From: Julien Grall Date: Mon, 20 Jan 2020 14:10:57 +0000 (+0000) Subject: xen/x86: domain: Remove specific case when allocating struct domain X-Git-Tag: archive/raspbian/4.14.0+80-gd101b417b7-1+rpi1^2~63^2~766 X-Git-Url: https://dgit.raspbian.org/%22http://www.example.com/cgi/%22/%22http:/www.example.com/cgi/%22?a=commitdiff_plain;h=7608f33452ae417ee2b7406e06add7c4e12db9fa;p=xen.git xen/x86: domain: Remove specific case when allocating struct domain Commit 8916fcf4577 "x86/domain: compile with lock_profile=y enabled" allowed the struct domain to use more than a PAGE_SIZE (i.e 4096). However, the function free_domheap_struct() will only free the first page. We could modify the free part to free the correct number of pages, but the structure has been fitting in a page (even with lock profile enabled) since commit 428607a410 "x86: shrink 'struct domain', was already PAGE_SIZE" (part of Xen 4.7). Therefore, the specific case for lock profile is now removed. This is not a security issue because struct domain can only be bigger than a page size for lock profiling. The feature can only be selected in DEBUG and EXPERT mode. Fixes: 8916fcf4577 ("x86/domain: compile with lock_profile=y enabled") Reported-by: David Woodhouse Signed-off-by: Julien Grall Reviewed-by: Andrew Cooper --- diff --git a/xen/arch/x86/domain.c b/xen/arch/x86/domain.c index 28fefa1f81..f53ae5ff86 100644 --- a/xen/arch/x86/domain.c +++ b/xen/arch/x86/domain.c @@ -313,7 +313,6 @@ static unsigned int __init noinline _domain_struct_bits(void) struct domain *alloc_domain_struct(void) { struct domain *d; - unsigned int order = get_order_from_bytes(sizeof(*d)); #ifdef CONFIG_BIGMEM const unsigned int bits = 0; #else @@ -327,18 +326,10 @@ struct domain *alloc_domain_struct(void) bits = _domain_struct_bits(); #endif - -#ifndef CONFIG_DEBUG_LOCK_PROFILE BUILD_BUG_ON(sizeof(*d) > PAGE_SIZE); -#endif - d = alloc_xenheap_pages(order, MEMF_bits(bits)); + d = alloc_xenheap_pages(0, MEMF_bits(bits)); if ( d != NULL ) - { - unsigned int sz; - - for ( sz = 0; sz < (PAGE_SIZE << order); sz += PAGE_SIZE ) - clear_page((void *)d + sz); - } + clear_page(d); return d; }