From c413fecc763e380ec93dc6faf726e7e735ade04e Mon Sep 17 00:00:00 2001 From: Rusty Russell Date: Tue, 11 Sep 2007 17:06:37 +1000 Subject: [PATCH] lguest: Fix guest crash when CONFIG_X86_USE_3DNOW=y One of the very first things lguest_init() does is a memcpy. On Athlon/Duron/K7 or CyrixIII/VIA-C3 or Geode GX/LX, this tries to use MMX. memcpy -> _mmx_memcpy -> kernel_fpu_begin -> clts -> paravirt_ops.clts But we haven't set paravirt_ops.clts yet, so we do the native version and crash. The simplest solution is to use __memcpy. Thanks to Michael Rasenberger for the bug report. Signed-off-by: Rusty Russell Signed-off-by: Linus Torvalds --- drivers/lguest/lguest.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/drivers/lguest/lguest.c b/drivers/lguest/lguest.c index 6e135ac0834f..ee1c6d05c3d3 100644 --- a/drivers/lguest/lguest.c +++ b/drivers/lguest/lguest.c @@ -964,11 +964,12 @@ __init void lguest_init(void *boot) { /* Copy boot parameters first: the Launcher put the physical location * in %esi, and head.S converted that to a virtual address and handed - * it to us. */ - memcpy(&boot_params, boot, PARAM_SIZE); + * it to us. We use "__memcpy" because "memcpy" sometimes tries to do + * tricky things to go faster, and we're not ready for that. */ + __memcpy(&boot_params, boot, PARAM_SIZE); /* The boot parameters also tell us where the command-line is: save * that, too. */ - memcpy(boot_command_line, __va(boot_params.hdr.cmd_line_ptr), + __memcpy(boot_command_line, __va(boot_params.hdr.cmd_line_ptr), COMMAND_LINE_SIZE); /* We're under lguest, paravirt is enabled, and we're running at -- 2.20.1