On Wed, Feb 8, 2012 at 1:52 AM, Orit Wasserman <[email protected]> wrote: > On 02/07/2012 05:09 PM, Zhi Yong Wu wrote: >> On Tue, Jan 31, 2012 at 8:29 PM, Orit Wasserman <[email protected]> wrote: >>> On 01/31/2012 05:35 AM, Zhi Yong Wu wrote: >>>> HI, >>>> >>>> Can anyone let me know know the difference between VMXON region and >>>> VMCS region? relationship? >>>> >>> >>> There is no relationship between them: >>> VMXON region is created per logical processor and used by it for VMX ops. >> VMXON is created per VMM, not per logical processor, right? > Not exactly ,it is per logical processor the only thing that it contain that > can effect the VMM is the VMCS version. > you can't do VMXON twice on the same logical processor (it will fail). > For example if kvm is run in non exclusive mode it will will vmxon/vmxoff > before/after running the guest ah, this case is for nested KVM > (I think vmware does it too). In exclusive mode it does VMXON when the kvm > module is loaded and VMOFF when it is removed, no other VMM can use VMX on > that logical processor. > So in theory, one VMM can do the VMXON and the other can just use VMX without > doing VMXON but it has to use the same VMCS version (there are changes to the > VMCS structure in different versions). very wonderful, thanks. > >> >> Intel spec says as below: >> >> Before entering VMX operation, the host VMM allocates a VMXON region. A VMM >> can >> host several virtual machines and have many VMCSs active under its >> management. >> A unique VMCS region is required for each virtual machine; a VMXON region is >> ^^^ if each vm has multiple logical processor, A unique VMCS region is >> required for each logical processor. >> required for the VMM itself. > >> >>> VMCS region is created for each guest vcpu and used both by the hypervisor >>> and the processor. >> I suddently have one question about logical processor and guest vcpu. >> What is their relationship? >> >>> >>>> It will be appreciated if you can make some comments. >>>> >>>> >>> >> >> >> >
-- Regards, Zhi Yong Wu -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
