[PATCH v2 3/4] qemu: make Hyperv settings exclusive to x86 and aarch64

[Andrea Bolognani]

On Tue, 2020-03-24 at 14:33 -0300, Daniel Henrique Barboza wrote:
> Hyperv features are supported by both x86 and aarch64. The <hyperv/>
> declaration in the XML by itself is benign to other architectures,
> but any of its 14 current features will break QEMU with an error
> like this (from ppc64):
> 
> qemu-kvm: Expected key=value format, found hv_relaxed
> 
> This is a more extreme case than the one for apic eoi because we
> would need an extra 'switch' statement, with all current Hyperv
> features in the body of qemuDomainDefValidateFeatures(), to
> check if the user attempted to activate any of them. It's easier to
> simply fail to launch with any 'hyperv' declaration in the XML for
> every arch which is not x86 and aarch64.
> 
> A fair disclaimer about Windows and PowerPC: the last Windows version
> that ran in the architecture is the hall of famer Windows NT 4.0,
> launched in 1996 and with end of extended support for the Server
> version in 2004 [1]. I am acknowledging that there might be Windows
> NT 4.0 users running in PowerPC, but not enough people running it
> under KVM/QEMU to justify Libvirt allowing 'hyperv' to exist in the
> domain XML of ppc64 domains.
> 
> [1] https://en.wikipedia.org/wiki/Windows_NT_4.0
> 
> Suggested-by: Andrea Bolognani <abologna at redhat.com>
> Signed-off-by: Daniel Henrique Barboza <danielhb413 at gmail.com>
> ---
>  src/qemu/qemu_domain.c | 13 ++++++++++++-
>  1 file changed, 12 insertions(+), 1 deletion(-)

Reviewed-by: Andrea Bolognani <abologna at redhat.com>

-- 
Andrea Bolognani / Red Hat / Virtualization