qemu/target-loongarch-Add-loongson-binary-translation-fea.patch

From 962f649aa5a06169f0ac23f61e273f0860942ebb Mon Sep 17 00:00:00 2001
From: Bibo Mao <maobibo@loongson.cn>
Date: Sun, 29 Sep 2024 15:04:04 +0800
Subject: [PATCH 57/78] target/loongarch: Add loongson binary translation
 feature

Loongson Binary Translation (LBT) is used to accelerate binary
translation, which contains 4 scratch registers (scr0 to scr3), x86/ARM
eflags (eflags) and x87 fpu stack pointer (ftop).

Now LBT feature is added in kvm mode, not supported in TCG mode since
it is not emulated. Feature variable lbt is added with OnOffAuto type,
If lbt feature is not supported with KVM host, it reports error if there
is lbt=on command line.

If there is no any command line about lbt parameter, it checks whether
KVM host supports lbt feature and set the corresponding value in cpucfg.

Signed-off-by: Bibo Mao <maobibo@loongson.cn>
Reviewed-by: Song Gao <gaosong@loongson.cn>
Message-Id: <20240929070405.235200-2-maobibo@loongson.cn>
Signed-off-by: Song Gao <gaosong@loongson.cn>
Signed-off-by: Xianglai Li <lixianglai@loongson.cn>
---
 target/loongarch/cpu.c                | 20 ++++++++++
 target/loongarch/cpu.h                |  6 +++
 target/loongarch/kvm/kvm.c            | 57 ++++++++++++++++++++++++++-
 target/loongarch/loongarch-qmp-cmds.c |  2 +-
 4 files changed, 83 insertions(+), 2 deletions(-)

diff --git a/target/loongarch/cpu.c b/target/loongarch/cpu.c
index d6a13de901..a57067938d 100644
--- a/target/loongarch/cpu.c
+++ b/target/loongarch/cpu.c
@@ -737,6 +737,18 @@ static void loongarch_set_pmnum(Object *obj, Visitor *v,
     }
 }
 
+static bool loongarch_get_lbt(Object *obj, Error **errp)
+{
+    return LOONGARCH_CPU(obj)->lbt != ON_OFF_AUTO_OFF;
+}
+
+static void loongarch_set_lbt(Object *obj, bool value, Error **errp)
+{
+    LoongArchCPU *cpu = LOONGARCH_CPU(obj);
+
+    cpu->lbt = value ? ON_OFF_AUTO_ON : ON_OFF_AUTO_OFF;
+}
+
 void loongarch_cpu_post_init(Object *obj)
 {
     LoongArchCPU *cpu = LOONGARCH_CPU(obj);
@@ -756,6 +768,14 @@ void loongarch_cpu_post_init(Object *obj)
                                 loongarch_set_pmnum, NULL,
                                 (void *)&value);
         }
+
+	cpu->lbt = ON_OFF_AUTO_AUTO;
+        object_property_add_bool(obj, "lbt", loongarch_get_lbt,
+                                 loongarch_set_lbt);
+        object_property_set_description(obj, "lbt",
+                                   "Set off to disable Binary Tranlation.");
+    } else {
+        cpu->lbt = ON_OFF_AUTO_OFF;
     }
 }
 
diff --git a/target/loongarch/cpu.h b/target/loongarch/cpu.h
index 19bcad28de..3e2bcbf608 100644
--- a/target/loongarch/cpu.h
+++ b/target/loongarch/cpu.h
@@ -155,6 +155,7 @@ FIELD(CPUCFG2, LLFTP_VER, 15, 3)
 FIELD(CPUCFG2, LBT_X86, 18, 1)
 FIELD(CPUCFG2, LBT_ARM, 19, 1)
 FIELD(CPUCFG2, LBT_MIPS, 20, 1)
+FIELD(CPUCFG2, LBT_ALL, 18, 3)
 FIELD(CPUCFG2, LSPW, 21, 1)
 FIELD(CPUCFG2, LAM, 22, 1)
 
@@ -285,6 +286,10 @@ struct LoongArchTLB {
 typedef struct LoongArchTLB LoongArchTLB;
 #endif
 
+enum loongarch_features {
+    LOONGARCH_FEATURE_LBT, /* loongson binary translation extension */
+};
+
 typedef struct CPUArchState {
     uint64_t gpr[32];
     uint64_t pc;
@@ -388,6 +393,7 @@ struct ArchCPU {
     CPULoongArchState env;
     QEMUTimer timer;
     uint32_t  phy_id;
+    OnOffAuto lbt;
 
     /* 'compatible' string for this CPU for Linux device trees */
     const char *dtb_compatible;
diff --git a/target/loongarch/kvm/kvm.c b/target/loongarch/kvm/kvm.c
index 90c8379c46..567404bdb5 100644
--- a/target/loongarch/kvm/kvm.c
+++ b/target/loongarch/kvm/kvm.c
@@ -9,6 +9,7 @@
 #include <sys/ioctl.h>
 #include <linux/kvm.h>
 
+#include "qapi/error.h"
 #include "qemu/timer.h"
 #include "qemu/error-report.h"
 #include "qemu/main-loop.h"
@@ -786,17 +787,71 @@ static void kvm_loongarch_vm_stage_change(void *opaque, bool running,
     }
 }
 
+static bool kvm_feature_supported(CPUState *cs, enum loongarch_features feature)
+{
+    int ret;
+    struct kvm_device_attr attr;
+
+    switch (feature) {
+    case LOONGARCH_FEATURE_LBT:
+        /*
+         * Return all if all the LBT features are supported such as:
+         *  KVM_LOONGARCH_VM_FEAT_X86BT
+         *  KVM_LOONGARCH_VM_FEAT_ARMBT
+         *  KVM_LOONGARCH_VM_FEAT_MIPSBT
+         */
+        attr.group = KVM_LOONGARCH_VM_FEAT_CTRL;
+        attr.attr = KVM_LOONGARCH_VM_FEAT_X86BT;
+        ret = kvm_vm_ioctl(kvm_state, KVM_HAS_DEVICE_ATTR, &attr);
+        attr.attr = KVM_LOONGARCH_VM_FEAT_ARMBT;
+        ret |= kvm_vm_ioctl(kvm_state, KVM_HAS_DEVICE_ATTR, &attr);
+        attr.attr = KVM_LOONGARCH_VM_FEAT_MIPSBT;
+        ret |= kvm_vm_ioctl(kvm_state, KVM_HAS_DEVICE_ATTR, &attr);
+        return (ret == 0);
+    default:
+        return false;
+    }
+}
+
+static int kvm_cpu_check_lbt(CPUState *cs, Error **errp)
+{
+    CPULoongArchState *env = cpu_env(cs);
+    LoongArchCPU *cpu = LOONGARCH_CPU(cs);
+    bool kvm_supported;
+
+    kvm_supported = kvm_feature_supported(cs, LOONGARCH_FEATURE_LBT);
+    if (cpu->lbt == ON_OFF_AUTO_ON) {
+        if (kvm_supported) {
+            env->cpucfg[2] = FIELD_DP32(env->cpucfg[2], CPUCFG2, LBT_ALL, 7);
+        } else {
+            error_setg(errp, "'lbt' feature not supported by KVM on this host");
+            return -ENOTSUP;
+        }
+    } else if ((cpu->lbt == ON_OFF_AUTO_AUTO) && kvm_supported) {
+        env->cpucfg[2] = FIELD_DP32(env->cpucfg[2], CPUCFG2, LBT_ALL, 7);
+    }
+
+    return 0;
+}
+
 int kvm_arch_init_vcpu(CPUState *cs)
 {
     uint64_t val;
+    int ret;
+    Error *local_err = NULL;
 
+    ret = 0;
     qemu_add_vm_change_state_handler(kvm_loongarch_vm_stage_change, cs);
 
     if (!kvm_get_one_reg(cs, KVM_REG_LOONGARCH_DEBUG_INST, &val)) {
         brk_insn = val;
     }
 
-    return 0;
+    ret = kvm_cpu_check_lbt(cs, &local_err);
+    if (ret < 0) {
+        error_report_err(local_err);
+    }
+    return ret;
 }
 
 int kvm_arch_destroy_vcpu(CPUState *cs)
diff --git a/target/loongarch/loongarch-qmp-cmds.c b/target/loongarch/loongarch-qmp-cmds.c
index 2612f43de9..644b528824 100644
--- a/target/loongarch/loongarch-qmp-cmds.c
+++ b/target/loongarch/loongarch-qmp-cmds.c
@@ -42,7 +42,7 @@ CpuDefinitionInfoList *qmp_query_cpu_definitions(Error **errp)
 }
 
 static const char *cpu_model_advertised_features[] = {
-    "lsx", "lasx", "pmu", "pmnum", NULL
+    "lsx", "lasx", "lbt", "pmu", "pmnum", NULL
 };
 
 CpuModelExpansionInfo *qmp_query_cpu_model_expansion(CpuModelExpansionType type,
-- 
2.39.1