Re: kvm-60: kexec in guest crashes the host

[Avi Kivity <avi@qumranet.com>]

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Avi Kivity wrote:
> Dan Aloni wrote:
>   
>> On Wed, Feb 20, 2008 at 11:09:44AM +0200, Avi Kivity wrote:
>>   
>>     
>>> Dan Aloni wrote:
>>>     
>>>       
>>>> It happens at 100% of the times I invoke kexec.
>>>>
>>>>   
>>>>       
>>>>         
>>> Can you provide a commandline which triggers this? I'm completely 
>>> ignorant wrt kexec.
>>>     
>>>       
>> I managed to verify that this problem can be reproduced with the 
>> 2.6.16.60 tree.
>>
>> Also, it's worth to note that with '-no-kvm' the kexec procedure works
>> successfully and the second kernel executes.
>>
>> Please use the .config that that I attached to this mail, and also apply
>> the patch I supplied (it fixes a build problem that 2.6.16 has with the 
>> newer binutils versions and x86_64). I use gcc-4.1.2 to build the kernel.
>>
>> Once you have the bzImage of that guest kernel, use a root filesystem 
>> and boot it straight into /bin/bash.
>>
>> Now, assuming that your guest rootfs has kexec-utils package installed, 
>> do the following:
>>
>>   mount -t proc proc /proc
>>   kexec -l bzImage --command-line='ro root=/dev/hda1 init=/bin/bash'
>>   kexec -e
>>
>> BTW, if you use the serial console with the '-nographic' switch, then
>> you might want to use kexec a little differently:
>>
>>   kexec -l bzImage --command-line='ro root=/dev/hda1 init=/bin/bash console=ttyS0,115200' --serial=ttyS0 --serial-baud=115200           
>>   
>>     
>
> I managed to reproduce it (FC6 kernel kexecing itself).  It is Intel 
> specific.
>
>   

The attached patch fixes the problem for me.

-- 
error compiling committee.c: too many arguments to function


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diff --git a/kernel/vmx.c b/kernel/vmx.c
index 7ce02d2..ccc8174 100644
--- a/kernel/vmx.c
+++ b/kernel/vmx.c
@@ -1356,6 +1356,7 @@ static void vmx_set_efer(struct kvm_vcpu *vcpu, u64 efer)
 
 		msr->data = efer & ~EFER_LME;
 	}
+	vmx_load_host_state(vmx);
 	setup_msrs(vmx);
 }
 

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