Re: [PATCH] x86/retpoline: Fill return stack buffer on vmexit

[David Woodhouse]

On Wed, 2018-01-10 at 18:14 -0600, Tom Lendacky wrote:
> On 1/10/2018 5:47 PM, David Woodhouse wrote:
> > On Wed, 2018-01-10 at 22:51 +0000, David Woodhouse wrote:
> >> In accordance with the Intel and AMD documentation, we need to overwrite
> >> all entries in the RSB on exiting a guest, to prevent malicious branch
> >> target predictions from affecting the host kernel. This is needed both
> >> for retpoline and for IBRS.
> >>
> >> Signed-off-by: David Woodhouse <dwmw@xxxxxxxxxxxx>
> >> ---
> >> Untested in this form although it's a variant on what we've had already.
> >> I have an army of machines willing to do my bidding but nested virt
> >> is non-trivial and I figure I might as well post it as someone else
> >> can probably test it in less than the time it takes me to work out how.
> >Â
> > Now smoke tested with Intel VT-x, but not yet on AMD. Tom, would you be
> > able to do that?
> 
> Yes, I'll try to get to it as soon as I can, but it might be tomorrow
> (morning).

Thanks. I've pushed an updated version to
http://git.infradead.org/users/dwmw2/linux-retpoline.git/

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