Re: [PATCH v1 0/4] KVM: MMU: 5 level EPT/shadow support
From: Paolo Bonzini
Date: Mon Aug 14 2017 - 03:32:51 EST
On 12/08/2017 15:35, Yu Zhang wrote:
> Intel's existing processors limit the maximum linear address width to
> 48 bits, and the maximum physical address width to 46 bits. And the
> upcoming processors will extend maximum linear address width to 57 bits
> and maximum physical address width can go upto 52 bits in practical.
>
> With linear address width greater than 48, a new paging mode in IA-32e
> is introduced - 5 level paging(also known as LA57). And to support VMs
> with this feature, KVM MMU code need to be extended.
>
> And to achieve this, this patchset:
> 1> leverages 2 qemu parameters: +la57 and phys-bits to expose wider linear
> address width and physical address width to the VM;
> 2> extends shadow logic to construct 5 level shadow page for VMs running
> in LA57 mode;
> 3> extends ept logic to construct 5 level ept table for VMs whose maximum
> physical width exceeds 48 bits.
Thanks, this looks good. I only had a few suggestions in my reply to
patch 3.
Paolo