[Qemu-devel] [RFC PATCH 3/9] spapr: Add ibm, processor-radix-AP-encodings to the device tree

[Sam Bobroff <sam.bobroff@au1.ibm.com>]

Use the new ioctl, KVM_PPC_GET_RMMU_INFO, to fetch radix MMU
information from KVM and present the page encodings in the device tree
under ibm,processor-radix-AP-encodings. This provides page size
information to the guest which is necessary for it to use radix mode.

Signed-off-by: Sam Bobroff <sam.bobroff@au1.ibm.com>
---
 hw/ppc/spapr.c   |  7 +++++++
 target/ppc/cpu.h |  5 +++++
 target/ppc/kvm.c | 32 +++++++++++++++++++++++++++++++-
 3 files changed, 43 insertions(+), 1 deletion(-)

diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
index a642e663d4..d629e2630c 100644
--- a/hw/ppc/spapr.c
+++ b/hw/ppc/spapr.c
@@ -496,6 +496,13 @@ static void spapr_populate_cpu_dt(CPUState *cs, void *fdt, int offset,
 
     _FDT(spapr_fixup_cpu_smt_dt(fdt, offset, cpu,
                                 ppc_get_compat_smt_threads(cpu)));
+
+    if (env->radix_page_info.count) {
+        _FDT((fdt_setprop(fdt, offset, "ibm,processor-radix-AP-encodings",
+                          env->radix_page_info.entries,
+                          env->radix_page_info.count *
+                          sizeof(env->radix_page_info.entries[0]))));
+    }
 }
 
 static void spapr_populate_cpus_dt_node(void *fdt, sPAPRMachineState *spapr)
diff --git a/target/ppc/cpu.h b/target/ppc/cpu.h
index afb7ddbdd0..5a96d98b6f 100644
--- a/target/ppc/cpu.h
+++ b/target/ppc/cpu.h
@@ -914,6 +914,10 @@ struct ppc_segment_page_sizes {
     struct ppc_one_seg_page_size sps[PPC_PAGE_SIZES_MAX_SZ];
 };
 
+struct ppc_radix_page_info {
+    uint32_t count;
+    uint32_t entries[PPC_PAGE_SIZES_MAX_SZ];
+};
 
 /*****************************************************************************/
 /* The whole PowerPC CPU context */
@@ -1053,6 +1057,7 @@ struct CPUPPCState {
     ppc_slb_t vrma_slb;
     target_ulong rmls;
     bool ci_large_pages;
+    struct ppc_radix_page_info radix_page_info;
 #endif
 
 #if defined(TARGET_PPC64) && !defined(CONFIG_USER_ONLY)
diff --git a/target/ppc/kvm.c b/target/ppc/kvm.c
index ec92c64159..390d6342cc 100644
--- a/target/ppc/kvm.c
+++ b/target/ppc/kvm.c
@@ -328,6 +328,18 @@ static void kvm_get_smmu_info(PowerPCCPU *cpu, struct kvm_ppc_smmu_info *info)
     kvm_get_fallback_smmu_info(cpu, info);
 }
 
+static bool kvm_get_rmmu_info(PowerPCCPU *cpu, struct kvm_ppc_rmmu_info *info)
+{
+    CPUState *cs = CPU(cpu);
+    int ret;
+
+    if (kvm_check_extension(cs->kvm_state, KVM_CAP_PPC_MMU_RADIX)) {
+        ret = kvm_vm_ioctl(cs->kvm_state, KVM_PPC_GET_RMMU_INFO, info);
+        return (ret == 0);
+    }
+    return false;
+}
+
 static long gethugepagesize(const char *mem_path)
 {
     struct statfs fs;
@@ -441,9 +453,11 @@ static void kvm_fixup_page_sizes(PowerPCCPU *cpu)
 {
     static struct kvm_ppc_smmu_info smmu_info;
     static bool has_smmu_info;
+    static struct kvm_ppc_rmmu_info rmmu_info;
+    static bool has_rmmu_info;
     CPUPPCState *env = &cpu->env;
     long rampagesize;
-    int iq, ik, jq, jk;
+    int iq, ik, jq, jk, i;
     bool has_64k_pages = false;
 
     /* We only handle page sizes for 64-bit server guests for now */
@@ -508,6 +522,22 @@ static void kvm_fixup_page_sizes(PowerPCCPU *cpu)
     if (!has_64k_pages) {
         env->mmu_model &= ~POWERPC_MMU_64K;
     }
+
+    /* Collect radix page info from kernel if not already */
+    if (!has_rmmu_info) {
+        env->radix_page_info.count = 0;
+        if (kvm_get_rmmu_info(cpu, &rmmu_info)) {
+            for (i = 0; i < 8; i++) {
+                if (rmmu_info.ap_encodings[i]) {
+                    env->radix_page_info.entries[i] =
+                        cpu_to_be32(rmmu_info.ap_encodings[i]);
+                    env->radix_page_info.count++;
+                }
+            }
+        }
+        has_rmmu_info = true;
+    }
+
 }
 #else /* defined (TARGET_PPC64) */
 
-- 
2.11.0