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Commit 78393fdd authored by Andy Lutomirski's avatar Andy Lutomirski Committed by Ingo Molnar
Browse files

selftests/x86/entry_from_vm86: Add test cases for POPF 



POPF is currently broken -- add tests to catch the error.  This
results in:

   [RUN]	POPF with VIP set and IF clear from vm86 mode
   [INFO]	Exited vm86 mode due to STI
   [FAIL]	Incorrect return reason (started at eip = 0xd, ended at eip = 0xf)

because POPF currently fails to check IF before reporting a pending
interrupt.

This patch also makes the FAIL message a bit more informative.

Reported-by: default avatarBart Oldeman <bartoldeman@gmail.com>
Signed-off-by: default avatarAndy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stas Sergeev <stsp@list.ru>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
Link: http://lkml.kernel.org/r/a16270b5cfe7832d6d00c479d0f871066cbdb52b.1521003603.git.luto@kernel.org


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 327d53d0

tools/testing/selftests/x86/entry_from_vm86.c

+27 −3
Original line number Diff line number Diff line
@@ -95,6 +95,10 @@ asm ( 
	"int3\n\t"

	"vmcode_int80:\n\t"

	"int $0x80\n\t"

	"vmcode_popf_hlt:\n\t"

	"push %ax\n\t"

	"popf\n\t"

	"hlt\n\t"

	"vmcode_umip:\n\t"

	/* addressing via displacements */

	"smsw (2052)\n\t"
@@ -124,8 +128,8 @@ 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_umip_str[], vmcode_umip_sldt[];

	vmcode_sti[], vmcode_int3[], vmcode_int80[], vmcode_popf_hlt[],

	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,
@@ -175,7 +179,7 @@ static bool do_test(struct vm86plus_struct *v86, unsigned long eip, 
	    (VM86_TYPE(ret) == rettype && VM86_ARG(ret) == retarg)) {

		printf("[OK]\tReturned correctly\n");

	} else {

		printf("[FAIL]\tIncorrect return reason\n");

		printf("[FAIL]\tIncorrect return reason (started at eip = 0x%lx, ended at eip = 0x%lx)\n", eip, v86->regs.eip);

		nerrs++;

	}
@@ -264,6 +268,9 @@ int main(void) 
	v86.regs.ds = load_addr / 16;

	v86.regs.es = load_addr / 16;



	/* Use the end of the page as our stack. */

	v86.regs.esp = 4096;



	assert((v86.regs.cs & 3) == 0);	/* Looks like RPL = 0 */



	/* #BR -- should deliver SIG??? */
@@ -295,6 +302,23 @@ int main(void) 
	v86.regs.eflags &= ~X86_EFLAGS_IF;

	do_test(&v86, vmcode_sti - vmcode, VM86_STI, 0, "STI with VIP set");



	/* POPF with VIP set but IF clear: should not trap */

	v86.regs.eflags = X86_EFLAGS_VIP;

	v86.regs.eax = 0;

	do_test(&v86, vmcode_popf_hlt - vmcode, VM86_UNKNOWN, 0, "POPF with VIP set and IF clear");



	/* POPF with VIP set and IF set: should trap */

	v86.regs.eflags = X86_EFLAGS_VIP;

	v86.regs.eax = X86_EFLAGS_IF;

	do_test(&v86, vmcode_popf_hlt - vmcode, VM86_STI, 0, "POPF with VIP and IF set");



	/* POPF with VIP clear and IF set: should not trap */

	v86.regs.eflags = 0;

	v86.regs.eax = X86_EFLAGS_IF;

	do_test(&v86, vmcode_popf_hlt - vmcode, VM86_UNKNOWN, 0, "POPF with VIP clear and IF set");



	v86.regs.eflags = 0;



	/* INT3 -- should cause #BP */

	do_test(&v86, vmcode_int3 - vmcode, VM86_TRAP, 3, "INT3");