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[Qemu-ppc] [PATCH for-2.10 1/5] pseries: Stubs for HPT resizing


From: David Gibson
Subject: [Qemu-ppc] [PATCH for-2.10 1/5] pseries: Stubs for HPT resizing
Date: Fri, 10 Mar 2017 12:13:24 +1100

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.

For now we only allow resizing with TCG, allowing it with KVM will require
kernel changes as well.

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>
Reviewed-by: Suraj Jitindar Singh <address@hidden>
---
 hw/ppc/spapr.c         | 75 ++++++++++++++++++++++++++++++++++++++++++++++++++
 hw/ppc/spapr_hcall.c   | 36 ++++++++++++++++++++++++
 hw/ppc/trace-events    |  2 ++
 include/hw/ppc/spapr.h | 11 ++++++++
 target/ppc/kvm.c       | 12 ++++++++
 target/ppc/kvm_ppc.h   |  5 ++++
 6 files changed, 141 insertions(+)

diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
index 7525c60..06b436d 100644
--- a/hw/ppc/spapr.c
+++ b/hw/ppc/spapr.c
@@ -808,6 +808,11 @@ static void spapr_dt_rtas(sPAPRMachineState *spapr, void 
*fdt)
     if (!kvm_enabled() || kvmppc_spapr_use_multitce()) {
         add_str(hypertas, "hcall-multi-tce");
     }
+
+    if (spapr->resize_hpt != SPAPR_RESIZE_HPT_DISABLED) {
+        add_str(hypertas, "hcall-hpt-resize");
+    }
+
     _FDT(fdt_setprop(fdt, rtas, "ibm,hypertas-functions",
                      hypertas->str, hypertas->len));
     g_string_free(hypertas, TRUE);
@@ -1991,11 +1996,40 @@ static void ppc_spapr_init(MachineState *machine)
     long load_limit, fw_size;
     char *filename;
     int smt = kvmppc_smt_threads();
+    Error *resize_hpt_err = NULL;
 
     msi_nonbroken = true;
 
     QLIST_INIT(&spapr->phbs);
 
+    /* Check HPT resizing availability */
+    kvmppc_check_papr_resize_hpt(&resize_hpt_err);
+    if (spapr->resize_hpt == SPAPR_RESIZE_HPT_DEFAULT) {
+        /*
+         * If the user explicitly requested a mode we should either
+         * supply it, or fail completely (which we do below).  But if
+         * it's not set explicitly, we reset our mode to something
+         * that works
+         */
+        if (resize_hpt_err) {
+            spapr->resize_hpt = SPAPR_RESIZE_HPT_DISABLED;
+            error_free(resize_hpt_err);
+            resize_hpt_err = NULL;
+        } else {
+            spapr->resize_hpt = smc->resize_hpt_default;
+        }
+    }
+
+    assert(spapr->resize_hpt != SPAPR_RESIZE_HPT_DEFAULT);
+
+    if ((spapr->resize_hpt != SPAPR_RESIZE_HPT_DISABLED) && resize_hpt_err) {
+        /*
+         * User requested HPT resize, but this host can't supply it.  Bail out
+         */
+        error_report_err(resize_hpt_err);
+        exit(1);
+    }
+
     /* Allocate RMA if necessary */
     rma_alloc_size = kvmppc_alloc_rma(&rma);
 
@@ -2406,6 +2440,40 @@ static void spapr_set_modern_hotplug_events(Object *obj, 
bool value,
     spapr->use_hotplug_event_source = value;
 }
 
+static char *spapr_get_resize_hpt(Object *obj, Error **errp)
+{
+    sPAPRMachineState *spapr = SPAPR_MACHINE(obj);
+
+    switch (spapr->resize_hpt) {
+    case SPAPR_RESIZE_HPT_DEFAULT:
+        return g_strdup("default");
+    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, "default") == 0) {
+        spapr->resize_hpt = SPAPR_RESIZE_HPT_DEFAULT;
+    } else 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);
@@ -2426,6 +2494,12 @@ static void spapr_machine_initfn(Object *obj)
                                     " place of standard EPOW events when 
possible"
                                     " (required for memory hot-unplug 
support)",
                                     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)
@@ -3083,6 +3157,7 @@ static void spapr_machine_class_init(ObjectClass *oc, 
void *data)
     smc->dr_lmb_enabled = true;
     smc->tcg_default_cpu = "POWER8";
     mc->has_hotpluggable_cpus = true;
+    smc->resize_hpt_default = SPAPR_RESIZE_HPT_DISABLED;
     fwc->get_dev_path = spapr_get_fw_dev_path;
     nc->nmi_monitor_handler = spapr_nmi;
     smc->phb_placement = spapr_phb_placement;
diff --git a/hw/ppc/spapr_hcall.c b/hw/ppc/spapr_hcall.c
index f05a90e..9f88960 100644
--- a/hw/ppc/spapr_hcall.c
+++ b/hw/ppc/spapr_hcall.c
@@ -352,6 +352,38 @@ 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_sprg0(PowerPCCPU *cpu, sPAPRMachineState *spapr,
                                 target_ulong opcode, target_ulong *args)
 {
@@ -1072,6 +1104,10 @@ static void hypercall_register_types(void)
     /* hcall-bulk */
     spapr_register_hypercall(H_BULK_REMOVE, h_bulk_remove);
 
+    /* hcall-hpt-resize */
+    spapr_register_hypercall(H_RESIZE_HPT_PREPARE, h_resize_hpt_prepare);
+    spapr_register_hypercall(H_RESIZE_HPT_COMMIT, h_resize_hpt_commit);
+
     /* hcall-splpar */
     spapr_register_hypercall(H_REGISTER_VPA, h_register_vpa);
     spapr_register_hypercall(H_CEDE, h_cede);
diff --git a/hw/ppc/trace-events b/hw/ppc/trace-events
index 43d265f..7c77cc6 100644
--- a/hw/ppc/trace-events
+++ b/hw/ppc/trace-events
@@ -16,6 +16,8 @@ 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 explicit_match, uint32_t new_pvr) 
"current=%x, explicit_match=%u, new=%x"
+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
diff --git a/include/hw/ppc/spapr.h b/include/hw/ppc/spapr.h
index ba9e689..4d2c89c 100644
--- a/include/hw/ppc/spapr.h
+++ b/include/hw/ppc/spapr.h
@@ -42,6 +42,13 @@ typedef struct sPAPRMachineClass sPAPRMachineClass;
 #define SPAPR_MACHINE_CLASS(klass) \
     OBJECT_CLASS_CHECK(sPAPRMachineClass, klass, TYPE_SPAPR_MACHINE)
 
+typedef enum {
+    SPAPR_RESIZE_HPT_DEFAULT = 0,
+    SPAPR_RESIZE_HPT_DISABLED,
+    SPAPR_RESIZE_HPT_ENABLED,
+    SPAPR_RESIZE_HPT_REQUIRED,
+} sPAPRResizeHPT;
+
 /**
  * sPAPRMachineClass:
  */
@@ -57,6 +64,7 @@ struct sPAPRMachineClass {
                           uint64_t *buid, hwaddr *pio, 
                           hwaddr *mmio32, hwaddr *mmio64,
                           unsigned n_dma, uint32_t *liobns, Error **errp);
+    sPAPRResizeHPT resize_hpt_default;
 };
 
 /**
@@ -72,6 +80,7 @@ struct sPAPRMachineState {
     ICSState *ics;
     sPAPRRTCState rtc;
 
+    sPAPRResizeHPT resize_hpt;
     void *htab;
     uint32_t htab_shift;
     uint64_t patb_entry; /* Process tbl registed in H_REGISTER_PROCESS_TABLE */
@@ -361,6 +370,8 @@ struct sPAPRMachineState {
 #define H_XIRR_X                0x2FC
 #define H_RANDOM                0x300
 #define H_SET_MODE              0x31C
+#define H_RESIZE_HPT_PREPARE    0x36C
+#define H_RESIZE_HPT_COMMIT     0x370
 #define H_SIGNAL_SYS_RESET      0x380
 #define MAX_HCALL_OPCODE        H_SIGNAL_SYS_RESET
 
diff --git a/target/ppc/kvm.c b/target/ppc/kvm.c
index 9f1f132..97591d2 100644
--- a/target/ppc/kvm.c
+++ b/target/ppc/kvm.c
@@ -22,6 +22,7 @@
 #include <linux/kvm.h>
 
 #include "qemu-common.h"
+#include "qapi/error.h"
 #include "qemu/error-report.h"
 #include "cpu.h"
 #include "cpu-models.h"
@@ -2598,3 +2599,14 @@ int kvmppc_enable_hwrng(void)
 
     return kvmppc_enable_hcall(kvm_state, H_RANDOM);
 }
+
+void kvmppc_check_papr_resize_hpt(Error **errp)
+{
+    if (!kvm_enabled()) {
+        return;
+    }
+
+    /* TODO: Check for resize-capable KVM implementations */
+
+    error_setg(errp, "Hash page table resizing not available with this KVM 
version");
+}
diff --git a/target/ppc/kvm_ppc.h b/target/ppc/kvm_ppc.h
index 8e9f42d..cd3b234 100644
--- a/target/ppc/kvm_ppc.h
+++ b/target/ppc/kvm_ppc.h
@@ -56,6 +56,7 @@ bool kvmppc_has_cap_htm(void);
 int kvmppc_enable_hwrng(void);
 int kvmppc_put_books_sregs(PowerPCCPU *cpu);
 PowerPCCPUClass *kvm_ppc_get_host_cpu_class(void);
+void kvmppc_check_papr_resize_hpt(Error **errp);
 
 bool kvmppc_is_mem_backend_page_size_ok(char *obj_path);
 
@@ -267,6 +268,10 @@ static inline PowerPCCPUClass 
*kvm_ppc_get_host_cpu_class(void)
     return NULL;
 }
 
+static inline void kvmppc_check_papr_resize_hpt(Error **errp)
+{
+    return;
+}
 #endif
 
 #ifndef CONFIG_KVM
-- 
2.9.3




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