Re: [Qemu-stable] [PATCH v4 1/3] block/qcow2: refactoring of threaded encryption code

[Vladimir Sementsov-Ogievskiy]

13.09.2019 15:59, Maxim Levitsky wrote:
> This commit tries to clarify few function arguments,
> and add comments describing the encrypt/decrypt interface
> 
> Signed-off-by: Maxim Levitsky <address@hidden>
> ---
>   block/qcow2-cluster.c |  9 ++++---
>   block/qcow2-threads.c | 62 ++++++++++++++++++++++++++++++++++---------
>   block/qcow2.c         |  5 ++--
>   block/qcow2.h         |  8 +++---
>   4 files changed, 61 insertions(+), 23 deletions(-)
> 
> diff --git a/block/qcow2-cluster.c b/block/qcow2-cluster.c
> index f09cc992af..46b0854d7e 100644
> --- a/block/qcow2-cluster.c
> +++ b/block/qcow2-cluster.c
> @@ -463,8 +463,8 @@ static int coroutine_fn 
> do_perform_cow_read(BlockDriverState *bs,
>   }
>   
>   static bool coroutine_fn do_perform_cow_encrypt(BlockDriverState *bs,
> -                                                uint64_t src_cluster_offset,
> -                                                uint64_t cluster_offset,
> +                                                uint64_t 
> guest_cluster_offset,
> +                                                uint64_t host_cluster_offset,
>                                                   unsigned offset_in_cluster,
>                                                   uint8_t *buffer,
>                                                   unsigned bytes)
> @@ -474,8 +474,9 @@ static bool coroutine_fn 
> do_perform_cow_encrypt(BlockDriverState *bs,
>           assert((offset_in_cluster & ~BDRV_SECTOR_MASK) == 0);
>           assert((bytes & ~BDRV_SECTOR_MASK) == 0);
>           assert(s->crypto);
> -        if (qcow2_co_encrypt(bs, cluster_offset,
> -                             src_cluster_offset + offset_in_cluster,
> +        if (qcow2_co_encrypt(bs,
> +                             host_cluster_offset + offset_in_cluster,
> +                             guest_cluster_offset + offset_in_cluster,

oops, seems you accidentally fixed the bug, which you are going to fix in the 
next
patch, as now correct offsets are given to qcow2_co_encrypt :)

and next patch no is a simple no-logic-change refactoring, so at least commit 
message
should be changed.

>                                buffer, bytes) < 0) {
>               return false;
>           }
> diff --git a/block/qcow2-threads.c b/block/qcow2-threads.c
> index 3b1e63fe41..9646243a9b 100644
> --- a/block/qcow2-threads.c
> +++ b/block/qcow2-threads.c
> @@ -234,15 +234,15 @@ static int qcow2_encdec_pool_func(void *opaque)
>   }
>   
>   static int coroutine_fn
> -qcow2_co_encdec(BlockDriverState *bs, uint64_t file_cluster_offset,
> -                  uint64_t offset, void *buf, size_t len, Qcow2EncDecFunc 
> func)
> +qcow2_co_encdec(BlockDriverState *bs, uint64_t host_offset,
> +                uint64_t guest_offset, void *buf, size_t len,
> +                Qcow2EncDecFunc func)
>   {
>       BDRVQcow2State *s = bs->opaque;
> +
>       Qcow2EncDecData arg = {
>           .block = s->crypto,
> -        .offset = s->crypt_physical_offset ?
> -                      file_cluster_offset + offset_into_cluster(s, offset) :
> -                      offset,
> +        .offset = s->crypt_physical_offset ? host_offset : guest_offset,

Nice change. Obviously original design was worse.

>           .buf = buf,
>           .len = len,
>           .func = func,
> @@ -251,18 +251,54 @@ qcow2_co_encdec(BlockDriverState *bs, uint64_t 
> file_cluster_offset,
>       return qcow2_co_process(bs, qcow2_encdec_pool_func, &arg);
>   }
>   
> +
> +/*
> + * qcow2_co_encrypt()
> + *
> + * Encrypts one or more contiguous aligned sectors
> + *
> + * @host_offset - underlying storage offset of the first sector of the
> + * data to be encrypted
> +
> + * @guest_offset - guest (virtual) offset of the first sector of the
> + * data to be encrypted
> + *
> + * @buf - buffer with the data to encrypt, that after encryption
> + *        will be written to the underlying storage device at
> + *        @host_offset
> + *
> + * @len - length of the buffer (must be a BDRV_SECTOR_SIZE multiple)
> + *
> + * Depending on the encryption method, @host_cluster_offset and/or 
> @guest_offset
> + * may be used for generating the initialization vector for
> + * encryption.
> + *
> + * Note that while the whole range must be aligned on sectors, it
> + * does not have to be aligned on clusters and can also cross cluster
> + * boundaries
> + *
> + */
>   int coroutine_fn
> -qcow2_co_encrypt(BlockDriverState *bs, uint64_t file_cluster_offset,
> -                 uint64_t offset, void *buf, size_t len)
> +qcow2_co_encrypt(BlockDriverState *bs, uint64_t host_offset,
> +                 uint64_t guest_offset, void *buf, size_t len)
>   {
> -    return qcow2_co_encdec(bs, file_cluster_offset, offset, buf, len,
> -                             qcrypto_block_encrypt);
> +    return qcow2_co_encdec(bs, host_offset, guest_offset, buf, len,
> +                           qcrypto_block_encrypt);
>   }
>   
> +
> +/*
> + * qcow2_co_decrypt()
> + *
> + * Decrypts one or more contiguous aligned sectors
> + * Similar to qcow2_co_encrypt
> + *
> + */
> +
>   int coroutine_fn
> -qcow2_co_decrypt(BlockDriverState *bs, uint64_t file_cluster_offset,
> -                 uint64_t offset, void *buf, size_t len)
> +qcow2_co_decrypt(BlockDriverState *bs, uint64_t host_offset,
> +                 uint64_t guest_offset, void *buf, size_t len)
>   {
> -    return qcow2_co_encdec(bs, file_cluster_offset, offset, buf, len,
> -                             qcrypto_block_decrypt);
> +    return qcow2_co_encdec(bs, host_offset, guest_offset, buf, len,
> +                           qcrypto_block_decrypt);
>   }
> diff --git a/block/qcow2.c b/block/qcow2.c
> index 0882ff6e92..7ec50157e0 100644
> --- a/block/qcow2.c
> +++ b/block/qcow2.c
> @@ -2065,7 +2065,8 @@ static coroutine_fn int 
> qcow2_co_preadv_part(BlockDriverState *bs,
>   
>                   assert((offset & (BDRV_SECTOR_SIZE - 1)) == 0);
>                   assert((cur_bytes & (BDRV_SECTOR_SIZE - 1)) == 0);
> -                if (qcow2_co_decrypt(bs, cluster_offset, offset,
> +                if (qcow2_co_decrypt(bs, cluster_offset + offset_in_cluster,
> +                                     offset,
>                                        cluster_data, cur_bytes) < 0) {
>                       ret = -EIO;
>                       goto fail;
> @@ -2284,7 +2285,7 @@ static coroutine_fn int qcow2_co_pwritev_part(
>               qemu_iovec_to_buf(qiov, qiov_offset + bytes_done,
>                                 cluster_data, cur_bytes);
>   
> -            if (qcow2_co_encrypt(bs, cluster_offset, offset,
> +            if (qcow2_co_encrypt(bs, cluster_offset + offset_in_cluster, 
> offset,
>                                    cluster_data, cur_bytes) < 0) {
>                   ret = -EIO;
>                   goto out_unlocked;
> diff --git a/block/qcow2.h b/block/qcow2.h
> index 998bcdaef1..a488d761ff 100644
> --- a/block/qcow2.h
> +++ b/block/qcow2.h
> @@ -758,10 +758,10 @@ ssize_t coroutine_fn
>   qcow2_co_decompress(BlockDriverState *bs, void *dest, size_t dest_size,
>                       const void *src, size_t src_size);
>   int coroutine_fn
> -qcow2_co_encrypt(BlockDriverState *bs, uint64_t file_cluster_offset,
> -                 uint64_t offset, void *buf, size_t len);
> +qcow2_co_encrypt(BlockDriverState *bs, uint64_t host_offset,
> +                 uint64_t guest_offset, void *buf, size_t len);
>   int coroutine_fn
> -qcow2_co_decrypt(BlockDriverState *bs, uint64_t file_cluster_offset,
> -                 uint64_t offset, void *buf, size_t len);
> +qcow2_co_decrypt(BlockDriverState *bs, uint64_t host_offset,
> +                 uint64_t guest_offset, void *buf, size_t len);
>   
>   #endif
> 


-- 
Best regards,
Vladimir