[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: propagating vmgenid outward and upward
From: |
Michael S. Tsirkin |
Subject: |
Re: propagating vmgenid outward and upward |
Date: |
Wed, 2 Mar 2022 12:27:24 -0500 |
On Wed, Mar 02, 2022 at 05:32:07PM +0100, Jason A. Donenfeld wrote:
> Hi Michael,
>
> On Wed, Mar 02, 2022 at 11:22:46AM -0500, Michael S. Tsirkin wrote:
> > > Because that 16 byte read of vmgenid is not atomic. Let's say you read
> > > the first 8 bytes, and then the VM is forked.
> >
> > But at this point when VM was forked plaintext key and nonce are all in
> > buffer, and you previously indicated a fork at this point is harmless.
> > You wrote "If it changes _after_ that point of check ... it doesn't
> > matter:"
>
> Ahhh, fair point. I think you're right.
>
> Alright, so all we're talking about here is an ordinary 16-byte read,
> and 16 bytes of storage per keypair, and a 16-byte comparison.
>
> Still seems much worse than just having a single word...
>
> Jason
And it is, I saw a 30% higher overhead, it is however 30% of a very
low number ;)
--
MST
- Re: propagating vmgenid outward and upward, (continued)
- Re: propagating vmgenid outward and upward, Michael S. Tsirkin, 2022/03/02
- Re: propagating vmgenid outward and upward, Jason A. Donenfeld, 2022/03/02
- Re: propagating vmgenid outward and upward, Michael S. Tsirkin, 2022/03/02
- Re: propagating vmgenid outward and upward, Jason A. Donenfeld, 2022/03/02
- Re: propagating vmgenid outward and upward, Michael S. Tsirkin, 2022/03/02
- Re: propagating vmgenid outward and upward, Jason A. Donenfeld, 2022/03/02
- Re: propagating vmgenid outward and upward, Michael S. Tsirkin, 2022/03/02
- Re: propagating vmgenid outward and upward, Jason A. Donenfeld, 2022/03/02
- Re: propagating vmgenid outward and upward, Michael S. Tsirkin, 2022/03/02
- Re: propagating vmgenid outward and upward, Jason A. Donenfeld, 2022/03/02
- Re: propagating vmgenid outward and upward,
Michael S. Tsirkin <=
- Re: propagating vmgenid outward and upward, Michael S. Tsirkin, 2022/03/03
- Re: propagating vmgenid outward and upward, Michael S. Tsirkin, 2022/03/02
Re: propagating vmgenid outward and upward, Michael S. Tsirkin, 2022/03/01
Re: propagating vmgenid outward and upward, Greg KH, 2022/03/01
Re: propagating vmgenid outward and upward, Jason A. Donenfeld, 2022/03/02
Re: propagating vmgenid outward and upward, Alexander Graf, 2022/03/09