From 0c6781ee6a5f0df55eab6be8a92853d3154c0c7b Mon Sep 17 00:00:00 2001 From: Konrad Rzeszutek Wilk Date: Thu, 13 Jun 2013 16:09:03 +0200 Subject: [PATCH] tmem: Don't use map_domain_page for long-life-time pages When using tmem with Xen 4.3 (and debug build) we end up with: (XEN) Xen BUG at domain_page.c:143 (XEN) ----[ Xen-4.3-unstable x86_64 debug=y Not tainted ]---- (XEN) CPU: 3 (XEN) RIP: e008:[] map_domain_page+0x61d/0x6e1 .. (XEN) Xen call trace: (XEN) [] map_domain_page+0x61d/0x6e1 (XEN) [] cli_get_page+0x15e/0x17b (XEN) [] tmh_copy_from_client+0x150/0x284 (XEN) [] do_tmem_put+0x323/0x5c4 (XEN) [] do_tmem_op+0x5a0/0xbd0 (XEN) [] syscall_enter+0xeb/0x145 (XEN) A bit of debugging revealed that the map_domain_page and unmap_domain_page are meant for short life-time mappings. And that those mappings are finite. In the 2 VCPU guest we only have 32 entries and once we have exhausted those we trigger the BUG_ON condition. The two functions - tmh_persistent_pool_page_[get,put] are used by the xmem_pool when xmem_pool_[alloc,free] are called. These xmem_pool_* function are wrapped in macro and functions - the entry points are via: tmem_malloc and tmem_page_alloc. In both cases the users are in the hypervisor and they do not seem to suffer from using the hypervisor virtual addresses. Suggested-by: Jan Beulich Signed-off-by: Konrad Rzeszutek Wilk --- xen/common/tmem_xen.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) diff --git a/xen/common/tmem_xen.c b/xen/common/tmem_xen.c index 3a1f3c912b..736a8c30fa 100644 --- a/xen/common/tmem_xen.c +++ b/xen/common/tmem_xen.c @@ -385,7 +385,7 @@ static void *tmh_persistent_pool_page_get(unsigned long size) if ( (pi = _tmh_alloc_page_thispool(d)) == NULL ) return NULL; ASSERT(IS_VALID_PAGE(pi)); - return __map_domain_page(pi); + return page_to_virt(pi); } static void tmh_persistent_pool_page_put(void *page_va) @@ -393,8 +393,7 @@ static void tmh_persistent_pool_page_put(void *page_va) struct page_info *pi; ASSERT(IS_PAGE_ALIGNED(page_va)); - pi = mfn_to_page(domain_page_map_to_mfn(page_va)); - unmap_domain_page(page_va); + pi = mfn_to_page(virt_to_mfn(page_va)); ASSERT(IS_VALID_PAGE(pi)); _tmh_free_page_thispool(pi); } -- 2.39.5