On 08/31/10 18:28, Avi Kivity wrote:
> On 08/31/2010 03:17 PM, Jes.Sorensen@xxxxxxxxxx wrote:
>> From: Jes Sorensen<Jes.Sorensen@xxxxxxxxxx>
>>
>> We regularly see bug reports over this one, however it is a write to
>> a read-only register which some operating systems (including Linux)
>> tend to write to once in a while.
>>
>> Ignore the writes since they do no harm.
>>
>
> Does Linux write it with wrmsr_safe()? If not, I don't see how it
> works. If it does, then we shouldn't ignore the write, instead issue
> the #GP as usual, but be silent about it.
To be honest, I am having a hard time determining where the write
happens. I looked at this with Gleb and the rip obtained by
kvm_read_rip(vcpu) in the code doesn't indicate anything that resembles
a wrmsr().
It was either a
560 outb(0xfe, 0x64); /* pulse reset low */
or
49 asm volatile("sti; hlt": : :"memory");
which makes no sense to me, but given it's x86, I am not sure if it
could have come from the BIOS or something during reboot?
Jes
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