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| -rw-r--r-- | docs/about/deprecated.rst | 21 | ||||
| -rw-r--r-- | meson.build | 6 |
2 files changed, 27 insertions, 0 deletions
diff --git a/docs/about/deprecated.rst b/docs/about/deprecated.rst index 05e4ce8cf1..98c32991c9 100644 --- a/docs/about/deprecated.rst +++ b/docs/about/deprecated.rst @@ -434,6 +434,27 @@ ABI is long-obsolete. We are therefore deprecating both OABI support and NWFPE emulation, and they will be removed in a future QEMU release. +Build features +-------------- + +Crypto AF_ALG backend (since 11.2) +---------------------------------- + +The use of the AF_ALG backend for cryptography has been deprecated +with no replacement. + +The AF_ALG interface is deprecated by Linux 7.2 and all support +for hardware accelerators has been removed. It will thus always be +slower than userspace crypto due to the overhead of copying data +to kernel space. The GNUTLS, Nettle and GCrypt libraries supported +by QEMU all include a variety of hardware optimized crypto +implementations which should suffice for typical needs. + +For the virtio-crypto device, the 'cryptodev-backend-lkcf' backend +can offload some operations to the kernel via the keyctl syscall, +and the 'cryptodev-vhost-user' backend can offload the device +backend to an external process which can integrate with crypto +accelerators. Backwards compatibility ----------------------- diff --git a/meson.build b/meson.build index 2a022c4d85..ec9b05414a 100644 --- a/meson.build +++ b/meson.build @@ -5059,3 +5059,9 @@ if not actually_reloc and (host_os == 'windows' or get_option('relocatable')) message('QEMU will have to be installed under ' + get_option('prefix') + '.') message('Use --disable-relocatable to remove this warning.') endif + +if get_option('crypto_afalg').enabled() + warning('Use of the AF_ALG crypto backend is deprecated, ' + + 'since Linux 7.2 has deprecated the AF_ALG interface ' + + 'and removed its ability to use hardware accelerators.') +endif |