Hi Udo,
Thanks for your reply. When I run my test cases on real physical hardware I can run it through properly and also run in unrestricted guest mode. Looks like Nested VT on Qemu_KVM environment is buggy. Anyway thanks for looking into this problem and giving nice thought.
Regards Avinash.
On Mon, Nov 11, 2013 at 5:27 PM, Udo Steinberg <udo@...121...> wrote:
On Fri, 8 Nov 2013 12:30:10 +0530 avinash singh (AS) wrote:
AS> However, I also modified my test program to delegate IO ports upfront AS> before launching vcpu. But I still get vcpu_ioaccess_handler invoked. AS> Please see below,
In line 347, there is the following piece of code:
bool success = utcb_main->append_item(Io_crd(0, ORDER_64k), HOTSPOT, MAP_FROM_KERNEL, false);
I added "false" at the end to make the difference explicit. When running that piece of code I'm getting the following output:
NOVA Microhypervisor v6-d5b54fa (x86_32): Sep 5 2013 16:18:28 [gcc 4.9.0]
[ 0] CORE:0:0:0 6:3c:3:1 [10] Intel(R) Core(TM) i7-4770 CPU @ 3.40GHz [ 3] CORE:0:3:0 6:3c:3:1 [10] Intel(R) Core(TM) i7-4770 CPU @ 3.40GHz [ 1] CORE:0:1:0 6:3c:3:1 [10] Intel(R) Core(TM) i7-4770 CPU @ 3.40GHz [ 7] CORE:0:3:1 6:3c:3:1 [10] Intel(R) Core(TM) i7-4770 CPU @ 3.40GHz [ 5] CORE:0:1:1 6:3c:3:1 [10] Intel(R) Core(TM) i7-4770 CPU @ 3.40GHz [ 4] CORE:0:0:1 6:3c:3:1 [10] Intel(R) Core(TM) i7-4770 CPU @ 3.40GHz [ 6] CORE:0:2:1 6:3c:3:1 [10] Intel(R) Core(TM) i7-4770 CPU @ 3.40GHz [ 2] CORE:0:2:0 6:3c:3:1 [10] Intel(R) Core(TM) i7-4770 CPU @ 3.40GHz Hello world All Portal created! runcpuid addr 0x02001000 eip is initialized 0x00001000 cs 0x02000000 npt fault handler .. host_adddr 0x01001000 got cpuid intercept! IOACCES invoked IP 0x00001007 dx 0x000003f8 IOACCES invoked IP 0x00001007 dx 0x000003f8 IOACCESS: Duplicate Request... [ 0] Killed EC:0xc0011a00 SC:0xc0013500 V:0xd CS:0x1b EIP:0x1001717 CR2:0x0 ERR:0x0 (PT not found) [ 0] Killed EC:0xc0011b00 SC:0xc0013500 V:0x1e CR0:0x10031 CR3:0x0 CR4:0x0 (IPC Abort)
As expected, I/O accesses cause VM exits because the G-bit has not been set.
So then I've changed line 347 as follows:
bool success = utcb_main->append_item(Io_crd(0, ORDER_64k), HOTSPOT, MAP_FROM_KERNEL, true);
and I'm getting the following output:
NOVA Microhypervisor v6-d5b54fa (x86_32): Sep 5 2013 16:18:28 [gcc 4.9.0]
[ 0] CORE:0:0:0 6:3c:3:1 [10] Intel(R) Core(TM) i7-4770 CPU @ 3.40GHz [ 4] CORE:0:0:1 6:3c:3:1 [10] Intel(R) Core(TM) i7-4770 CPU @ 3.40GHz [ 2] CORE:0:2:0 6:3c:3:1 [10] Intel(R) Core(TM) i7-4770 CPU @ 3.40GHz [ 6] CORE:0:2:1 6:3c:3:1 [10] Intel(R) Core(TM) i7-4770 CPU @ 3.40GHz [ 3] CORE:0:3:0 6:3c:3:1 [10] Intel(R) Core(TM) i7-4770 CPU @ 3.40GHz [ 5] CORE:0:1:1 6:3c:3:1 [10] Intel(R) Core(TM) i7-4770 CPU @ 3.40GHz [ 7] CORE:0:3:1 6:3c:3:1 [10] Intel(R) Core(TM) i7-4770 CPU @ 3.40GHz [ 1] CORE:0:1:0 6:3c:3:1 [10] Intel(R) Core(TM) i7-4770 CPU @ 3.40GHz Hello world All Portal created! runcpuid addr 0x02001000 eip is initialized 0x00001000 cs 0x02000000 npt fault handler .. host_adddr 0x01001000 got cpuid intercept! Egot cpuid intercept! [ 0] Killed EC:0xc0012b00 SC:0xc0014500 V:0xc CR0:0x10031 CR3:0x0 CR4:0x0 (PT not found)
The EC is killed due to an unhandled HLT VM exit, which is expected. As you can see, there are no I/O exits and everything works as expected. Also note that the 'E' from startup.s line 46 is being printed to serial line in front of the CPUID output.
AS> I am not sure what is wrong here. Because same logic works for AMD process. AS> Please could you just see main.cc if something is I am doing wrong there. AS> Goal is to run cpuid ad oubt instruction in guest mode with paging disabled AS> and protected mode bit on.
I believe the problem is that you run NOVA as a nested hypervisor under KVM and if KVM is not virtualizing VMX correctly, then you get these kind of problems. Can you try running your tests on bare hardware (as I did) to see if they work correctly there?
AS> > AS> My question is, does NOVA kernel supports to run intel cpu in AS> > AS> unrestricted guest mode? or is there any trick to do that so. Please AS> > AS> help me if I am missing something. AS> > AS> > NOVA automatically enables unrestricted guest if the CPU supports it. The AS> > feature is supported on processors based on the Westmere or newer AS> > microarchitectures. Unrestricted guest will be disabled, if the user AS> AS> [ 0] VMCS:0x017ef000 REV:0x11e57ed0 EPT:0 URG:0 VNMI:1 VPID:0 AS> [ 0] CORE:0:0:0 6:f:b:0 [1] Intel(R) Core(TM)2 Duo CPU T7700 @ 2.40GHz
First of all, the VMCS revision identifier looks really odd. Secondly, the virtual CPU claims not to support EPT or unrestricted guest, as you can see from the EPT and URG fields both showing a 0. This means KVM is not emulating EPT/URG support and thus NOVA cannot enable it. Again, running the test on bare hardware may be a better idea, because you rule out KVM as a potential source of bugs.
Let me know what else you find out.
Cheers, Udo