ppc: Clean up and QOMify hypercall emulation

The pseries machine type is a bit unusual in that it runs a paravirtualized
guest.  The guest expects to interact with a hypervisor, and qemu
emulates the functions of that hypervisor directly, rather than executing
hypervisor code within the emulated system.

To implement this in TCG, we need to intercept hypercall instructions and
direct them to the machine's hypercall handlers, rather than attempting to
perform a privilege change within TCG.  This is controlled by a global
hook - cpu_ppc_hypercall.

This cleanup makes the handling a little cleaner and more extensible than
a single global variable.  Instead, each CPU to have hypercalls intercepted
has a pointer set to a QOM object implementing a new virtual hypervisor
interface.  A method in that interface is called by TCG when it sees a
hypercall instruction.  It's possible we may want to add other methods in
future.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Reviewed-by: Alexey Kardashevskiy <aik@ozlabs.ru>

1 files changed, 5 insertions, 3 deletions

diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
index ca78e314a5..a4774fb185 100644
--- a/hw/ppc/spapr.c
+++ b/hw/ppc/spapr.c
@@ -1005,7 +1005,8 @@ static uint64_t translate_kernel_address(void *opaque, uint64_t addr)
     return (addr & 0x0fffffff) + KERNEL_LOAD_ADDR;
 }
 
-static void emulate_spapr_hypercall(PowerPCCPU *cpu)
+static void emulate_spapr_hypercall(PPCVirtualHypervisor *vhyp,
+                                    PowerPCCPU *cpu)
 {
     CPUPPCState *env = &cpu->env;
 
@@ -1843,8 +1844,6 @@ static void ppc_spapr_init(MachineState *machine)
 
     QLIST_INIT(&spapr->phbs);
 
-    cpu_ppc_hypercall = emulate_spapr_hypercall;
-
     /* Allocate RMA if necessary */
     rma_alloc_size = kvmppc_alloc_rma(&rma);
 
@@ -2680,6 +2679,7 @@ static void spapr_machine_class_init(ObjectClass *oc, void *data)
     FWPathProviderClass *fwc = FW_PATH_PROVIDER_CLASS(oc);
     NMIClass *nc = NMI_CLASS(oc);
     HotplugHandlerClass *hc = HOTPLUG_HANDLER_CLASS(oc);
+    PPCVirtualHypervisorClass *vhc = PPC_VIRTUAL_HYPERVISOR_CLASS(oc);
 
     mc->desc = "pSeries Logical Partition (PAPR compliant)";
 
@@ -2711,6 +2711,7 @@ static void spapr_machine_class_init(ObjectClass *oc, void *data)
     fwc->get_dev_path = spapr_get_fw_dev_path;
     nc->nmi_monitor_handler = spapr_nmi;
     smc->phb_placement = spapr_phb_placement;
+    vhc->hypercall = emulate_spapr_hypercall;
 }
 
 static const TypeInfo spapr_machine_info = {
@@ -2726,6 +2727,7 @@ static const TypeInfo spapr_machine_info = {
         { TYPE_FW_PATH_PROVIDER },
         { TYPE_NMI },
         { TYPE_HOTPLUG_HANDLER },
+        { TYPE_PPC_VIRTUAL_HYPERVISOR },
         { }
     },
 };