On Wed, Jun 05, 2013 at 05:23:18PM +0800, 李春奇 <Arthur Chunqi Li> wrote: > Yes, I load kvm-intel with unrestricted_guest=0 and the emulator runs > well. I will give another test case in x86/realmode.c later. > The test fails for me on CPU without unrestricted guest support. This means you either test on fixed kernel or unrestricted_guest=0 is broken. > BTW, what is the action when a 64-bit instruction executes in > x86/realmode.c? Should I add 64-bit insn tests only in x86/emulator.c? > Yes, 64-bit or 32-bit instructions should be added to x86/emulator.c. > On Wed, Jun 5, 2013 at 4:27 PM, Gleb Natapov <gleb@xxxxxxxxxx> wrote: > > On Wed, Jun 05, 2013 at 03:00:33PM +0800, 李春奇 <Arthur Chunqi Li> wrote: > >> Yes, that should be the point. x86/realmode.c is always running in > >> emulation mode. I added the testing here there but no error occurred. I > >> cannot find the reason. > >> > >> The code is as follows added to x86/realmode.c > >> static void test_nopl(void) > >> { > >> MK_INSN(nopl, ".byte 0x0f, 0x1f, 0x00\n\r"); > >> exec_in_big_real_mode(&insn_nopl); > >> report("nopl", 0, 1); > >> } > >> > >> and I objdump from realmode.flat is as follows: > >> 00006458 <insn_code_nopl>: > >> 6458: 0f 1f 00 nopl (%eax) > >> > >> But there cause no error when executing this insn. Why? > >> > > Because you probably use cpu that supports unrestricted mode or use AMD > > processor. Can you try loading kvm-intel with unrestricted_guest=0 > > option? > > > >> > >> On Wed, Jun 5, 2013 at 2:42 PM, Gleb Natapov <gleb@xxxxxxxxxx> wrote: > >> > >> > On Wed, Jun 05, 2013 at 10:16:46AM +0800, 李春奇 <Arthur Chunqi Li> wrote: > >> > > Add multibyte NOP test case to kvm-unit-tests. This case can test one > >> > > of bugs when booting RHEL5.9 64-bit. > >> > > > >> > Adding the test to x86/realmode.c will be much easier. > >> > > >> > > Signed-off-by: Arthur Chunqi Li <yzt356@xxxxxxxxx> > >> > > --- > >> > > x86/emulator.c | 33 +++++++++++++++++++++++++++++++++ > >> > > 1 file changed, 33 insertions(+) > >> > > > >> > > diff --git a/x86/emulator.c b/x86/emulator.c > >> > > index 96576e5..f26c70f 100644 > >> > > --- a/x86/emulator.c > >> > > +++ b/x86/emulator.c > >> > > @@ -901,6 +901,37 @@ static void test_simplealu(u32 *mem) > >> > > report("test", *mem == 0x8400); > >> > > } > >> > > > >> > > +static void test_nopl(uint64_t *mem, uint8_t *insn_page, > >> > > + uint8_t *alt_insn_page, void *insn_ram) > >> > > +{ > >> > > + ulong *cr3 = (ulong *)read_cr3(); > >> > > + > >> > > + // Pad with RET instructions > >> > > + memset(insn_page, 0xc3, 4096); > >> > > + memset(alt_insn_page, 0xc3, 4096); > >> > > + // Place a trapping instruction in the page to trigger a VMEXIT > >> > > + insn_page[0] = 0x89; // mov %eax, (%rax) > >> > > + insn_page[1] = 0x00; > >> > > + insn_page[2] = 0x90; // nop > >> > > + // Place nopl 0x0(%eax) in alt_insn_page for emulator to execuate > >> > > + alt_insn_page[0] = 0x0f; // nop DWORD ptr[EAX] > >> > > + alt_insn_page[1] = 0x1f; > >> > > + alt_insn_page[2] = 0x00; > >> > > + > >> > > + // Load the code TLB with insn_page, but point the page tables at > >> > > + // alt_insn_page (and keep the data TLB clear, for AMD decode > >> > assist). > >> > > + // This will make the CPU trap on the insn_page instruction but the > >> > > + // hypervisor will see alt_insn_page. > >> > > + install_page(cr3, virt_to_phys(insn_page), insn_ram); > >> > > + // Load code TLB > >> > > + invlpg(insn_ram); > >> > > + asm volatile("call *%0" : : "r"(insn_ram + 3)); > >> > > + // Trap, let hypervisor emulate at alt_insn_page > >> > > + install_page(cr3, virt_to_phys(alt_insn_page), insn_ram); > >> > > + asm volatile("call *%0" : : "r"(insn_ram), "a"(mem)); > >> > > + report("nopl", 1); > >> > > +} > >> > > + > >> > > int main() > >> > > { > >> > > void *mem; > >> > > @@ -964,6 +995,8 @@ int main() > >> > > > >> > > test_string_io_mmio(mem); > >> > > > >> > > + test_nopl(mem, insn_page, alt_insn_page, insn_ram); > >> > > + > >> > > printf("\nSUMMARY: %d tests, %d failures\n", tests, fails); > >> > > return fails ? 1 : 0; > >> > > } > >> > > -- > >> > > 1.7.9.5 > >> > > >> > -- > >> > Gleb. > >> > > >> > >> > >> > >> -- > >> Arthur Chunqi Li > >> Department of Computer Science > >> School of EECS > >> Peking University > >> Beijing, China > > > > -- > > Gleb. > > > > -- > Arthur Chunqi Li > Department of Computer Science > School of EECS > Peking University > Beijing, China -- Gleb. -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html