Add support for H_SCM_HEALTH hcall described at [1] for spapr
nvdimms. This enables guest to detect the 'unarmed' status of a
specific spapr nvdimm identified by its DRC and if its unarmed, mark
the region backed by the nvdimm as read-only.
The patch adds h_scm_health() to handle the H_SCM_HEALTH hcall which
returns two 64-bit bitmaps (health bitmap, health bitmap mask) derived
from 'struct nvdimm->unarmed' member.
Linux kernel side changes to enable handling of 'unarmed' nvdimms for
ppc64 are proposed at [2].
References:
[1] "Hypercall Op-codes (hcalls)"
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/powerpc/papr_hcalls.rst#n220
[2] "powerpc/papr_scm: Mark nvdimm as unarmed if needed during probe"
https://lore.kernel.org/linux-nvdimm/20210329113103.476760-1-vaibhav@xxxxxxxxxxxxx/
Signed-off-by: Vaibhav Jain <vaibhav@xxxxxxxxxxxxx>
---
Changelog
v3:
* Switched to PPC_BIT macro for definitions of the health bits. [ Greg, David ]
* Updated h_scm_health() to use a const uint64_t to denote supported
bits in 'hbitmap_mask'.
* Fixed an error check for drc->dev to return H_PARAMETER in case nvdimm
is not yet plugged in [ Greg ]
* Fixed an wrong error check for ensuring drc and drc-type are correct
[ Greg ]
v2:
* Added a check for drc->dev to ensure that the dimm is plugged in
when servicing H_SCM_HEALTH. [ Shiva ]
* Instead of accessing the 'nvdimm->unarmed' member directly use the
object_property_get_bool accessor to fetch it. [ Shiva ]
* Update the usage of PAPR_PMEM_UNARMED* macros [ Greg ]
* Updated patch description reference#1 to point appropriate section
in the documentation. [ Greg ]
---
hw/ppc/spapr_nvdimm.c | 36 ++++++++++++++++++++++++++++++++++++
include/hw/ppc/spapr.h | 3 ++-
2 files changed, 38 insertions(+), 1 deletion(-)
diff --git a/hw/ppc/spapr_nvdimm.c b/hw/ppc/spapr_nvdimm.c
index b46c36917c..252204e25f 100644
--- a/hw/ppc/spapr_nvdimm.c
+++ b/hw/ppc/spapr_nvdimm.c
@@ -31,6 +31,10 @@
#include "qemu/range.h"
#include "hw/ppc/spapr_numa.h"
+/* DIMM health bitmap bitmap indicators. Taken from kernel's papr_scm.c */
+/* SCM device is unable to persist memory contents */
+#define PAPR_PMEM_UNARMED PPC_BIT(0)
+
bool spapr_nvdimm_validate(HotplugHandler *hotplug_dev, NVDIMMDevice *nvdimm,
uint64_t size, Error **errp)
{
@@ -467,6 +471,37 @@ static target_ulong h_scm_unbind_all(PowerPCCPU *cpu, SpaprMachineState *spapr,
return H_SUCCESS;
}
+static target_ulong h_scm_health(PowerPCCPU *cpu, SpaprMachineState *spapr,
+ target_ulong opcode, target_ulong *args)
+{
+
+ NVDIMMDevice *nvdimm;
+ uint64_t hbitmap = 0;
+ uint32_t drc_index = args[0];
+ SpaprDrc *drc = spapr_drc_by_index(drc_index);
+ const uint64_t hbitmap_mask = PAPR_PMEM_UNARMED;
+
+
+ /* Ensure that the drc is valid & is valid PMEM dimm and is plugged in */
+ if (!drc || !drc->dev ||
+ spapr_drc_type(drc) != SPAPR_DR_CONNECTOR_TYPE_PMEM) {
+ return H_PARAMETER;
+ }
+
+ nvdimm = NVDIMM(drc->dev);
+
+ /* Update if the nvdimm is unarmed and send its status via health bitmaps */
+ if (object_property_get_bool(OBJECT(nvdimm), NVDIMM_UNARMED_PROP, NULL)) {
+ hbitmap |= PAPR_PMEM_UNARMED;
+ }
+
+ /* Update the out args with health bitmap/mask */
+ args[0] = hbitmap;
+ args[1] = hbitmap_mask;
+
+ return H_SUCCESS;
+}
+
static void spapr_scm_register_types(void)
{
/* qemu/scm specific hcalls */
@@ -475,6 +510,7 @@ static void spapr_scm_register_types(void)
spapr_register_hypercall(H_SCM_BIND_MEM, h_scm_bind_mem);
spapr_register_hypercall(H_SCM_UNBIND_MEM, h_scm_unbind_mem);
spapr_register_hypercall(H_SCM_UNBIND_ALL, h_scm_unbind_all);
+ spapr_register_hypercall(H_SCM_HEALTH, h_scm_health);
}
type_init(spapr_scm_register_types)
diff --git a/include/hw/ppc/spapr.h b/include/hw/ppc/spapr.h
index 47cebaf3ac..6e1eafb05d 100644
--- a/include/hw/ppc/spapr.h
+++ b/include/hw/ppc/spapr.h
@@ -538,8 +538,9 @@ struct SpaprMachineState {
#define H_SCM_BIND_MEM 0x3EC
#define H_SCM_UNBIND_MEM 0x3F0
#define H_SCM_UNBIND_ALL 0x3FC
+#define H_SCM_HEALTH 0x400
-#define MAX_HCALL_OPCODE H_SCM_UNBIND_ALL
+#define MAX_HCALL_OPCODE H_SCM_HEALTH
/* The hcalls above are standardized in PAPR and implemented by pHyp
* as well.
--
2.30.2
