From 8f38106de8d023be8b3b28955df3615637c65dd9 Mon Sep 17 00:00:00 2001 From: Luke Shumaker Date: Thu, 28 Dec 2017 06:42:12 -0500 Subject: [PATCH 08/10] 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 --- linux-user/elfload.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) diff --git a/linux-user/elfload.c b/linux-user/elfload.c index 5c0ad65611..1b7583d659 100644 --- a/linux-user/elfload.c +++ b/linux-user/elfload.c @@ -1871,6 +1871,11 @@ 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 @@ -1905,11 +1910,6 @@ 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, -- 2.15.1