On 2019-10-21 14:37, Christoffer Dall wrote:
On Sun, Oct 20, 2019 at 11:25:24AM +0100, Marc Zyngier wrote:
Hi Christoffer,
On Fri, 11 Oct 2019 12:07:04 +0100,
Christoffer Dall <christoffer.dall@xxxxxxx> wrote:
>
> When a guest accesses memory outside the memory slots, KVM usually
> bounces the access back to userspace with KVM_EXIT_MMIO. However,
on
> arm/arm64 systems, certain load/store instructions did not provide
> decoding info for the hypervisor to emulate the instruction, and
in this
> case KVM has rather rudely returned -ENOSYS and printed a not
overly
> helpful error message:
>
> load/store instruction decoding not implemented
>
> This patch series improves the error message and allows userspace
to be
> notified of this event instead of receiving -ENOSYS, and also
allows
> userspace to ask KVM to inject an external abort to the guest,
which it
> can use for any memory access that it either cannot handle.
>
> One remaining case which this patch set does not address is if the
guest
> accesses an in-kernel emulated device, such as the VGIC, but using
a
> load/store instruction which doesn't provide decode info. With
these
> patches, this will return to userspace for it to handle, but
there's no
> way for userspace to return the decoding information to KVM and
have KVM
> complete the access to the in-kernel emulated device. I have no
plans
> to address this limitation.
You had some pending comments on patch 2, and you seem to indicate
that you would respin the series. Do you have plans to do so in the
coming days? I'd like to put that series into -next, but I can
either
wait for your respin, or queue it as it is and apply fixes on top.
I think those for v2 and this is v3 which should address those
concerns.
Did I miss something or manage to confuse mysel here?
Gah! No, it looks like the mistake is mine. I've mixed the two series
in my
Inbox, and the result is a total brain-fart. Ignore me.
I'll queue these patches ASAP.
Thanks,
M.
--
Jazz is not dead. It just smells funny...
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