_pages, + struct page **pages) +{+ /* XXX Handle devices which support 64-bit DMA address only for now */ + if (dma_get_mask(dev) != DMA_BIT_MASK(64)) + return -EINVAL; + + return alloc_unpopulated_pages(nr_pages, pages, true); +} +EXPORT_SYMBOL(xen_alloc_unpopulated_dma_pages); + +/** + * xen_free_unpopulated_dma_pages - return unpopulated DMAable pages + * @dev: valid struct device pointer + * @nr_pages: Number of pages + * @pages: pages to return + */+void xen_free_unpopulated_dma_pages(struct device *dev, unsigned int nr_pages, + struct page **pages) +{ + free_unpopulated_pages(nr_pages, pages, true); +} +EXPORT_SYMBOL(xen_free_unpopulated_dma_pages); + static int __init unpopulated_init(void) { int ret; @@ -237,9 +296,19 @@ static int __init unpopulated_init(void) if (!xen_domain()) return -ENODEV; + dma_pool = gen_pool_create(PAGE_SHIFT, NUMA_NO_NODE); + if (!dma_pool) { + pr_err("xen:unpopulated: Cannot create DMA pool\n"); + return -ENOMEM; + } + + gen_pool_set_algo(dma_pool, gen_pool_best_fit, NULL); + ret = arch_xen_unpopulated_init(&target_resource); if (ret) {pr_err("xen:unpopulated: Cannot initialize target resource\n"); + gen_pool_destroy(dma_pool); + dma_pool = NULL; target_resource = NULL; } [snip]I think, regarding on the approach we would likely need to do some renaming for fill_list, page_list, list_lock, etc. Both options work in my Arm64 based environment, not sure regarding x86. Or do we have another option here? I would be happy to go any route. What do you think? #ifdef CONFIG_XEN_HAVE_PVMMU if (!xen_feature(XENFEAT_auto_translated_physmap)) { ret = xen_alloc_p2m_entry(page_to_pfn(pg)); if (ret < 0) { unsigned int j; for (j = 0; j <= i; j++) { pages[j]->zone_device_data = page_list; page_list = pages[j]; list_count++; } goto out; } } #endif } } out: mutex_unlock(&list_lock); return ret; }+ if (!dma_pool) + return -ENODEV; + + /* XXX Handle devices which support 64-bit DMA address only for now */ + if (dma_get_mask(dev) != DMA_BIT_MASK(64)) + return -EINVAL; + + while (!(vaddr = (void *)gen_pool_alloc(dma_pool, nr_pages * PAGE_SIZE))) { + if (filled) + return -ENOMEM; + else { + ret = fill_dma_pool(nr_pages); + if (ret) + return ret; + + filled = true; + } + } + + for (i = 0; i < nr_pages; i++) + pages[i] = virt_to_page(vaddr + PAGE_SIZE * i); + + return 0; +} +EXPORT_SYMBOL(xen_alloc_unpopulated_dma_pages); + +/** + * xen_free_unpopulated_dma_pages - return unpopulated DMAable pages + * @dev: valid struct device pointer + * @nr_pages: Number of pages + * @pages: pages to return + */ +void xen_free_unpopulated_dma_pages(struct device *dev, unsigned int nr_pages, + struct page **pages) +{ + void *vaddr; + + if (!dma_pool) + return; + + vaddr = page_to_virt(pages[0]); + + gen_pool_free(dma_pool, (unsigned long)vaddr, nr_pages * PAGE_SIZE); +} +EXPORT_SYMBOL(xen_free_unpopulated_dma_pages); + static int __init unpopulated_init(void) { int ret; @@ -241,8 +399,17 @@ static int __init unpopulated_init(void) if (ret) { pr_err("xen:unpopulated: Cannot initialize target resource\n"); target_resource = NULL; + return ret; }+ dma_pool = gen_pool_create(PAGE_SHIFT, NUMA_NO_NODE);+ if (!dma_pool) { + pr_err("xen:unpopulated: Cannot create DMA pool\n"); + return -ENOMEM; + } + + gen_pool_set_algo(dma_pool, gen_pool_best_fit, NULL); + return ret; } early_initcall(unpopulated_init); diff --git a/include/xen/xen.h b/include/xen/xen.h index a99bab8..a6a7a59 100644 --- a/include/xen/xen.h +++ b/include/xen/xen.h @@ -52,9 +52,15 @@ bool xen_biovec_phys_mergeable(const struct bio_vec *vec1, extern u64 xen_saved_max_mem_size; #endif+struct device;+ #ifdef CONFIG_XEN_UNPOPULATED_ALLOC int xen_alloc_unpopulated_pages(unsigned int nr_pages, struct page **pages); void xen_free_unpopulated_pages(unsigned int nr_pages, struct page **pages); +int xen_alloc_unpopulated_dma_pages(struct device *dev, unsigned int nr_pages, + struct page **pages); +void xen_free_unpopulated_dma_pages(struct device *dev, unsigned int nr_pages, + struct page **pages); #include <linux/ioport.h> int arch_xen_unpopulated_init(struct resource **res); #else @@ -69,6 +75,15 @@ static inline void xen_free_unpopulated_pages(unsigned int nr_pages, { xen_free_ballooned_pages(nr_pages, pages); } +static inline int xen_alloc_unpopulated_dma_pages(struct device *dev, + unsigned int nr_pages, struct page **pages) +{ + return -1; +} +static inline void xen_free_unpopulated_dma_pages(struct device *dev, + unsigned int nr_pages, struct page **pages) +{ +} #endifGiven that we have these stubs, maybe we don't need to #ifdef the so much code in the next patch ok, I will analyze -- Regards, Oleksandr Tyshchenko
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