virtio-crypto: implement RSA algorithm

Support rsa & pkcs1pad(rsa,sha1) with priority 150.

Test with QEMU built-in backend, it works fine.
1, The self-test framework of crypto layer works fine in guest kernel
2, Test with Linux guest(with asym support), the following script
test(note that pkey_XXX is supported only in a newer version of keyutils):
  - both public key & private key
  - create/close session
  - encrypt/decrypt/sign/verify basic driver operation
  - also test with kernel crypto layer(pkey add/query)

All the cases work fine.

rm -rf *.der *.pem *.pfx
modprobe pkcs8_key_parser # if CONFIG_PKCS8_PRIVATE_KEY_PARSER=m
rm -rf /tmp/data
dd if=/dev/random of=/tmp/data count=1 bs=226

openssl req -nodes -x509 -newkey rsa:2048 -keyout key.pem -out cert.pem -subj "/C=CN/ST=BJ/L=HD/O=qemu/OU=dev/CN=qemu/emailAddress=qemu@qemu.org"
openssl pkcs8 -in key.pem -topk8 -nocrypt -outform DER -out key.der
openssl x509 -in cert.pem -inform PEM -outform DER -out cert.der

PRIV_KEY_ID=`cat key.der | keyctl padd asymmetric test_priv_key @s`
echo "priv key id = "$PRIV_KEY_ID
PUB_KEY_ID=`cat cert.der | keyctl padd asymmetric test_pub_key @s`
echo "pub key id = "$PUB_KEY_ID

keyctl pkey_query $PRIV_KEY_ID 0
keyctl pkey_query $PUB_KEY_ID 0

echo "Enc with priv key..."
keyctl pkey_encrypt $PRIV_KEY_ID 0 /tmp/data enc=pkcs1 >/tmp/enc.priv
echo "Dec with pub key..."
keyctl pkey_decrypt $PRIV_KEY_ID 0 /tmp/enc.priv enc=pkcs1 >/tmp/dec
cmp /tmp/data /tmp/dec

echo "Sign with priv key..."
keyctl pkey_sign $PRIV_KEY_ID 0 /tmp/data enc=pkcs1 hash=sha1 > /tmp/sig
echo "Verify with pub key..."
keyctl pkey_verify $PRIV_KEY_ID 0 /tmp/data /tmp/sig enc=pkcs1 hash=sha1

echo "Enc with pub key..."
keyctl pkey_encrypt $PUB_KEY_ID 0 /tmp/data enc=pkcs1 >/tmp/enc.pub
echo "Dec with priv key..."
keyctl pkey_decrypt $PRIV_KEY_ID 0 /tmp/enc.pub enc=pkcs1 >/tmp/dec
cmp /tmp/data /tmp/dec

echo "Verify with pub key..."
keyctl pkey_verify $PUB_KEY_ID 0 /tmp/data /tmp/sig enc=pkcs1 hash=sha1

[1 compiling warning during development]
Reported-by: kernel test robot <lkp@intel.com>

Co-developed-by: lei he <helei.sig11@bytedance.com>
Signed-off-by: lei he <helei.sig11@bytedance.com>
Signed-off-by: zhenwei pi <pizhenwei@bytedance.com>
Link: https://lore.kernel.org/r/20220302033917.1295334-4-pizhenwei@bytedance.com
Reviewed-by: Gonglei <arei.gonglei@huawei.com>
Signed-off-by: Nathan Chancellor <nathan@kernel.org> #Kconfig tweaks
Link: https://lore.kernel.org/r/20220308205309.2192502-1-nathan@kernel.org
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>