PPC: Add PV hypercall transport through fw_cfg

On KVM for PPC we need to tell the guest which instructions to use when
doing a hypercall. The clean way to do this is to go through an ioctl
from userspace and passing it on to the guest using the device tree.

So let's do the qemu part here: read out the hypercall and pass it on
to the guest's fw_cfg so openBIOS can read it out and expose it again.

Signed-off-by: Alexander Graf <agraf@suse.de>

5 files changed, 50 insertions, 0 deletions

diff --git a/hw/ppc.h b/hw/ppc.h
index de13092ae..125193210 100644
--- a/hw/ppc.h
+++ b/hw/ppc.h
@@ -47,5 +47,8 @@ enum {
 #define FW_CFG_PPC_HEIGHT	(FW_CFG_ARCH_LOCAL + 0x01)
 #define FW_CFG_PPC_DEPTH	(FW_CFG_ARCH_LOCAL + 0x02)
 #define FW_CFG_PPC_TBFREQ	(FW_CFG_ARCH_LOCAL + 0x03)
+#define FW_CFG_PPC_IS_KVM       (FW_CFG_ARCH_LOCAL + 0x05)
+#define FW_CFG_PPC_KVM_HC       (FW_CFG_ARCH_LOCAL + 0x06)
+#define FW_CFG_PPC_KVM_PID      (FW_CFG_ARCH_LOCAL + 0x07)
 
 #define PPC_SERIAL_MM_BAUDBASE 399193
diff --git a/hw/ppc_newworld.c b/hw/ppc_newworld.c
index 639dcde00..809a1cfcb 100644
--- a/hw/ppc_newworld.c
+++ b/hw/ppc_newworld.c
@@ -427,9 +427,16 @@ static void ppc_core99_init (ram_addr_t ram_size,
     fw_cfg_add_i16(fw_cfg, FW_CFG_PPC_HEIGHT, graphic_height);
     fw_cfg_add_i16(fw_cfg, FW_CFG_PPC_DEPTH, graphic_depth);
 
+    fw_cfg_add_i32(fw_cfg, FW_CFG_PPC_IS_KVM, kvm_enabled());
     if (kvm_enabled()) {
 #ifdef CONFIG_KVM
+        uint8_t *hypercall;
+
         fw_cfg_add_i32(fw_cfg, FW_CFG_PPC_TBFREQ, kvmppc_get_tbfreq());
+        hypercall = qemu_malloc(16);
+        kvmppc_get_hypercall(env, hypercall, 16);
+        fw_cfg_add_bytes(fw_cfg, FW_CFG_PPC_KVM_HC, hypercall, 16);
+        fw_cfg_add_i32(fw_cfg, FW_CFG_PPC_KVM_PID, getpid());
 #endif
     } else {
         fw_cfg_add_i32(fw_cfg, FW_CFG_PPC_TBFREQ, get_ticks_per_sec());
diff --git a/hw/ppc_oldworld.c b/hw/ppc_oldworld.c
index de6005e35..a12a81297 100644
--- a/hw/ppc_oldworld.c
+++ b/hw/ppc_oldworld.c
@@ -399,9 +399,16 @@ static void ppc_heathrow_init (ram_addr_t ram_size,
     fw_cfg_add_i16(fw_cfg, FW_CFG_PPC_HEIGHT, graphic_height);
     fw_cfg_add_i16(fw_cfg, FW_CFG_PPC_DEPTH, graphic_depth);
 
+    fw_cfg_add_i32(fw_cfg, FW_CFG_PPC_IS_KVM, kvm_enabled());
     if (kvm_enabled()) {
 #ifdef CONFIG_KVM
+        uint8_t *hypercall;
+
         fw_cfg_add_i32(fw_cfg, FW_CFG_PPC_TBFREQ, kvmppc_get_tbfreq());
+        hypercall = qemu_malloc(16);
+        kvmppc_get_hypercall(env, hypercall, 16);
+        fw_cfg_add_bytes(fw_cfg, FW_CFG_PPC_KVM_HC, hypercall, 16);
+        fw_cfg_add_i32(fw_cfg, FW_CFG_PPC_KVM_PID, getpid());
 #endif
     } else {
         fw_cfg_add_i32(fw_cfg, FW_CFG_PPC_TBFREQ, get_ticks_per_sec());
diff --git a/target-ppc/kvm.c b/target-ppc/kvm.c
index 1079ce1e6..14d6365ee 100644
--- a/target-ppc/kvm.c
+++ b/target-ppc/kvm.c
@@ -327,6 +327,38 @@ uint32_t kvmppc_get_tbfreq(void)
     return retval;
 }
 
+int kvmppc_get_hypercall(CPUState *env, uint8_t *buf, int buf_len)
+{
+    uint32_t *hc = (uint32_t*)buf;
+
+#ifdef KVM_CAP_PPC_GET_PVINFO
+    struct kvm_ppc_pvinfo pvinfo;
+
+    if (kvm_check_extension(env->kvm_state, KVM_CAP_PPC_GET_PVINFO) &&
+        !kvm_vm_ioctl(env->kvm_state, KVM_PPC_GET_PVINFO, &pvinfo)) {
+        memcpy(buf, pvinfo.hcall, buf_len);
+
+        return 0;
+    }
+#endif
+
+    /*
+     * Fallback to always fail hypercalls:
+     *
+     *     li r3, -1
+     *     nop
+     *     nop
+     *     nop
+     */
+
+    hc[0] = 0x3860ffff;
+    hc[1] = 0x60000000;
+    hc[2] = 0x60000000;
+    hc[3] = 0x60000000;
+
+    return 0;
+}
+
 bool kvm_arch_stop_on_emulation_error(CPUState *env)
 {
     return true;
diff --git a/target-ppc/kvm_ppc.h b/target-ppc/kvm_ppc.h
index e8d66e88e..65e31c9b9 100644
--- a/target-ppc/kvm_ppc.h
+++ b/target-ppc/kvm_ppc.h
@@ -15,5 +15,6 @@ int kvmppc_read_host_property(const char *node_path, const char *prop,
                                      void *val, size_t len);
 
 uint32_t kvmppc_get_tbfreq(void);
+int kvmppc_get_hypercall(CPUState *env, uint8_t *buf, int buf_len);
 
 #endif /* __KVM_PPC_H__ */