Re: [Xen-devel] [PATCH v02 6/7] arm: introduce do_translate_pagetable hypercall

[Julien Grall <julien.grall@xxxxxxxxxx>]

Hi Andrii,

On 26/06/14 12:07, Andrii Tseglytskyi wrote:
> +long do_translate_pagetable(int cmd, 
> XEN_GUEST_HANDLE_PARAM(xen_pagetable_addr_t) pgt_addr)
> +{
> +    struct xen_pagetable_addr pgt;
> +    struct mmu_info *mmu = NULL;
> +
> +    if ( copy_from_guest(&pgt, pgt_addr, 1) )
> +        return -EFAULT;
> +
> +    mmu = mmu_lookup(pgt.reg);
> +    if ( !mmu )
> +    {
> +        pr_mmu("can't get mmu for addr 0x%08x", pgt.reg);
> +        return -EINVAL;
> +    }
> +
> +    pgt.maddr = mmu_translate_pagetable(mmu, pgt.paddr);
> +
> +    return copy_to_guest(pgt_addr, &pgt, 1);
> +}
> +
AFAIU, nothing prevents a malicious guest to call this hypercall and 
screw the pagetable of the MMU.
Regards,

--
Julien Grall

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