[PATCH 2/2] target/ppc: add support for Hypervisor Facility Unavailable Exception

[Cédric Le Goater]

The privileged message send and clear instructions (msgsndp & msgclrp)
are privileged, but will generate a hypervisor facility unavailable
exception if not enabled in the HFSCR and executed in privileged
non-hypervisor state.

Add checks when accessing the DPDES register and when using the
msgsndp and msgclrp isntructions.

Based on previous work from Suraj Jitindar Singh.

Cc: Suraj Jitindar Singh <address@hidden>
Signed-off-by: Cédric Le Goater <address@hidden>
---
 target/ppc/cpu.h         |  6 ++++++
 target/ppc/excp_helper.c | 13 +++++++++++++
 target/ppc/misc_helper.c | 27 +++++++++++++++++++++++++++
 3 files changed, 46 insertions(+)

diff --git a/target/ppc/cpu.h b/target/ppc/cpu.h
index d175ec9a641d..1ff6afbccdb2 100644
--- a/target/ppc/cpu.h
+++ b/target/ppc/cpu.h
@@ -397,6 +397,10 @@ typedef struct ppc_v3_pate_t {
 #define PSSCR_ESL         PPC_BIT(42) /* Enable State Loss */
 #define PSSCR_EC          PPC_BIT(43) /* Exit Criterion */
 
+/* HFSCR bits */
+#define HFSCR_MSGP     PPC_BIT(53) /* Privileged Message Send Facilities */
+#define HFSCR_IC_MSGP  0xA
+
 #define msr_sf   ((env->msr >> MSR_SF)   & 1)
 #define msr_isf  ((env->msr >> MSR_ISF)  & 1)
 #define msr_shv  ((env->msr >> MSR_SHV)  & 1)
@@ -1332,6 +1336,8 @@ void cpu_ppc_set_vhyp(PowerPCCPU *cpu, 
PPCVirtualHypervisor *vhyp);
 #endif
 
 void store_fpscr(CPUPPCState *env, uint64_t arg, uint32_t mask);
+void helper_hfscr_facility_check(CPUPPCState *env, uint32_t bit,
+                                 const char *caller, uint32_t cause);
 
 static inline uint64_t ppc_dump_gpr(CPUPPCState *env, int gprn)
 {
diff --git a/target/ppc/excp_helper.c b/target/ppc/excp_helper.c
index 343f3a6b30c4..3887f8888c6c 100644
--- a/target/ppc/excp_helper.c
+++ b/target/ppc/excp_helper.c
@@ -471,6 +471,15 @@ static inline void powerpc_excp(PowerPCCPU *cpu, int 
excp_model, int excp)
     case POWERPC_EXCP_FU:         /* Facility unavailable exception          */
 #ifdef TARGET_PPC64
         env->spr[SPR_FSCR] |= ((target_ulong)env->error_code << 56);
+#endif
+        break;
+    case POWERPC_EXCP_HV_FU:     /* Hypervisor Facility Unavailable Exception 
*/
+#ifdef TARGET_PPC64
+        env->spr[SPR_HFSCR] |= ((target_ulong)env->error_code << FSCR_IC_POS);
+        srr0 = SPR_HSRR0;
+        srr1 = SPR_HSRR1;
+        new_msr |= (target_ulong)MSR_HVB;
+        new_msr |= env->msr & ((target_ulong)1 << MSR_RI);
 #endif
         break;
     case POWERPC_EXCP_PIT:       /* Programmable interval timer interrupt    */
@@ -1287,6 +1296,8 @@ void helper_book3s_msgclrp(CPUPPCState *env, target_ulong 
rb)
 {
     int irq = book3s_dbell2irq(rb, false);
 
+    helper_hfscr_facility_check(env, HFSCR_MSGP, "msgclrp", HFSCR_IC_MSGP);
+
     if (irq < 0) {
         return;
     }
@@ -1303,6 +1314,8 @@ void helper_book3s_msgsndp(CPUPPCState *env, target_ulong 
rb)
     int irq = book3s_dbell2irq(rb, false);
     int pir = env->spr_cb[SPR_PIR].default_value;
 
+    helper_hfscr_facility_check(env, HFSCR_MSGP, "msgsndp", HFSCR_IC_MSGP);
+
     if (irq < 0) {
         return;
     }
diff --git a/target/ppc/misc_helper.c b/target/ppc/misc_helper.c
index 66b5b0824208..2ff6bed10228 100644
--- a/target/ppc/misc_helper.c
+++ b/target/ppc/misc_helper.c
@@ -41,6 +41,18 @@ void helper_store_dump_spr(CPUPPCState *env, uint32_t sprn)
 }
 
 #ifdef TARGET_PPC64
+static void raise_hv_fu_exception(CPUPPCState *env, uint32_t bit,
+                                  const char *caller, uint32_t cause,
+                                  uintptr_t raddr)
+{
+    qemu_log_mask(LOG_GUEST_ERROR, "HV Facility %d is unavailable (%s)\n",
+                  bit, caller);
+
+    env->spr[SPR_HFSCR] &= ~((target_ulong)FSCR_IC_MASK << FSCR_IC_POS);
+
+    raise_exception_err_ra(env, POWERPC_EXCP_HV_FU, cause, raddr);
+}
+
 static void raise_fu_exception(CPUPPCState *env, uint32_t bit,
                                uint32_t sprn, uint32_t cause,
                                uintptr_t raddr)
@@ -55,6 +67,17 @@ static void raise_fu_exception(CPUPPCState *env, uint32_t 
bit,
 }
 #endif
 
+void helper_hfscr_facility_check(CPUPPCState *env, uint32_t bit,
+                                 const char *caller, uint32_t cause)
+{
+#ifdef TARGET_PPC64
+    if ((env->msr_mask & MSR_HVB) && !msr_hv &&
+                                     !(env->spr[SPR_HFSCR] & (1UL << bit))) {
+        raise_hv_fu_exception(env, bit, caller, cause, GETPC());
+    }
+#endif
+}
+
 void helper_fscr_facility_check(CPUPPCState *env, uint32_t bit,
                                 uint32_t sprn, uint32_t cause)
 {
@@ -114,6 +137,8 @@ target_ulong helper_load_dpdes(CPUPPCState *env)
 {
     target_ulong dpdes = 0;
 
+    helper_hfscr_facility_check(env, HFSCR_MSGP, "load DPDES", HFSCR_IC_MSGP);
+
     /* TODO: TCG supports only one thread */
     if (env->pending_interrupts & (1 << PPC_INTERRUPT_DOORBELL)) {
         dpdes |= (env->spr_cb[SPR_PIR].default_value & DBELL_TIRTAG_MASK);
@@ -127,6 +152,8 @@ void helper_store_dpdes(CPUPPCState *env, target_ulong val)
     PowerPCCPU *cpu = env_archcpu(env);
     CPUState *cs = CPU(cpu);
 
+    helper_hfscr_facility_check(env, HFSCR_MSGP, "store DPDES", HFSCR_IC_MSGP);
+
     /* TODO: TCG supports only one thread */
     if (val & ~0x1) {
         qemu_log_mask(LOG_GUEST_ERROR, "Invalid DPDES register value "
-- 
2.21.1