AWS uses KVM in the kernel but they have a different, non-open source userspace stack for EC2; plus Firecracker which is open source but is only used for Lambda, and runs on EC2 bare metal instances.
Google also uses KVM with a variety of userspace stacks: a proprietary one (tied to a lot of internal Google infrastructure but overall a lot more similar to QEMU than Amazon's) for GCE, gVisor for AppEngine or whatever it is called these days, crosvm for ChromeOS, and QEMU for Android Emulator.
Google also uses KVM with a variety of userspace stacks: a proprietary one (tied to a lot of internal Google infrastructure but overall a lot more similar to QEMU than Amazon's) for GCE, gVisor for AppEngine or whatever it is called these days, crosvm for ChromeOS, and QEMU for Android Emulator.