[Qemu-devel] [PATCH] spapr: compute interrupt vector address from LPCR

["Cédric Le Goater" <clg@fr.ibm.com>]

This address is changed by the linux kernel using the H_SET_MODE hcall
and needs to be migrated in order to restart a spapr VM running in
TCG. This can be done using the AIL bits from the LPCR register.

The patch introduces a spapr_h_set_mode_resource_addr() helper to
share some code with the H_SET_MODE hcall.

Signed-off-by: Cédric Le Goater <clg@fr.ibm.com>
---
 hw/ppc/spapr.c         |   21 +++++++++++++++++++++
 hw/ppc/spapr_hcall.c   |   13 ++-----------
 include/hw/ppc/spapr.h |   14 ++++++++++++++
 3 files changed, 37 insertions(+), 11 deletions(-)

Index: qemu-dgibson-for-2.6.git/hw/ppc/spapr.c
===================================================================
--- qemu-dgibson-for-2.6.git.orig/hw/ppc/spapr.c
+++ qemu-dgibson-for-2.6.git/hw/ppc/spapr.c
@@ -1244,6 +1244,24 @@ static bool spapr_vga_init(PCIBus *pci_b
     }
 }
 
+static int load_excp_prefix(void)
+{
+    CPUState *cs;
+
+    CPU_FOREACH(cs) {
+        CPUPPCState *env = &POWERPC_CPU(cs)->env;
+        int ail = (env->spr[SPR_LPCR] & LPCR_AIL) >> LPCR_AIL_SHIFT;
+
+        env->excp_prefix = spapr_h_set_mode_resource_addr(ail);
+        if (env->excp_prefix == H_UNSUPPORTED_FLAG) {
+            error_report("LPCR has an invalid AIL value");
+            return -EINVAL;
+        }
+    }
+
+    return 0;
+}
+
 static int spapr_post_load(void *opaque, int version_id)
 {
     sPAPRMachineState *spapr = (sPAPRMachineState *)opaque;
@@ -1257,6 +1275,9 @@ static int spapr_post_load(void *opaque,
         err = spapr_rtc_import_offset(spapr->rtc, spapr->rtc_offset);
     }
 
+    if (!err) {
+        err = load_excp_prefix();
+    }
     return err;
 }
 
Index: qemu-dgibson-for-2.6.git/include/hw/ppc/spapr.h
===================================================================
--- qemu-dgibson-for-2.6.git.orig/include/hw/ppc/spapr.h
+++ qemu-dgibson-for-2.6.git/include/hw/ppc/spapr.h
@@ -561,6 +561,20 @@ struct sPAPREventLogEntry {
     QTAILQ_ENTRY(sPAPREventLogEntry) next;
 };
 
+static inline target_ulong spapr_h_set_mode_resource_addr(target_ulong mflags)
+{
+    switch (mflags) {
+    case H_SET_MODE_ADDR_TRANS_NONE:
+        return 0;
+    case H_SET_MODE_ADDR_TRANS_0001_8000:
+        return 0x18000;
+    case H_SET_MODE_ADDR_TRANS_C000_0000_0000_4000:
+        return 0xC000000000004000ULL;
+    default:
+        return H_UNSUPPORTED_FLAG;
+    }
+}
+
 void spapr_events_init(sPAPRMachineState *sm);
 void spapr_events_fdt_skel(void *fdt, uint32_t epow_irq);
 int spapr_h_cas_compose_response(sPAPRMachineState *sm,
Index: qemu-dgibson-for-2.6.git/hw/ppc/spapr_hcall.c
===================================================================
--- qemu-dgibson-for-2.6.git.orig/hw/ppc/spapr_hcall.c
+++ qemu-dgibson-for-2.6.git/hw/ppc/spapr_hcall.c
@@ -835,17 +835,8 @@ static target_ulong h_set_mode_resource_
         return H_P4;
     }
 
-    switch (mflags) {
-    case H_SET_MODE_ADDR_TRANS_NONE:
-        prefix = 0;
-        break;
-    case H_SET_MODE_ADDR_TRANS_0001_8000:
-        prefix = 0x18000;
-        break;
-    case H_SET_MODE_ADDR_TRANS_C000_0000_0000_4000:
-        prefix = 0xC000000000004000ULL;
-        break;
-    default:
+    prefix = spapr_h_set_mode_resource_addr(mflags);
+    if (prefix == H_UNSUPPORTED_FLAG) {
         return H_UNSUPPORTED_FLAG;
     }