On Mon, Jun 27, 2016 at 10:34:32AM -0700, Dan Williams wrote: > On Sun, Jun 26, 2016 at 11:46 PM, Lee, Chun-Yi <joeyli.kernel@xxxxxxxxx> wrote: > > This patch adds logic to treat volatile virtual CD region as pmem > > region, then /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 > > > > The ramdisk function in EDK2/OVMF generates a ACPI0012 root device that > > it contains empty _STA but without _DSM: > > > > DefinitionBlock ("ssdt2.aml", "SSDT", 2, "INTEL ", "RamDisk ", 0x00001000) > > { > > Scope (\_SB) > > { > > Device (NVDR) > > { > > Name (_HID, "ACPI0012") // _HID: Hardware ID > > Name (_STR, Unicode ("NVDIMM Root Device")) // _STR: Description String > > Method (_STA, 0, NotSerialized) // _STA: Status > > { > > Return (0x0F) > > } > > } > > } > > } > > > > In section 5.2.25.2 of ACPI 6.1 spec, it mentions that the "SPA Range > > Structure Index" of VCD SPA shall be set to zero. That means VCD SPA > > will not be associated by any NVDIMM region mapping. > > > > The VCD's SPA Range Structure in NFIT is similar to virtual disk region > > as following: > > > > [028h 0040 2] Subtable Type : 0000 [System Physical Address Range] > > [02Ah 0042 2] Length : 0038 > > > > [02Ch 0044 2] Range Index : 0000 > > [02Eh 0046 2] Flags (decoded below) : 0000 > > Add/Online Operation Only : 0 > > Proximity Domain Valid : 0 > > [030h 0048 4] Reserved : 00000000 > > [034h 0052 4] Proximity Domain : 00000000 > > [038h 0056 16] Address Range GUID : 77AB535A-45FC-624B-5560-F7B281D1F96E > > [048h 0072 8] Address Range Base : 00000000B6ABD018 > > [050h 0080 8] Address Range Length : 0000000005500000 > > [058h 0088 8] Memory Map Attribute : 0000000000000000 > > > > The way to not associate a SPA range is to never reference it from a "flush hint", > > "interleave", or "control region" table. > > > > After testing on OVMF, pmem driver can support the region that it doesn't > > assoicate to any NVDIMM mapping. So, treat VCD like pmem is a idea to get > > a pmem block device that it contains iso. > > > > v3: > > To simplify patch, removed VCD region in libnvdimm. > > > > v2: > > Removed the code for setting VCD to a read-only region. > > > > Cc: Gary Lin <GLin@xxxxxxxx> > > Cc: Dan Williams <dan.j.williams@xxxxxxxxx> > > Cc: Ross Zwisler <ross.zwisler@xxxxxxxxxxxxxxx> > > Cc: "Rafael J. Wysocki" <rjw@xxxxxxxxxxxxx> > > Cc: Linda Knippers <linda.knippers@xxxxxxx> > > Signed-off-by: Lee, Chun-Yi <jlee@xxxxxxxx> > > --- > > drivers/acpi/nfit.c | 8 +++++++- > > drivers/nvdimm/region_devs.c | 26 +++++++++++++++++++++++++- > > include/linux/libnvdimm.h | 2 ++ > > 3 files changed, 34 insertions(+), 2 deletions(-) > > > > Index: linux/drivers/acpi/nfit.c > > =================================================================== > > --- linux.orig/drivers/acpi/nfit.c > > +++ linux/drivers/acpi/nfit.c > > @@ -1995,7 +1995,7 @@ static int acpi_nfit_register_region(str > > if (nfit_spa->nd_region) > > return 0; > > > > - if (spa->range_index == 0) { > > + if (spa->range_index == 0 && nfit_spa_type(spa) != NFIT_SPA_VCD) { > > dev_dbg(acpi_desc->dev, "%s: detected invalid spa index\n", > > __func__); > > If we're adding the special casing might as well add it for all > "virtual spa" tables. I.e. introduce nfit_spa_is_virtual() and have > it check for: NFIT_SPA_VDISK, NFIT_SPA_VCD, NFIT_SPA_PDISK, and > NFIT_SPA_PCD. Thanks for your suggestion. I will update and send version four. Joey Lee -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
