spapr: Simplify handling of pre ISA 3.0 guest workaround handling

Certain old guest versions don't understand the radix MMU introduced with
POWER ISA 3.0, but incorrectly select it if presented with the option at
CAS time.  We workaround this in qemu by explicitly excluding the radix
(and other ISA 3.0 linked) options if the guest doesn't explicitly note
support for ISA 3.0.

This is handled by the 'cas_legacy_guest_workaround' flag, which is pretty
vague.  Rename it to 'cas_pre_isa3_guest' to be clearer about what it's for.

In addition, we unnecessarily call spapr_populate_pa_features() with
different options when initially constructing the device tree and when
adjusting it at CAS time.  At the initial construct time cas_pre_isa3_guest
is already false, so we can still use the flag, rather than explicitly
overriding it to be false at the callsite.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Reviewed-by: Cédric Le Goater <clg@kaod.org>
Reviewed-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Alexey Kardashevskiy <aik@ozlabs.ru>

diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
index 2725b139a7f0d8041d1f1547230c57d39ddd9af8..b906ac6547b6a314e069caee484c5eea3ea33a2f 100644 (file)
--- a/hw/ppc/spapr.c
+++ b/hw/ppc/spapr.c
@@ -220,8 +220,7 @@ static int spapr_fixup_cpu_numa_dt(void *fdt, int offset, PowerPCCPU *cpu)
 /* Populate the "ibm,pa-features" property */
 static void spapr_populate_pa_features(SpaprMachineState *spapr,
                                        PowerPCCPU *cpu,
-                                       void *fdt, int offset,
-                                       bool legacy_guest)
+                                       void *fdt, int offset)
 {
     uint8_t pa_features_206[] = { 6, 0,
         0xf6, 0x1f, 0xc7, 0x00, 0x80, 0xc0 };
@@ -287,7 +286,7 @@ static void spapr_populate_pa_features(SpaprMachineState *spapr,
     if ((spapr_get_cap(spapr, SPAPR_CAP_HTM) != 0) && pa_size > 24) {
         pa_features[24] |= 0x80;    /* Transactional memory support */
     }
-    if (legacy_guest && pa_size > 40) {
+    if (spapr->cas_pre_isa3_guest && pa_size > 40) {
         /* Workaround for broken kernels that attempt (guest) radix
          * mode when they can't handle it, if they see the radix bit set
          * in pa-features. So hide it from them. */
@@ -350,8 +349,7 @@ static int spapr_fixup_cpu_dt(void *fdt, SpaprMachineState *spapr)
             return ret;
         }
 
-        spapr_populate_pa_features(spapr, cpu, fdt, offset,
-                                   spapr->cas_legacy_guest_workaround);
+        spapr_populate_pa_features(spapr, cpu, fdt, offset);
     }
     return ret;
 }
@@ -553,7 +551,7 @@ static void spapr_populate_cpu_dt(CPUState *cs, void *fdt, int offset,
                           page_sizes_prop, page_sizes_prop_size)));
     }
 
-    spapr_populate_pa_features(spapr, cpu, fdt, offset, false);
+    spapr_populate_pa_features(spapr, cpu, fdt, offset);
 
     _FDT((fdt_setprop_cell(fdt, offset, "ibm,chip-id",
                            cs->cpu_index / vcpus_per_socket)));

diff --git a/hw/ppc/spapr_hcall.c b/hw/ppc/spapr_hcall.c
index 23e4bdb829c56671cf5e3755ac3a991de2e35a3b..3d3a67149ac487a7d4673cd6a0b16f171c741eda 100644 (file)
--- a/hw/ppc/spapr_hcall.c
+++ b/hw/ppc/spapr_hcall.c
@@ -1765,8 +1765,7 @@ static target_ulong h_client_architecture_support(PowerPCCPU *cpu,
             exit(EXIT_FAILURE);
         }
     }
-    spapr->cas_legacy_guest_workaround = !spapr_ovec_test(ov1_guest,
-                                                          OV1_PPC_3_00);
+    spapr->cas_pre_isa3_guest = !spapr_ovec_test(ov1_guest, OV1_PPC_3_00);
     spapr_ovec_cleanup(ov1_guest);
     if (!spapr->cas_reboot) {
         /* If spapr_machine_reset() did not set up a HPT but one is necessary

diff --git a/include/hw/ppc/spapr.h b/include/hw/ppc/spapr.h
index 03111fd55bc81d08947388b4d593e04bde6478b8..dfec8e8e767fa222a8616f542e40af9689f33d54 100644 (file)
--- a/include/hw/ppc/spapr.h
+++ b/include/hw/ppc/spapr.h
@@ -175,7 +175,7 @@ struct SpaprMachineState {
 
     /* ibm,client-architecture-support option negotiation */
     bool cas_reboot;
-    bool cas_legacy_guest_workaround;
+    bool cas_pre_isa3_guest;
     SpaprOptionVector *ov5;         /* QEMU-supported option vectors */
     SpaprOptionVector *ov5_cas;     /* negotiated (via CAS) option vectors */
     uint32_t max_compat_pvr;