Re: [Qemu-ppc] [PATCH v2 1/4] tests: adding 'check_exception' RTAS implementation

[Michael Roth]

Quoting Daniel Henrique Barboza (2017-10-31 15:43:27)
> In the sPAPR guest, events such as device hotplug/unplug are
> retrieved by the check_exception RTAS call after the guest
> receives an IRQ pulse. For both hotplug and unplug operations,
> guest intervention is required to transit the DRC state of
> the attached device to the configured state.
> 
> Without guest intervention, we are still able of qtesting hotplug
> devices in the same manner that we support device hotplug in
> early (pre-CAS) stages.
> 
> Unfortunately, hot unplugs qtests relies on callbacks that demands
> guest intervention to complete - otherwise we risk leaving the guest
> in an inconsistent state that might impact other hotplug/unplug
> operations later on. If we want to make hot unplug qtests we'll
> need to simulate the guest behavior in the scenario in which a
> hot unplug is received, allowing the hot unplug process to go
> as intended.
> 
> This patch is the first step towards hot unplug qtests in sPAPR,
> implementing the check_exception RTAS hypercall in libqos. This
> hypercall is used to fetch events such as hotplug/hot unplug from
> the sPAPR machine after the guest receives an IRQ pulse (or,
> in the case of the test implemented here, we simply know when
> there is/isn't an event to be retrieved).
> 
> Signed-off-by: Daniel Henrique Barboza <address@hidden>
> ---
>  tests/libqos/rtas.c | 37 +++++++++++++++++++++++++
>  tests/libqos/rtas.h |  2 ++
>  tests/rtas-test.c   | 77 
> +++++++++++++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 116 insertions(+)
> 
> diff --git a/tests/libqos/rtas.c b/tests/libqos/rtas.c
> index 0269803ce0..fdeab448f7 100644
> --- a/tests/libqos/rtas.c
> +++ b/tests/libqos/rtas.c
> @@ -114,3 +114,40 @@ int qrtas_ibm_write_pci_config(QGuestAllocator *alloc, 
> uint64_t buid,
> 
>      return 0;
>  }
> +
> +/*
> + * check_exception as defined by PAPR 2.7+, 7.3.3.2

Now that we have a public LoPAPR I think it's better to reference that
when possible.