Re: [Qemu-devel] [PATCH V9 4/4] tests: Add migration test for aarch64

[Wei Huang]

On 09/26/2018 11:31 AM, Dr. David Alan Gilbert wrote:
> * Wei Huang (address@hidden) wrote:
>> This patch adds migration test support for aarch64. The test code, which
>> implements the same functionality as x86, is booted as a kernel in qemu.
>> Here are the design choices we make for aarch64:
>>
>>  * We choose this -kernel approach because aarch64 QEMU doesn't provide a
>>    built-in fw like x86 does. So instead of relying on a boot loader, we
>>    use -kernel approach for aarch64.
>>  * The serial output is sent to PL011 directly.
>>  * The physical memory base for mach-virt machine is 0x40000000. We change
>>    the start_address and end_address for aarch64.
>>
>> In addition to providing the binary, this patch also includes the source
>> code and the build script in tests/migration/aarch64. So users can change
>> the source and/or re-compile the binary as they wish.
>>
>> Reviewed-by: Juan Quintela <address@hidden>
>> Signed-off-by: Wei Huang <address@hidden>
> 
> I've had to bounce this patch (kept the other 3) because the test
> is actually failing on aarch64 kvm.
> It's about 1 in 5 for me on one of the larger (40ish core) boxes which
> is otherwise idle.
> 
> /aarch64/migration/precopy/unix: Memory content inconsistency at 43cf1000 
> first_byte = 5 last_byte = 4 current = 5 hit_edge = 1
> Memory content inconsistency at 43cf2000 first_byte = 5 last_byte = 4 current 
> = 5 hit_edge = 1
> Memory content inconsistency at 43cf3000 first_byte = 5 last_byte = 4 current 
> = 5 hit_edge = 1
> Memory content inconsistency at 43cf4000 first_byte = 5 last_byte = 4 current 
> = 5 hit_edge = 1
> Memory content inconsistency at 43cf5000 first_byte = 5 last_byte = 4 current 
> = 5 hit_edge = 1
> Memory content inconsistency at 43cf6000 first_byte = 5 last_byte = 4 current 
> = 5 hit_edge = 1
> Memory content inconsistency at 43cf7000 first_byte = 5 last_byte = 4 current 
> = 5 hit_edge = 1

Thanks, Dave. The root cause is the wrong place of cache invalidation.
Here is the fix which has been tested on Amberwing. Could you please
verify it from your side? After that, I can either send in a new patch
or you can help me revise the existing one.

Thanks,
-Wei


diff --git a/tests/migration/aarch64/a-b-kernel.S
b/tests/migration/aarch64/a-b-
index 507af30..c8d2720 100644
--- a/tests/migration/aarch64/a-b-kernel.S
+++ b/tests/migration/aarch64/a-b-kernel.S
@@ -50,15 +50,15 @@ mainloop:
         mov     x4, x0

 innerloop:
-        /* clean cache because el2 might still cache guest data under
KVM */
-        dc      civac, x4
-
         /* increment the first byte of each page by 1 */
         ldrb    w3, [x4]
         add     w3, w3, #1
         and     w3, w3, #0xff
         strb    w3, [x4]

+        /* clean cache because el2 might still cache guest data under
KVM */
+        dc      civac, x4
+
         add     x4, x4, #TEST_MEM_PAGE_SIZE
         cmp     x4, x1
         blt     innerloop


> 
> Dave
> 
>> ---
>>  tests/Makefile.include               |  1 +
>>  tests/migration-test.c               | 27 +++++++++++--
>>  tests/migration/Makefile             |  2 +-
>>  tests/migration/aarch64/Makefile     | 20 ++++++++++
>>  tests/migration/aarch64/a-b-kernel.S | 75 
>> ++++++++++++++++++++++++++++++++++++
>>  tests/migration/aarch64/a-b-kernel.h | 19 +++++++++
>>  tests/migration/migration-test.h     |  9 +++++
>>  7 files changed, 148 insertions(+), 5 deletions(-)
>>  create mode 100644 tests/migration/aarch64/Makefile
>>  create mode 100644 tests/migration/aarch64/a-b-kernel.S
>>  create mode 100644 tests/migration/aarch64/a-b-kernel.h
>>
>> diff --git a/tests/Makefile.include b/tests/Makefile.include
>> index 87c81d1..fab8fb9 100644
>> --- a/tests/Makefile.include
>> +++ b/tests/Makefile.include
>> @@ -390,6 +390,7 @@ check-qtest-arm-y += tests/hexloader-test$(EXESUF)
>>  check-qtest-aarch64-y = tests/numa-test$(EXESUF)
>>  check-qtest-aarch64-$(CONFIG_SDHCI) += tests/sdhci-test$(EXESUF)
>>  check-qtest-aarch64-y += tests/boot-serial-test$(EXESUF)
>> +check-qtest-aarch64-y += tests/migration-test$(EXESUF)
>>  
>>  check-qtest-microblazeel-y = $(check-qtest-microblaze-y)
>>  
>> diff --git a/tests/migration-test.c b/tests/migration-test.c
>> index 17c6896..ecfae0b 100644
>> --- a/tests/migration-test.c
>> +++ b/tests/migration-test.c
>> @@ -86,12 +86,13 @@ static const char *tmpfs;
>>   * repeatedly. It outputs a 'B' at a fixed rate while it's still running.
>>   */
>>  #include "tests/migration/i386/a-b-bootblock.h"
>> +#include "tests/migration/aarch64/a-b-kernel.h"
>>  
>> -static void init_bootfile_x86(const char *bootpath)
>> +static void init_bootfile(const char *bootpath, void *content)
>>  {
>>      FILE *bootfile = fopen(bootpath, "wb");
>>  
>> -    g_assert_cmpint(fwrite(x86_bootsect, 512, 1, bootfile), ==, 1);
>> +    g_assert_cmpint(fwrite(content, 512, 1, bootfile), ==, 1);
>>      fclose(bootfile);
>>  }
>>  
>> @@ -428,7 +429,7 @@ static int test_migrate_start(QTestState **from, 
>> QTestState **to,
>>      got_stop = false;
>>  
>>      if (strcmp(arch, "i386") == 0 || strcmp(arch, "x86_64") == 0) {
>> -        init_bootfile_x86(bootpath);
>> +        init_bootfile(bootpath, x86_bootsect);
>>          cmd_src = g_strdup_printf("-machine accel=%s -m 150M"
>>                                    " -name source,debug-threads=on"
>>                                    " -serial file:%s/src_serial"
>> @@ -459,6 +460,24 @@ static int test_migrate_start(QTestState **from, 
>> QTestState **to,
>>  
>>          start_address = PPC_TEST_MEM_START;
>>          end_address = PPC_TEST_MEM_END;
>> +    } else if (strcmp(arch, "aarch64") == 0) {
>> +        init_bootfile(bootpath, aarch64_kernel);
>> +        cmd_src = g_strdup_printf("-machine virt,accel=%s,gic-version=max "
>> +                                  "-name vmsource,debug-threads=on -cpu max 
>> "
>> +                                  "-m 150M -serial file:%s/src_serial "
>> +                                  "-kernel %s ",
>> +                                  accel, tmpfs, bootpath);
>> +        cmd_dst = g_strdup_printf("-machine virt,accel=%s,gic-version=max "
>> +                                  "-name vmdest,debug-threads=on -cpu max "
>> +                                  "-m 150M -serial file:%s/dest_serial "
>> +                                  "-kernel %s "
>> +                                  "-incoming %s ",
>> +                                  accel, tmpfs, bootpath, uri);
>> +
>> +        start_address = ARM_TEST_MEM_START;
>> +        end_address = ARM_TEST_MEM_END;
>> +
>> +        g_assert(sizeof(aarch64_kernel) <= ARM_TEST_MAX_KERNEL_SIZE);
>>      } else {
>>          g_assert_not_reached();
>>      }
>> @@ -545,7 +564,7 @@ static void test_deprecated(void)
>>  {
>>      QTestState *from;
>>  
>> -    from = qtest_start("");
>> +    from = qtest_start("-machine none");
>>  
>>      deprecated_set_downtime(from, 0.12345);
>>      deprecated_set_speed(from, 12345);
>> diff --git a/tests/migration/Makefile b/tests/migration/Makefile
>> index a9ed875..13af934 100644
>> --- a/tests/migration/Makefile
>> +++ b/tests/migration/Makefile
>> @@ -5,7 +5,7 @@
>>  # See the COPYING file in the top-level directory.
>>  #
>>  
>> -TARGET_LIST = i386
>> +TARGET_LIST = i386 aarch64
>>  
>>  SRC_PATH = ../..
>>  
>> diff --git a/tests/migration/aarch64/Makefile 
>> b/tests/migration/aarch64/Makefile
>> new file mode 100644
>> index 0000000..d440fa8
>> --- /dev/null
>> +++ b/tests/migration/aarch64/Makefile
>> @@ -0,0 +1,20 @@
>> +# To specify cross compiler prefix, use CROSS_PREFIX=
>> +#   $ make CROSS_PREFIX=aarch64-linux-gnu-
>> +
>> +.PHONY: all clean
>> +all: a-b-kernel.h
>> +
>> +a-b-kernel.h: aarch64.kernel
>> +    echo "$$__note" > header.tmp
>> +    xxd -i $< | sed -e 's/.*int.*//' >> header.tmp
>> +    mv header.tmp $@
>> +
>> +aarch64.kernel: aarch64.elf
>> +    $(CROSS_PREFIX)objcopy -O binary $< $@
>> +
>> +aarch64.elf: a-b-kernel.S
>> +    $(CROSS_PREFIX)gcc -o $@ -nostdlib -Wl,--build-id=none $<
>> +
>> +clean:
>> +    @rm -rf *.kernel *.elf
>> +
>> diff --git a/tests/migration/aarch64/a-b-kernel.S 
>> b/tests/migration/aarch64/a-b-kernel.S
>> new file mode 100644
>> index 0000000..507af30
>> --- /dev/null
>> +++ b/tests/migration/aarch64/a-b-kernel.S
>> @@ -0,0 +1,75 @@
>> +#
>> +# Copyright (c) 2018 Red Hat, Inc. and/or its affiliates
>> +#
>> +# Author:
>> +#   Wei Huang <address@hidden>
>> +#
>> +# This work is licensed under the terms of the GNU GPL, version 2 or later.
>> +# See the COPYING file in the top-level directory.
>> +#
>> +# Note: Please make sure the compiler compiles the assembly code below with
>> +# pc-relative address. Also the branch instructions should use relative
>> +# addresses only.
>> +
>> +#include "../migration-test.h"
>> +
>> +.section .text
>> +
>> +        .globl  _start
>> +
>> +_start:
>> +        /* disable MMU to use phys mem address */
>> +        mrs     x0, sctlr_el1
>> +        bic     x0, x0, #(1<<0)
>> +        msr     sctlr_el1, x0
>> +        isb
>> +
>> +        /* traverse test memory region */
>> +        mov     x0, #ARM_TEST_MEM_START
>> +        mov     x1, #ARM_TEST_MEM_END
>> +
>> +        /* output char 'A' to PL011 */
>> +        mov     w3, 'A'
>> +        mov     x2, #ARM_MACH_VIRT_UART
>> +        strb    w3, [x2]
>> +
>> +        /* clean up memory */
>> +        mov     w3, #0
>> +        mov     x4, x0
>> +clean:
>> +        strb    w3, [x4]
>> +        add     x4, x4, #TEST_MEM_PAGE_SIZE
>> +        cmp     x4, x1
>> +        ble     clean
>> +
>> +        /* w5 keeps a counter so we can limit the output speed */
>> +        mov     w5, #0
>> +
>> +        /* main body */
>> +mainloop:
>> +        mov     x4, x0
>> +
>> +innerloop:
>> +        /* clean cache because el2 might still cache guest data under KVM */
>> +        dc      civac, x4
>> +
>> +        /* increment the first byte of each page by 1 */
>> +        ldrb    w3, [x4]
>> +        add     w3, w3, #1
>> +        and     w3, w3, #0xff
>> +        strb    w3, [x4]
>> +
>> +        add     x4, x4, #TEST_MEM_PAGE_SIZE
>> +        cmp     x4, x1
>> +        blt     innerloop
>> +
>> +        add     w5, w5, #1
>> +        and     w5, w5, #0xff
>> +        cmp     w5, #0
>> +        bne     mainloop
>> +
>> +        /* output char 'B' to PL011 */
>> +        mov     w3, 'B'
>> +        strb    w3, [x2]
>> +
>> +        b       mainloop
>> diff --git a/tests/migration/aarch64/a-b-kernel.h 
>> b/tests/migration/aarch64/a-b-kernel.h
>> new file mode 100644
>> index 0000000..521125e
>> --- /dev/null
>> +++ b/tests/migration/aarch64/a-b-kernel.h
>> @@ -0,0 +1,19 @@
>> +/* This file is automatically generated from the assembly file in
>> + * tests/migration/aarch64. Edit that file and then run "make all"
>> + * inside tests/migration to update, and then remember to send both
>> + * the header and the assembler differences in your patch submission.
>> + */
>> +unsigned char aarch64_kernel[] = {
>> +  0x00, 0x10, 0x38, 0xd5, 0x00, 0xf8, 0x7f, 0x92, 0x00, 0x10, 0x18, 0xd5,
>> +  0xdf, 0x3f, 0x03, 0xd5, 0x00, 0x02, 0xa8, 0xd2, 0x01, 0xc8, 0xa8, 0xd2,
>> +  0x23, 0x08, 0x80, 0x52, 0x02, 0x20, 0xa1, 0xd2, 0x43, 0x00, 0x00, 0x39,
>> +  0x03, 0x00, 0x80, 0x52, 0xe4, 0x03, 0x00, 0xaa, 0x83, 0x00, 0x00, 0x39,
>> +  0x84, 0x04, 0x40, 0x91, 0x9f, 0x00, 0x01, 0xeb, 0xad, 0xff, 0xff, 0x54,
>> +  0x05, 0x00, 0x80, 0x52, 0xe4, 0x03, 0x00, 0xaa, 0x24, 0x7e, 0x0b, 0xd5,
>> +  0x83, 0x00, 0x40, 0x39, 0x63, 0x04, 0x00, 0x11, 0x63, 0x1c, 0x00, 0x12,
>> +  0x83, 0x00, 0x00, 0x39, 0x84, 0x04, 0x40, 0x91, 0x9f, 0x00, 0x01, 0xeb,
>> +  0x2b, 0xff, 0xff, 0x54, 0xa5, 0x04, 0x00, 0x11, 0xa5, 0x1c, 0x00, 0x12,
>> +  0xbf, 0x00, 0x00, 0x71, 0x81, 0xfe, 0xff, 0x54, 0x43, 0x08, 0x80, 0x52,
>> +  0x43, 0x00, 0x00, 0x39, 0xf1, 0xff, 0xff, 0x17
>> +};
>> +
>> diff --git a/tests/migration/migration-test.h 
>> b/tests/migration/migration-test.h
>> index c4c0c52..6939a13 100644
>> --- a/tests/migration/migration-test.h
>> +++ b/tests/migration/migration-test.h
>> @@ -18,4 +18,13 @@
>>  #define PPC_TEST_MEM_START (1 * 1024 * 1024)
>>  #define PPC_TEST_MEM_END   (100 * 1024 * 1024)
>>  
>> +/* ARM */
>> +#define ARM_TEST_MEM_START (0x40000000 + 1 * 1024 * 1024)
>> +#define ARM_TEST_MEM_END   (0x40000000 + 100 * 1024 * 1024)
>> +#define ARM_MACH_VIRT_UART 0x09000000
>> +/* AArch64 kernel load address is 0x40080000, and the test memory starts at
>> + * 0x40100000. So the maximum allowable kernel size is 512KB.
>> + */
>> +#define ARM_TEST_MAX_KERNEL_SIZE (512 * 1024)
>> +
>>  #endif /* _TEST_MIGRATION_H_ */
>> -- 
>> 1.8.3.1
>>
>>
> --
> Dr. David Alan Gilbert / address@hidden / Manchester, UK
>