Re: [PATCH 0/3] KVM: x86: Fix fault-related bugs in LTR/LLDT emulation

From: Nadav Amit
Date: Mon Jul 11 2022 - 21:07:54 EST


On Jul 11, 2022, at 4:27 PM, Sean Christopherson <seanjc@xxxxxxxxxx> wrote:

> Patch 1 fixes a bug found by syzkaller where KVM attempts to set the
> TSS.busy bit during LTR before checking that the new TSS.base is valid.
>
> Patch 2 fixes a bug found by inspection (when reading the APM to verify
> the non-canonical logic is correct) where KVM doesn't provide the correct
> error code if the new TSS.base is non-canonical.
>
> Patch 3 makes the "dangling userspace I/O" WARN_ON two separate WARN_ON_ONCE
> so that a KVM bug doesn't spam the kernel log (keeping the WARN is desirable
> specifically to detect these types of bugs).

Hi Sean,

If/when you find that I screwed up, would you be kind enough to cc me?

Very likely I won’t be able to assist too much in fixing the bugs under my
current affiliation, but it is always interesting to see the escapees of
Intel’s validation tools… ;-)

Only if you can.

Thanks,
Nadav

[ p.s. - please use my gmail account for the matter ]