pseries: Allow KVM Book3S-HV on PPC970 CPUS

At present, using the hypervisor aware Book3S-HV KVM will only work
with qemu on POWER7 CPUs.  PPC970 CPUs also have hypervisor
capability, but they lack the VRMA feature which makes assigning guest
memory easier.

In order to allow KVM Book3S-HV on PPC970, we need to specially
allocate the first chunk of guest memory (the "Real Mode Area" or
RMA), so that it is physically contiguous.

Sufficiently recent host kernels allow such contiguous RMAs to be
allocated, with a kvm capability advertising whether the feature is
available and/or necessary on this hardware.  This patch enables qemu
to use this support, thus allowing kvm acceleration of pseries qemu
machines on PPC970 hardware.

Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Alexander Graf <agraf@suse.de>

---

agraf: fix to use memory api

1 files changed, 44 insertions, 12 deletions

diff --git a/hw/spapr.c b/hw/spapr.c
index c2675e1cc1..193398b7a1 100644
--- a/hw/spapr.c
+++ b/hw/spapr.c
@@ -91,6 +91,7 @@ qemu_irq spapr_allocate_irq(uint32_t hint, uint32_t *irq_num)
 }
 
 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,
                                    const char *boot_device,
@@ -99,7 +100,9 @@ static void *spapr_create_fdt_skel(const char *cpu_model,
 {
     void *fdt;
     CPUState *env;
-    uint64_t mem_reg_property[] = { 0, cpu_to_be64(ram_size) };
+    uint64_t mem_reg_property_rma[] = { 0, cpu_to_be64(rma_size) };
+    uint64_t mem_reg_property_nonrma[] = { cpu_to_be64(rma_size),
+                                           cpu_to_be64(ram_size - rma_size) };
     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)};
@@ -145,15 +148,25 @@ static void *spapr_create_fdt_skel(const char *cpu_model,
 
     _FDT((fdt_end_node(fdt)));
 
-    /* memory node */
+    /* memory node(s) */
     _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, "reg", mem_reg_property_rma,
+                       sizeof(mem_reg_property_rma))));
     _FDT((fdt_end_node(fdt)));
 
+    if (ram_size > rma_size) {
+        char mem_name[32];
+
+        sprintf(mem_name, "memory@%" PRIx64, (uint64_t)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_nonrma,
+                           sizeof(mem_reg_property_nonrma))));
+        _FDT((fdt_end_node(fdt)));
+    }
+
     /* cpus */
     _FDT((fdt_begin_node(fdt, "cpus")));
 
@@ -346,6 +359,7 @@ 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;
     uint32_t initrd_base;
     long kernel_size, initrd_size, fw_size;
     long pteg_shift = 17;
@@ -354,10 +368,23 @@ static void ppc_spapr_init(ram_addr_t ram_size,
     spapr = g_malloc(sizeof(*spapr));
     cpu_ppc_hypercall = emulate_spapr_hypercall;
 
-    /* We place the device tree just below either the top of RAM, or
-     * 2GB, so that it can be processed with 32-bit code if
-     * necessary */
-    spapr->fdt_addr = MIN(ram_size, 0x80000000) - FDT_MAX_SIZE;
+    /* Allocate RMA if necessary */
+    rma_alloc_size = kvmppc_alloc_rma("ppc_spapr.rma", sysmem);
+
+    if (rma_alloc_size == -1) {
+        hw_error("qemu: Unable to create RMA\n");
+        exit(1);
+    }
+    if (rma_alloc_size && (rma_alloc_size < ram_size)) {
+        rma_size = rma_alloc_size;
+    } else {
+        rma_size = ram_size;
+    }
+
+    /* We place the device tree 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 */
+    spapr->fdt_addr = MIN(rma_size, 0x80000000) - FDT_MAX_SIZE;
     spapr->rtas_addr = spapr->fdt_addr - RTAS_MAX_SIZE;
 
     /* init CPUs */
@@ -382,8 +409,13 @@ static void ppc_spapr_init(ram_addr_t ram_size,
 
     /* allocate RAM */
     spapr->ram_limit = ram_size;
-    memory_region_init_ram(ram, NULL, "ppc_spapr.ram", spapr->ram_limit);
-    memory_region_add_subregion(sysmem, 0, ram);
+    if (spapr->ram_limit > rma_alloc_size) {
+        ram_addr_t nonrma_base = rma_alloc_size;
+        ram_addr_t nonrma_size = spapr->ram_limit - rma_alloc_size;
+
+        memory_region_init_ram(ram, NULL, "ppc_spapr.ram", nonrma_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
@@ -507,7 +539,7 @@ static void ppc_spapr_init(ram_addr_t ram_size,
     }
 
     /* Prepare the device tree */
-    spapr->fdt_skel = spapr_create_fdt_skel(cpu_model,
+    spapr->fdt_skel = spapr_create_fdt_skel(cpu_model, rma_size,
                                             initrd_base, initrd_size,
                                             boot_device, kernel_cmdline,
                                             pteg_shift + 7);