From f5775e0b6116b7e2425ccf535243b21768566d87 Mon Sep 17 00:00:00 2001 From: David Vrabel Date: Mon, 19 Jan 2015 11:08:05 +0000 Subject: x86/xen: discard RAM regions above the maximum reservation During setup, discard RAM regions that are above the maximum reservation (instead of marking them as E820_UNUSABLE). This allows hotplug memory to be placed at these addresses. Signed-off-by: David Vrabel Reviewed-by: Daniel Kiper --- arch/x86/xen/setup.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) (limited to 'arch') diff --git a/arch/x86/xen/setup.c b/arch/x86/xen/setup.c index 1c30e4ab1022..387b60d9bd0e 100644 --- a/arch/x86/xen/setup.c +++ b/arch/x86/xen/setup.c @@ -829,6 +829,8 @@ char * __init xen_memory_setup(void) addr = xen_e820_map[0].addr; size = xen_e820_map[0].size; while (i < xen_e820_map_entries) { + bool discard = false; + chunk_size = size; type = xen_e820_map[i].type; @@ -843,10 +845,11 @@ char * __init xen_memory_setup(void) xen_add_extra_mem(pfn_s, n_pfns); xen_max_p2m_pfn = pfn_s + n_pfns; } else - type = E820_UNUSABLE; + discard = true; } - xen_align_and_add_e820_region(addr, chunk_size, type); + if (!discard) + xen_align_and_add_e820_region(addr, chunk_size, type); addr += chunk_size; size -= chunk_size; -- cgit v1.2.3 From 81b286e0f1fe520f2a96f736ffa7e508ac9139ba Mon Sep 17 00:00:00 2001 From: David Vrabel Date: Thu, 25 Jun 2015 13:12:46 +0100 Subject: xen/balloon: make alloc_xenballoon_pages() always allocate low pages All users of alloc_xenballoon_pages() wanted low memory pages, so remove the option for high memory. Signed-off-by: David Vrabel Reviewed-by: Daniel Kiper --- arch/x86/xen/grant-table.c | 2 +- drivers/xen/balloon.c | 21 ++++++++------------- drivers/xen/grant-table.c | 2 +- drivers/xen/privcmd.c | 2 +- drivers/xen/xenbus/xenbus_client.c | 3 +-- include/xen/balloon.h | 3 +-- 6 files changed, 13 insertions(+), 20 deletions(-) (limited to 'arch') diff --git a/arch/x86/xen/grant-table.c b/arch/x86/xen/grant-table.c index 1580e7a5a4cf..e079500b17f3 100644 --- a/arch/x86/xen/grant-table.c +++ b/arch/x86/xen/grant-table.c @@ -133,7 +133,7 @@ static int __init xlated_setup_gnttab_pages(void) kfree(pages); return -ENOMEM; } - rc = alloc_xenballooned_pages(nr_grant_frames, pages, 0 /* lowmem */); + rc = alloc_xenballooned_pages(nr_grant_frames, pages); if (rc) { pr_warn("%s Couldn't balloon alloc %ld pfns rc:%d\n", __func__, nr_grant_frames, rc); diff --git a/drivers/xen/balloon.c b/drivers/xen/balloon.c index ac6391bd8029..7ec933d505d2 100644 --- a/drivers/xen/balloon.c +++ b/drivers/xen/balloon.c @@ -136,17 +136,16 @@ static void balloon_append(struct page *page) } /* balloon_retrieve: rescue a page from the balloon, if it is not empty. */ -static struct page *balloon_retrieve(bool prefer_highmem) +static struct page *balloon_retrieve(bool require_lowmem) { struct page *page; if (list_empty(&ballooned_pages)) return NULL; - if (prefer_highmem) - page = list_entry(ballooned_pages.prev, struct page, lru); - else - page = list_entry(ballooned_pages.next, struct page, lru); + page = list_entry(ballooned_pages.next, struct page, lru); + if (require_lowmem && PageHighMem(page)) + return NULL; list_del(&page->lru); if (PageHighMem(page)) @@ -521,24 +520,20 @@ EXPORT_SYMBOL_GPL(balloon_set_new_target); * alloc_xenballooned_pages - get pages that have been ballooned out * @nr_pages: Number of pages to get * @pages: pages returned - * @highmem: allow highmem pages * @return 0 on success, error otherwise */ -int alloc_xenballooned_pages(int nr_pages, struct page **pages, bool highmem) +int alloc_xenballooned_pages(int nr_pages, struct page **pages) { int pgno = 0; struct page *page; mutex_lock(&balloon_mutex); while (pgno < nr_pages) { - page = balloon_retrieve(highmem); - if (page && (highmem || !PageHighMem(page))) { + page = balloon_retrieve(true); + if (page) { pages[pgno++] = page; } else { enum bp_state st; - if (page) - balloon_append(page); - st = decrease_reservation(nr_pages - pgno, - highmem ? GFP_HIGHUSER : GFP_USER); + st = decrease_reservation(nr_pages - pgno, GFP_USER); if (st != BP_DONE) goto out_undo; } diff --git a/drivers/xen/grant-table.c b/drivers/xen/grant-table.c index 62f591f8763c..a4b702c9ac68 100644 --- a/drivers/xen/grant-table.c +++ b/drivers/xen/grant-table.c @@ -687,7 +687,7 @@ int gnttab_alloc_pages(int nr_pages, struct page **pages) int i; int ret; - ret = alloc_xenballooned_pages(nr_pages, pages, false); + ret = alloc_xenballooned_pages(nr_pages, pages); if (ret < 0) return ret; diff --git a/drivers/xen/privcmd.c b/drivers/xen/privcmd.c index 5e9adac928e6..b199ad3d4587 100644 --- a/drivers/xen/privcmd.c +++ b/drivers/xen/privcmd.c @@ -401,7 +401,7 @@ static int alloc_empty_pages(struct vm_area_struct *vma, int numpgs) if (pages == NULL) return -ENOMEM; - rc = alloc_xenballooned_pages(numpgs, pages, 0); + rc = alloc_xenballooned_pages(numpgs, pages); if (rc != 0) { pr_warn("%s Could not alloc %d pfns rc:%d\n", __func__, numpgs, rc); diff --git a/drivers/xen/xenbus/xenbus_client.c b/drivers/xen/xenbus/xenbus_client.c index 2ba09c1195c8..aa304d05101b 100644 --- a/drivers/xen/xenbus/xenbus_client.c +++ b/drivers/xen/xenbus/xenbus_client.c @@ -614,8 +614,7 @@ static int xenbus_map_ring_valloc_hvm(struct xenbus_device *dev, if (!node) return -ENOMEM; - err = alloc_xenballooned_pages(nr_grefs, node->hvm.pages, - false /* lowmem */); + err = alloc_xenballooned_pages(nr_grefs, node->hvm.pages); if (err) goto out_err; diff --git a/include/xen/balloon.h b/include/xen/balloon.h index c8aee7a8b8d2..83efdeb243bf 100644 --- a/include/xen/balloon.h +++ b/include/xen/balloon.h @@ -22,8 +22,7 @@ extern struct balloon_stats balloon_stats; void balloon_set_new_target(unsigned long target); -int alloc_xenballooned_pages(int nr_pages, struct page **pages, - bool highmem); +int alloc_xenballooned_pages(int nr_pages, struct page **pages); void free_xenballooned_pages(int nr_pages, struct page **pages); struct device; -- cgit v1.2.3 From 8edfcf882eb91ec9028c7334f90f6ef3db5b0fcf Mon Sep 17 00:00:00 2001 From: David Vrabel Date: Wed, 22 Jul 2015 14:48:09 +0100 Subject: x86/xen: export xen_alloc_p2m_entry() Rename alloc_p2m() to xen_alloc_p2m_entry() and export it. This is useful for ensuring that a p2m entry is allocated (i.e., not a shared missing or identity entry) so that subsequent set_phys_to_machine() calls will require no further allocations. Signed-off-by: David Vrabel Reviewed-by: Daniel Kiper --- v3: - Make xen_alloc_p2m_entry() a nop on auto-xlate guests. --- arch/x86/include/asm/xen/page.h | 2 ++ arch/x86/xen/p2m.c | 19 +++++++++++++------ 2 files changed, 15 insertions(+), 6 deletions(-) (limited to 'arch') diff --git a/arch/x86/include/asm/xen/page.h b/arch/x86/include/asm/xen/page.h index 0679e11d2cf7..b922fa4bb4a1 100644 --- a/arch/x86/include/asm/xen/page.h +++ b/arch/x86/include/asm/xen/page.h @@ -43,6 +43,8 @@ extern unsigned long *xen_p2m_addr; extern unsigned long xen_p2m_size; extern unsigned long xen_max_p2m_pfn; +extern int xen_alloc_p2m_entry(unsigned long pfn); + extern unsigned long get_phys_to_machine(unsigned long pfn); extern bool set_phys_to_machine(unsigned long pfn, unsigned long mfn); extern bool __set_phys_to_machine(unsigned long pfn, unsigned long mfn); diff --git a/arch/x86/xen/p2m.c b/arch/x86/xen/p2m.c index 660b3cfef234..cab9f766bb06 100644 --- a/arch/x86/xen/p2m.c +++ b/arch/x86/xen/p2m.c @@ -530,7 +530,7 @@ static pte_t *alloc_p2m_pmd(unsigned long addr, pte_t *pte_pg) * the new pages are installed with cmpxchg; if we lose the race then * simply free the page we allocated and use the one that's there. */ -static bool alloc_p2m(unsigned long pfn) +int xen_alloc_p2m_entry(unsigned long pfn) { unsigned topidx; unsigned long *top_mfn_p, *mid_mfn; @@ -540,6 +540,9 @@ static bool alloc_p2m(unsigned long pfn) unsigned long addr = (unsigned long)(xen_p2m_addr + pfn); unsigned long p2m_pfn; + if (xen_feature(XENFEAT_auto_translated_physmap)) + return 0; + ptep = lookup_address(addr, &level); BUG_ON(!ptep || level != PG_LEVEL_4K); pte_pg = (pte_t *)((unsigned long)ptep & ~(PAGE_SIZE - 1)); @@ -548,7 +551,7 @@ static bool alloc_p2m(unsigned long pfn) /* PMD level is missing, allocate a new one */ ptep = alloc_p2m_pmd(addr, pte_pg); if (!ptep) - return false; + return -ENOMEM; } if (p2m_top_mfn && pfn < MAX_P2M_PFN) { @@ -566,7 +569,7 @@ static bool alloc_p2m(unsigned long pfn) mid_mfn = alloc_p2m_page(); if (!mid_mfn) - return false; + return -ENOMEM; p2m_mid_mfn_init(mid_mfn, p2m_missing); @@ -592,7 +595,7 @@ static bool alloc_p2m(unsigned long pfn) p2m = alloc_p2m_page(); if (!p2m) - return false; + return -ENOMEM; if (p2m_pfn == PFN_DOWN(__pa(p2m_missing))) p2m_init(p2m); @@ -625,8 +628,9 @@ static bool alloc_p2m(unsigned long pfn) HYPERVISOR_shared_info->arch.max_pfn = xen_p2m_last_pfn; } - return true; + return 0; } +EXPORT_SYMBOL(xen_alloc_p2m_entry); unsigned long __init set_phys_range_identity(unsigned long pfn_s, unsigned long pfn_e) @@ -688,7 +692,10 @@ bool __set_phys_to_machine(unsigned long pfn, unsigned long mfn) bool set_phys_to_machine(unsigned long pfn, unsigned long mfn) { if (unlikely(!__set_phys_to_machine(pfn, mfn))) { - if (!alloc_p2m(pfn)) + int ret; + + ret = xen_alloc_p2m_entry(pfn); + if (ret < 0) return false; return __set_phys_to_machine(pfn, mfn); -- cgit v1.2.3 From 5031612b5eaf15cb6471c6e936a515090810c8f1 Mon Sep 17 00:00:00 2001 From: Julien Grall Date: Tue, 21 Jul 2015 17:57:20 +0100 Subject: arm/xen: Drop pte_mfn and mfn_pte They are not used in common code expect in one place in balloon.c which is only compiled when Linux is using PV MMU. It's not the case on ARM. Rather than worrying how to handle the 64KB case, drop them. Signed-off-by: Julien Grall Reviewed-by: Stefano Stabellini Signed-off-by: David Vrabel --- arch/arm/include/asm/xen/page.h | 3 --- 1 file changed, 3 deletions(-) (limited to 'arch') diff --git a/arch/arm/include/asm/xen/page.h b/arch/arm/include/asm/xen/page.h index 127956353b00..98c9fc38b945 100644 --- a/arch/arm/include/asm/xen/page.h +++ b/arch/arm/include/asm/xen/page.h @@ -13,9 +13,6 @@ #define phys_to_machine_mapping_valid(pfn) (1) -#define pte_mfn pte_pfn -#define mfn_pte pfn_pte - /* Xen machine address */ typedef struct xmaddr { phys_addr_t maddr; -- cgit v1.2.3 From 008c320a96d218712043f8db0111d5472697785c Mon Sep 17 00:00:00 2001 From: Julien Grall Date: Fri, 19 Jun 2015 17:49:03 +0100 Subject: xen/grant: Introduce helpers to split a page into grant Currently, a grant is always based on the Xen page granularity (i.e 4KB). When Linux is using a different page granularity, a single page will be split between multiple grants. The new helpers will be in charge of splitting the Linux page into grants and call a function given by the caller on each grant. Also provide an helper to count the number of grants within a given contiguous region. Note that the x86/include/asm/xen/page.h is now including xen/interface/grant_table.h rather than xen/grant_table.h. It's necessary because xen/grant_table.h depends on asm/xen/page.h and will break the compilation. Furthermore, only definition in interface/grant_table.h is required. Signed-off-by: Julien Grall Reviewed-by: David Vrabel Reviewed-by: Stefano Stabellini Signed-off-by: David Vrabel --- arch/x86/include/asm/xen/page.h | 2 +- drivers/xen/grant-table.c | 26 +++++++++++++++++++++++++ include/xen/grant_table.h | 42 +++++++++++++++++++++++++++++++++++++++++ 3 files changed, 69 insertions(+), 1 deletion(-) (limited to 'arch') diff --git a/arch/x86/include/asm/xen/page.h b/arch/x86/include/asm/xen/page.h index b922fa4bb4a1..fe58e3a935de 100644 --- a/arch/x86/include/asm/xen/page.h +++ b/arch/x86/include/asm/xen/page.h @@ -12,7 +12,7 @@ #include #include -#include +#include #include /* Xen machine address */ diff --git a/drivers/xen/grant-table.c b/drivers/xen/grant-table.c index a4b702c9ac68..dbeaa67dec47 100644 --- a/drivers/xen/grant-table.c +++ b/drivers/xen/grant-table.c @@ -776,6 +776,32 @@ void gnttab_batch_copy(struct gnttab_copy *batch, unsigned count) } EXPORT_SYMBOL_GPL(gnttab_batch_copy); +void gnttab_foreach_grant_in_range(struct page *page, + unsigned int offset, + unsigned int len, + xen_grant_fn_t fn, + void *data) +{ + unsigned int goffset; + unsigned int glen; + unsigned long xen_pfn; + + len = min_t(unsigned int, PAGE_SIZE - offset, len); + goffset = xen_offset_in_page(offset); + + xen_pfn = page_to_xen_pfn(page) + XEN_PFN_DOWN(offset); + + while (len) { + glen = min_t(unsigned int, XEN_PAGE_SIZE - goffset, len); + fn(pfn_to_gfn(xen_pfn), goffset, glen, data); + + goffset = 0; + xen_pfn++; + len -= glen; + } +} +EXPORT_SYMBOL_GPL(gnttab_foreach_grant_in_range); + int gnttab_map_refs(struct gnttab_map_grant_ref *map_ops, struct gnttab_map_grant_ref *kmap_ops, struct page **pages, unsigned int count) diff --git a/include/xen/grant_table.h b/include/xen/grant_table.h index 4478f4b4aae2..05b5b08c2afc 100644 --- a/include/xen/grant_table.h +++ b/include/xen/grant_table.h @@ -45,8 +45,10 @@ #include #include +#include #include #include +#include #define GNTTAB_RESERVED_XENSTORE 1 @@ -224,4 +226,44 @@ static inline struct xen_page_foreign *xen_page_foreign(struct page *page) #endif } +/* Split Linux page in chunk of the size of the grant and call fn + * + * Parameters of fn: + * gfn: guest frame number + * offset: offset in the grant + * len: length of the data in the grant. + * data: internal information + */ +typedef void (*xen_grant_fn_t)(unsigned long gfn, unsigned int offset, + unsigned int len, void *data); + +void gnttab_foreach_grant_in_range(struct page *page, + unsigned int offset, + unsigned int len, + xen_grant_fn_t fn, + void *data); + +/* Helper to get to call fn only on the first "grant chunk" */ +static inline void gnttab_for_one_grant(struct page *page, unsigned int offset, + unsigned len, xen_grant_fn_t fn, + void *data) +{ + /* The first request is limited to the size of one grant */ + len = min_t(unsigned int, XEN_PAGE_SIZE - (offset & ~XEN_PAGE_MASK), + len); + + gnttab_foreach_grant_in_range(page, offset, len, fn, data); +} + +/* Get the number of grant in a specified region + * + * start: Offset from the beginning of the first page + * len: total length of data (can cross multiple page) + */ +static inline unsigned int gnttab_count_grant(unsigned int start, + unsigned int len) +{ + return XEN_PFN_UP(xen_offset_in_page(start) + len); +} + #endif /* __ASM_GNTTAB_H__ */ -- cgit v1.2.3 From 5ed5451d997f7a86c62a5557efc00dc3836dc559 Mon Sep 17 00:00:00 2001 From: Julien Grall Date: Tue, 5 May 2015 16:37:49 +0100 Subject: xen/grant-table: Make it running on 64KB granularity The Xen interface is using 4KB page granularity. This means that each grant is 4KB. The current implementation allocates a Linux page per grant. On Linux using 64KB page granularity, only the first 4KB of the page will be used. We could decrease the memory wasted by sharing the page with multiple grant. It will require some care with the {Set,Clear}ForeignPage macro. Note that no changes has been made in the x86 code because both Linux and Xen will only use 4KB page granularity. Signed-off-by: Julien Grall Reviewed-by: David Vrabel Reviewed-by: Stefano Stabellini Signed-off-by: David Vrabel --- arch/arm/xen/p2m.c | 6 +++--- drivers/xen/grant-table.c | 6 +++--- 2 files changed, 6 insertions(+), 6 deletions(-) (limited to 'arch') diff --git a/arch/arm/xen/p2m.c b/arch/arm/xen/p2m.c index 887596c67b12..0ed01f2d5ee4 100644 --- a/arch/arm/xen/p2m.c +++ b/arch/arm/xen/p2m.c @@ -93,8 +93,8 @@ int set_foreign_p2m_mapping(struct gnttab_map_grant_ref *map_ops, for (i = 0; i < count; i++) { if (map_ops[i].status) continue; - set_phys_to_machine(map_ops[i].host_addr >> PAGE_SHIFT, - map_ops[i].dev_bus_addr >> PAGE_SHIFT); + set_phys_to_machine(map_ops[i].host_addr >> XEN_PAGE_SHIFT, + map_ops[i].dev_bus_addr >> XEN_PAGE_SHIFT); } return 0; @@ -108,7 +108,7 @@ int clear_foreign_p2m_mapping(struct gnttab_unmap_grant_ref *unmap_ops, int i; for (i = 0; i < count; i++) { - set_phys_to_machine(unmap_ops[i].host_addr >> PAGE_SHIFT, + set_phys_to_machine(unmap_ops[i].host_addr >> XEN_PAGE_SHIFT, INVALID_P2M_ENTRY); } diff --git a/drivers/xen/grant-table.c b/drivers/xen/grant-table.c index dbeaa67dec47..72d633962095 100644 --- a/drivers/xen/grant-table.c +++ b/drivers/xen/grant-table.c @@ -642,7 +642,7 @@ int gnttab_setup_auto_xlat_frames(phys_addr_t addr) if (xen_auto_xlat_grant_frames.count) return -EINVAL; - vaddr = xen_remap(addr, PAGE_SIZE * max_nr_gframes); + vaddr = xen_remap(addr, XEN_PAGE_SIZE * max_nr_gframes); if (vaddr == NULL) { pr_warn("Failed to ioremap gnttab share frames (addr=%pa)!\n", &addr); @@ -654,7 +654,7 @@ int gnttab_setup_auto_xlat_frames(phys_addr_t addr) return -ENOMEM; } for (i = 0; i < max_nr_gframes; i++) - pfn[i] = PFN_DOWN(addr) + i; + pfn[i] = XEN_PFN_DOWN(addr) + i; xen_auto_xlat_grant_frames.vaddr = vaddr; xen_auto_xlat_grant_frames.pfn = pfn; @@ -1004,7 +1004,7 @@ static void gnttab_request_version(void) { /* Only version 1 is used, which will always be available. */ grant_table_version = 1; - grefs_per_grant_frame = PAGE_SIZE / sizeof(struct grant_entry_v1); + grefs_per_grant_frame = XEN_PAGE_SIZE / sizeof(struct grant_entry_v1); gnttab_interface = &gnttab_v1_ops; pr_info("Grant tables using version %d layout\n", grant_table_version); -- cgit v1.2.3 From 250c9af3d831139317009eaebbe82e20d23a581f Mon Sep 17 00:00:00 2001 From: Julien Grall Date: Tue, 5 May 2015 16:36:56 +0100 Subject: arm/xen: Add support for 64KB page granularity The hypercall interface is always using 4KB page granularity. This is requiring to use xen page definition macro when we deal with hypercall. Note that pfn_to_gfn is working with a Xen pfn (i.e 4KB). We may want to rename pfn_gfn to make this explicit. We also allocate a 64KB page for the shared page even though only the first 4KB is used. I don't think this is really important for now as it helps to have the pointer 4KB aligned (XENMEM_add_to_physmap is taking a Xen PFN). Signed-off-by: Julien Grall Reviewed-by: Stefano Stabellini Signed-off-by: David Vrabel --- arch/arm/include/asm/xen/page.h | 15 +++++++++++++-- arch/arm/xen/enlighten.c | 6 +++--- 2 files changed, 16 insertions(+), 5 deletions(-) (limited to 'arch') diff --git a/arch/arm/include/asm/xen/page.h b/arch/arm/include/asm/xen/page.h index 98c9fc38b945..e3d94cfa4d46 100644 --- a/arch/arm/include/asm/xen/page.h +++ b/arch/arm/include/asm/xen/page.h @@ -28,6 +28,17 @@ typedef struct xpaddr { #define INVALID_P2M_ENTRY (~0UL) +/* + * The pseudo-physical frame (pfn) used in all the helpers is always based + * on Xen page granularity (i.e 4KB). + * + * A Linux page may be split across multiple non-contiguous Xen page so we + * have to keep track with frame based on 4KB page granularity. + * + * PV drivers should never make a direct usage of those helpers (particularly + * pfn_to_gfn and gfn_to_pfn). + */ + unsigned long __pfn_to_mfn(unsigned long pfn); extern struct rb_root phys_to_mach; @@ -64,8 +75,8 @@ static inline unsigned long bfn_to_pfn(unsigned long bfn) #define bfn_to_local_pfn(bfn) bfn_to_pfn(bfn) /* VIRT <-> GUEST conversion */ -#define virt_to_gfn(v) (pfn_to_gfn(virt_to_pfn(v))) -#define gfn_to_virt(m) (__va(gfn_to_pfn(m) << PAGE_SHIFT)) +#define virt_to_gfn(v) (pfn_to_gfn(virt_to_phys(v) >> XEN_PAGE_SHIFT)) +#define gfn_to_virt(m) (__va(gfn_to_pfn(m) << XEN_PAGE_SHIFT)) /* Only used in PV code. But ARM guests are always HVM. */ static inline xmaddr_t arbitrary_virt_to_machine(void *vaddr) diff --git a/arch/arm/xen/enlighten.c b/arch/arm/xen/enlighten.c index eeeab074e154..50b4769aad8b 100644 --- a/arch/arm/xen/enlighten.c +++ b/arch/arm/xen/enlighten.c @@ -89,8 +89,8 @@ static void xen_percpu_init(void) pr_info("Xen: initializing cpu%d\n", cpu); vcpup = per_cpu_ptr(xen_vcpu_info, cpu); - info.mfn = __pa(vcpup) >> PAGE_SHIFT; - info.offset = offset_in_page(vcpup); + info.mfn = virt_to_gfn(vcpup); + info.offset = xen_offset_in_page(vcpup); err = HYPERVISOR_vcpu_op(VCPUOP_register_vcpu_info, cpu, &info); BUG_ON(err); @@ -213,7 +213,7 @@ static int __init xen_guest_init(void) xatp.domid = DOMID_SELF; xatp.idx = 0; xatp.space = XENMAPSPACE_shared_info; - xatp.gpfn = __pa(shared_info_page) >> PAGE_SHIFT; + xatp.gpfn = virt_to_gfn(shared_info_page); if (HYPERVISOR_memory_op(XENMEM_add_to_physmap, &xatp)) BUG(); -- cgit v1.2.3 From 291be10fd7511101d44cf98166d049bd31bc7600 Mon Sep 17 00:00:00 2001 From: Julien Grall Date: Wed, 9 Sep 2015 15:17:33 +0100 Subject: xen/swiotlb: Pass addresses rather than frame numbers to xen_arch_need_swiotlb With 64KB page granularity support, the frame number will be different. It will be easier to modify the behavior in a single place rather than in each caller. Signed-off-by: Julien Grall Reviewed-by: Stefano Stabellini Signed-off-by: David Vrabel --- arch/arm/include/asm/xen/page.h | 4 ++-- arch/arm/xen/mm.c | 7 +++++-- arch/x86/include/asm/xen/page.h | 4 ++-- drivers/xen/swiotlb-xen.c | 4 ++-- 4 files changed, 11 insertions(+), 8 deletions(-) (limited to 'arch') diff --git a/arch/arm/include/asm/xen/page.h b/arch/arm/include/asm/xen/page.h index e3d94cfa4d46..415dbc6e43fd 100644 --- a/arch/arm/include/asm/xen/page.h +++ b/arch/arm/include/asm/xen/page.h @@ -115,8 +115,8 @@ static inline bool set_phys_to_machine(unsigned long pfn, unsigned long mfn) #define xen_unmap(cookie) iounmap((cookie)) bool xen_arch_need_swiotlb(struct device *dev, - unsigned long pfn, - unsigned long bfn); + phys_addr_t phys, + dma_addr_t dev_addr); unsigned long xen_get_swiotlb_free_pages(unsigned int order); #endif /* _ASM_ARM_XEN_PAGE_H */ diff --git a/arch/arm/xen/mm.c b/arch/arm/xen/mm.c index 6dd911d1f0ac..7b517e913762 100644 --- a/arch/arm/xen/mm.c +++ b/arch/arm/xen/mm.c @@ -138,9 +138,12 @@ void __xen_dma_sync_single_for_device(struct device *hwdev, } bool xen_arch_need_swiotlb(struct device *dev, - unsigned long pfn, - unsigned long bfn) + phys_addr_t phys, + dma_addr_t dev_addr) { + unsigned long pfn = PFN_DOWN(phys); + unsigned long bfn = PFN_DOWN(dev_addr); + return (!hypercall_cflush && (pfn != bfn) && !is_device_dma_coherent(dev)); } diff --git a/arch/x86/include/asm/xen/page.h b/arch/x86/include/asm/xen/page.h index fe58e3a935de..f5fb840b43e8 100644 --- a/arch/x86/include/asm/xen/page.h +++ b/arch/x86/include/asm/xen/page.h @@ -298,8 +298,8 @@ void make_lowmem_page_readwrite(void *vaddr); #define xen_unmap(cookie) iounmap((cookie)) static inline bool xen_arch_need_swiotlb(struct device *dev, - unsigned long pfn, - unsigned long bfn) + phys_addr_t phys, + dma_addr_t dev_addr) { return false; } diff --git a/drivers/xen/swiotlb-xen.c b/drivers/xen/swiotlb-xen.c index 79bc4933b13e..0a5a0e949862 100644 --- a/drivers/xen/swiotlb-xen.c +++ b/drivers/xen/swiotlb-xen.c @@ -392,7 +392,7 @@ dma_addr_t xen_swiotlb_map_page(struct device *dev, struct page *page, */ if (dma_capable(dev, dev_addr, size) && !range_straddles_page_boundary(phys, size) && - !xen_arch_need_swiotlb(dev, PFN_DOWN(phys), PFN_DOWN(dev_addr)) && + !xen_arch_need_swiotlb(dev, phys, dev_addr) && !swiotlb_force) { /* we are not interested in the dma_addr returned by * xen_dma_map_page, only in the potential cache flushes executed @@ -551,7 +551,7 @@ xen_swiotlb_map_sg_attrs(struct device *hwdev, struct scatterlist *sgl, dma_addr_t dev_addr = xen_phys_to_bus(paddr); if (swiotlb_force || - xen_arch_need_swiotlb(hwdev, PFN_DOWN(paddr), PFN_DOWN(dev_addr)) || + xen_arch_need_swiotlb(hwdev, paddr, dev_addr) || !dma_capable(hwdev, dev_addr, sg->length) || range_straddles_page_boundary(paddr, sg->length)) { phys_addr_t map = swiotlb_tbl_map_single(hwdev, -- cgit v1.2.3 From 9435cce87950d805e6c8315410f2cb8ff6b2c6a2 Mon Sep 17 00:00:00 2001 From: Julien Grall Date: Wed, 9 Sep 2015 15:18:45 +0100 Subject: xen/swiotlb: Add support for 64KB page granularity Swiotlb is used on ARM64 to support DMA on platform where devices are not protected by an SMMU. Furthermore it's only enabled for DOM0. While Xen is always using 4KB page granularity in the stage-2 page table, Linux ARM64 may either use 4KB or 64KB. This means that a Linux page can be spanned accross multiple Xen page. The Swiotlb code has to validate that the buffer used for DMA is physically contiguous in the memory. As a Linux page can't be shared between local memory and foreign page by design (the balloon code always removing entirely a Linux page), the changes in the code are very minimal because we only need to check the first Xen PFN. Note that it may be possible to optimize the function check_page_physically_contiguous to avoid looping over every Xen PFN for local memory. Although I will let this optimization for a follow-up. Signed-off-by: Julien Grall Reviewed-by: Stefano Stabellini Signed-off-by: David Vrabel --- arch/arm/include/asm/xen/page-coherent.h | 26 +++++++++++++-------- arch/arm/xen/mm.c | 38 ++++++++++++++++++++++--------- drivers/xen/swiotlb-xen.c | 39 ++++++++++++++++---------------- 3 files changed, 63 insertions(+), 40 deletions(-) (limited to 'arch') diff --git a/arch/arm/include/asm/xen/page-coherent.h b/arch/arm/include/asm/xen/page-coherent.h index efd562412850..0375c8caa061 100644 --- a/arch/arm/include/asm/xen/page-coherent.h +++ b/arch/arm/include/asm/xen/page-coherent.h @@ -35,11 +35,15 @@ static inline void xen_dma_map_page(struct device *hwdev, struct page *page, dma_addr_t dev_addr, unsigned long offset, size_t size, enum dma_data_direction dir, struct dma_attrs *attrs) { - bool local = PFN_DOWN(dev_addr) == page_to_pfn(page); - /* Dom0 is mapped 1:1, so if pfn == mfn the page is local otherwise - * is a foreign page grant-mapped in dom0. If the page is local we - * can safely call the native dma_ops function, otherwise we call - * the xen specific function. */ + bool local = XEN_PFN_DOWN(dev_addr) == page_to_xen_pfn(page); + /* + * Dom0 is mapped 1:1, while the Linux page can be spanned accross + * multiple Xen page, it's not possible to have a mix of local and + * foreign Xen page. So if the first xen_pfn == mfn the page is local + * otherwise it's a foreign page grant-mapped in dom0. If the page is + * local we can safely call the native dma_ops function, otherwise we + * call the xen specific function. + */ if (local) __generic_dma_ops(hwdev)->map_page(hwdev, page, offset, size, dir, attrs); else @@ -51,10 +55,14 @@ static inline void xen_dma_unmap_page(struct device *hwdev, dma_addr_t handle, struct dma_attrs *attrs) { unsigned long pfn = PFN_DOWN(handle); - /* Dom0 is mapped 1:1, so calling pfn_valid on a foreign mfn will - * always return false. If the page is local we can safely call the - * native dma_ops function, otherwise we call the xen specific - * function. */ + /* + * Dom0 is mapped 1:1, while the Linux page can be spanned accross + * multiple Xen page, it's not possible to have a mix of local and + * foreign Xen page. Dom0 is mapped 1:1, so calling pfn_valid on a + * foreign mfn will always return false. If the page is local we can + * safely call the native dma_ops function, otherwise we call the xen + * specific function. + */ if (pfn_valid(pfn)) { if (__generic_dma_ops(hwdev)->unmap_page) __generic_dma_ops(hwdev)->unmap_page(hwdev, handle, size, dir, attrs); diff --git a/arch/arm/xen/mm.c b/arch/arm/xen/mm.c index 7b517e913762..7c34f7126b04 100644 --- a/arch/arm/xen/mm.c +++ b/arch/arm/xen/mm.c @@ -48,22 +48,22 @@ static void dma_cache_maint(dma_addr_t handle, unsigned long offset, size_t size, enum dma_data_direction dir, enum dma_cache_op op) { struct gnttab_cache_flush cflush; - unsigned long pfn; + unsigned long xen_pfn; size_t left = size; - pfn = (handle >> PAGE_SHIFT) + offset / PAGE_SIZE; - offset %= PAGE_SIZE; + xen_pfn = (handle >> XEN_PAGE_SHIFT) + offset / XEN_PAGE_SIZE; + offset %= XEN_PAGE_SIZE; do { size_t len = left; /* buffers in highmem or foreign pages cannot cross page * boundaries */ - if (len + offset > PAGE_SIZE) - len = PAGE_SIZE - offset; + if (len + offset > XEN_PAGE_SIZE) + len = XEN_PAGE_SIZE - offset; cflush.op = 0; - cflush.a.dev_bus_addr = pfn << PAGE_SHIFT; + cflush.a.dev_bus_addr = xen_pfn << XEN_PAGE_SHIFT; cflush.offset = offset; cflush.length = len; @@ -79,7 +79,7 @@ static void dma_cache_maint(dma_addr_t handle, unsigned long offset, HYPERVISOR_grant_table_op(GNTTABOP_cache_flush, &cflush, 1); offset = 0; - pfn++; + xen_pfn++; left -= len; } while (left); } @@ -141,10 +141,26 @@ bool xen_arch_need_swiotlb(struct device *dev, phys_addr_t phys, dma_addr_t dev_addr) { - unsigned long pfn = PFN_DOWN(phys); - unsigned long bfn = PFN_DOWN(dev_addr); - - return (!hypercall_cflush && (pfn != bfn) && !is_device_dma_coherent(dev)); + unsigned int xen_pfn = XEN_PFN_DOWN(phys); + unsigned int bfn = XEN_PFN_DOWN(dev_addr); + + /* + * The swiotlb buffer should be used if + * - Xen doesn't have the cache flush hypercall + * - The Linux page refers to foreign memory + * - The device doesn't support coherent DMA request + * + * The Linux page may be spanned acrros multiple Xen page, although + * it's not possible to have a mix of local and foreign Xen page. + * Furthermore, range_straddles_page_boundary is already checking + * if buffer is physically contiguous in the host RAM. + * + * Therefore we only need to check the first Xen page to know if we + * require a bounce buffer because the device doesn't support coherent + * memory and we are not able to flush the cache. + */ + return (!hypercall_cflush && (xen_pfn != bfn) && + !is_device_dma_coherent(dev)); } int xen_create_contiguous_region(phys_addr_t pstart, unsigned int order, diff --git a/drivers/xen/swiotlb-xen.c b/drivers/xen/swiotlb-xen.c index 0a5a0e949862..7399782c0998 100644 --- a/drivers/xen/swiotlb-xen.c +++ b/drivers/xen/swiotlb-xen.c @@ -76,27 +76,27 @@ static unsigned long xen_io_tlb_nslabs; static u64 start_dma_addr; /* - * Both of these functions should avoid PFN_PHYS because phys_addr_t + * Both of these functions should avoid XEN_PFN_PHYS because phys_addr_t * can be 32bit when dma_addr_t is 64bit leading to a loss in * information if the shift is done before casting to 64bit. */ static inline dma_addr_t xen_phys_to_bus(phys_addr_t paddr) { - unsigned long bfn = pfn_to_bfn(PFN_DOWN(paddr)); - dma_addr_t dma = (dma_addr_t)bfn << PAGE_SHIFT; + unsigned long bfn = pfn_to_bfn(XEN_PFN_DOWN(paddr)); + dma_addr_t dma = (dma_addr_t)bfn << XEN_PAGE_SHIFT; - dma |= paddr & ~PAGE_MASK; + dma |= paddr & ~XEN_PAGE_MASK; return dma; } static inline phys_addr_t xen_bus_to_phys(dma_addr_t baddr) { - unsigned long pfn = bfn_to_pfn(PFN_DOWN(baddr)); - dma_addr_t dma = (dma_addr_t)pfn << PAGE_SHIFT; + unsigned long xen_pfn = bfn_to_pfn(XEN_PFN_DOWN(baddr)); + dma_addr_t dma = (dma_addr_t)xen_pfn << XEN_PAGE_SHIFT; phys_addr_t paddr = dma; - paddr |= baddr & ~PAGE_MASK; + paddr |= baddr & ~XEN_PAGE_MASK; return paddr; } @@ -106,7 +106,7 @@ static inline dma_addr_t xen_virt_to_bus(void *address) return xen_phys_to_bus(virt_to_phys(address)); } -static int check_pages_physically_contiguous(unsigned long pfn, +static int check_pages_physically_contiguous(unsigned long xen_pfn, unsigned int offset, size_t length) { @@ -114,11 +114,11 @@ static int check_pages_physically_contiguous(unsigned long pfn, int i; int nr_pages; - next_bfn = pfn_to_bfn(pfn); - nr_pages = (offset + length + PAGE_SIZE-1) >> PAGE_SHIFT; + next_bfn = pfn_to_bfn(xen_pfn); + nr_pages = (offset + length + XEN_PAGE_SIZE-1) >> XEN_PAGE_SHIFT; for (i = 1; i < nr_pages; i++) { - if (pfn_to_bfn(++pfn) != ++next_bfn) + if (pfn_to_bfn(++xen_pfn) != ++next_bfn) return 0; } return 1; @@ -126,28 +126,27 @@ static int check_pages_physically_contiguous(unsigned long pfn, static inline int range_straddles_page_boundary(phys_addr_t p, size_t size) { - unsigned long pfn = PFN_DOWN(p); - unsigned int offset = p & ~PAGE_MASK; + unsigned long xen_pfn = XEN_PFN_DOWN(p); + unsigned int offset = p & ~XEN_PAGE_MASK; - if (offset + size <= PAGE_SIZE) + if (offset + size <= XEN_PAGE_SIZE) return 0; - if (check_pages_physically_contiguous(pfn, offset, size)) + if (check_pages_physically_contiguous(xen_pfn, offset, size)) return 0; return 1; } static int is_xen_swiotlb_buffer(dma_addr_t dma_addr) { - unsigned long bfn = PFN_DOWN(dma_addr); - unsigned long pfn = bfn_to_local_pfn(bfn); - phys_addr_t paddr; + unsigned long bfn = XEN_PFN_DOWN(dma_addr); + unsigned long xen_pfn = bfn_to_local_pfn(bfn); + phys_addr_t paddr = XEN_PFN_PHYS(xen_pfn); /* If the address is outside our domain, it CAN * have the same virtual address as another address * in our domain. Therefore _only_ check address within our domain. */ - if (pfn_valid(pfn)) { - paddr = PFN_PHYS(pfn); + if (pfn_valid(PFN_DOWN(paddr))) { return paddr >= virt_to_phys(xen_io_tlb_start) && paddr < virt_to_phys(xen_io_tlb_end); } -- cgit v1.2.3 From d5f985c834fbfdedcb629b009ba272ad50add5ac Mon Sep 17 00:00:00 2001 From: Juergen Gross Date: Mon, 14 Sep 2015 15:20:52 +0200 Subject: xen/arm: correct comment in enlighten.c Correct a comment in arch/arm/xen/enlighten.c referencing a wrong source file. Signed-off-by: Juergen Gross Acked-by: Stefano Stabellini Signed-off-by: David Vrabel --- arch/arm/xen/enlighten.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'arch') diff --git a/arch/arm/xen/enlighten.c b/arch/arm/xen/enlighten.c index 50b4769aad8b..dad4ffb0934c 100644 --- a/arch/arm/xen/enlighten.c +++ b/arch/arm/xen/enlighten.c @@ -284,7 +284,7 @@ void xen_arch_resume(void) { } void xen_arch_suspend(void) { } -/* In the hypervisor.S file. */ +/* In the hypercall.S file. */ EXPORT_SYMBOL_GPL(HYPERVISOR_event_channel_op); EXPORT_SYMBOL_GPL(HYPERVISOR_grant_table_op); EXPORT_SYMBOL_GPL(HYPERVISOR_xen_version); -- cgit v1.2.3 From a314e3eb845389b8f68130c79a63832229dea87b Mon Sep 17 00:00:00 2001 From: Stefano Stabellini Date: Thu, 22 Oct 2015 16:20:46 +0000 Subject: xen/arm: Enable cpu_hotplug.c Build cpu_hotplug for ARM and ARM64 guests. Rename arch_(un)register_cpu to xen_(un)register_cpu and provide an empty implementation on ARM and ARM64. On x86 just call arch_(un)register_cpu as we are already doing. Initialize cpu_hotplug on ARM. Signed-off-by: Stefano Stabellini Reviewed-by: Julien Grall Reviewed-by: Boris Ostrovsky --- arch/arm/include/asm/xen/hypervisor.h | 10 ++++++++++ arch/x86/include/asm/xen/hypervisor.h | 5 +++++ arch/x86/xen/enlighten.c | 15 +++++++++++++++ drivers/xen/Makefile | 2 -- drivers/xen/cpu_hotplug.c | 8 ++++++-- 5 files changed, 36 insertions(+), 4 deletions(-) (limited to 'arch') diff --git a/arch/arm/include/asm/xen/hypervisor.h b/arch/arm/include/asm/xen/hypervisor.h index 04ff8e7b37df..95251512e2c4 100644 --- a/arch/arm/include/asm/xen/hypervisor.h +++ b/arch/arm/include/asm/xen/hypervisor.h @@ -26,4 +26,14 @@ void __init xen_early_init(void); static inline void xen_early_init(void) { return; } #endif +#ifdef CONFIG_HOTPLUG_CPU +static inline void xen_arch_register_cpu(int num) +{ +} + +static inline void xen_arch_unregister_cpu(int num) +{ +} +#endif + #endif /* _ASM_ARM_XEN_HYPERVISOR_H */ diff --git a/arch/x86/include/asm/xen/hypervisor.h b/arch/x86/include/asm/xen/hypervisor.h index d866959e5685..8b2d4bea9962 100644 --- a/arch/x86/include/asm/xen/hypervisor.h +++ b/arch/x86/include/asm/xen/hypervisor.h @@ -57,4 +57,9 @@ static inline bool xen_x2apic_para_available(void) } #endif +#ifdef CONFIG_HOTPLUG_CPU +void xen_arch_register_cpu(int num); +void xen_arch_unregister_cpu(int num); +#endif + #endif /* _ASM_X86_XEN_HYPERVISOR_H */ diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c index 993b7a71386d..5774800ff583 100644 --- a/arch/x86/xen/enlighten.c +++ b/arch/x86/xen/enlighten.c @@ -75,6 +75,7 @@ #include #include #include +#include #ifdef CONFIG_ACPI #include @@ -1899,3 +1900,17 @@ const struct hypervisor_x86 x86_hyper_xen = { .set_cpu_features = xen_set_cpu_features, }; EXPORT_SYMBOL(x86_hyper_xen); + +#ifdef CONFIG_HOTPLUG_CPU +void xen_arch_register_cpu(int num) +{ + arch_register_cpu(num); +} +EXPORT_SYMBOL(xen_arch_register_cpu); + +void xen_arch_unregister_cpu(int num) +{ + arch_unregister_cpu(num); +} +EXPORT_SYMBOL(xen_arch_unregister_cpu); +#endif diff --git a/drivers/xen/Makefile b/drivers/xen/Makefile index e293bc507cbc..aa8a7f71f310 100644 --- a/drivers/xen/Makefile +++ b/drivers/xen/Makefile @@ -1,6 +1,4 @@ -ifeq ($(filter y, $(CONFIG_ARM) $(CONFIG_ARM64)),) obj-$(CONFIG_HOTPLUG_CPU) += cpu_hotplug.o -endif obj-$(CONFIG_X86) += fallback.o obj-y += grant-table.o features.o balloon.o manage.o preempt.o obj-y += events/ diff --git a/drivers/xen/cpu_hotplug.c b/drivers/xen/cpu_hotplug.c index cc6513a176b0..43de1f51b53f 100644 --- a/drivers/xen/cpu_hotplug.c +++ b/drivers/xen/cpu_hotplug.c @@ -11,7 +11,7 @@ static void enable_hotplug_cpu(int cpu) { if (!cpu_present(cpu)) - arch_register_cpu(cpu); + xen_arch_register_cpu(cpu); set_cpu_present(cpu, true); } @@ -19,7 +19,7 @@ static void enable_hotplug_cpu(int cpu) static void disable_hotplug_cpu(int cpu) { if (cpu_present(cpu)) - arch_unregister_cpu(cpu); + xen_arch_unregister_cpu(cpu); set_cpu_present(cpu, false); } @@ -102,7 +102,11 @@ static int __init setup_vcpu_hotplug_event(void) static struct notifier_block xsn_cpu = { .notifier_call = setup_cpu_watcher }; +#ifdef CONFIG_X86 if (!xen_pv_domain()) +#else + if (!xen_domain()) +#endif return -ENODEV; register_xenstore_notifier(&xsn_cpu); -- cgit v1.2.3 From cb9644bf3b549d20656cca02e8a6332c67cf37d6 Mon Sep 17 00:00:00 2001 From: Stefano Stabellini Date: Thu, 22 Oct 2015 16:22:46 +0000 Subject: xen/arm: don't try to re-register vcpu_info on cpu_hotplug. Call disable_percpu_irq on CPU_DYING and enable_percpu_irq when the cpu is coming up. Signed-off-by: Stefano Stabellini Reviewed-by: Julien Grall --- arch/arm/xen/enlighten.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) (limited to 'arch') diff --git a/arch/arm/xen/enlighten.c b/arch/arm/xen/enlighten.c index dad4ffb0934c..fc7ea529f462 100644 --- a/arch/arm/xen/enlighten.c +++ b/arch/arm/xen/enlighten.c @@ -86,6 +86,14 @@ static void xen_percpu_init(void) int err; int cpu = get_cpu(); + /* + * VCPUOP_register_vcpu_info cannot be called twice for the same + * vcpu, so if vcpu_info is already registered, just get out. This + * can happen with cpu-hotplug. + */ + if (per_cpu(xen_vcpu, cpu) != NULL) + goto after_register_vcpu_info; + pr_info("Xen: initializing cpu%d\n", cpu); vcpup = per_cpu_ptr(xen_vcpu_info, cpu); @@ -96,6 +104,7 @@ static void xen_percpu_init(void) BUG_ON(err); per_cpu(xen_vcpu, cpu) = vcpup; +after_register_vcpu_info: enable_percpu_irq(xen_events_irq, 0); put_cpu(); } @@ -124,6 +133,9 @@ static int xen_cpu_notification(struct notifier_block *self, case CPU_STARTING: xen_percpu_init(); break; + case CPU_DYING: + disable_percpu_irq(xen_events_irq); + break; default: break; } -- cgit v1.2.3 From 914beb9fc26d6225295b8315ab54026f8f22755c Mon Sep 17 00:00:00 2001 From: David Vrabel Date: Wed, 28 Oct 2015 13:39:05 +0000 Subject: x86/xen: add reschedule point when mapping foreign GFNs Mapping a large range of foreign GFNs can take a long time, add a reschedule point after each batch of 16 GFNs. Signed-off-by: David Vrabel Reviewed-by: Boris Ostrovsky --- arch/x86/xen/mmu.c | 1 + 1 file changed, 1 insertion(+) (limited to 'arch') diff --git a/arch/x86/xen/mmu.c b/arch/x86/xen/mmu.c index 9c479fe40459..ac161db63388 100644 --- a/arch/x86/xen/mmu.c +++ b/arch/x86/xen/mmu.c @@ -2888,6 +2888,7 @@ static int do_remap_gfn(struct vm_area_struct *vma, addr += range; if (err_ptr) err_ptr += batch; + cond_resched(); } out: -- cgit v1.2.3 From abed7d0710e8f892c267932a9492ccf447674fb8 Mon Sep 17 00:00:00 2001 From: Zhenzhong Duan Date: Tue, 27 Oct 2015 15:19:52 -0400 Subject: xen: fix the check of e_pfn in xen_find_pfn_range On some NUMA system, after dom0 up, we see below warning even if there are enough pfn ranges that could be used for remapping: "Unable to find available pfn range, not remapping identity pages" Fix it to avoid getting a memory region of zero size in xen_find_pfn_range. Signed-off-by: Zhenzhong Duan Reviewed-by: Juergen Gross Signed-off-by: Konrad Rzeszutek Wilk Signed-off-by: David Vrabel --- arch/x86/xen/setup.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'arch') diff --git a/arch/x86/xen/setup.c b/arch/x86/xen/setup.c index 387b60d9bd0e..d1fac0e53d57 100644 --- a/arch/x86/xen/setup.c +++ b/arch/x86/xen/setup.c @@ -212,7 +212,7 @@ static unsigned long __init xen_find_pfn_range(unsigned long *min_pfn) e_pfn = PFN_DOWN(entry->addr + entry->size); /* We only care about E820 after this */ - if (e_pfn < *min_pfn) + if (e_pfn <= *min_pfn) continue; s_pfn = PFN_UP(entry->addr); -- cgit v1.2.3