On Sun, Jun 26, 2016 at 5:15 PM, sepanta s <sapanta...@gmail.com> wrote:
> > > > On Fri, Jun 24, 2016 at 8:10 PM, Tamas K Lengyel <ta...@tklengyel.com> > wrote: > >> >> On Jun 24, 2016 05:19, "Razvan Cojocaru" <rcojoc...@bitdefender.com> >> wrote: >> > >> > On 06/24/2016 02:05 PM, George Dunlap wrote: >> > > On Wed, Jun 22, 2016 at 12:38 PM, sepanta s <sapanta...@gmail.com> >> wrote: >> > >> Hi, >> > >> Is it possible to monitor the access on the pages withp2m_type_t >> > >> p2m_ram_shared? >> > > >> > > cc'ing Tamas and Razvan >> > >> > Thanks for the CC. Judging by the "if ( npfec.write_access && (p2mt == >> > p2m_ram_shared) )" line in hvm_hap_nested_page_fault() (from >> > xen/arch/x86/hvm/hvm.c), I'd say it certainly looks possible. But I >> > don't know what the context of the question is. >> > >> > >> > Thanks, >> > Razvan >> > The question is just getting the gfn and mfn of the page which is as type: > p2m_ram_shared to see which pages are written and unshared. > >> Yes, p2m_ram_shared type pages can be monitored with mem_access just as >> normal pages. The only part that may be tricky is if you map the page into >> your monitoring application while the page is shared. Your handle will >> continue to be valid even if the page is unshared but it will continue to >> point to the shared page. However, even if you catch write access events to >> the shared page that will lead to unsharing, the mem_access notification is >> sent before unsharing. I just usually do unsharing myself in the mem_access >> callback manually for monitored pages for this reason. I might change the >> flow in 4.8 to send the notification after the unsharing happened to >> simplify this. >> >> Tamas >> > Thanks, but in mem_access , what APIs can be used to see such events ? > Should I mark the shared pages as rx only ?
_______________________________________________ Xen-devel mailing list Xen-devel@lists.xen.org https://lists.xen.org/xen-devel
