[PATCH v2] nfit: add Hyper-V NVDIMM DSM command set to white list

[Dexuan Cui]

Add the Hyper-V _DSM command set to the white list of NVDIMM command
sets.

This command set is documented at http://www.uefi.org/RFIC_LIST
(see "Virtual NVDIMM 0x1901").

Thanks Dan Williams <dan.j.williams@xxxxxxxxx> for writing the
comment change.

Signed-off-by: Dexuan Cui <decui@xxxxxxxxxxxxx>
Reviewed-by: Michael Kelley <mikelley@xxxxxxxxxxxxx>
---

Changes in v2:
    Updated the comment and changelog (Thanks, Dan!)
    Rebased to the tag libnvdimm-fixes-5.0-rc4 of the nvdimm tree.

 drivers/acpi/nfit/core.c   | 17 ++++++++++++++---
 drivers/acpi/nfit/nfit.h   |  6 +++++-
 include/uapi/linux/ndctl.h |  1 +
 3 files changed, 20 insertions(+), 4 deletions(-)

diff --git a/drivers/acpi/nfit/core.c b/drivers/acpi/nfit/core.c
index e18ade5d74e9..a9270c99be72 100644
--- a/drivers/acpi/nfit/core.c
+++ b/drivers/acpi/nfit/core.c
@@ -1861,9 +1861,17 @@ static int acpi_nfit_add_dimm(struct acpi_nfit_desc *acpi_desc,
 	dev_set_drvdata(&adev_dimm->dev, nfit_mem);
 
 	/*
-	 * Until standardization materializes we need to consider 4
-	 * different command sets.  Note, that checking for function0 (bit0)
-	 * tells us if any commands are reachable through this GUID.
+	 * There are 4 "legacy" NVDIMM command sets
+	 * (NVDIMM_FAMILY_{INTEL,MSFT,HPE1,HPE2}) that were created before
+	 * an EFI working group was established to constrain this
+	 * proliferation. The nfit driver probes for the supported command
+	 * set by GUID. Note, if you're a platform developer looking to add
+	 * a new command set to this probe, consider using an existing set,
+	 * or otherwise seek approval to publish the command set at
+	 * http://www.uefi.org/RFIC_LIST.
+	 *
+	 * Note, that checking for function0 (bit0) tells us if any commands
+	 * are reachable through this GUID.
 	 */
 	for (i = 0; i <= NVDIMM_FAMILY_MAX; i++)
 		if (acpi_check_dsm(adev_dimm->handle, to_nfit_uuid(i), 1, 1))
@@ -1886,6 +1894,8 @@ static int acpi_nfit_add_dimm(struct acpi_nfit_desc *acpi_desc,
 			dsm_mask &= ~(1 << 8);
 	} else if (nfit_mem->family == NVDIMM_FAMILY_MSFT) {
 		dsm_mask = 0xffffffff;
+	} else if (nfit_mem->family == NVDIMM_FAMILY_HYPERV) {
+		dsm_mask = 0x1f;
 	} else {
 		dev_dbg(dev, "unknown dimm command family\n");
 		nfit_mem->family = -1;
@@ -3729,6 +3739,7 @@ static __init int nfit_init(void)
 	guid_parse(UUID_NFIT_DIMM_N_HPE1, &nfit_uuid[NFIT_DEV_DIMM_N_HPE1]);
 	guid_parse(UUID_NFIT_DIMM_N_HPE2, &nfit_uuid[NFIT_DEV_DIMM_N_HPE2]);
 	guid_parse(UUID_NFIT_DIMM_N_MSFT, &nfit_uuid[NFIT_DEV_DIMM_N_MSFT]);
+	guid_parse(UUID_NFIT_DIMM_N_HYPERV, &nfit_uuid[NFIT_DEV_DIMM_N_HYPERV]);
 
 	nfit_wq = create_singlethread_workqueue("nfit");
 	if (!nfit_wq)
diff --git a/drivers/acpi/nfit/nfit.h b/drivers/acpi/nfit/nfit.h
index 33691aecfcee..4de167b4f76f 100644
--- a/drivers/acpi/nfit/nfit.h
+++ b/drivers/acpi/nfit/nfit.h
@@ -34,11 +34,14 @@
 /* https://msdn.microsoft.com/library/windows/hardware/mt604741 */
 #define UUID_NFIT_DIMM_N_MSFT "1ee68b36-d4bd-4a1a-9a16-4f8e53d46e05"
 
+/* http://www.uefi.org/RFIC_LIST (see "Virtual NVDIMM 0x1901") */
+#define UUID_NFIT_DIMM_N_HYPERV "5746c5f2-a9a2-4264-ad0e-e4ddc9e09e80"
+
 #define ACPI_NFIT_MEM_FAILED_MASK (ACPI_NFIT_MEM_SAVE_FAILED \
 		| ACPI_NFIT_MEM_RESTORE_FAILED | ACPI_NFIT_MEM_FLUSH_FAILED \
 		| ACPI_NFIT_MEM_NOT_ARMED | ACPI_NFIT_MEM_MAP_FAILED)
 
-#define NVDIMM_FAMILY_MAX NVDIMM_FAMILY_MSFT
+#define NVDIMM_FAMILY_MAX NVDIMM_FAMILY_HYPERV
 
 #define NVDIMM_STANDARD_CMDMASK \
 (1 << ND_CMD_SMART | 1 << ND_CMD_SMART_THRESHOLD | 1 << ND_CMD_DIMM_FLAGS \
@@ -94,6 +97,7 @@ enum nfit_uuids {
 	NFIT_DEV_DIMM_N_HPE1 = NVDIMM_FAMILY_HPE1,
 	NFIT_DEV_DIMM_N_HPE2 = NVDIMM_FAMILY_HPE2,
 	NFIT_DEV_DIMM_N_MSFT = NVDIMM_FAMILY_MSFT,
+	NFIT_DEV_DIMM_N_HYPERV = NVDIMM_FAMILY_HYPERV,
 	NFIT_SPA_VOLATILE,
 	NFIT_SPA_PM,
 	NFIT_SPA_DCR,
diff --git a/include/uapi/linux/ndctl.h b/include/uapi/linux/ndctl.h
index f57c9e434d2d..de5d90212409 100644
--- a/include/uapi/linux/ndctl.h
+++ b/include/uapi/linux/ndctl.h
@@ -243,6 +243,7 @@ struct nd_cmd_pkg {
 #define NVDIMM_FAMILY_HPE1 1
 #define NVDIMM_FAMILY_HPE2 2
 #define NVDIMM_FAMILY_MSFT 3
+#define NVDIMM_FAMILY_HYPERV 4
 
 #define ND_IOCTL_CALL			_IOWR(ND_IOCTL, ND_CMD_CALL,\
 					struct nd_cmd_pkg)
-- 
2.19.1