[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] RE: [Xen-devel] Dom heap virtual address question
>From: Daniel Magenheimer >Sent: 2008年8月27日 7:49 > >Silly x86-related memory question from someone who has only >used global virtual address machines for too many years: > >Is it possible to take the result of an alloc_domheap_pages() >(struct page_info *) and convert this to a virtual address >that can be used at a later time in the hypervisor (not >in a domain)? E.g. > >va = mfn_to_virt(page_to_mfn(alloc_domheap_pages())) > : >(many seconds later, still in hypervisor) > : >a = *(unsigned int *)va; This only applies to 64bit xen which directly maps all memory in a large enough virtual address range. For 32bit xen, mfn_to_virt only applies to xenheap pages. > >Or is it necessary to do a va = map_domain_page(mfn) >then unmap_domain_page(va) around each usage? (And >if so do I need the _global version of these?) map/unmap_domain_page is cleaner wrap, suitable for both 32bit and 64bit xen. For 64bit xen, it's actually a macro to mfn_to_virt and thus map/unmap is light. you can use _global version if you'd like to access that page from any domain context and don't want to local map/unmap frequently. Thanks, Kevin _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxxxxxxxx http://lists.xensource.com/xen-devel
|
![]() |
Lists.xenproject.org is hosted with RackSpace, monitoring our |