Messages in this thread | | | Subject | Re: [PATCH v3 15/20] kvm: arm/arm64: Allow tuning the physical address size for VM | From | Suzuki K Poulose <> | Date | Mon, 2 Jul 2018 14:31:13 +0100 |
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On 02/07/18 14:13, Marc Zyngier wrote: > On 29/06/18 12:15, Suzuki K Poulose wrote: >> Allow specifying the physical address size for a new VM via >> the kvm_type argument for KVM_CREATE_VM ioctl. This allows >> us to finalise the stage2 page table format as early as possible >> and hence perform the right checks on the memory slots without >> complication. The size is encoded as Log2(PA_Size) in the bits[7:0] >> of the type field and can encode more information in the future if >> required. The IPA size is still capped at 40bits. > > Can't we relax this? There is no technical reason (AFAICS) not to allow > going down to 36bit IPA if the user has requested it.
Sure, we can.
> > If we run on a 36bit IPA system, the default would fail. But if the user > specified "please give me a 36bit IPA VM", we could satisfy that > requirement and allow them to run their stupidly small guest!
Absolutely. I will fix this in the next version.
Cheers Suzuki
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