The patch adds the 'sync-dax' property to the nvdimm device.
When the sync-dax is 'off', the device tree property
"hcall-flush-required" is added to the nvdimm node which makes the
guest to issue H_SCM_FLUSH hcalls to request for flushes explicitly.
This would be the default behaviour without sync-dax property set
for the nvdimm device.
The sync-dax="on" would mean the guest need not make flush requests
to the qemu. On previous machine versions the sync-dax is set to be
"on" by default using the hw_compat magic.
Signed-off-by: Shivaprasad G Bhat <sbhat@xxxxxxxxxxxxx>
---
hw/core/machine.c | 1 +
hw/mem/nvdimm.c | 1 +
hw/ppc/spapr_nvdimm.c | 17 +++++++++++++++++
include/hw/mem/nvdimm.h | 10 ++++++++++
include/hw/ppc/spapr.h | 1 +
5 files changed, 30 insertions(+)
diff --git a/hw/core/machine.c b/hw/core/machine.c
index 257a664ea2..f843643574 100644
--- a/hw/core/machine.c
+++ b/hw/core/machine.c
@@ -41,6 +41,7 @@ GlobalProperty hw_compat_5_2[] = {
{ "PIIX4_PM", "smm-compat", "on"},
{ "virtio-blk-device", "report-discard-granularity", "off" },
{ "virtio-net-pci", "vectors", "3"},
+ { "nvdimm", "sync-dax", "on" },
};
const size_t hw_compat_5_2_len = G_N_ELEMENTS(hw_compat_5_2);
diff --git a/hw/mem/nvdimm.c b/hw/mem/nvdimm.c
index 7397b67156..8f0e29b191 100644
--- a/hw/mem/nvdimm.c
+++ b/hw/mem/nvdimm.c
@@ -229,6 +229,7 @@ static void nvdimm_write_label_data(NVDIMMDevice *nvdimm, const void *buf,
static Property nvdimm_properties[] = {
DEFINE_PROP_BOOL(NVDIMM_UNARMED_PROP, NVDIMMDevice, unarmed, false),
+ DEFINE_PROP_BOOL(NVDIMM_SYNC_DAX_PROP, NVDIMMDevice, sync_dax, false),
DEFINE_PROP_END_OF_LIST(),
};
diff --git a/hw/ppc/spapr_nvdimm.c b/hw/ppc/spapr_nvdimm.c
index 883317c1ed..dd1c90251b 100644
--- a/hw/ppc/spapr_nvdimm.c
+++ b/hw/ppc/spapr_nvdimm.c
@@ -125,6 +125,9 @@ static int spapr_dt_nvdimm(SpaprMachineState *spapr, void *fdt,
uint64_t lsize = nvdimm->label_size;
uint64_t size = object_property_get_int(OBJECT(nvdimm), PC_DIMM_SIZE_PROP,
NULL);
+ bool sync_dax = object_property_get_bool(OBJECT(nvdimm),
+ NVDIMM_SYNC_DAX_PROP,
+ &error_abort);
drc = spapr_drc_by_id(TYPE_SPAPR_DRC_PMEM, slot);
g_assert(drc);
@@ -159,6 +162,11 @@ static int spapr_dt_nvdimm(SpaprMachineState *spapr, void *fdt,
"operating-system")));
_FDT(fdt_setprop(fdt, child_offset, "ibm,cache-flush-required", NULL, 0));
+ if (!sync_dax) {
+ _FDT(fdt_setprop(fdt, child_offset, "ibm,hcall-flush-required",
+ NULL, 0));
+ }
+
return child_offset;
}
@@ -567,10 +575,12 @@ static target_ulong h_scm_flush(PowerPCCPU *cpu, SpaprMachineState *spapr,
target_ulong opcode, target_ulong *args)
{
int ret;
+ bool sync_dax;
uint32_t drc_index = args[0];
uint64_t continue_token = args[1];
SpaprDrc *drc = spapr_drc_by_index(drc_index);
PCDIMMDevice *dimm;
+ NVDIMMDevice *nvdimm;
HostMemoryBackend *backend = NULL;
SpaprNVDIMMDeviceFlushState *state;
ThreadPool *pool = aio_get_thread_pool(qemu_get_aio_context());
@@ -580,6 +590,13 @@ static target_ulong h_scm_flush(PowerPCCPU *cpu, SpaprMachineState *spapr,
return H_PARAMETER;
}
+ nvdimm = NVDIMM(drc->dev);
+ sync_dax = object_property_get_bool(OBJECT(nvdimm), NVDIMM_SYNC_DAX_PROP,
+ &error_abort);
+ if (sync_dax) {
+ return H_UNSUPPORTED;
+ }
+
if (continue_token != 0) {
ret = spapr_nvdimm_get_flush_status(continue_token);
if (H_IS_LONG_BUSY(ret)) {
diff --git a/include/hw/mem/nvdimm.h b/include/hw/mem/nvdimm.h
index bcf62f825c..f82979cf2f 100644
--- a/include/hw/mem/nvdimm.h
+++ b/include/hw/mem/nvdimm.h
@@ -51,6 +51,7 @@ OBJECT_DECLARE_TYPE(NVDIMMDevice, NVDIMMClass, NVDIMM)
#define NVDIMM_LABEL_SIZE_PROP "label-size"
#define NVDIMM_UUID_PROP "uuid"
#define NVDIMM_UNARMED_PROP "unarmed"
+#define NVDIMM_SYNC_DAX_PROP "sync-dax"
struct NVDIMMDevice {
/* private */
@@ -85,6 +86,15 @@ struct NVDIMMDevice {
*/
bool unarmed;
+ /*
+ * On PPC64,
+ * The 'off' value results in the hcall-flush-required property set
+ * in the device tree for pseries machines. When 'off', the guest
+ * initiates explicit flush requests to the backend device ensuring
+ * write persistence.
+ */
+ bool sync_dax;
+
/*
* The PPC64 - spapr requires each nvdimm device have a uuid.
*/
diff --git a/include/hw/ppc/spapr.h b/include/hw/ppc/spapr.h
index 7c27fb3e2d..51c35488a4 100644
--- a/include/hw/ppc/spapr.h
+++ b/include/hw/ppc/spapr.h
@@ -333,6 +333,7 @@ struct SpaprMachineState {
#define H_P7 -60
#define H_P8 -61
#define H_P9 -62
+#define H_UNSUPPORTED -67
#define H_OVERLAP -68
#define H_UNSUPPORTED_FLAG -256
#define H_MULTI_THREADS_ACTIVE -9005
