August 2016
Intermediate to advanced
468 pages
9h 53m
English
Content preview from Mastering KVM VirtualizationBecome an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.
Execution flow of vCPU
Finally, we are into the vCPU execution flow which helps us to put everything together and understand what happens under the hood.
I hope you didn't forget that the QEMU creates a posix thread for a vCPU of the guest and ioctl(), which is responsible for running a CPU and has the KVM_RUN arg (#define KVM_RUN_IO(KVMIO, 0x80)). vCPU thread executes ioctl(.., KVM_RUN, ...) to run the guest code. As these are posix threads, the Linux kernel can schedule these threads as with any other process/thread in the system.
Let us see how it all works:
Qemu-kvm User Space: kvm_init_vcpu () kvm_arch_init_vcpu() qemu_init_vcpu() qemu_kvm_start_vcpu() qemu_kvm_cpu_thread_fn() while (1) { if (cpu_can_run(cpu)) { r = kvm_cpu_exec(cpu); } } kvm_cpu_exec ...Become an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
and much more.
Read now
Unlock full access
More than 5,000 organizations count on O’Reilly
O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.Julian F.
I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.Amir M.
I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.