On Mon, Jun 4, 2018 at 10:08 AM, Luck, Tony <[email protected]> wrote: > On Sat, Jun 02, 2018 at 10:23:20PM -0700, Dan Williams wrote: >> +static inline int set_mce_nospec(unsigned long pfn) >> +{ >> + int rc; >> + >> + rc = set_memory_uc((unsigned long) __va(PFN_PHYS(pfn)), 1); > > You should really do the decoy_addr thing here that I had in mce_unmap_kpfn(). > Putting the virtual address of the page you mustn't accidentally prefetch > from into a register is a pretty good way to make sure that the processor > does do a prefetch.
Maybe I'm misreading, but doesn't that make the page completely inaccessible? We still want to read pmem through the driver and the linear mapping with memcpy_mcsafe(). Alternatively I could just drop this patch and setup a private / alias mapping for the pmem driver to use. It seems aliased mappings would be the safer option, but I want to make sure I've comprehended your suggestion correctly? _______________________________________________ Linux-nvdimm mailing list [email protected] https://lists.01.org/mailman/listinfo/linux-nvdimm
