kvm: Add missing bits to support live migration

This patch adds the missing hooks to allow live migration in KVM mode.
It adds proper synchronization before/after saving/restoring the VCPU
states (note: PPC is untested), hooks into
cpu_physical_memory_set_dirty_tracking() to enable dirty memory logging
at KVM level, and synchronizes that drity log into QEMU's view before
running ram_live_save().

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>

exec.c

@@ -516,6 +516,8 @@ static void cpu_common_save(QEMUFile *f, void *opaque)
 {
     CPUState *env = opaque;
 
+    cpu_synchronize_state(env, 0);
+
     qemu_put_be32s(f, &env->halted);
     qemu_put_be32s(f, &env->interrupt_request);
 }
@@ -533,6 +535,7 @@ static int cpu_common_load(QEMUFile *f, void *opaque, int version_id)
        version_id is increased. */
     env->interrupt_request &= ~0x01;
     tlb_flush(env, 1);
+    cpu_synchronize_state(env, 1);
 
     return 0;
 }
@@ -1923,6 +1926,9 @@ void cpu_physical_memory_reset_dirty(ram_addr_t start, ram_addr_t end,
 int cpu_physical_memory_set_dirty_tracking(int enable)
 {
     in_migration = enable;
+    if (kvm_enabled()) {
+        return kvm_set_migration_log(enable);
+    }
     return 0;
 }
 

target-i386/machine.c

@@ -4,6 +4,7 @@
 #include "hw/isa.h"
 
 #include "exec-all.h"
+#include "kvm.h"
 
 static void cpu_put_seg(QEMUFile *f, SegmentCache *dt)
 {
@@ -29,6 +30,8 @@ void cpu_save(QEMUFile *f, void *opaque)
     int32_t a20_mask;
     int i;
 
+    cpu_synchronize_state(env, 0);
+
     for(i = 0; i < CPU_NB_REGS; i++)
         qemu_put_betls(f, &env->regs[i]);
     qemu_put_betls(f, &env->eip);
@@ -321,5 +324,6 @@ int cpu_load(QEMUFile *f, void *opaque, int version_id)
     /* XXX: compute redundant hflags bits */
     env->hflags = hflags;
     tlb_flush(env, 1);
+    cpu_synchronize_state(env, 1);
     return 0;
 }

target-ppc/machine.c

@@ -1,11 +1,14 @@
 #include "hw/hw.h"
 #include "hw/boards.h"
+#include "kvm.h"
 
 void cpu_save(QEMUFile *f, void *opaque)
 {
     CPUState *env = (CPUState *)opaque;
     unsigned int i, j;
 
+    cpu_synchronize_state(env, 0);
+
     for (i = 0; i < 32; i++)
         qemu_put_betls(f, &env->gpr[i]);
 #if !defined(TARGET_PPC64)
@@ -174,5 +177,7 @@ int cpu_load(QEMUFile *f, void *opaque, int version_id)
     qemu_get_sbe32s(f, &env->mmu_idx);
     qemu_get_sbe32s(f, &env->power_mode);
 
+    cpu_synchronize_state(env, 1);
+
     return 0;
 }

vl.c

@@ -3232,13 +3232,18 @@ static int ram_save_live(QEMUFile *f, int stage, void *opaque)
 {
     ram_addr_t addr;
 
+    if (cpu_physical_sync_dirty_bitmap(0, last_ram_offset) != 0) {
+        qemu_file_set_error(f);
+        return 0;
+    }
+
     if (stage == 1) {
         /* Make sure all dirty bits are set */
         for (addr = 0; addr < last_ram_offset; addr += TARGET_PAGE_SIZE) {
             if (!cpu_physical_memory_get_dirty(addr, MIGRATION_DIRTY_FLAG))
                 cpu_physical_memory_set_dirty(addr);
         }
-        
+
         /* Enable dirty memory tracking */
         cpu_physical_memory_set_dirty_tracking(1);