Re: [Qemu-devel] Questions about gcc linker errors in crypto sub-directory

["Daniel P. Berrange" <berrange@redhat.com>]

On Mon, Sep 26, 2016 at 09:03:45AM +0000, Gonglei (Arei) wrote:
> Hi Daniel,
> 
> I'm coding cryptodev-vhost-user.c as a new cryptodev backend,
> but the gcc report some linker errors:
> 
> crypto/cryptodev-vhost-user.o: In function `qcrypto_cryptodev_vhost_crypto_cleanup':
> /mnt/sdb/gonglei/qemu.git/qemu/crypto/cryptodev-vhost-user.c:87: undefined reference to `vhost_dev_cleanup'
> crypto/cryptodev-vhost-user.o: In function `qcrypto_cryptodev_vhost_crypto_init':
> /mnt/sdb/gonglei/qemu.git/qemu/crypto/cryptodev-vhost-user.c:126: undefined reference to `vhost_dev_init'
> crypto/cryptodev-vhost-user.o: In function `qcrypto_cryptodev_vhost_user_opened':
> /mnt/sdb/gonglei/qemu.git/qemu/crypto/cryptodev-vhost-user.c:187: undefined reference to `qemu_chr_find'
> /mnt/sdb/gonglei/qemu.git/qemu/crypto/cryptodev-vhost-user.c:194: undefined reference to `qemu_chr_fe_claim_no_fail'
> crypto/cryptodev-vhost-user.o: In function `qcrypto_cryptodev_vhost_user_event':
> /mnt/sdb/gonglei/qemu.git/qemu/crypto/cryptodev-vhost-user.c:213: undefined reference to `qemu_chr_set_reconnect_time'
> crypto/cryptodev-vhost-user.o: In function `qcrypto_cryptodev_vhost_user_init':
> /mnt/sdb/gonglei/qemu.git/qemu/crypto/cryptodev-vhost-user.c:257: undefined reference to `qemu_chr_add_handlers'
> crypto/cryptodev-vhost-user.o: In function `qcrypto_cryptodev_vhost_user_finalize':
> /mnt/sdb/gonglei/qemu.git/qemu/crypto/cryptodev-vhost-user.c:353: undefined reference to `qemu_chr_add_handlers'
> /mnt/sdb/gonglei/qemu.git/qemu/crypto/cryptodev-vhost-user.c:354: undefined reference to `qemu_chr_fe_release'
> collect2: ld returned 1 exit status
> make: *** [qemu-nbd] Error 1
> 
> Currently I only change the crypto/Makefile.objs:
> 
> diff --git a/crypto/Makefile.objs b/crypto/Makefile.objs
> index b9ad26a..575f64e 100644
> --- a/crypto/Makefile.objs
> +++ b/crypto/Makefile.objs
> @@ -28,6 +28,7 @@ crypto-obj-y += block-qcow.o
>  crypto-obj-y += block-luks.o
>  crypto-obj-y += cryptodev.o
>  crypto-obj-y += cryptodev-builtin.o
> +crypto-obj-y += cryptodev-vhost-user.o

The $(crypto-obj-y) variable is intended to only contain general purpose
crypto code, since it needs to be linked to all QEMU programs. Your
cryptodev file is specific to system emulators, so must only be linked
to the system emulator targets. Thus, it should not be added to the
crypto-obj-y variable.

It probably needs to be added to either common-obj-y or obj-y - I can't
remember which is "best"

Regards,
Daniel
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