board-qemu: add private hcall to inform host on "phandle" update

The "interrupt-map" property in each PHB node references the "phandle"
property of the "interrupt-controller" node. This is used by the guest
OS to setup IRQs for any PCI device plugged into the PHB. QEMU sets this
property to an arbitrary value in the flattened DT passed to SLOF.

Since commit 82954d4c10, SLOF has some generic code to convert all
references to any "phandle" property to a SLOF specific value.

This is is perfectly okay for coldplug devices, since the guest OS only
sees the converted value in "interrupt-map". It is a problem though for
hotplug devices. Since they don't go through SLOF, the guest OS receives
the arbitrary value set by QEMU and fails to setup IRQs.

In order to support PHB hotplug, this patch introduces a new private
hcall, which allows SLOF to tell QEMU that a "phandle" was converted
from an old value to a new value.

Suggested-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Greg Kurz <groug@kaod.org>
Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>

board-qemu/slof/fdt.fs

@@ -308,18 +308,28 @@ fdt-claim-reserve
    3drop
 ;
 
+\ Tell QEMU about the updated phandle:
+: fdt-hv-update-phandle ( old new -- )
+   hv-update-phandle ?dup IF
+      \ Ignore hcall not implemented error, print error otherwise
+      dup -2 <> IF ." HV-UPDATE-PHANDLE error: " . cr ELSE drop THEN
+   THEN
+;
+
 \ Replace one FDT phandle "val" with a OF1275 phandle "node" in the
 \ whole tree:
 : fdt-update-phandle ( val node -- )
    >r
    FALSE TO (fdt-phandle-replaced)
-   r@ s" /" find-node               ( val node root )
-   fdt-replace-all-phandles
+   r@ 2dup s" /" find-node          ( val node val node root )
+   fdt-replace-all-phandles         ( val node )
    (fdt-phandle-replaced) IF
+      fdt-hv-update-phandle
       r@ set-node
       s" phandle" delete-property
       s" linux,phandle" delete-property
    ELSE
+      2drop
       diagnostic-mode? IF
          cr ." Warning: Did not replace phandle in " r@ node>path type cr
       THEN

lib/libhvcall/hvcall.code

@@ -129,3 +129,10 @@ PRIM(check_X2d_and_X2d_patch_X2d_sc1)
 
 	patch_broken_sc1((void*)start, (void*)end, (void*)patch_ins);
 MIRP
+
+// : hv-update-phandle ( old_phandle new_phandle -- res )
+PRIM(hv_X2d_update_X2d_phandle)
+	uint32_t new_phandle = TOS.u; POP;
+	uint32_t old_phandle = TOS.u;
+	TOS.u = hv_generic(KVMPPC_H_UPDATE_PHANDLE, old_phandle, new_phandle);
+MIRP

lib/libhvcall/hvcall.in

@@ -31,4 +31,5 @@ cod(RX!)
 cod(hv-logical-memop)
 cod(hv-cas)
 cod(hv-rtas-update)
+cod(hv-update-phandle)
 cod(get-print-version)

lib/libhvcall/libhvcall.h

@@ -25,6 +25,7 @@
 /* Client Architecture support */
 #define KVMPPC_H_CAS            (KVMPPC_HCALL_BASE + 0x2)
 #define KVMPPC_H_RTAS_UPDATE    (KVMPPC_HCALL_BASE + 0x3)
+#define KVMPPC_H_UPDATE_PHANDLE (KVMPPC_HCALL_BASE + 0x4)
 
 #ifndef __ASSEMBLY__