[Qemu-ppc] [RFC PATCH 01/26] spapr: introduce the XIVE_EXPLOIT option in CAS

[Cédric Le Goater]

On POWER9, the Client Architecture Support (CAS) negotiation process
determines whether the guest operates in XIVE Legacy compatibility
(the former POWER8 interrupt model) or in XIVE exploitation mode (the
newer POWER9 interrupt model).

Bit 7 of Byte 23 of vector 5 is used for this purpose.

Signed-off-by: Cédric Le Goater <address@hidden>
---
 hw/ppc/spapr.c              | 13 +++++++------
 include/hw/ppc/spapr_ovec.h |  1 +
 2 files changed, 8 insertions(+), 6 deletions(-)

diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
index d4d781876b27..27b12adc3582 100644
--- a/hw/ppc/spapr.c
+++ b/hw/ppc/spapr.c
@@ -910,7 +910,8 @@ static void spapr_dt_ov5_platform_support(void *fdt, int 
chosen)
 {
     PowerPCCPU *first_ppc_cpu = POWERPC_CPU(first_cpu);
 
-    char val[2 * 3] = {
+    char val[2 * 4] = {
+        23, 0x00, /* Xive mode: 0 = legacy (as in ISA 2.7), 1 = Exploitation */
         24, 0x00, /* Hash/Radix, filled in below. */
         25, 0x00, /* Hash options: Segment Tables == no, GTSE == no. */
         26, 0x40, /* Radix options: GTSE == yes. */
@@ -918,19 +919,19 @@ static void spapr_dt_ov5_platform_support(void *fdt, int 
chosen)
 
     if (kvm_enabled()) {
         if (kvmppc_has_cap_mmu_radix() && kvmppc_has_cap_mmu_hash_v3()) {
-            val[1] = 0x80; /* OV5_MMU_BOTH */
+            val[3] = 0x80; /* OV5_MMU_BOTH */
         } else if (kvmppc_has_cap_mmu_radix()) {
-            val[1] = 0x40; /* OV5_MMU_RADIX_300 */
+            val[3] = 0x40; /* OV5_MMU_RADIX_300 */
         } else {
-            val[1] = 0x00; /* Hash */
+            val[3] = 0x00; /* Hash */
         }
     } else {
         if (first_ppc_cpu->env.mmu_model & POWERPC_MMU_V3) {
             /* V3 MMU supports both hash and radix (with dynamic switching) */
-            val[1] = 0xC0;
+            val[3] = 0xC0;
         } else {
             /* Otherwise we can only do hash */
-            val[1] = 0x00;
+            val[3] = 0x00;
         }
     }
     _FDT(fdt_setprop(fdt, chosen, "ibm,arch-vec-5-platform-support",
diff --git a/include/hw/ppc/spapr_ovec.h b/include/hw/ppc/spapr_ovec.h
index f088833204de..0b464e22e75d 100644
--- a/include/hw/ppc/spapr_ovec.h
+++ b/include/hw/ppc/spapr_ovec.h
@@ -50,6 +50,7 @@ typedef struct sPAPROptionVector sPAPROptionVector;
 #define OV5_DRCONF_MEMORY       OV_BIT(2, 2)
 #define OV5_FORM1_AFFINITY      OV_BIT(5, 0)
 #define OV5_HP_EVT              OV_BIT(6, 5)
+#define OV5_XIVE_EXPLOIT        OV_BIT(23, 7)
 
 /* ISA 3.00 MMU features: */
 #define OV5_MMU_BOTH            OV_BIT(24, 0) /* Radix and hash */
-- 
2.7.5