[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [Qemu-devel] [PATCH 4/6] crypto: convert xts_tweak_encdec to use xts
From: |
Daniel P . Berrangé |
Subject: |
Re: [Qemu-devel] [PATCH 4/6] crypto: convert xts_tweak_encdec to use xts_uint128 type |
Date: |
Tue, 9 Oct 2018 16:06:29 +0100 |
User-agent: |
Mutt/1.10.1 (2018-07-13) |
On Tue, Oct 09, 2018 at 05:02:39PM +0200, Alberto Garcia wrote:
> On Tue 09 Oct 2018 02:55:39 PM CEST, Daniel P. Berrangé wrote:
> > Using 64-bit arithmetic increases the performance for xts-aes-128
> > when built with gcrypt:
> >
> > Encrypt: 235 MB/s -> 320 MB/s
> > Decrypt: 245 MB/s -> 325 MB/s
> >
> > Signed-off-by: Daniel P. Berrangé <address@hidden>
> > ---
> > crypto/xts.c | 52 +++++++++++++++++++++++++++++++++-------------------
> > 1 file changed, 33 insertions(+), 19 deletions(-)
> >
> > diff --git a/crypto/xts.c b/crypto/xts.c
> > index ded4365191..f109c8a3ee 100644
> > --- a/crypto/xts.c
> > +++ b/crypto/xts.c
> > @@ -31,6 +31,12 @@ typedef struct {
> > uint64_t b;
> > } xts_uint128;
> >
> > +#define xts_uint128_xor(D, S1, S2) \
> > + do { \
> > + (D)->a = (S1)->a ^ (S2)->a; \
> > + (D)->b = (S1)->b ^ (S2)->b; \
> > + } while (0)
> > +
> > static void xts_mult_x(uint8_t *I)
> > {
> > int x;
> > @@ -59,25 +65,19 @@ static void xts_mult_x(uint8_t *I)
> > */
> > static void xts_tweak_encdec(const void *ctx,
> > xts_cipher_func *func,
> > - const uint8_t *src,
> > - uint8_t *dst,
> > - uint8_t *iv)
> > + const xts_uint128 *src,
> > + xts_uint128 *dst,
> > + xts_uint128 *iv)
> > {
> > - unsigned long x;
> > -
> > /* tweak encrypt block i */
> > - for (x = 0; x < XTS_BLOCK_SIZE; x++) {
> > - dst[x] = src[x] ^ iv[x];
> > - }
> > + xts_uint128_xor(dst, src, iv);
> >
> > - func(ctx, XTS_BLOCK_SIZE, dst, dst);
> > + func(ctx, XTS_BLOCK_SIZE, (uint8_t *)dst, (uint8_t *)dst);
>
> In the line of what I said earlier, perhaps it's clearer if you leave
> everything as uint8_t * and simply make xts_uint128_xor() treat the
> array as xts_uint128 internally.
>
> > for (i = 0; i < lim; i++) {
> > - xts_tweak_encdec(datactx, decfunc, src, dst, (uint8_t *)&T);
> > + xts_uint128 S, D;
> > +
> > + memcpy(&S, src, XTS_BLOCK_SIZE);
> > + xts_tweak_encdec(datactx, decfunc, &S, &D, &T);
> > + memcpy(dst, &D, XTS_BLOCK_SIZE);
>
> Why do you need S and D?
I think src & dst pointers can't be guaranteed to be aligned sufficiently
for int64 operations, if we just cast from uint8t*.
Regards,
Daniel
--
|: https://berrange.com -o- https://www.flickr.com/photos/dberrange :|
|: https://libvirt.org -o- https://fstop138.berrange.com :|
|: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|
- Re: [Qemu-devel] [PATCH 3/6] crypto: introduce a xts_uint128 data type, (continued)
[Qemu-devel] [PATCH 5/6] crypto: convert xts_mult_x to use xts_uint128 type, Daniel P . Berrangé, 2018/10/09
[Qemu-devel] [PATCH 6/6] crypto: annotate xts_tweak_encdec as inlineable, Daniel P . Berrangé, 2018/10/09
[Qemu-devel] [PATCH 4/6] crypto: convert xts_tweak_encdec to use xts_uint128 type, Daniel P . Berrangé, 2018/10/09
Re: [Qemu-devel] [PATCH 0/6] crypto: improve performance of XTS cipher mode, Marc-André Lureau, 2018/10/09