Hi guys, let me shortly introduce myself. I''m a student and recently work on my bachelor thesis. My goal is to write a little hypervisor. I''m not quite sure if this is the right mailing list, but i guess you''ll gonna tell me. i have two quick questions: 1. before i can use the vmxon instruction i do have to set vmxe flag in cr4 register. but what if some hypervisor is already running? is there a way to check if one is running?? 2. before i set the vmxe bit in cr4, i check if it is already enabled. i do this while my module gets loaded. but i observed a strange thing. sometimes the vmxe bit seems to be set while the other time it isn''t. do you have any explanation for that behaviour? do i have to check if the bit is set before actually setting it? I''ve looked at a few hypervisor projects and it seems that no one does it. my primary thought was, if the bit is set a hypervisor is running, but i don''t think that''s true anymore. so do i need the check? greetings
Hi guys, let me shortly introduce myself. I''m a student and recently work on my bachelor thesis. My goal is to write a little hypervisor. I''m not quite sure if this is the right mailing list, but i guess you''ll gonna tell me. i have two quick questions: 1. before i can use the vmxon instruction i do have to set vmxe flag in cr4 register. but what if some hypervisor is already running? is there a way to check if one is running?? 2. before i set the vmxe bit in cr4, i check if it is already enabled. i do this while my module gets loaded. but i observed a strange thing. sometimes the vmxe bit seems to be set while the other time it isn''t. do you have any explanation for that behaviour? do i have to check if the bit is set before actually setting it? I''ve looked at a few hypervisor projects and it seems that no one does it. my primary thought was, if the bit is set a hypervisor is running, but i don''t think that''s true anymore. so do i need the check? greetings
At 02:44 +0200 on 21 Jun (1340246688), palutke.ralph@gmx.de wrote:> Hi guys, > > let me shortly introduce myself. I''m a student and recently work on my bachelor thesis. My goal is to write a little hypervisor. > I''m not quite sure if this is the right mailing list, but i guess you''ll gonna tell me. > i have two quick questions: > > 1. before i can use the vmxon instruction i do have to set vmxe flag in cr4 register. but what if some hypervisor is already running? is there a way to check > if one is running??A lot of hypervisors report their presence in CPUID leaves - have a look at xen-detect in the tools/ directory for how to spot Xen. Tim.