Re: [Xen-devel] [PATCH V2 3/7]: PVH: mmu related changes.

From: Ian Campbell
Date: Fri Oct 12 2012 - 04:57:52 EST


On Thu, 2012-10-11 at 22:58 +0100, Mukesh Rathor wrote:
> @@ -2177,8 +2210,19 @@ static const struct pv_mmu_ops xen_mmu_ops __initconst = {
>
> void __init xen_init_mmu_ops(void)
> {
> - x86_init.mapping.pagetable_reserve = xen_mapping_pagetable_reserve;
> x86_init.paging.pagetable_init = xen_pagetable_init;
> +
> + if (xen_feature(XENFEAT_auto_translated_physmap)) {
> + pv_mmu_ops.flush_tlb_others = xen_flush_tlb_others;
> +
> + /* For PCI devices to map iomem. */
> + if (xen_initial_domain()) {
> + pv_mmu_ops.set_pte = native_set_pte;
> + pv_mmu_ops.set_pte_at = native_set_pte_at;

What do these end up being for the !xen_initial_domain case? I'd have
expected native_FOO.

> +int xen_unmap_domain_mfn_range(struct vm_area_struct *vma)
> +{
> + int numpgs = (vma->vm_end - vma->vm_start) >> PAGE_SHIFT;
> + struct page **pages = vma ? vma->vm_private_data : NULL;

I thought we agreed to keep uses of vm_private_data in the privcmd
driver?

I think you should just add pages and nr as direct parameters to this
function, which is symmetric with the map call.

> +
> + if (!pages || !xen_feature(XENFEAT_auto_translated_physmap))
> + return 0;
> +
> + while (numpgs--) {
> +
> + /* the mmu has already cleaned up the process mmu resources at
> + * this point (lookup_address will return NULL). */
> + unsigned long pfn = page_to_pfn(pages[numpgs]);
> +
> + pvh_rem_xen_p2m(pfn, 1);
> + }
> + /* We don't need to flush tlbs because as part of pvh_rem_xen_p2m(),
> + * the hypervisor will do tlb flushes after removing the p2m entries
> + * from the EPT/NPT */
> + return 0;
> +}
> +EXPORT_SYMBOL_GPL(xen_unmap_domain_mfn_range);
[...]
> diff --git a/drivers/xen/privcmd.c b/drivers/xen/privcmd.c
> index ef63895..63d9ee8 100644
> --- a/drivers/xen/privcmd.c
> +++ b/drivers/xen/privcmd.c
> @@ -178,7 +178,7 @@ static int mmap_mfn_range(void *data, void *state)
> msg->va & PAGE_MASK,
> msg->mfn, msg->npages,
> vma->vm_page_prot,
> - st->domain);
> + st->domain, NULL);

Might it be useful to BUG_ON(!pages) in pvh_remap_gmfn_range?

Ian.

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