On 03/27/2018 11:31 PM, Paul Mackerras wrote: > This changes the hypervisor page fault handler for radix guests to use > the generic KVM __gfn_to_pfn_memslot() function instead of using > get_user_pages_fast() and then handling the case of VM_PFNMAP vmas > specially. The old code missed the case of VM_IO vmas; with this > change, VM_IO vmas will now be handled correctly by code within > __gfn_to_pfn_memslot. > > Currently, __gfn_to_pfn_memslot calls hva_to_pfn, which only uses > __get_user_pages_fast for the initial lookup in the cases where > either atomic or async is set. Since we are not setting either > atomic or async, we do our own __get_user_pages_fast first, for now. > > This also adds code to check for the KVM_MEM_READONLY flag on the > memslot. If it is set and this is a write access, we synthesize a > data storage interrupt for the guest. > > In the case where the page is not normal RAM (i.e. page == NULL in > kvmppc_book3s_radix_page_fault(), we read the PTE from the Linux page > tables because we need the mapping attribute bits as well as the PFN. > (The mapping attribute bits indicate whether accesses have to be > non-cacheable and/or guarded.) > > Signed-off-by: Paul Mackerras <paulus@xxxxxxxxxx> > --- > v2: Read the Linux PTE for the non-RAM case to get the attribute bits. Tested-by: Cédric Le Goater <clg@xxxxxxxx> I have used patches [1-4]/5 + 5/5 v2 on top of 4.16-rc7 and tested a guest using P9 XIVE exploitation mode. It works fine. Thanks, C.
