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Message-ID: <b3c882d2-0135-430c-8179-784f78be0902@arm.com>
Date:   Fri, 1 Dec 2023 09:29:23 +0000
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Subject: Re: [PATCH v5 5/5] selftests/mm: add UFFDIO_MOVE ioctl test
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To:     Suren Baghdasaryan <surenb@google.com>, akpm@linux-foundation.org
Cc:     viro@zeniv.linux.org.uk, brauner@kernel.org, shuah@kernel.org,
        aarcange@redhat.com, lokeshgidra@google.com, peterx@redhat.com,
        david@redhat.com, hughd@google.com, mhocko@suse.com,
        axelrasmussen@google.com, rppt@kernel.org, willy@infradead.org,
        Liam.Howlett@oracle.com, jannh@google.com, zhangpeng362@huawei.com,
        bgeffon@google.com, kaleshsingh@google.com, ngeoffray@google.com,
        jdduke@google.com, linux-mm@kvack.org,
        linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-kselftest@vger.kernel.org, kernel-team@android.com
References: <20231121171643.3719880-1-surenb@google.com>
 <20231121171643.3719880-6-surenb@google.com>
From:   Ryan Roberts <ryan.roberts@arm.com>
In-Reply-To: <20231121171643.3719880-6-surenb@google.com>
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On 21/11/2023 17:16, Suren Baghdasaryan wrote:
> Add tests for new UFFDIO_MOVE ioctl which uses uffd to move source
> into destination buffer while checking the contents of both after
> the move. After the operation the content of the destination buffer
> should match the original source buffer's content while the source
> buffer should be zeroed. Separate tests are designed for PMD aligned and
> unaligned cases because they utilize different code paths in the kernel.
> 
> Signed-off-by: Suren Baghdasaryan <surenb@google.com>
> ---
>  tools/testing/selftests/mm/uffd-common.c     |  24 +++
>  tools/testing/selftests/mm/uffd-common.h     |   1 +
>  tools/testing/selftests/mm/uffd-unit-tests.c | 189 +++++++++++++++++++
>  3 files changed, 214 insertions(+)
> 
> diff --git a/tools/testing/selftests/mm/uffd-common.c b/tools/testing/selftests/mm/uffd-common.c
> index fb3bbc77fd00..b0ac0ec2356d 100644
> --- a/tools/testing/selftests/mm/uffd-common.c
> +++ b/tools/testing/selftests/mm/uffd-common.c
> @@ -631,6 +631,30 @@ int copy_page(int ufd, unsigned long offset, bool wp)
>  	return __copy_page(ufd, offset, false, wp);
>  }
>  
> +int move_page(int ufd, unsigned long offset, unsigned long len)
> +{
> +	struct uffdio_move uffdio_move;
> +
> +	if (offset + len > nr_pages * page_size)
> +		err("unexpected offset %lu and length %lu\n", offset, len);
> +	uffdio_move.dst = (unsigned long) area_dst + offset;
> +	uffdio_move.src = (unsigned long) area_src + offset;
> +	uffdio_move.len = len;
> +	uffdio_move.mode = UFFDIO_MOVE_MODE_ALLOW_SRC_HOLES;
> +	uffdio_move.move = 0;
> +	if (ioctl(ufd, UFFDIO_MOVE, &uffdio_move)) {
> +		/* real retval in uffdio_move.move */
> +		if (uffdio_move.move != -EEXIST)
> +			err("UFFDIO_MOVE error: %"PRId64,
> +			    (int64_t)uffdio_move.move);

Hi Suren,

FYI this error is triggering in mm-unstable (715b67adf4c8):

Testing move-pmd on anon... ERROR: UFFDIO_MOVE error: -16 (errno=16,
@uffd-common.c:648)

I'm running in a VM on Apple M2 (arm64). I haven't debugged any further, but
happy to go deeper if you can direct.

Thanks,
Ryan


> +		wake_range(ufd, uffdio_move.dst, len);
> +	} else if (uffdio_move.move != len) {
> +		err("UFFDIO_MOVE error: %"PRId64, (int64_t)uffdio_move.move);
> +	} else
> +		return 1;
> +	return 0;
> +}