Re: [PATCH 1/7] MIPS: KVM/locore.S: Don't preserve host ASID around vcpu_run

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On Mon, May 09, 2016 at 04:22:33PM +0200, Paolo Bonzini wrote:

> On 06/05/2016 15:36, James Hogan wrote:
> > - It is actually redundant, since the host ASID will be restored
> >   correctly by kvm_arch_vcpu_put(), which is called almost immediately
> >   after kvm_arch_vcpu_ioctl_run() returns.
> 
> What happens if the guest does a rogue access to the area where the host
> kernel resides?  Would that cause a wrong entry in the TLB?

The kernel and lowmem reside in KSEG0/XKPYS which are "unmapped segments".
Unmapped means, the TLB isn't accessed at all nor does the ASID matter
in the address translation process in one of these unmapped segments.

  Ralf
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