Re: [Qemu-arm] [RFC PATCH 0/2] target: Build with CONFIG_SEMIHOSTING disabled

[Peter Maydell]

On Fri, 31 May 2019 at 17:40, Philippe Mathieu-Daudé <address@hidden> wrote:
> I'll see what happened to Samuel series "Support disabling TCG on ARM"
> and see if it can be salvaged:
> https://lists.gnu.org/archive/html/qemu-devel/2018-11/msg02451.html

That would certainly be useful.

> I suppose in this thread:
> https://lists.gnu.org/archive/html/qemu-devel/2018-11/msg05641.html
> you refer to this series (not yet merged):
> https://lists.gnu.org/archive/html/qemu-devel/2019-05/msg03137.html
>
> I'll try to figure what "KVM injection of interrupts" is.

This is about some (rare) cases where userspace QEMU in a KVM
setup determines that it needs to deliver an exception to the
guest, and does that by adjusting the CPU state appropriately
(changing PC, PSTATE, ESR_EL1, etc etc) before telling KVM
to KVM_RUN again. Currently we only need that for some places
where we're doing debugging of the guest, but there is that
pending patchset that would also like to do it in case of
a detected hardware memory error. (Most of the time when the
guest takes an exception it's because the host kernel/KVM
have determined that it's necessary and done the relevant
messing with the guest CPU state.)

thanks
-- PMM