Ring privilege of host linux kernel
As we have known, in KVM full virtualization, guest VM is running in non-root mode and KVM is running in root mode. While, in non-root mode, guest kernel is running in Ring 0 and Apps are running in Ring 3. However, what about the ring privilege for host linux?
In my knowledge, host linux is not controlled by VMX instructions and VMCS/VMCB. therefore, host linux should be running in root mode. Before we install KVM, host linux just run in Ring 0 (at that time, there is no root mode or non-root mode because VMX is not active). Hence, after we install KVM module, host linux kernel should be still in Ring 0 of root mode and Apps in host should run in Ring 3 of root mode. Is KVM running in higher privileged mode like Ring -1 of root mode or also running in Ring 0 of root mode?
Maybe my thoughts about KVM privilege ring is not correct. :-) Please give me some comments and I will really appreciate for your help.
Thank you,
Best Regards,
Min Li
Quoted 5 lines · On Thu, Mar 07, 2013 at 10:56:34PM -0500, [email protected] wrote:
As we have known, in KVM full virtualization, guest VM is running in non-root mode and KVM is running in root mode. While, in non-root mode, guest kernel is running in Ring 0 and Apps are running in Ring
3. However, what about the ring privilege for host linux?
Quoted 9 lines
In my knowledge, host linux is not controlled by VMX instructions and VMCS/VMCB. therefore, host linux should be running in root mode. Before we install KVM, host linux just run in Ring 0 (at that time, there is no root mode or non-root mode because VMX is not active). Hence, after we install KVM module, host linux kernel should be still in Ring 0 of root mode and Apps in host should run in Ring 3 of root mode. Is KVM running in higher privileged mode like Ring -1 of root mode or also running in Ring 0 of root mode?
KVM and the Linux kernel are running in Ring 0 in root mode.
--
Gleb.
Quoted 15 lines · Gleb Natapov
Quoted 5 lines · On Thu, Mar 07, 2013 at 10:56:34PM -0500, [email protected] wrote:
As we have known, in KVM full virtualization, guest VM is running in non-root mode and KVM is running in root mode. While, in non-root mode, guest kernel is running in Ring 0 and Apps are running in Ring
3. However, what about the ring privilege for host linux?Quoted 9 lines
In my knowledge, host linux is not controlled by VMX instructions and VMCS/VMCB. therefore, host linux should be running in root mode. Before we install KVM, host linux just run in Ring 0 (at that time, there is no root mode or non-root mode because VMX is not active). Hence, after we install KVM module, host linux kernel should be still in Ring 0 of root mode and Apps in host should run in Ring 3 of root mode. Is KVM running in higher privileged mode like Ring -1 of root mode or also running in Ring 0 of root mode?
Quoted 4 lines
KVM and the Linux kernel are running in Ring 0 in root mode.
--
Gleb.
Hi, Gleb
Really appreciate for your answer because this question has
confused me for several days.
Best,
Min