Comment 7 for bug 1712803

------- Comment From <email address hidden> 2018-01-24 14:13 EDT-------
The reason for this bug is because the h_set_sprg0 and h_page_init hypervisor calls were not yet implemented in Qemu 2.5. The problem was solved by two patches. They implement one hypercall each.

https://github.com/qemu/qemu/commit/423576f771db8c6dbb944ddb8dc15b472f62de4a

This is a very simple hypercall that only sets up the SPRG0
register for the guest (since writing to SPRG0 was only permitted
to the hypervisor in older versions of the PowerISA).

https://github.com/qemu/qemu/commit/3240dd9a6924df18dfccb83defa0914065da076e

This hypercall either initializes a page with zeros, or copies
another page.
According to LoPAPR, the i-cache of the page should also be
flushed if using H_ICACHE_INVALIDATE or H_ICACHE_SYNCHRONIZE,
and the d-cache should be synchronized to the RAM if the
H_ICACHE_SYNCHRONIZE flag is used. For this, two new functions
are introduced, kvmppc_dcbst_range() and kvmppc_icbi()_range, which
use the corresponding assembler instructions to flush the caches
if running with KVM on Power. If the code runs with TCG instead,
the code only uses tb_flush(), assuming that this will be
enough for synchronization.