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Re: [Qemu-devel] [PATCH 5/6] crypto: convert xts_mult_x to use xts_uint1
From: |
Daniel P . Berrangé |
Subject: |
Re: [Qemu-devel] [PATCH 5/6] crypto: convert xts_mult_x to use xts_uint128 type |
Date: |
Tue, 9 Oct 2018 14:55:34 +0100 |
User-agent: |
Mutt/1.10.1 (2018-07-13) |
On Tue, Oct 09, 2018 at 03:52:53PM +0200, Alberto Garcia wrote:
> On Tue 09 Oct 2018 02:55:40 PM CEST, Daniel P. Berrangé wrote:
> > -static void xts_mult_x(uint8_t *I)
> > +static void xts_mult_x(xts_uint128 *I)
> > {
> > - int x;
> > - uint8_t t, tt;
> > + uint64_t tt;
> >
> > - for (x = t = 0; x < 16; x++) {
> > - tt = I[x] >> 7;
> > - I[x] = ((I[x] << 1) | t) & 0xFF;
> > - t = tt;
> > - }
> > - if (tt) {
> > - I[0] ^= 0x87;
> > + tt = I->a >> 63;
> > + I->a = I->a << 1;
> > +
> > + if (I->b >> 63) {
> > + I->a ^= 0x87;
> > }
> > + I->b = (I->b << 1) | tt;
> > }
>
> Does this work fine in big-endian CPUs?
Hmm, that's a good question. I'd expect tests/test-crypto-xts to crash
and burn if it doesn't, so guess I'll need to find somewhere to validate
that.
Regards,
Daniel
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[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