Re: [PATCH 3/4] kvm-unit-tests: VMX: Add test cases for I/O bitmaps

[Jan Kiszka <jan.kiszka@web.de>]

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On 2013-08-15 10:09, Arthur Chunqi Li wrote:
> On Thu, Aug 15, 2013 at 3:58 PM, Jan Kiszka <jan.kiszka@web.de> wrote:
>> On 2013-08-15 09:51, Arthur Chunqi Li wrote:
>>> On Thu, Aug 15, 2013 at 3:40 PM, Jan Kiszka <jan.kiszka@web.de> wrote:
>>>> On 2013-08-13 17:56, Arthur Chunqi Li wrote:
>>>>> Add test cases for I/O bitmaps, including corner cases.
>>>>
>>>> Would be good to briefly list the corner cases here.
>>>>
>>>>>
>>>>> Signed-off-by: Arthur Chunqi Li <yzt356@gmail.com>
>>>>> ---
>>>>>  x86/vmx.h       |    6 +-
>>>>>  x86/vmx_tests.c |  167 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
>>>>>  2 files changed, 170 insertions(+), 3 deletions(-)
>>>>>
>>>>> diff --git a/x86/vmx.h b/x86/vmx.h
>>>>> index 18961f1..dba8b20 100644
>>>>> --- a/x86/vmx.h
>>>>> +++ b/x86/vmx.h
>>>>> @@ -417,15 +417,15 @@ enum Ctrl1 {
>>>>>       "popf\n\t"
>>>>>
>>>>>  #define VMX_IO_SIZE_MASK             0x7
>>>>> -#define _VMX_IO_BYTE                 1
>>>>> -#define _VMX_IO_WORD                 2
>>>>> +#define _VMX_IO_BYTE                 0
>>>>> +#define _VMX_IO_WORD                 1
>>>>>  #define _VMX_IO_LONG                 3
>>>>>  #define VMX_IO_DIRECTION_MASK                (1ul << 3)
>>>>>  #define VMX_IO_IN                    (1ul << 3)
>>>>>  #define VMX_IO_OUT                   0
>>>>>  #define VMX_IO_STRING                        (1ul << 4)
>>>>>  #define VMX_IO_REP                   (1ul << 5)
>>>>> -#define VMX_IO_OPRAND_DX             (1ul << 6)
>>>>> +#define VMX_IO_OPRAND_IMM            (1ul << 6)
>>>>>  #define VMX_IO_PORT_MASK             0xFFFF0000
>>>>>  #define VMX_IO_PORT_SHIFT            16
>>>>>
>>>>> diff --git a/x86/vmx_tests.c b/x86/vmx_tests.c
>>>>> index 44be3f4..ad28c4c 100644
>>>>> --- a/x86/vmx_tests.c
>>>>> +++ b/x86/vmx_tests.c
>>>>> @@ -2,10 +2,13 @@
>>>>>  #include "msr.h"
>>>>>  #include "processor.h"
>>>>>  #include "vm.h"
>>>>> +#include "io.h"
>>>>>
>>>>>  u64 ia32_pat;
>>>>>  u64 ia32_efer;
>>>>>  u32 stage;
>>>>> +void *io_bitmap_a, *io_bitmap_b;
>>>>> +u16 ioport;
>>>>>
>>>>>  static inline void vmcall()
>>>>>  {
>>>>> @@ -473,6 +476,168 @@ static int cr_shadowing_exit_handler()
>>>>>       return VMX_TEST_VMEXIT;
>>>>>  }
>>>>>
>>>>> +static void iobmp_init()
>>>>> +{
>>>>> +     u32 ctrl_cpu0;
>>>>> +
>>>>> +     io_bitmap_a = alloc_page();
>>>>> +     io_bitmap_a = alloc_page();
>>>>> +     memset(io_bitmap_a, 0x0, PAGE_SIZE);
>>>>> +     memset(io_bitmap_b, 0x0, PAGE_SIZE);
>>>>> +     ctrl_cpu0 = vmcs_read(CPU_EXEC_CTRL0);
>>>>> +     ctrl_cpu0 |= CPU_IO_BITMAP;
>>>>> +     ctrl_cpu0 &= (~CPU_IO);
>>>>> +     vmcs_write(CPU_EXEC_CTRL0, ctrl_cpu0);
>>>>> +     vmcs_write(IO_BITMAP_A, (u64)io_bitmap_a);
>>>>> +     vmcs_write(IO_BITMAP_B, (u64)io_bitmap_b);
>>>>> +}
>>>>> +
>>>>> +static void iobmp_main()
>>>>> +{
>>>>> +/*
>>>>> +     data = (u8 *)io_bitmap_b;
>>>>> +     ioport = 0xffff;
>>>>> +     data[(ioport - 0x8000) /8] |= (1 << (ioport % 8));
>>>>> +     inb(ioport);
>>>>> +     outb(0, ioport);
>>>>> +*/
>>>>
>>>> Forgotten debug code?
>>>>
>>>>> +     // stage 0, test IO pass
>>>>> +     set_stage(0);
>>>>> +     inb(0x5000);
>>>>> +     outb(0x0, 0x5000);
>>>>> +     if (stage != 0)
>>>>> +             report("I/O bitmap - I/O pass", 0);
>>>>> +     else
>>>>> +             report("I/O bitmap - I/O pass", 1);
>>>>> +     // test IO width, in/out
>>>>> +     ((u8 *)io_bitmap_a)[0] = 0xFF;
>>>>> +     set_stage(2);
>>>>> +     inb(0x0);
>>>>> +     if (stage != 3)
>>>>> +             report("I/O bitmap - trap in", 0);
>>>>> +     else
>>>>> +             report("I/O bitmap - trap in", 1);
>>>>> +     set_stage(3);
>>>>> +     outw(0x0, 0x0);
>>>>> +     if (stage != 4)
>>>>> +             report("I/O bitmap - trap out", 0);
>>>>> +     else
>>>>> +             report("I/O bitmap - trap out", 1);
>>>>> +     set_stage(4);
>>>>> +     inl(0x0);
>>>>
>>>> Forgot to check the progress?
>>>>
>>>>> +     // test low/high IO port
>>>>> +     set_stage(5);
>>>>> +     ((u8 *)io_bitmap_a)[0x5000 / 8] = (1 << (0x5000 % 8));
>>>>> +     inb(0x5000);
>>>>> +     if (stage == 6)
>>>>> +             report("I/O bitmap - I/O port, low part", 1);
>>>>> +     else
>>>>> +             report("I/O bitmap - I/O port, low part", 0);
>>>>> +     set_stage(6);
>>>>> +     ((u8 *)io_bitmap_b)[0x1000 / 8] = (1 << (0x1000 % 8));
>>>>> +     inb(0x9000);
>>>>> +     if (stage == 7)
>>>>> +             report("I/O bitmap - I/O port, high part", 1);
>>>>> +     else
>>>>> +             report("I/O bitmap - I/O port, high part", 0);
>>>>> +     // test partial pass
>>>>> +     set_stage(7);
>>>>> +     inl(0x4FFF);
>>>>> +     if (stage == 8)
>>>>> +             report("I/O bitmap - partial pass", 1);
>>>>> +     else
>>>>> +             report("I/O bitmap - partial pass", 0);
>>>>> +     // test overrun
>>>>> +     set_stage(8);
>>>>> +     memset(io_bitmap_b, 0xFF, PAGE_SIZE);
>>>>> +     inl(0xFFFF);
>>>>
>>>> Let's check the expected stage also here.
>>> The check is below "if (stage == 9)", the following "memset" is just
>>> used to prevent I/O mask to printf.
>>
>> Right, there is an i/o instruction missing below after the second memset
>> - or I cannot follow what you are trying to test. The above inl would
>> always trigger, independent of the wrap-around. Only if you clear both
>> bitmaps, we get to the "interesting" scenario. So something is still
>> wrong here, no?
> Yes, we need to memset io_bit_map_a to 0 here. The above inl and the
> test "if (stage == 9)" are cooperatively used to test I/O overrun:
> test 4 bits width "in" to 0xFFFF.

The point is that, according to our understanding of the SDM, we should
even see a trap in this wrap-around scenario if both bitmaps are cleared.

Jan



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