lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
Open Source and information security mailing list archives
| ||
|
Date: Fri, 29 May 2015 12:34:32 -0700 From: Dan Williams <dan.j.williams@...el.com> To: Toshi Kani <toshi.kani@...com> Cc: Borislav Petkov <bp@...en8.de>, Ross Zwisler <ross.zwisler@...ux.intel.com>, "H. Peter Anvin" <hpa@...or.com>, Thomas Gleixner <tglx@...utronix.de>, Ingo Molnar <mingo@...hat.com>, Andrew Morton <akpm@...ux-foundation.org>, Arnd Bergmann <arnd@...db.de>, linux-mm@...ck.org, "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>, X86 ML <x86@...nel.org>, "linux-nvdimm@...ts.01.org" <linux-nvdimm@...ts.01.org>, Juergen Gross <jgross@...e.com>, Stefan Bader <stefan.bader@...onical.com>, Andy Lutomirski <luto@...capital.net>, Henrique de Moraes Holschuh <hmh@....eng.br>, Yigal Korman <yigal@...xistor.com>, Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>, "Elliott, Robert (Server Storage)" <Elliott@...com>, Luis Rodriguez <mcgrof@...e.com>, Christoph Hellwig <hch@....de>, Matthew Wilcox <willy@...ux.intel.com> Subject: Re: [PATCH v10 12/12] drivers/block/pmem: Map NVDIMM with ioremap_wt() On Fri, May 29, 2015 at 11:32 AM, Toshi Kani <toshi.kani@...com> wrote: > On Fri, 2015-05-29 at 11:19 -0700, Dan Williams wrote: >> On Fri, May 29, 2015 at 8:03 AM, Toshi Kani <toshi.kani@...com> wrote: >> > On Fri, 2015-05-29 at 07:43 -0700, Dan Williams wrote: >> >> On Fri, May 29, 2015 at 2:11 AM, Borislav Petkov <bp@...en8.de> wrote: >> >> > On Wed, May 27, 2015 at 09:19:04AM -0600, Toshi Kani wrote: >> >> >> The pmem driver maps NVDIMM with ioremap_nocache() as we cannot > : >> >> >> - pmem->virt_addr = ioremap_nocache(pmem->phys_addr, pmem->size); >> >> >> + pmem->virt_addr = ioremap_wt(pmem->phys_addr, pmem->size); >> >> >> if (!pmem->virt_addr) >> >> >> goto out_release_region; >> >> > >> >> > Dan, Ross, what about this one? >> >> > >> >> > ACK to pick it up as a temporary solution? >> >> >> >> I see that is_new_memtype_allowed() is updated to disallow some >> >> combinations, but the manual seems to imply any mixing of memory types >> >> is unsupported. Which worries me even in the current code where we >> >> have uncached mappings in the driver, and potentially cached DAX >> >> mappings handed out to userspace. >> > >> > is_new_memtype_allowed() is not to allow some combinations of mixing of >> > memory types. When it is allowed, the requested type of ioremap_xxx() >> > is changed to match with the existing map type, so that mixing of memory >> > types does not happen. >> >> Yes, but now if the caller was expecting one memory type and gets >> another one that is something I think the driver would want to know. >> At a minimum I don't think we want to get emails about pmem driver >> performance problems when someone's platform is silently degrading WB >> to UC for example. > > The pmem driver creates an ioremap map to an NVDIMM range first. So, > there will be no conflict at this point, unless there is a conflicting > driver claiming the same NVDIMM range. Hmm, I thought it would be WB due to this comment in is_new_memtype_allowed() /* * PAT type is always WB for untracked ranges, so no need to check. */ -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Powered by blists - more mailing lists