Hi Quentin,

On Mon, 02 Aug 2021 14:11:07 +0100,
Quentin Perret [off-list ref] wrote:

Hi Marc,

On Monday 02 Aug 2021 at 13:38:29 (+0100), Marc Zyngier wrote:

quoted

The HYP rodata section is currently lumped together with the BSS,
which isn't exactly what is expected (it gets registered with
kmemleak, for example).

Move it away so that it is actually marked RO. As an added
benefit, it isn't registered with kmemleak anymore.

2d7bf218ca73 ("KVM: arm64: Add .hyp.data..ro_after_init ELF section")
states explicitly that the hyp ro_after_init section should remain RW in
the host as it is expected to modify it before initializing EL2. But I
can't seem to trigger anything with this patch applied, so I'll look
into this a bit more.

The switch to RO happens quite late. And if the host was to actually
try and change things there, it would be screwed anyway (we will have
already removed the pages from its S2).

I wouldn't be surprised if this was a consequence of the way we now
build the HYP object, and the comment in the original commit may not
be valid anymore.

quoted

Fixes: 380e18ade4a5 ("KVM: arm64: Introduce a BSS section for use at Hyp")

Not sure this is the patch to blame?

My bad, this is plain wrong. I'm not sure it can be applied earlier
though if my rambling above is correct.

Thanks,

	M.

-- 
Without deviation from the norm, progress is not possible.