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Subject: Re:  [PATCH v2 0/4] virtio-crypto: support ECDSA algorithm
From:   Lei He <helei.sig11@bytedance.com>
In-Reply-To: <Yr1nybJ9eSNgU24i@gondor.apana.org.au>
Date:   Thu, 30 Jun 2022 20:44:18 +0800
Cc:     Lei He <helei.sig11@bytedance.com>, davem@davemloft.net,
        dhowells@redhat.com, "Michael S. Tsirkin" <mst@redhat.com>,
        linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org,
        =?utf-8?Q?=22Daniel_P_=2E_Berrang=C3=A9=22?= <berrange@redhat.com>,
        zhenwei pi <pizhenwei@bytedance.com>
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To:     Herbert Xu <herbert@gondor.apana.org.au>
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On Jun 30, 2022, at 5:07 PM, Herbert Xu <herbert@gondor.apana.org.au> =
wrote:

>=20
> On Thu, Jun 30, 2022 at 04:30:39PM +0800, Lei He wrote:
>>=20
>> I have explained above why we need a driver that supports ECDSA, and =
this patch
>> enables virtio-crypto to support ECDSA. I think this is a good time =
to support ECDSA
>> in the kernel crypto framework, and there will be more drivers =
supporting ECDSA in the=20
>> future.
>> Looking forward to your opinion :-).
>=20
> Until there are drivers in the kernel it's pointless to implement
> this.
>=20

I guess you mean that if there are no drivers in the linux kernel source =
tree that supports the=20
ECDSA, then there is no way under linux to offload ECDSA to other =
devices, so even if the
virtio-crypto can get the akcipher request, it can=E2=80=99t do better, =
right? I have some different opinions
 on this:
1. There does exist hardware for offloading ECDSA calculations, for =
example, IBM PCIe
Cryptographic Coprocessor, Intel QAT, etc, and those chips are already =
on the market now.
Of course, they also provided corresponding drivers to access these =
devices, but for some reason,
these drivers have not been submitted to the kernel source tree now.
2. With this patch, when we use QEMU to create a virtual machine, people =
can directly access the=20
virtio-crypto device without caring about where these akcipher requests =
are executed, and no need
to update drivers(and other stuff) for guest kernel when the  =
co-processor is updated.=20
3.  I will communicate with the Intel QAT team about their plans to =
provide ECDSA support and ECDH=20
support.