On 09/18/2018 10:00 AM, Sandy Harris wrote:
> Is a fix that only deals with a subset of the problem worth
> considering? Just patch the VM support code so that any time a VM is
> either booted or re-started after a save, the host system drops in
> some entropy, This looks relatively easy to do, at
On 05/04/2016 11:35 PM, H. Peter Anvin wrote:
> The disagreement here is the priority between these points.
Yes.
As usual, all the extremes are wrong.
Tradeoffs must be made.
Perspective and judgment are required.
> In my very strong opinion, "no undefined behavior" per the C standard
> is way
On 05/04/2016 04:06 PM, Andi Kleen wrote:
> gcc always converts it before it could
[make a difference].
At the moment, current versions of gcc treat the idiomatic
ror/rol code as something they support ... but older versions
do not, and future version may not.
The gcc guys have made it very clea
On 05/04/2016 02:56 PM, H. Peter Anvin wrote:
>> Beware that shifting by an amount >= the number of bits in the
>> word remains Undefined Behavior.
> This construct has been supported as a rotate since at least gcc2.
How then should we understand the story told in commit d7e35dfa?
Is the story wr
usion.
commit ba83b16d8430ee6104aa1feeed4ff7a82b02747a
Author: John Denker
Date: Wed May 4 13:55:51 2016 -0700
Make ror64, rol64, ror32, ror16, rol16, ror8, and rol8
consistent with rol32 in their handling of shifting by a zero amount.
Same overall rationale as in d7e35dfa, just more consis
-107,7 +107,7 @@ static inline __u64 ror64(__u64 word, unsigned int shift)
*/
static inline __u32 rol32(__u32 word, unsigned int shift)
{
- return (word << shift) | (word >> (32 - shift));
+ return (word << shift) | (word >> ((-shift) & 31));
}
/**
commit 03b97ee
