From 028c1fadf4a98e344d268c0d01a8fbecef4d01f8 Mon Sep 17 00:00:00 2001 From: Ricardo Neri Date: Sun, 5 Nov 2017 18:27:57 -0800 Subject: selftests/x86: Add tests for the STR and SLDT instructions commit a9e017d5619eb371460c8e516f4684def62bef3a upstream. The STR and SLDT instructions are not valid when running on virtual-8086 mode and generate an invalid operand exception. These two instructions are protected by the Intel User-Mode Instruction Prevention (UMIP) security feature. In protected mode, if UMIP is enabled, these instructions generate a general protection fault if called from CPL > 0. Linux traps the general protection fault and emulates the instructions sgdt, sidt and smsw; but not str and sldt. These tests are added to verify that the emulation code does not emulate these two instructions but the expected invalid operand exception is seen. Tests fallback to exit with INT3 in case emulation does happen. Signed-off-by: Ricardo Neri Reviewed-by: Thomas Gleixner Cc: Andrew Morton Cc: Andy Lutomirski Cc: Borislav Petkov Cc: Borislav Petkov Cc: Brian Gerst Cc: Chen Yucong Cc: Chris Metcalf Cc: Dave Hansen Cc: Denys Vlasenko Cc: Fenghua Yu Cc: H. Peter Anvin Cc: Huang Rui Cc: Jiri Slaby Cc: Jonathan Corbet Cc: Josh Poimboeuf Cc: Linus Torvalds Cc: Masami Hiramatsu Cc: Michael S. Tsirkin Cc: Paolo Bonzini Cc: Paul Gortmaker Cc: Peter Zijlstra Cc: Ravi V. Shankar Cc: Shuah Khan Cc: Tony Luck Cc: Vlastimil Babka Cc: ricardo.neri@intel.com Link: http://lkml.kernel.org/r/1509935277-22138-13-git-send-email-ricardo.neri-calderon@linux.intel.com Signed-off-by: Ingo Molnar Signed-off-by: Greg Kroah-Hartman --- tools/testing/selftests/x86/entry_from_vm86.c | 18 +++++++++++++++++- 1 file changed, 17 insertions(+), 1 deletion(-) (limited to 'tools') diff --git a/tools/testing/selftests/x86/entry_from_vm86.c b/tools/testing/selftests/x86/entry_from_vm86.c index 881be02f3fab..6e85f0d0498d 100644 --- a/tools/testing/selftests/x86/entry_from_vm86.c +++ b/tools/testing/selftests/x86/entry_from_vm86.c @@ -111,6 +111,11 @@ asm ( "smsw %ax\n\t" "mov %ax, (2080)\n\t" "int3\n\t" + "vmcode_umip_str:\n\t" + "str %eax\n\t" + "vmcode_umip_sldt:\n\t" + "sldt %eax\n\t" + "int3\n\t" ".size vmcode, . - vmcode\n\t" "end_vmcode:\n\t" ".code32\n\t" @@ -119,7 +124,8 @@ asm ( extern unsigned char vmcode[], end_vmcode[]; extern unsigned char vmcode_bound[], vmcode_sysenter[], vmcode_syscall[], - vmcode_sti[], vmcode_int3[], vmcode_int80[], vmcode_umip[]; + vmcode_sti[], vmcode_int3[], vmcode_int80[], vmcode_umip[], + vmcode_umip_str[], vmcode_umip_sldt[]; /* Returns false if the test was skipped. */ static bool do_test(struct vm86plus_struct *v86, unsigned long eip, @@ -226,6 +232,16 @@ void do_umip_tests(struct vm86plus_struct *vm86, unsigned char *test_mem) printf("[FAIL]\tAll the results of SIDT should be the same.\n"); else printf("[PASS]\tAll the results from SIDT are identical.\n"); + + sethandler(SIGILL, sighandler, 0); + do_test(vm86, vmcode_umip_str - vmcode, VM86_SIGNAL, 0, + "STR instruction"); + clearhandler(SIGILL); + + sethandler(SIGILL, sighandler, 0); + do_test(vm86, vmcode_umip_sldt - vmcode, VM86_SIGNAL, 0, + "SLDT instruction"); + clearhandler(SIGILL); } int main(void) -- cgit v1.2.3