[Qemu-ppc] [RFCv2 3/6] pseries: Stubs for HPT resizing

[David Gibson]

This introduces stub implementations of the H_RESIZE_HPT_PREPARE and
H_RESIZE_HPT_COMMIT hypercalls which we hope to add in a PAPR
extension to allow run time resizing of a guest's hash page table.  It
also adds a new machine property for controlling whether this new
facility is available.

Finally, it adds a new string to the hypertas property in the device
tree, advertising to the guest the availability of the HPT resizing
hypercalls.  This is a tentative suggested value, and would need to be
standardized by PAPR before being merged.

Signed-off-by: David Gibson <address@hidden>
---
 hw/ppc/spapr.c         | 40 ++++++++++++++++++++++++++++++++++++++++
 hw/ppc/spapr_hcall.c   | 37 +++++++++++++++++++++++++++++++++++++
 include/hw/ppc/spapr.h | 11 ++++++++++-
 trace-events           |  2 ++
 4 files changed, 89 insertions(+), 1 deletion(-)

diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
index bb701e3..b7bd1c1 100644
--- a/hw/ppc/spapr.c
+++ b/hw/ppc/spapr.c
@@ -317,6 +317,7 @@ static void *spapr_create_fdt_skel(hwaddr initrd_base,
                                    const char *kernel_cmdline,
                                    uint32_t epow_irq)
 {
+    sPAPRMachineState *spapr = SPAPR_MACHINE(qdev_get_machine());
     void *fdt;
     uint32_t start_prop = cpu_to_be32(initrd_base);
     uint32_t end_prop = cpu_to_be32(initrd_base + initrd_size);
@@ -336,6 +337,9 @@ static void *spapr_create_fdt_skel(hwaddr initrd_base,
     add_str(hypertas, "hcall-splpar");
     add_str(hypertas, "hcall-bulk");
     add_str(hypertas, "hcall-set-mode");
+    if (spapr->resize_hpt != SPAPR_RESIZE_HPT_DISABLED) {
+        add_str(hypertas, "hcall-hpt-resize");
+    }
     add_str(qemu_hypertas, "hcall-memop1");
 
     fdt = g_malloc0(FDT_MAX_SIZE);
@@ -2100,6 +2104,36 @@ static void spapr_set_kvm_type(Object *obj, const char 
*value, Error **errp)
     spapr->kvm_type = g_strdup(value);
 }
 
+static char *spapr_get_resize_hpt(Object *obj, Error **errp)
+{
+    sPAPRMachineState *spapr = SPAPR_MACHINE(obj);
+
+    switch (spapr->resize_hpt) {
+    case SPAPR_RESIZE_HPT_DISABLED:
+        return g_strdup("disabled");
+    case SPAPR_RESIZE_HPT_ENABLED:
+        return g_strdup("enabled");
+    case SPAPR_RESIZE_HPT_REQUIRED:
+        return g_strdup("required");
+    }
+    assert(0);
+}
+
+static void spapr_set_resize_hpt(Object *obj, const char *value, Error **errp)
+{
+    sPAPRMachineState *spapr = SPAPR_MACHINE(obj);
+
+    if (strcmp(value, "disabled") == 0) {
+        spapr->resize_hpt = SPAPR_RESIZE_HPT_DISABLED;
+    } else if (strcmp(value, "enabled") == 0) {
+        spapr->resize_hpt = SPAPR_RESIZE_HPT_ENABLED;
+    } else if (strcmp(value, "required") == 0) {
+        spapr->resize_hpt = SPAPR_RESIZE_HPT_REQUIRED;
+    } else {
+        error_setg(errp, "Bad value for \"resize-hpt\" property");
+    }
+}
+
 static void spapr_machine_initfn(Object *obj)
 {
     sPAPRMachineState *spapr = SPAPR_MACHINE(obj);
@@ -2110,6 +2144,12 @@ static void spapr_machine_initfn(Object *obj)
     object_property_set_description(obj, "kvm-type",
                                     "Specifies the KVM virtualization mode 
(HV, PR)",
                                     NULL);
+
+    object_property_add_str(obj, "resize-hpt",
+                            spapr_get_resize_hpt, spapr_set_resize_hpt, NULL);
+    object_property_set_description(obj, "resize-hpt",
+                                    "Resizing of the Hash Page Table (enabled, 
disabled, required)",
+                                    NULL);
 }
 
 static void spapr_machine_finalizefn(Object *obj)
diff --git a/hw/ppc/spapr_hcall.c b/hw/ppc/spapr_hcall.c
index a535c73..f285d34 100644
--- a/hw/ppc/spapr_hcall.c
+++ b/hw/ppc/spapr_hcall.c
@@ -331,6 +331,38 @@ static target_ulong h_read(PowerPCCPU *cpu, 
sPAPRMachineState *spapr,
     return H_SUCCESS;
 }
 
+static target_ulong h_resize_hpt_prepare(PowerPCCPU *cpu,
+                                         sPAPRMachineState *spapr,
+                                         target_ulong opcode,
+                                         target_ulong *args)
+{
+    target_ulong flags = args[0];
+    target_ulong shift = args[1];
+
+    if (spapr->resize_hpt == SPAPR_RESIZE_HPT_DISABLED) {
+        return H_AUTHORITY;
+    }
+
+    trace_spapr_h_resize_hpt_prepare(flags, shift);
+    return H_HARDWARE;
+}
+
+static target_ulong h_resize_hpt_commit(PowerPCCPU *cpu,
+                                        sPAPRMachineState *spapr,
+                                        target_ulong opcode,
+                                        target_ulong *args)
+{
+    target_ulong flags = args[0];
+    target_ulong shift = args[1];
+
+    if (spapr->resize_hpt == SPAPR_RESIZE_HPT_DISABLED) {
+        return H_AUTHORITY;
+    }
+
+    trace_spapr_h_resize_hpt_commit(flags, shift);
+    return H_HARDWARE;
+}
+
 static target_ulong h_set_dabr(PowerPCCPU *cpu, sPAPRMachineState *spapr,
                                target_ulong opcode, target_ulong *args)
 {
@@ -989,6 +1021,11 @@ static void hypercall_register_types(void)
     /* hcall-bulk */
     spapr_register_hypercall(H_BULK_REMOVE, h_bulk_remove);
 
+    /* hcall-hpt-resize */
+    spapr_register_hypercall(KVMPPC_H_RESIZE_HPT_PREPARE,
+                             h_resize_hpt_prepare);
+    spapr_register_hypercall(KVMPPC_H_RESIZE_HPT_COMMIT, h_resize_hpt_commit);
+
     /* hcall-dabr */
     spapr_register_hypercall(H_SET_DABR, h_set_dabr);
 
diff --git a/include/hw/ppc/spapr.h b/include/hw/ppc/spapr.h
index 4e3dce5..6136d45 100644
--- a/include/hw/ppc/spapr.h
+++ b/include/hw/ppc/spapr.h
@@ -42,6 +42,12 @@ struct sPAPRMachineClass {
 /**
  * sPAPRMachineState:
  */
+typedef enum {
+    SPAPR_RESIZE_HPT_DISABLED = 0,
+    SPAPR_RESIZE_HPT_ENABLED,
+    SPAPR_RESIZE_HPT_REQUIRED,
+} sPAPRResizeHPT;
+
 struct sPAPRMachineState {
     /*< private >*/
     MachineState parent_obj;
@@ -52,6 +58,7 @@ struct sPAPRMachineState {
     XICSState *icp;
     DeviceState *rtc;
 
+    sPAPRResizeHPT resize_hpt;
     void *htab;
     uint32_t htab_shift;
     hwaddr rma_size;
@@ -351,7 +358,9 @@ struct sPAPRMachineState {
 #define KVMPPC_H_LOGICAL_MEMOP  (KVMPPC_HCALL_BASE + 0x1)
 /* Client Architecture support */
 #define KVMPPC_H_CAS            (KVMPPC_HCALL_BASE + 0x2)
-#define KVMPPC_HCALL_MAX        KVMPPC_H_CAS
+#define KVMPPC_H_RESIZE_HPT_PREPARE (KVMPPC_HCALL_BASE + 0x3)
+#define KVMPPC_H_RESIZE_HPT_COMMIT  (KVMPPC_HCALL_BASE + 0x4)
+#define KVMPPC_HCALL_MAX        KVMPPC_H_RESIZE_HPT_COMMIT
 
 typedef struct sPAPRDeviceTreeUpdateHeader {
     uint32_t version_id;
diff --git a/trace-events b/trace-events
index c9ac144..45b4971 100644
--- a/trace-events
+++ b/trace-events
@@ -1403,6 +1403,8 @@ spapr_cas_continue(unsigned long n) "Copy changes to the 
guest: %ld bytes"
 # hw/ppc/spapr_hcall.c
 spapr_cas_pvr_try(uint32_t pvr) "%x"
 spapr_cas_pvr(uint32_t cur_pvr, bool cpu_match, uint32_t new_pvr, uint64_t 
pcr) "current=%x, cpu_match=%u, new=%x, compat flags=%"PRIx64
+spapr_h_resize_hpt_prepare(uint64_t flags, uint64_t shift) "flags=0x%"PRIx64", 
shift=%"PRIu64
+spapr_h_resize_hpt_commit(uint64_t flags, uint64_t shift) "flags=0x%"PRIx64", 
shift=%"PRIu64
 
 # hw/ppc/spapr_iommu.c
 spapr_iommu_put(uint64_t liobn, uint64_t ioba, uint64_t tce, uint64_t ret) 
"liobn=%"PRIx64" ioba=0x%"PRIx64" tce=0x%"PRIx64" ret=%"PRId64
-- 
2.5.0