Re: [PATCH v2] target/arm: Fix SVE STR increment

["Alex Bennée" <alex.bennee@linaro.org>]

Richard Henderson <richard.henderson@linaro.org> writes:

> The previous change missed updating one of the increments and
> one of the MemOps.  Add a test case for all vector lengths.
>
> Cc: qemu-stable@nongnu.org
> Fixes: e6dd5e782be ("target/arm: Use tcg_gen_qemu_{ld, st}_i128 in gen_sve_{ld, st}r")
> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

This was Cd'd for stable but didn't make it in. There is a trivial
re-base conflict but I can re-send the patch if that helps.

With this:

   tuxrun --runtime docker \
     --qemu-binary ~/lsrc/qemu.git/builds/bisect/qemu-system-aarch64 \
     --device qemu-arm64 --boot-args rw \
     --kernel https://storage.tuxsuite.com/public/linaro/lkft/builds/2XmWuGCI7saydsrZw4FcWSu6JGQ/Image.gz \
     --modules https://storage.tuxsuite.com/public/linaro/lkft/builds/2XmWuGCI7saydsrZw4FcWSu6JGQ/modules.tar.xz \
     --rootfs https://storage.tuxboot.com/debian/bookworm/arm64/rootfs.ext4.xz \
     --parameters SHARD_INDEX=4 --parameters SKIPFILE=skipfile-lkft.yaml \
     --parameters SHARD_NUMBER=4 \
     --parameters KSELFTEST=https://storage.tuxsuite.com/public/linaro/lkft/builds/2XmWuGCI7saydsrZw4FcWSu6JGQ/kselftest.tar.xz \
     --image docker.io/linaro/tuxrun-dispatcher:v0.52.0 --tests kselftest-arm64 --timeouts boot=30 kselftest-arm64=60

on my branch:

  https://gitlab.com/stsquad/qemu/-/tree/for-8.1-stable?ref_type=heads

the test works.

> ---
>  target/arm/tcg/translate-sve.c    |  5 ++--
>  tests/tcg/aarch64/sve-str.c       | 49 +++++++++++++++++++++++++++++++
>  tests/tcg/aarch64/Makefile.target |  6 +++-
>  3 files changed, 57 insertions(+), 3 deletions(-)
>  create mode 100644 tests/tcg/aarch64/sve-str.c
>
> diff --git a/target/arm/tcg/translate-sve.c b/target/arm/tcg/translate-sve.c
> index 7b39962f20..296e7d1ce2 100644
> --- a/target/arm/tcg/translate-sve.c
> +++ b/target/arm/tcg/translate-sve.c
> @@ -4294,7 +4294,7 @@ void gen_sve_str(DisasContext *s, TCGv_ptr base, int vofs,
>          t0 = tcg_temp_new_i64();
>          t1 = tcg_temp_new_i64();
>          t16 = tcg_temp_new_i128();
> -        for (i = 0; i < len_align; i += 8) {
> +        for (i = 0; i < len_align; i += 16) {
>              tcg_gen_ld_i64(t0, base, vofs + i);
>              tcg_gen_ld_i64(t1, base, vofs + i + 8);
>              tcg_gen_concat_i64_i128(t16, t0, t1);
> @@ -4320,7 +4320,8 @@ void gen_sve_str(DisasContext *s, TCGv_ptr base, int vofs,
>          t16 = tcg_temp_new_i128();
>          tcg_gen_concat_i64_i128(t16, t0, t1);
>  
> -        tcg_gen_qemu_st_i128(t16, clean_addr, midx, MO_LEUQ);
> +        tcg_gen_qemu_st_i128(t16, clean_addr, midx,
> +                             MO_LE | MO_128 | MO_ATOM_NONE);
>          tcg_gen_addi_i64(clean_addr, clean_addr, 16);
>  
>          tcg_gen_brcondi_ptr(TCG_COND_LTU, i, len_align, loop);
> diff --git a/tests/tcg/aarch64/sve-str.c b/tests/tcg/aarch64/sve-str.c
> new file mode 100644
> index 0000000000..551f0d6f18
> --- /dev/null
> +++ b/tests/tcg/aarch64/sve-str.c
> @@ -0,0 +1,49 @@
> +#include <stdio.h>
> +#include <sys/prctl.h>
> +
> +#define N  (256+16)
> +
> +static int __attribute__((noinline)) test(int vl)
> +{
> +    unsigned char buf[N];
> +    int err = 0;
> +
> +    for (int i = 0; i < N; ++i) {
> +        buf[i] = (unsigned char)i;
> +    }
> +
> +    asm volatile (
> +        "mov z0.b, #255\n\t"
> +        "str z0, %0"
> +        : : "m" (buf) : "z0", "memory");
> +
> +    for (int i = 0; i < vl; ++i) {
> +        if (buf[i] != 0xff) {
> +            fprintf(stderr, "vl %d, index %d, expected 255, got %d\n",
> +                    vl, i, buf[i]);
> +            err = 1;
> +        }
> +    }
> +
> +    for (int i = vl; i < N; ++i) {
> +        if (buf[i] != (unsigned char)i) {
> +            fprintf(stderr, "vl %d, index %d, expected %d, got %d\n",
> +                    vl, i, (unsigned char)i, buf[i]);
> +            err = 1;
> +        }
> +    }
> +
> +    return err;
> +}
> +
> +int main()
> +{
> +    int err = 0;
> +
> +    for (int i = 16; i <= 256; i += 16) {
> +        if (prctl(PR_SVE_SET_VL, i, 0, 0, 0, 0) == i) {
> +            err |= test(i);
> +        }
> +    }
> +    return err;
> +}
> diff --git a/tests/tcg/aarch64/Makefile.target b/tests/tcg/aarch64/Makefile.target
> index 62b38c792f..c6542b5f1b 100644
> --- a/tests/tcg/aarch64/Makefile.target
> +++ b/tests/tcg/aarch64/Makefile.target
> @@ -103,7 +103,11 @@ sha512-sve: CFLAGS=-O3 -march=armv8.1-a+sve
>  sha512-sve: sha512.c
>  	$(CC) $(CFLAGS) $(EXTRA_CFLAGS) $< -o $@ $(LDFLAGS)
>  
> -TESTS += sha512-sve
> +sve-str: CFLAGS=-O1 -march=armv8.1-a+sve
> +sve-str: sve-str.c
> +	$(CC) $(CFLAGS) $(EXTRA_CFLAGS) $< -o $@ $(LDFLAGS)
> +
> +TESTS += sha512-sve sve-str
>  
>  ifneq ($(GDB),)
>  GDB_SCRIPT=$(SRC_PATH)/tests/guest-debug/run-test.py

-- 
Alex Bennée
Virtualisation Tech Lead @ Linaro