Re: [PATCH v5 04/13] ARM: KVM: Memory virtualization setup

[Avi Kivity <avi@redhat.com>]

On 12/11/2011 12:24 PM, Christoffer Dall wrote:
> This commit introduces the framework for guest memory management
> through the use of 2nd stage translation. Each VM has a pointer
> to a level-1 tabled (the pgd field in struct kvm_arch) which is
> used for the 2nd stage translations. Entries are added when handling
> guest faults (later patch) and the table itself can be allocated and
> freed through the following functions implemented in
> arch/arm/kvm/arm_mmu.c:
>  - kvm_alloc_stage2_pgd(struct kvm *kvm);
>  - kvm_free_stage2_pgd(struct kvm *kvm);
>
> Further, each entry in TLBs and caches are tagged with a VMID
> identifier in addition to ASIDs. The VMIDs are managed using
> a bitmap and assigned when creating the VM in kvm_arch_init_vm()
> where the 2nd stage pgd is also allocated. The table is freed in
> kvm_arch_destroy_vm(). Both functions are called from the main
> KVM code.
>
>  
>  struct kvm_arch {
> -	pgd_t *pgd;     /* 1-level 2nd stage table */
> +	u32    vmid;	/* The VMID used for the virt. memory system */
> +	pgd_t *pgd;	/* 1-level 2nd stage table */
> +	u64    vttbr;	/* VTTBR value associated with above pgd and vmid */
>  };
>

I can't say I have a solid grasp here, but my feeling is that vmid needs
to be per-vcpu.  Otherwise vcpu 1 can migrate to a cpu that previously
ran vcpu 0, and reuse its tlb since they have the same vmid.

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