From: Luke Shumaker Date: Thu, 28 Dec 2017 18:08:11 +0000 (-0500) Subject: linux-user: init_guest_space: Don't try to align if we'll reject it X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=aac362e46f13305fd9b4abfe7d0068595d4555f2;p=qemu.git linux-user: init_guest_space: Don't try to align if we'll reject it If the ensure-alignment code gets triggered, then the "if (host_start && real_start != current_start)" check will always trigger, so save 2 syscalls and put that check first. Note that we can't just switch to using MAP_FIXED for that check, because then we couldn't differentiate between a failure because "there isn't enough space" and "there isn't enough space *here*". Signed-off-by: Luke Shumaker Message-Id: <20171228180814.9749-9-lukeshu@lukeshu.com> Reviewed-by: Peter Maydell Signed-off-by: Laurent Vivier --- diff --git a/linux-user/elfload.c b/linux-user/elfload.c index c6491a8d35..5c64299961 100644 --- a/linux-user/elfload.c +++ b/linux-user/elfload.c @@ -1845,6 +1845,11 @@ unsigned long init_guest_space(unsigned long host_start, return (unsigned long)-1; } + /* Check to see if the address is valid. */ + if (host_start && real_start != current_start) { + goto try_again; + } + /* Ensure the address is properly aligned. */ if (real_start & ~qemu_host_page_mask) { /* Ideally, we adjust like @@ -1879,11 +1884,6 @@ unsigned long init_guest_space(unsigned long host_start, aligned_start = real_start; } - /* Check to see if the address is valid. */ - if (host_start && aligned_start != current_start) { - goto try_again; - } - #if defined(TARGET_ARM) && !defined(TARGET_AARCH64) /* On 32-bit ARM, we need to also be able to map the commpage. */ int valid = init_guest_commpage(aligned_start - guest_start,