Slow Bullets by Alastair Reynolds

From the author of the Revelation Space series comes an interstellar adventure of war, identity, betrayal, and the preservation of civilization itself.
A vast conflict, one that has encompassed hundreds of worlds and solar systems, appears to be finally at an end. A conscripted soldier is beginning to consider her life after the war and the family she has left behind. But for Scur-and for humanity-peace is not to be.
On the brink of the ceasefire, Scur is captured by a renegade war criminal, and left for dead in the ruins of a bunker. She revives aboard a prisoner transport vessel. Something has gone terribly wrong with the ship.
Passengers-combatants from both sides of the war-are waking up from hibernation far too soon. Their memories, embedded in bullets, are the only links to a world which is no longer recognizable. And Scur will be reacquainted with her old enemy, but with much higher stakes than just her own life.