pseries: Add support for new KVM hash table control call

This adds support for then new "reset htab" ioctl which allows qemu
to properly cleanup the MMU hash table when the guest is reset. With
the corresponding kernel support, reset of a guest now works properly.

This also paves the way for indicating a different size hash table
to the kernel and for the kernel to be able to impose limits on
the requested size.
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: NDavid Gibson <david@gibson.dropbear.id.au>
Signed-off-by: NAlexander Graf <agraf@suse.de>

hw/spapr.c

@@ -85,6 +85,8 @@
 
 #define PHANDLE_XICP            0x00001111
 
+#define HTAB_SIZE(spapr)        (1ULL << ((spapr)->htab_shift))
+
 sPAPREnvironment *spapr;
 
 int spapr_allocate_irq(int hint, enum xics_irq_type type)
@@ -134,12 +136,13 @@ int spapr_allocate_irq_block(int num, enum xics_irq_type type)
     return first;
 }
 
-static int spapr_set_associativity(void *fdt, sPAPREnvironment *spapr)
+static int spapr_fixup_cpu_dt(void *fdt, sPAPREnvironment *spapr)
 {
     int ret = 0, offset;
     CPUPPCState *env;
     char cpu_model[32];
     int smt = kvmppc_smt_threads();
+    uint32_t pft_size_prop[] = {0, cpu_to_be32(spapr->htab_shift)};
 
     assert(spapr->cpu_model);
 
@@ -163,8 +166,16 @@ static int spapr_set_associativity(void *fdt, sPAPREnvironment *spapr)
             return offset;
         }
 
-        ret = fdt_setprop(fdt, offset, "ibm,associativity", associativity,
-                          sizeof(associativity));
+        if (nb_numa_nodes > 1) {
+            ret = fdt_setprop(fdt, offset, "ibm,associativity", associativity,
+                              sizeof(associativity));
+            if (ret < 0) {
+                return ret;
+            }
+        }
+
+        ret = fdt_setprop(fdt, offset, "ibm,pft-size",
+                          pft_size_prop, sizeof(pft_size_prop));
         if (ret < 0) {
             return ret;
         }
@@ -206,45 +217,36 @@ static size_t create_page_sizes_prop(CPUPPCState *env, uint32_t *prop,
     return (p - prop) * sizeof(uint32_t);
 }
 
+#define _FDT(exp) \
+    do { \
+        int ret = (exp);                                           \
+        if (ret < 0) {                                             \
+            fprintf(stderr, "qemu: error creating device tree: %s: %s\n", \
+                    #exp, fdt_strerror(ret));                      \
+            exit(1);                                               \
+        }                                                          \
+    } while (0)
+
+
 static void *spapr_create_fdt_skel(const char *cpu_model,
-                                   target_phys_addr_t rma_size,
                                    target_phys_addr_t initrd_base,
                                    target_phys_addr_t initrd_size,
                                    target_phys_addr_t kernel_size,
                                    const char *boot_device,
-                                   const char *kernel_cmdline,
-                                   long hash_shift)
+                                   const char *kernel_cmdline)
 {
     void *fdt;
     CPUPPCState *env;
-    uint64_t mem_reg_property[2];
     uint32_t start_prop = cpu_to_be32(initrd_base);
     uint32_t end_prop = cpu_to_be32(initrd_base + initrd_size);
-    uint32_t pft_size_prop[] = {0, cpu_to_be32(hash_shift)};
     char hypertas_prop[] = "hcall-pft\0hcall-term\0hcall-dabr\0hcall-interrupt"
         "\0hcall-tce\0hcall-vio\0hcall-splpar\0hcall-bulk";
     char qemu_hypertas_prop[] = "hcall-memop1";
+    uint32_t refpoints[] = {cpu_to_be32(0x4), cpu_to_be32(0x4)};
     uint32_t interrupt_server_ranges_prop[] = {0, cpu_to_be32(smp_cpus)};
-    int i;
     char *modelname;
-    int smt = kvmppc_smt_threads();
+    int i, smt = kvmppc_smt_threads();
     unsigned char vec5[] = {0x0, 0x0, 0x0, 0x0, 0x0, 0x80};
-    uint32_t refpoints[] = {cpu_to_be32(0x4), cpu_to_be32(0x4)};
-    uint32_t associativity[] = {cpu_to_be32(0x4), cpu_to_be32(0x0),
-                                cpu_to_be32(0x0), cpu_to_be32(0x0),
-                                cpu_to_be32(0x0)};
-    char mem_name[32];
-    target_phys_addr_t node0_size, mem_start;
-
-#define _FDT(exp) \
-    do { \
-        int ret = (exp);                                           \
-        if (ret < 0) {                                             \
-            fprintf(stderr, "qemu: error creating device tree: %s: %s\n", \
-                    #exp, fdt_strerror(ret));                      \
-            exit(1);                                               \
-        }                                                          \
-    } while (0)
 
     fdt = g_malloc0(FDT_MAX_SIZE);
     _FDT((fdt_create(fdt, FDT_MAX_SIZE)));
@@ -289,55 +291,6 @@ static void *spapr_create_fdt_skel(const char *cpu_model,
 
     _FDT((fdt_end_node(fdt)));
 
-    /* memory node(s) */
-    node0_size = (nb_numa_nodes > 1) ? node_mem[0] : ram_size;
-    if (rma_size > node0_size) {
-        rma_size = node0_size;
-    }
-
-    /* RMA */
-    mem_reg_property[0] = 0;
-    mem_reg_property[1] = cpu_to_be64(rma_size);
-    _FDT((fdt_begin_node(fdt, "memory@0")));
-    _FDT((fdt_property_string(fdt, "device_type", "memory")));
-    _FDT((fdt_property(fdt, "reg", mem_reg_property,
-        sizeof(mem_reg_property))));
-    _FDT((fdt_property(fdt, "ibm,associativity", associativity,
-        sizeof(associativity))));
-    _FDT((fdt_end_node(fdt)));
-
-    /* RAM: Node 0 */
-    if (node0_size > rma_size) {
-        mem_reg_property[0] = cpu_to_be64(rma_size);
-        mem_reg_property[1] = cpu_to_be64(node0_size - rma_size);
-
-        sprintf(mem_name, "memory@" TARGET_FMT_lx, rma_size);
-        _FDT((fdt_begin_node(fdt, mem_name)));
-        _FDT((fdt_property_string(fdt, "device_type", "memory")));
-        _FDT((fdt_property(fdt, "reg", mem_reg_property,
-                           sizeof(mem_reg_property))));
-        _FDT((fdt_property(fdt, "ibm,associativity", associativity,
-                           sizeof(associativity))));
-        _FDT((fdt_end_node(fdt)));
-    }
-
-    /* RAM: Node 1 and beyond */
-    mem_start = node0_size;
-    for (i = 1; i < nb_numa_nodes; i++) {
-        mem_reg_property[0] = cpu_to_be64(mem_start);
-        mem_reg_property[1] = cpu_to_be64(node_mem[i]);
-        associativity[3] = associativity[4] = cpu_to_be32(i);
-        sprintf(mem_name, "memory@" TARGET_FMT_lx, mem_start);
-        _FDT((fdt_begin_node(fdt, mem_name)));
-        _FDT((fdt_property_string(fdt, "device_type", "memory")));
-        _FDT((fdt_property(fdt, "reg", mem_reg_property,
-            sizeof(mem_reg_property))));
-        _FDT((fdt_property(fdt, "ibm,associativity", associativity,
-            sizeof(associativity))));
-        _FDT((fdt_end_node(fdt)));
-        mem_start += node_mem[i];
-    }
-
     /* cpus */
     _FDT((fdt_begin_node(fdt, "cpus")));
 
@@ -389,8 +342,6 @@ static void *spapr_create_fdt_skel(const char *cpu_model,
         _FDT((fdt_property_cell(fdt, "timebase-frequency", tbfreq)));
         _FDT((fdt_property_cell(fdt, "clock-frequency", cpufreq)));
         _FDT((fdt_property_cell(fdt, "ibm,slb-size", env->slb_nr)));
-        _FDT((fdt_property(fdt, "ibm,pft-size",
-                           pft_size_prop, sizeof(pft_size_prop))));
         _FDT((fdt_property_string(fdt, "status", "okay")));
         _FDT((fdt_property(fdt, "64-bit", NULL, 0)));
 
@@ -489,6 +440,68 @@ static void *spapr_create_fdt_skel(const char *cpu_model,
     return fdt;
 }
 
+static int spapr_populate_memory(sPAPREnvironment *spapr, void *fdt)
+{
+    uint32_t associativity[] = {cpu_to_be32(0x4), cpu_to_be32(0x0),
+                                cpu_to_be32(0x0), cpu_to_be32(0x0),
+                                cpu_to_be32(0x0)};
+    char mem_name[32];
+    target_phys_addr_t node0_size, mem_start;
+    uint64_t mem_reg_property[2];
+    int i, off;
+
+    /* memory node(s) */
+    node0_size = (nb_numa_nodes > 1) ? node_mem[0] : ram_size;
+    if (spapr->rma_size > node0_size) {
+        spapr->rma_size = node0_size;
+    }
+
+    /* RMA */
+    mem_reg_property[0] = 0;
+    mem_reg_property[1] = cpu_to_be64(spapr->rma_size);
+    off = fdt_add_subnode(fdt, 0, "memory@0");
+    _FDT(off);
+    _FDT((fdt_setprop_string(fdt, off, "device_type", "memory")));
+    _FDT((fdt_setprop(fdt, off, "reg", mem_reg_property,
+                      sizeof(mem_reg_property))));
+    _FDT((fdt_setprop(fdt, off, "ibm,associativity", associativity,
+                      sizeof(associativity))));
+
+    /* RAM: Node 0 */
+    if (node0_size > spapr->rma_size) {
+        mem_reg_property[0] = cpu_to_be64(spapr->rma_size);
+        mem_reg_property[1] = cpu_to_be64(node0_size - spapr->rma_size);
+
+        sprintf(mem_name, "memory@" TARGET_FMT_lx, spapr->rma_size);
+        off = fdt_add_subnode(fdt, 0, mem_name);
+        _FDT(off);
+        _FDT((fdt_setprop_string(fdt, off, "device_type", "memory")));
+        _FDT((fdt_setprop(fdt, off, "reg", mem_reg_property,
+                          sizeof(mem_reg_property))));
+        _FDT((fdt_setprop(fdt, off, "ibm,associativity", associativity,
+                          sizeof(associativity))));
+    }
+
+    /* RAM: Node 1 and beyond */
+    mem_start = node0_size;
+    for (i = 1; i < nb_numa_nodes; i++) {
+        mem_reg_property[0] = cpu_to_be64(mem_start);
+        mem_reg_property[1] = cpu_to_be64(node_mem[i]);
+        associativity[3] = associativity[4] = cpu_to_be32(i);
+        sprintf(mem_name, "memory@" TARGET_FMT_lx, mem_start);
+        off = fdt_add_subnode(fdt, 0, mem_name);
+        _FDT(off);
+        _FDT((fdt_setprop_string(fdt, off, "device_type", "memory")));
+        _FDT((fdt_setprop(fdt, off, "reg", mem_reg_property,
+                          sizeof(mem_reg_property))));
+        _FDT((fdt_setprop(fdt, off, "ibm,associativity", associativity,
+                          sizeof(associativity))));
+        mem_start += node_mem[i];
+    }
+
+    return 0;
+}
+
 static void spapr_finalize_fdt(sPAPREnvironment *spapr,
                                target_phys_addr_t fdt_addr,
                                target_phys_addr_t rtas_addr,
@@ -503,6 +516,12 @@ static void spapr_finalize_fdt(sPAPREnvironment *spapr,
     /* open out the base tree into a temp buffer for the final tweaks */
     _FDT((fdt_open_into(spapr->fdt_skel, fdt, FDT_MAX_SIZE)));
 
+    ret = spapr_populate_memory(spapr, fdt);
+    if (ret < 0) {
+        fprintf(stderr, "couldn't setup memory nodes in fdt\n");
+        exit(1);
+    }
+
     ret = spapr_populate_vdevice(spapr->vio_bus, fdt);
     if (ret < 0) {
         fprintf(stderr, "couldn't setup vio devices in fdt\n");
@@ -525,11 +544,9 @@ static void spapr_finalize_fdt(sPAPREnvironment *spapr,
     }
 
     /* Advertise NUMA via ibm,associativity */
-    if (nb_numa_nodes > 1) {
-        ret = spapr_set_associativity(fdt, spapr);
-        if (ret < 0) {
-            fprintf(stderr, "Couldn't set up NUMA device tree properties\n");
-        }
+    ret = spapr_fixup_cpu_dt(fdt, spapr);
+    if (ret < 0) {
+        fprintf(stderr, "Couldn't finalize CPU device tree properties\n");
     }
 
     if (!spapr->has_graphics) {
@@ -559,10 +576,39 @@ static void emulate_spapr_hypercall(CPUPPCState *env)
     env->gpr[3] = spapr_hypercall(env, env->gpr[3], &env->gpr[4]);
 }
 
+static void spapr_reset_htab(sPAPREnvironment *spapr)
+{
+    long shift;
+
+    /* allocate hash page table.  For now we always make this 16mb,
+     * later we should probably make it scale to the size of guest
+     * RAM */
+
+    shift = kvmppc_reset_htab(spapr->htab_shift);
+
+    if (shift > 0) {
+        /* Kernel handles htab, we don't need to allocate one */
+        spapr->htab_shift = shift;
+    } else {
+        if (!spapr->htab) {
+            /* Allocate an htab if we don't yet have one */
+            spapr->htab = qemu_memalign(HTAB_SIZE(spapr), HTAB_SIZE(spapr));
+        }
+
+        /* And clear it */
+        memset(spapr->htab, 0, HTAB_SIZE(spapr));
+    }
+
+    /* Update the RMA size if necessary */
+    if (spapr->vrma_adjust) {
+        spapr->rma_size = kvmppc_rma_size(ram_size, spapr->htab_shift);
+    }
+}
+
 static void ppc_spapr_reset(void)
 {
-    /* flush out the hash table */
-    memset(spapr->htab, 0, spapr->htab_size);
+    /* Reset the hash table & recalc the RMA */
+    spapr_reset_htab(spapr);
 
     qemu_devices_reset();
 
@@ -591,6 +637,12 @@ static void spapr_cpu_reset(void *opaque)
     env->halted = 1;
 
     env->spr[SPR_HIOR] = 0;
+
+    env->external_htab = spapr->htab;
+    env->htab_base = -1;
+    env->htab_mask = HTAB_SIZE(spapr) - 1;
+    env->spr[SPR_SDR1] = (unsigned long)spapr->htab |
+        (spapr->htab_shift - 18);
 }
 
 /* Returns whether we want to use VGA or not */
@@ -624,11 +676,10 @@ static void ppc_spapr_init(ram_addr_t ram_size,
     int i;
     MemoryRegion *sysmem = get_system_memory();
     MemoryRegion *ram = g_new(MemoryRegion, 1);
-    target_phys_addr_t rma_alloc_size, rma_size;
+    target_phys_addr_t rma_alloc_size;
     uint32_t initrd_base = 0;
     long kernel_size = 0, initrd_size = 0;
     long load_limit, rtas_limit, fw_size;
-    long pteg_shift = 17;
     char *filename;
 
     msi_supported = true;
@@ -645,20 +696,39 @@ static void ppc_spapr_init(ram_addr_t ram_size,
         hw_error("qemu: Unable to create RMA\n");
         exit(1);
     }
+
     if (rma_alloc_size && (rma_alloc_size < ram_size)) {
-        rma_size = rma_alloc_size;
+        spapr->rma_size = rma_alloc_size;
     } else {
-        rma_size = ram_size;
+        spapr->rma_size = ram_size;
+
+        /* With KVM, we don't actually know whether KVM supports an
+         * unbounded RMA (PR KVM) or is limited by the hash table size
+         * (HV KVM using VRMA), so we always assume the latter
+         *
+         * In that case, we also limit the initial allocations for RTAS
+         * etc... to 256M since we have no way to know what the VRMA size
+         * is going to be as it depends on the size of the hash table
+         * isn't determined yet.
+         */
+        if (kvm_enabled()) {
+            spapr->vrma_adjust = 1;
+            spapr->rma_size = MIN(spapr->rma_size, 0x10000000);
+        }
     }
 
     /* We place the device tree and RTAS just below either the top of the RMA,
      * or just below 2GB, whichever is lowere, so that it can be
      * processed with 32-bit real mode code if necessary */
-    rtas_limit = MIN(rma_size, 0x80000000);
+    rtas_limit = MIN(spapr->rma_size, 0x80000000);
     spapr->rtas_addr = rtas_limit - RTAS_MAX_SIZE;
     spapr->fdt_addr = spapr->rtas_addr - FDT_MAX_SIZE;
     load_limit = spapr->fdt_addr - FW_OVERHEAD;
 
+    /* For now, always aim for a 16MB hash table */
+    /* FIXME: we should change this default based on RAM size */
+    spapr->htab_shift = 24;
+
     /* init CPUs */
     if (cpu_model == NULL) {
         cpu_model = kvm_enabled() ? "host" : "POWER7";
@@ -696,25 +766,6 @@ static void ppc_spapr_init(ram_addr_t ram_size,
         memory_region_add_subregion(sysmem, nonrma_base, ram);
     }
 
-    /* allocate hash page table.  For now we always make this 16mb,
-     * later we should probably make it scale to the size of guest
-     * RAM.  FIXME: setting the htab information in the CPU env really
-     * belongs at CPU reset time, but we can get away with it for now
-     * because the PAPR guest is not permitted to write SDR1 so in
-     * fact these settings will never change during the run */
-    spapr->htab_size = 1ULL << (pteg_shift + 7);
-    spapr->htab = qemu_memalign(spapr->htab_size, spapr->htab_size);
-
-    for (env = first_cpu; env != NULL; env = env->next_cpu) {
-        env->external_htab = spapr->htab;
-        env->htab_base = -1;
-        env->htab_mask = spapr->htab_size - 1;
-
-        /* Tell KVM that we're in PAPR mode */
-        env->spr[SPR_SDR1] = (unsigned long)spapr->htab |
-                             ((pteg_shift + 7) - 18);
-    }
-
     filename = qemu_find_file(QEMU_FILE_TYPE_BIOS, "spapr-rtas.bin");
     spapr->rtas_size = load_image_targphys(filename, spapr->rtas_addr,
                                            rtas_limit - spapr->rtas_addr);
@@ -787,7 +838,7 @@ static void ppc_spapr_init(ram_addr_t ram_size,
         }
     }
 
-    if (rma_size < (MIN_RMA_SLOF << 20)) {
+    if (spapr->rma_size < (MIN_RMA_SLOF << 20)) {
         fprintf(stderr, "qemu: pSeries SLOF firmware requires >= "
                 "%ldM guest RMA (Real Mode Area memory)\n", MIN_RMA_SLOF);
         exit(1);
@@ -839,11 +890,10 @@ static void ppc_spapr_init(ram_addr_t ram_size,
     spapr->entry_point = 0x100;
 
     /* Prepare the device tree */
-    spapr->fdt_skel = spapr_create_fdt_skel(cpu_model, rma_size,
+    spapr->fdt_skel = spapr_create_fdt_skel(cpu_model,
                                             initrd_base, initrd_size,
                                             kernel_size,
-                                            boot_device, kernel_cmdline,
-                                            pteg_shift + 7);
+                                            boot_device, kernel_cmdline);
     assert(spapr->fdt_skel != NULL);
 }
 

hw/spapr.h

@@ -15,7 +15,9 @@ typedef struct sPAPREnvironment {
 
     target_phys_addr_t ram_limit;
     void *htab;
-    long htab_size;
+    long htab_shift;
+    target_phys_addr_t rma_size;
+    int vrma_adjust;
     target_phys_addr_t fdt_addr, rtas_addr;
     long rtas_size;
     void *fdt_skel;

target-ppc/kvm.c

@@ -1010,6 +1010,7 @@ int kvmppc_smt_threads(void)
     return cap_ppc_smt ? cap_ppc_smt : 1;
 }
 
+#ifdef TARGET_PPC64
 off_t kvmppc_alloc_rma(const char *name, MemoryRegion *sysmem)
 {
     void *rma;
@@ -1053,6 +1054,16 @@ off_t kvmppc_alloc_rma(const char *name, MemoryRegion *sysmem)
     return size;
 }
 
+uint64_t kvmppc_rma_size(uint64_t current_size, unsigned int hash_shift)
+{
+    if (cap_ppc_rma >= 2) {
+        return current_size;
+    }
+    return MIN(current_size,
+               getrampagesize() << (hash_shift - 7));
+}
+#endif
+
 void *kvmppc_create_spapr_tce(uint32_t liobn, uint32_t window_size, int *pfd)
 {
     struct kvm_create_spapr_tce args = {
@@ -1112,6 +1123,24 @@ int kvmppc_remove_spapr_tce(void *table, int fd, uint32_t window_size)
     return 0;
 }
 
+int kvmppc_reset_htab(int shift_hint)
+{
+    uint32_t shift = shift_hint;
+
+    if (kvm_enabled() &&
+        kvm_check_extension(kvm_state, KVM_CAP_PPC_ALLOC_HTAB)) {
+        int ret;
+        ret = kvm_vm_ioctl(kvm_state, KVM_PPC_ALLOCATE_HTAB, &shift);
+        if (ret < 0) {
+            return ret;
+        }
+        return shift;
+    }
+
+    /* For now.. */
+    return 0;
+}
+
 static inline uint32_t mfpvr(void)
 {
     uint32_t pvr;

target-ppc/kvm_ppc.h

@@ -27,6 +27,8 @@ int kvmppc_smt_threads(void);
 off_t kvmppc_alloc_rma(const char *name, MemoryRegion *sysmem);
 void *kvmppc_create_spapr_tce(uint32_t liobn, uint32_t window_size, int *pfd);
 int kvmppc_remove_spapr_tce(void *table, int pfd, uint32_t window_size);
+int kvmppc_reset_htab(int shift_hint);
+uint64_t kvmppc_rma_size(uint64_t current_size, unsigned int hash_shift);
 #endif /* !CONFIG_USER_ONLY */
 const ppc_def_t *kvmppc_host_cpu_def(void);
 int kvmppc_fixup_cpu(CPUPPCState *env);
@@ -94,6 +96,23 @@ static inline int kvmppc_remove_spapr_tce(void *table, int pfd,
 {
     return -1;
 }
+
+static inline int kvmppc_reset_htab(int shift_hint)
+{
+    return -1;
+}
+
+static inline uint64_t kvmppc_rma_size(uint64_t current_size,
+                                       unsigned int hash_shift)
+{
+    return ram_size;
+}
+
+static inline int kvmppc_update_sdr1(CPUPPCState *env)
+{
+    return 0;
+}
+
 #endif /* !CONFIG_USER_ONLY */
 
 static inline const ppc_def_t *kvmppc_host_cpu_def(void)