From: joeyli <jlee@suse.com>
To: Dan Williams <dan.j.williams@intel.com>
Cc: "Lee, Chun-Yi" <joeyli.kernel@gmail.com>,
Ross Zwisler <ross.zwisler@linux.intel.com>,
"Rafael J. Wysocki" <rjw@rjwysocki.net>,
"linux-nvdimm@lists.01.org" <linux-nvdimm@ml01.01.org>,
Linux ACPI <linux-acpi@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Gary Lin <GLin@suse.com>
Subject: Re: [PATCH] libnvdimm, nfit: treat volatile virtual CD region as read-only pmem
Date: Sat, 4 Jun 2016 19:01:56 +0800 [thread overview]
Message-ID: <20160604110156.GA4558@linux-rxt1.site> (raw)
In-Reply-To: <CAPcyv4iLb9qzXZTLL5z-RH_CRObnRfzx=vGTvVvieJUEwNvtRw@mail.gmail.com>
Hi Dan,
Thanks for your review.
On Fri, Jun 03, 2016 at 12:27:34PM -0700, Dan Williams wrote:
> On Fri, Jun 3, 2016 at 12:13 AM, Lee, Chun-Yi <joeyli.kernel@gmail.com> wrote:
> > This patch adds codes to treat a volatile virtual CD region as a
> > read-only pmem region, then read-only /dev/pmem* device can be mounted
> > with iso9660.
> >
> > It's useful to work with the httpboot in EFI firmware to pull a remote
> > ISO file to the local memory region for booting and installation.
> >
> > Wiki page of UEFI HTTPBoot with OVMF:
> > https://en.opensuse.org/UEFI_HTTPBoot_with_OVMF
> >
> > Signed-off-by: Lee, Chun-Yi <jlee@suse.com>
> > Cc: Gary Lin <GLin@suse.com>
> > Cc: Dan Williams <dan.j.williams@intel.com>
> > Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
> > Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
> > ---
> > drivers/acpi/nfit.c | 8 +++++++-
> > drivers/nvdimm/region_devs.c | 26 +++++++++++++++++++++++++-
> > include/linux/libnvdimm.h | 2 ++
> > 3 files changed, 34 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/acpi/nfit.c b/drivers/acpi/nfit.c
> > index 2215fc8..b100a17 100644
> > --- a/drivers/acpi/nfit.c
> > +++ b/drivers/acpi/nfit.c
> > @@ -1949,6 +1949,7 @@ static int acpi_nfit_init_mapping(struct acpi_nfit_desc *acpi_desc,
> > switch (nfit_spa_type(spa)) {
> > case NFIT_SPA_PM:
> > case NFIT_SPA_VOLATILE:
> > + case NFIT_SPA_VCD:
> > nd_mapping->start = memdev->address;
> > nd_mapping->size = memdev->region_size;
> > break;
>
> Why do we need to distinguish NFIT_SPA_VOLATILE vs NFIT_SPA_VCD, i.e.
> what happens if something writes to a VCD device?
Actually I didn't try to write SPA-VCD device before. Every time I mount it
that the system responses read-only:
# mount /dev/pmem0 /mnt/
mount: /dev/pmem0 is write-protected, mounting read-only
If it can be written, then I think there have no difference between
NFIT_SPA_VOLATILE with NFIT_SPA_VCD region.
I implemented this patch to treat VCD region as read-only pmem because the
pmem region generates /dev/pmem* device that it can be mounted.
Maybe I missed. Does NFIT_SPA_VOLATILE region also generate a device in /dev
that it can be mounted with filesystem? Then I think treat the VCD region as
a read-only VOLATILE region that's also a solution.
Thanks a lot!
Joey Lee
next prev parent reply other threads:[~2016-06-04 11:02 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-06-03 7:13 [PATCH] libnvdimm, nfit: treat volatile virtual CD region as read-only pmem Lee, Chun-Yi
2016-06-03 19:27 ` Dan Williams
2016-06-04 11:01 ` joeyli [this message]
2016-06-04 16:24 ` Dan Williams
2016-06-05 14:45 ` joeyli
2016-06-05 14:52 ` joeyli
2016-06-09 22:08 ` Linda Knippers
2016-06-09 22:34 ` Dan Williams
2016-06-12 2:10 ` joeyli
2016-06-12 1:58 ` joeyli
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