From f7d69146549d717ef6cb5a68a3a4452391416f22 Mon Sep 17 00:00:00 2001 From: Alexander Graf Date: Thu, 24 Apr 2014 14:57:04 +0200 Subject: PPC: spapr: Expose /hypervisor node in device tree PR KVM supports an ePAPR compliant hypercall interface in parallel to the normal sPAPR one. Expose the ePAPR /hypervisor node and properties to the guest so it can use it. This enables magic page sharing on PR KVM with -M pseries. However we had a few nasty bugs in the magic page implementation on vcpus newer than 970 (p7, p8) that KVM now has workarounds for. It indicates that it does have these workarounds through the PPC_FIXUP_HCALL capability. To not expose broken guest kernels to issues on host kernels that don't have the fixups in place, we don't expose working hypercall instructions when the fixups are not available so that the guest can never active the magic page. Signed-off-by: Alexander Graf --- hw/ppc/spapr.c | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+) (limited to 'hw/ppc') diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c index 8f612c9347..c91c25a665 100644 --- a/hw/ppc/spapr.c +++ b/hw/ppc/spapr.c @@ -585,6 +585,26 @@ static void *spapr_create_fdt_skel(hwaddr initrd_base, /* event-sources */ spapr_events_fdt_skel(fdt, epow_irq); + /* /hypervisor node */ + if (kvm_enabled()) { + uint8_t hypercall[16]; + + /* indicate KVM hypercall interface */ + _FDT((fdt_begin_node(fdt, "hypervisor"))); + _FDT((fdt_property_string(fdt, "compatible", "linux,kvm"))); + if (kvmppc_has_cap_fixup_hcalls()) { + /* + * Older KVM versions with older guest kernels were broken with the + * magic page, don't allow the guest to map it. + */ + kvmppc_get_hypercall(first_cpu->env_ptr, hypercall, + sizeof(hypercall)); + _FDT((fdt_property(fdt, "hcall-instructions", hypercall, + sizeof(hypercall)))); + } + _FDT((fdt_end_node(fdt))); + } + _FDT((fdt_end_node(fdt))); /* close root node */ _FDT((fdt_finish(fdt))); -- cgit v1.2.3