[Qemu-devel] [PATCH] pseries: Add H_SET_MODE hcall to change guest exception endianness

[Anton Blanchard <anton@samba.org>]

Hi Anthony,

> > +    if (resource == 4) {
> 
> This ought to be a #define.  There's no else here, is that expected?
> Should you return failure for a different resource?

Good point, I made it a define. We were returning H_P2 for a different
resource, but it was a bit of a twisted maze of return statements. I
tried to clear it up in this version.

> Without knowing this interface better, a few things come to mind.
> 
> Is mflags a boolean?  If so, you can reduce this to a single loop and
> drop the switch() statement.  If mflags is truly a set of flags, it
> would be nice to use #define to give the flags a proper symbolic name.

Unfortunately it isn't a boolean, but yes it should have be made
clearer with a #define.

Anton
--

pseries: Add H_SET_MODE hcall to change guest exception endianness

H_SET_MODE is used for controlling various partition settings. One
of these settings is the endianness a guest takes its exceptions in.

Signed-off-by: Anton Blanchard <anton@samba.org>
---

diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
index 16bfab9..de639f6 100644
--- a/hw/ppc/spapr.c
+++ b/hw/ppc/spapr.c
@@ -262,7 +262,7 @@ static void *spapr_create_fdt_skel(const char *cpu_model,
     uint32_t start_prop = cpu_to_be32(initrd_base);
     uint32_t end_prop = cpu_to_be32(initrd_base + initrd_size);
     char hypertas_prop[] = "hcall-pft\0hcall-term\0hcall-dabr\0hcall-interrupt"
-        "\0hcall-tce\0hcall-vio\0hcall-splpar\0hcall-bulk";
+        "\0hcall-tce\0hcall-vio\0hcall-splpar\0hcall-bulk\0hcall-set-mode";
     char qemu_hypertas_prop[] = "hcall-memop1";
     uint32_t refpoints[] = {cpu_to_be32(0x4), cpu_to_be32(0x4)};
     uint32_t interrupt_server_ranges_prop[] = {0, cpu_to_be32(smp_cpus)};
diff --git a/hw/ppc/spapr_hcall.c b/hw/ppc/spapr_hcall.c
index 67d6cd9..89e6a00 100644
--- a/hw/ppc/spapr_hcall.c
+++ b/hw/ppc/spapr_hcall.c
@@ -657,6 +657,54 @@ static target_ulong h_logical_dcbf(PowerPCCPU *cpu, sPAPREnvironment *spapr,
     return H_SUCCESS;
 }
 
+static target_ulong h_set_mode(PowerPCCPU *cpu, sPAPREnvironment *spapr,
+                               target_ulong opcode, target_ulong *args)
+{
+    CPUState *cs;
+    target_ulong mflags = args[0];
+    target_ulong resource = args[1];
+    target_ulong value1 = args[2];
+    target_ulong value2 = args[3];
+    target_ulong ret = H_P2;
+
+    if (resource == H_SET_MODE_ENDIAN) {
+        if (value1) {
+            ret = H_P3;
+            goto out;
+        }
+        if (value2) {
+            ret = H_P4;
+            goto out;
+        }
+
+        switch (mflags) {
+        case H_SET_MODE_ENDIAN_BIG:
+            for (cs = first_cpu; cs != NULL; cs = cs->next_cpu) {
+                PowerPCCPU *cp = POWERPC_CPU(cs);
+                CPUPPCState *env = &cp->env;
+                env->spr[SPR_LPCR] &= ~LPCR_ILE;
+            }
+            ret = H_SUCCESS;
+            break;
+
+        case H_SET_MODE_ENDIAN_LITTLE:
+            for (cs = first_cpu; cs != NULL; cs = cs->next_cpu) {
+                PowerPCCPU *cp = POWERPC_CPU(cs);
+                CPUPPCState *env = &cp->env;
+                env->spr[SPR_LPCR] |= LPCR_ILE;
+            }
+            ret = H_SUCCESS;
+            break;
+
+        default:
+            ret = H_UNSUPPORTED_FLAG;
+        }
+    }
+
+out:
+    return ret;
+}
+
 static spapr_hcall_fn papr_hypercall_table[(MAX_HCALL_OPCODE / 4) + 1];
 static spapr_hcall_fn kvmppc_hypercall_table[KVMPPC_HCALL_MAX - KVMPPC_HCALL_BASE + 1];
 
@@ -734,6 +782,8 @@ static void hypercall_register_types(void)
 
     /* qemu/KVM-PPC specific hcalls */
     spapr_register_hypercall(KVMPPC_H_RTAS, h_rtas);
+
+    spapr_register_hypercall(H_SET_MODE, h_set_mode);
 }
 
 type_init(hypercall_register_types)
diff --git a/include/hw/ppc/spapr.h b/include/hw/ppc/spapr.h
index 9fc1972..ab42813 100644
--- a/include/hw/ppc/spapr.h
+++ b/include/hw/ppc/spapr.h
@@ -109,6 +109,15 @@ typedef struct sPAPREnvironment {
 #define H_NOT_ENOUGH_RESOURCES -44
 #define H_R_STATE         -45
 #define H_RESCINDEND      -46
+#define H_P2              -55
+#define H_P3              -56
+#define H_P4              -57
+#define H_P5              -58
+#define H_P6              -59
+#define H_P7              -60
+#define H_P8              -61
+#define H_P9              -62
+#define H_UNSUPPORTED_FLAG -256
 #define H_MULTI_THREADS_ACTIVE -9005
 
 
@@ -143,6 +152,11 @@ typedef struct sPAPREnvironment {
 #define H_PP1             (1ULL<<(63-62))
 #define H_PP2             (1ULL<<(63-63))
 
+/* H_SET_MODE flags */
+#define H_SET_MODE_ENDIAN		4
+#define  H_SET_MODE_ENDIAN_BIG		0
+#define  H_SET_MODE_ENDIAN_LITTLE	1
+
 /* VASI States */
 #define H_VASI_INVALID    0
 #define H_VASI_ENABLED    1
@@ -267,7 +281,8 @@ typedef struct sPAPREnvironment {
 #define H_GET_EM_PARMS          0x2B8
 #define H_SET_MPP               0x2D0
 #define H_GET_MPP               0x2D4
-#define MAX_HCALL_OPCODE        H_GET_MPP
+#define H_SET_MODE              0x31C
+#define MAX_HCALL_OPCODE        H_SET_MODE
 
 /* The hcalls above are standardized in PAPR and implemented by pHyp
  * as well.