From 335e4dd67b480c8fa571ea7e71af0d22047fcfb7 Mon Sep 17 00:00:00 2001 From: Jan Beulich Date: Tue, 4 Jan 2022 09:46:06 +0100 Subject: xen/x86: obtain upper 32 bits of video frame buffer address for Dom0 The hypervisor has been supplying this information for a couple of major releases. Make use of it. The need to set a flag in the capabilities field also points out that the prior setting of that field from the hypervisor interface's gbl_caps one was wrong, so that code gets deleted (there's also no equivalent of this in native boot code). Signed-off-by: Jan Beulich Reviewed-by: Boris Ostrovsky Link: https://lore.kernel.org/r/a3df8bf3-d044-b7bb-3383-cd5239d6d4af@suse.com Signed-off-by: Juergen Gross --- include/xen/interface/xen.h | 3 +++ 1 file changed, 3 insertions(+) (limited to 'include/xen') diff --git a/include/xen/interface/xen.h b/include/xen/interface/xen.h index 5e9916939268..0ca23eca2a9c 100644 --- a/include/xen/interface/xen.h +++ b/include/xen/interface/xen.h @@ -722,6 +722,9 @@ struct dom0_vga_console_info { uint32_t gbl_caps; /* Mode attributes (offset 0x0, VESA command 0x4f01). */ uint16_t mode_attrs; + uint16_t pad; + /* high 32 bits of lfb_base */ + uint32_t ext_lfb_base; } vesa_lfb; } u; }; -- cgit v1.2.3-70-g09d2 From 9dd060afe2dfd4e3f67b6732fdc681e52cd7cbd9 Mon Sep 17 00:00:00 2001 From: Oleksandr Tyshchenko Date: Thu, 9 Dec 2021 22:05:33 +0200 Subject: xen/balloon: Bring alloc(free)_xenballooned_pages helpers back This patch rolls back some of the changes introduced by commit 121f2faca2c0a "xen/balloon: rename alloc/free_xenballooned_pages" in order to make possible to still allocate xenballooned pages if CONFIG_XEN_UNPOPULATED_ALLOC is enabled. On Arm the unpopulated pages will be allocated on top of extended regions provided by Xen via device-tree (the subsequent patches will add required bits to support unpopulated-alloc feature on Arm). The problem is that extended regions feature has been introduced into Xen quite recently (during 4.16 release cycle). So this effectively means that Linux must only use unpopulated-alloc on Arm if it is running on "new Xen" which advertises these regions. But, it will only be known after parsing the "hypervisor" node at boot time, so before doing that we cannot assume anything. In order to keep working if CONFIG_XEN_UNPOPULATED_ALLOC is enabled and the extended regions are not advertised (Linux is running on "old Xen", etc) we need the fallback to alloc_xenballooned_pages(). This way we wouldn't reduce the amount of memory usable (wasting RAM pages) for any of the external mappings anymore (and eliminate XSA-300) with "new Xen", but would be still functional ballooning out RAM pages with "old Xen". Also rename alloc(free)_xenballooned_pages to xen_alloc(free)_ballooned_pages and make xen_alloc(free)_unpopulated_pages static inline in xen.h if CONFIG_XEN_UNPOPULATED_ALLOC is disabled. Signed-off-by: Oleksandr Tyshchenko Reviewed-by: Stefano Stabellini Link: https://lore.kernel.org/r/1639080336-26573-4-git-send-email-olekstysh@gmail.com Signed-off-by: Juergen Gross --- drivers/xen/balloon.c | 20 +++++++++----------- include/xen/balloon.h | 3 +++ include/xen/xen.h | 14 ++++++++++++++ 3 files changed, 26 insertions(+), 11 deletions(-) (limited to 'include/xen') diff --git a/drivers/xen/balloon.c b/drivers/xen/balloon.c index ba2ea11e0d3d..a2c4fc49c483 100644 --- a/drivers/xen/balloon.c +++ b/drivers/xen/balloon.c @@ -581,7 +581,6 @@ void balloon_set_new_target(unsigned long target) } EXPORT_SYMBOL_GPL(balloon_set_new_target); -#ifndef CONFIG_XEN_UNPOPULATED_ALLOC static int add_ballooned_pages(unsigned int nr_pages) { enum bp_state st; @@ -610,12 +609,12 @@ static int add_ballooned_pages(unsigned int nr_pages) } /** - * xen_alloc_unpopulated_pages - get pages that have been ballooned out + * xen_alloc_ballooned_pages - get pages that have been ballooned out * @nr_pages: Number of pages to get * @pages: pages returned * @return 0 on success, error otherwise */ -int xen_alloc_unpopulated_pages(unsigned int nr_pages, struct page **pages) +int xen_alloc_ballooned_pages(unsigned int nr_pages, struct page **pages) { unsigned int pgno = 0; struct page *page; @@ -652,23 +651,23 @@ int xen_alloc_unpopulated_pages(unsigned int nr_pages, struct page **pages) return 0; out_undo: mutex_unlock(&balloon_mutex); - xen_free_unpopulated_pages(pgno, pages); + xen_free_ballooned_pages(pgno, pages); /* - * NB: free_xenballooned_pages will only subtract pgno pages, but since + * NB: xen_free_ballooned_pages will only subtract pgno pages, but since * target_unpopulated is incremented with nr_pages at the start we need * to remove the remaining ones also, or accounting will be screwed. */ balloon_stats.target_unpopulated -= nr_pages - pgno; return ret; } -EXPORT_SYMBOL(xen_alloc_unpopulated_pages); +EXPORT_SYMBOL(xen_alloc_ballooned_pages); /** - * xen_free_unpopulated_pages - return pages retrieved with get_ballooned_pages + * xen_free_ballooned_pages - return pages retrieved with get_ballooned_pages * @nr_pages: Number of pages * @pages: pages to return */ -void xen_free_unpopulated_pages(unsigned int nr_pages, struct page **pages) +void xen_free_ballooned_pages(unsigned int nr_pages, struct page **pages) { unsigned int i; @@ -687,9 +686,9 @@ void xen_free_unpopulated_pages(unsigned int nr_pages, struct page **pages) mutex_unlock(&balloon_mutex); } -EXPORT_SYMBOL(xen_free_unpopulated_pages); +EXPORT_SYMBOL(xen_free_ballooned_pages); -#if defined(CONFIG_XEN_PV) +#if defined(CONFIG_XEN_PV) && !defined(CONFIG_XEN_UNPOPULATED_ALLOC) static void __init balloon_add_region(unsigned long start_pfn, unsigned long pages) { @@ -712,7 +711,6 @@ static void __init balloon_add_region(unsigned long start_pfn, balloon_stats.total_pages += extra_pfn_end - start_pfn; } #endif -#endif static int __init balloon_init(void) { diff --git a/include/xen/balloon.h b/include/xen/balloon.h index e93d4f0088c5..f78a6cc94f1a 100644 --- a/include/xen/balloon.h +++ b/include/xen/balloon.h @@ -26,6 +26,9 @@ extern struct balloon_stats balloon_stats; void balloon_set_new_target(unsigned long target); +int xen_alloc_ballooned_pages(unsigned int nr_pages, struct page **pages); +void xen_free_ballooned_pages(unsigned int nr_pages, struct page **pages); + #ifdef CONFIG_XEN_BALLOON void xen_balloon_init(void); #else diff --git a/include/xen/xen.h b/include/xen/xen.h index 9f031b5faa54..86c5b37684d9 100644 --- a/include/xen/xen.h +++ b/include/xen/xen.h @@ -52,7 +52,21 @@ bool xen_biovec_phys_mergeable(const struct bio_vec *vec1, extern u64 xen_saved_max_mem_size; #endif +#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); +#else +#include +static inline int xen_alloc_unpopulated_pages(unsigned int nr_pages, + struct page **pages) +{ + return xen_alloc_ballooned_pages(nr_pages, pages); +} +static inline void xen_free_unpopulated_pages(unsigned int nr_pages, + struct page **pages) +{ + xen_free_ballooned_pages(nr_pages, pages); +} +#endif #endif /* _XEN_XEN_H */ -- cgit v1.2.3-70-g09d2 From d1a928eac72962b562162c25baf45ce147e27247 Mon Sep 17 00:00:00 2001 From: Oleksandr Tyshchenko Date: Thu, 9 Dec 2021 22:05:34 +0200 Subject: xen/unpopulated-alloc: Add mechanism to use Xen resource The main reason of this change is that unpopulated-alloc code cannot be used in its current form on Arm, but there is a desire to reuse it to avoid wasting real RAM pages for the grant/foreign mappings. The problem is that system "iomem_resource" is used for the address space allocation, but the really unallocated space can't be figured out precisely by the domain on Arm without hypervisor involvement. For example, not all device I/O regions are known by the time domain starts creating grant/foreign mappings. And following the advise from "iomem_resource" we might end up reusing these regions by a mistake. So, the hypervisor which maintains the P2M for the domain is in the best position to provide unused regions of guest physical address space which could be safely used to create grant/foreign mappings. Introduce new helper arch_xen_unpopulated_init() which purpose is to create specific Xen resource based on the memory regions provided by the hypervisor to be used as unused space for Xen scratch pages. If arch doesn't define arch_xen_unpopulated_init() the default "iomem_resource" will be used. Update the arguments list of allocate_resource() in fill_list() to always allocate a region from the hotpluggable range (maximum possible addressable physical memory range for which the linear mapping could be created). If arch doesn't define arch_get_mappable_range() the default range (0,-1) will be used. The behaviour on x86 won't be changed by current patch as both arch_xen_unpopulated_init() and arch_get_mappable_range() are not implemented for it. Also fallback to allocate xenballooned pages (balloon out RAM pages) if we do not have any suitable resource to work with (target_resource is invalid) and as the result we won't be able to provide unpopulated pages on a request. Signed-off-by: Oleksandr Tyshchenko Reviewed-by: Stefano Stabellini Link: https://lore.kernel.org/r/1639080336-26573-5-git-send-email-olekstysh@gmail.com Signed-off-by: Juergen Gross --- drivers/xen/unpopulated-alloc.c | 86 +++++++++++++++++++++++++++++++++++++++-- include/xen/xen.h | 2 + 2 files changed, 84 insertions(+), 4 deletions(-) (limited to 'include/xen') diff --git a/drivers/xen/unpopulated-alloc.c b/drivers/xen/unpopulated-alloc.c index a03dc5b1f37b..a8b41057c382 100644 --- a/drivers/xen/unpopulated-alloc.c +++ b/drivers/xen/unpopulated-alloc.c @@ -8,6 +8,7 @@ #include +#include #include #include @@ -15,13 +16,29 @@ static DEFINE_MUTEX(list_lock); static struct page *page_list; static unsigned int list_count; +static struct resource *target_resource; + +/* + * If arch is not happy with system "iomem_resource" being used for + * the region allocation it can provide it's own view by creating specific + * Xen resource with unused regions of guest physical address space provided + * by the hypervisor. + */ +int __weak __init arch_xen_unpopulated_init(struct resource **res) +{ + *res = &iomem_resource; + + return 0; +} + static int fill_list(unsigned int nr_pages) { struct dev_pagemap *pgmap; - struct resource *res; + struct resource *res, *tmp_res = NULL; void *vaddr; unsigned int i, alloc_pages = round_up(nr_pages, PAGES_PER_SECTION); - int ret = -ENOMEM; + struct range mhp_range; + int ret; res = kzalloc(sizeof(*res), GFP_KERNEL); if (!res) @@ -30,14 +47,40 @@ static int fill_list(unsigned int nr_pages) res->name = "Xen scratch"; res->flags = IORESOURCE_MEM | IORESOURCE_BUSY; - ret = allocate_resource(&iomem_resource, res, - alloc_pages * PAGE_SIZE, 0, -1, + 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 (!tmp_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; @@ -95,6 +138,11 @@ static int fill_list(unsigned int nr_pages) 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); @@ -112,6 +160,14 @@ int xen_alloc_unpopulated_pages(unsigned int nr_pages, struct page **pages) unsigned int i; int ret = 0; + /* + * 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) + return xen_alloc_ballooned_pages(nr_pages, pages); + mutex_lock(&list_lock); if (list_count < nr_pages) { ret = fill_list(nr_pages - list_count); @@ -159,6 +215,11 @@ void xen_free_unpopulated_pages(unsigned int nr_pages, struct page **pages) { unsigned int i; + if (!target_resource) { + 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; @@ -201,3 +262,20 @@ static int __init init(void) } subsys_initcall(init); #endif + +static int __init unpopulated_init(void) +{ + int ret; + + if (!xen_domain()) + return -ENODEV; + + ret = arch_xen_unpopulated_init(&target_resource); + if (ret) { + pr_err("xen:unpopulated: Cannot initialize target resource\n"); + target_resource = NULL; + } + + return ret; +} +early_initcall(unpopulated_init); diff --git a/include/xen/xen.h b/include/xen/xen.h index 86c5b37684d9..a99bab817523 100644 --- a/include/xen/xen.h +++ b/include/xen/xen.h @@ -55,6 +55,8 @@ extern u64 xen_saved_max_mem_size; #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); +#include +int arch_xen_unpopulated_init(struct resource **res); #else #include static inline int xen_alloc_unpopulated_pages(unsigned int nr_pages, -- cgit v1.2.3-70-g09d2