[Qemu-ppc] [PATCH 3/4] Watchdog exit handling support

[Bharat Bhushan]

This patch adds the support to handle the exit caused by watchdog
(KVM_EXIT_WDT). In the handling we clear the TSR register.

Signed-off-by: Bharat Bhushan <address@hidden>
---
 hw/ppc_booke.c            |    5 +++++
 linux-headers/linux/kvm.h |    1 +
 target-ppc/cpu.h          |    1 +
 target-ppc/kvm.c          |   38 ++++++++++++++++++++++++++++++++++++++
 4 files changed, 45 insertions(+), 0 deletions(-)

diff --git a/hw/ppc_booke.c b/hw/ppc_booke.c
index 837a5b6..a9fba15 100644
--- a/hw/ppc_booke.c
+++ b/hw/ppc_booke.c
@@ -203,6 +203,11 @@ static void booke_wdt_cb(void *opaque)
                              booke_timer->wdt_timer);
 }
 
+void ppc_booke_wdt_clear_tsr(CPUPPCState *env, target_ulong tsr)
+{
+    env->spr[SPR_BOOKE_TSR] = tsr & ~(TSR_ENW | TSR_WIS | TSR_WRS_MASK);
+}
+
 void store_booke_tsr(CPUPPCState *env, target_ulong val)
 {
     env->spr[SPR_BOOKE_TSR] &= ~val;
diff --git a/linux-headers/linux/kvm.h b/linux-headers/linux/kvm.h
index 4b9e575..c1169ff 100644
--- a/linux-headers/linux/kvm.h
+++ b/linux-headers/linux/kvm.h
@@ -163,6 +163,7 @@ struct kvm_pit_config {
 #define KVM_EXIT_OSI              18
 #define KVM_EXIT_PAPR_HCALL      19
 #define KVM_EXIT_S390_UCONTROL   20
+#define KVM_EXIT_WDT              21
 
 /* For KVM_EXIT_INTERNAL_ERROR */
 #define KVM_INTERNAL_ERROR_EMULATION 1
diff --git a/target-ppc/cpu.h b/target-ppc/cpu.h
index ca2fc21..78212b4 100644
--- a/target-ppc/cpu.h
+++ b/target-ppc/cpu.h
@@ -1191,6 +1191,7 @@ void store_40x_dbcr0 (CPUPPCState *env, uint32_t val);
 void store_40x_sler (CPUPPCState *env, uint32_t val);
 void store_booke_tcr (CPUPPCState *env, target_ulong val);
 void store_booke_tsr (CPUPPCState *env, target_ulong val);
+void ppc_booke_wdt_clear_tsr(CPUPPCState *env, target_ulong tsr);
 void booke206_flush_tlb(CPUPPCState *env, int flags, const int check_iprot);
 target_phys_addr_t booke206_tlb_to_page_size(CPUPPCState *env, ppcmas_tlb_t 
*tlb);
 int ppcmas_tlb_check(CPUPPCState *env, ppcmas_tlb_t *tlb,
diff --git a/target-ppc/kvm.c b/target-ppc/kvm.c
index b6ef72d..6a37e94 100644
--- a/target-ppc/kvm.c
+++ b/target-ppc/kvm.c
@@ -32,6 +32,7 @@
 #include "device_tree.h"
 #include "hw/sysbus.h"
 #include "hw/spapr.h"
+#include "hw/watchdog.h"
 
 #include "hw/sysbus.h"
 #include "hw/spapr.h"
@@ -743,6 +744,37 @@ static int kvmppc_handle_dcr_write(CPUPPCState *env, 
uint32_t dcrn, uint32_t dat
     return 0;
 }
 
+static int kvm_arch_handle_watchdog(CPUPPCState *env)
+{
+    int ret;
+    struct kvm_sregs sregs;
+
+    watchdog_perform_action();
+
+    /*
+     * Clear watchdog interrupt condition by clearing TSR.
+     * Similar logic needed to be implemented for watchdog emulation in qemu
+     */
+    if (cap_booke_sregs) {
+        ret = kvm_vcpu_ioctl(env, KVM_GET_SREGS, &sregs);
+        if (ret < 0) {
+            return ret;
+        }
+
+        /* Clear TSR.ENW, TSR.WIS and TSR.WRS */
+        ppc_booke_wdt_clear_tsr(env, sregs.u.e.tsr);
+        sregs.u.e.tsr = env->spr[SPR_BOOKE_TSR];
+
+        sregs.u.e.update_special = KVM_SREGS_E_BASE | KVM_SREGS_E_UPDATE_TSR;
+        ret = kvm_vcpu_ioctl(env, KVM_SET_SREGS, &sregs);
+        if (ret < 0) {
+            return ret;
+        }
+    }
+
+    return 0;
+}
+
 int kvm_arch_handle_exit(CPUPPCState *env, struct kvm_run *run)
 {
     int ret;
@@ -769,6 +801,12 @@ int kvm_arch_handle_exit(CPUPPCState *env, struct kvm_run 
*run)
         ret = 1;
         break;
 #endif
+#ifdef KVM_EXIT_WDT
+    case KVM_EXIT_WDT:
+        dprintf("booke watchdog action\n");
+        ret = kvm_arch_handle_watchdog(env);
+        break;
+#endif
     default:
         fprintf(stderr, "KVM: unknown exit reason %d\n", run->exit_reason);
         ret = -1;
-- 
1.7.0.4