From ede09f502bfa771094753947df7ff55a04acd95c Mon Sep 17 00:00:00 2001
From: Sergej Schumilo <sergej@schumilo.de>
Date: Mon, 2 Jan 2023 08:54:50 +0100
Subject: [PATCH] some code cleanup and fix for another edge case

---
 hw/i386/pc_piix.c |  6 +++-
 hw/i386/pc_q35.c  | 16 +++++----
 nyx/mem_split.c   | 86 ++++++++++++-----------------------------------
 nyx/mem_split.h   |  2 --
 nyx/state/state.c |  3 +-
 nyx/state/state.h |  2 ++
 6 files changed, 40 insertions(+), 75 deletions(-)

diff --git a/hw/i386/pc_piix.c b/hw/i386/pc_piix.c
index aee332c1a0..60c0f96563 100644
--- a/hw/i386/pc_piix.c
+++ b/hw/i386/pc_piix.c
@@ -154,12 +154,16 @@ static void pc_init1(MachineState *machine,
             x86ms->below_4g_mem_size = lowmem;
 #ifdef QEMU_NYX
             GET_GLOBAL_STATE()->mem_mapping_type = PC_PIIX_MEM_TYPE;
+            GET_GLOBAL_STATE()->mem_mapping_low = lowmem;
+            GET_GLOBAL_STATE()->mem_mapping_high = 0x100000000;
 #endif
         } else {
             x86ms->above_4g_mem_size = 0;
             x86ms->below_4g_mem_size = machine->ram_size;
 #ifdef QEMU_NYX
-            GET_GLOBAL_STATE()->mem_mapping_type = PC_PIIX_MEM_LOW_TYPE;
+            GET_GLOBAL_STATE()->mem_mapping_type = PC_PIIX_MEM_TYPE;
+            GET_GLOBAL_STATE()->mem_mapping_low = lowmem;
+            GET_GLOBAL_STATE()->mem_mapping_high = 0;
 #endif
         }
     }
diff --git a/hw/i386/pc_q35.c b/hw/i386/pc_q35.c
index 93e6a2aa03..1285327a2d 100644
--- a/hw/i386/pc_q35.c
+++ b/hw/i386/pc_q35.c
@@ -150,14 +150,8 @@ static void pc_q35_init(MachineState *machine)
      */
     if (machine->ram_size >= 0xb0000000) {
         lowmem = 0x80000000;
-#ifdef QEMU_NYX
-        GET_GLOBAL_STATE()->mem_mapping_type = Q35_MEM_MEM_TYPE;
-#endif
     } else {
         lowmem = 0xb0000000;
-#ifdef QEMU_NYX
-        GET_GLOBAL_STATE()->mem_mapping_type = Q35_MEM_MEM_LOW_TYPE;
-#endif
     }
 
     /* Handle the machine opt max-ram-below-4g.  It is basically doing
@@ -181,9 +175,19 @@ static void pc_q35_init(MachineState *machine)
     if (machine->ram_size >= lowmem) {
         x86ms->above_4g_mem_size = machine->ram_size - lowmem;
         x86ms->below_4g_mem_size = lowmem;
+#ifdef QEMU_NYX
+        GET_GLOBAL_STATE()->mem_mapping_type = Q35_MEM_MEM_TYPE;
+        GET_GLOBAL_STATE()->mem_mapping_low = lowmem;
+        GET_GLOBAL_STATE()->mem_mapping_high = 0x100000000;
+#endif
     } else {
         x86ms->above_4g_mem_size = 0;
         x86ms->below_4g_mem_size = machine->ram_size;
+#ifdef QEMU_NYX
+        GET_GLOBAL_STATE()->mem_mapping_type = Q35_MEM_MEM_TYPE;
+        GET_GLOBAL_STATE()->mem_mapping_low = lowmem;
+        GET_GLOBAL_STATE()->mem_mapping_high = 0;
+#endif
     }
 
     if (xen_enabled()) {
diff --git a/nyx/mem_split.c b/nyx/mem_split.c
index ea8dd4a810..67bb1f3af3 100644
--- a/nyx/mem_split.c
+++ b/nyx/mem_split.c
@@ -2,84 +2,40 @@
 #include "nyx/state/state.h"
 #include "nyx/mem_split.h"
 
-#define PC_PIIX_LOW_MEM_SPLIT_START 0xe0000000
-
-#define PC_PIIX_MEM_SPLIT_START 0x0C0000000
-#define PC_PIXX_MEM_SPLIT_END   0x100000000
-
-#define Q35_MEM_SPLIT_START 0x080000000
-#define Q35_MEM_SPLIT_END   0x100000000
-
-#define Q35_LOW_MEM_SPLIT_START 0x0b0000000
-
 bool is_mem_mapping_supported(MemSplitType type){
-    return type == PC_PIIX_MEM_LOW_TYPE || type == PC_PIIX_MEM_TYPE || type == Q35_MEM_MEM_LOW_TYPE || type == Q35_MEM_MEM_TYPE;
+    return GET_GLOBAL_STATE()->mem_mapping_type != MEM_SPLIT_TYPE_INVALID;
 }
 
 uint64_t get_mem_split_start(void){
-    switch(GET_GLOBAL_STATE()->mem_mapping_type){
-        case PC_PIIX_MEM_LOW_TYPE: 
-            return PC_PIIX_LOW_MEM_SPLIT_START;
-        case PC_PIIX_MEM_TYPE: 
-            return PC_PIIX_MEM_SPLIT_START;
-        case Q35_MEM_MEM_LOW_TYPE:
-            return Q35_LOW_MEM_SPLIT_START;
-        case Q35_MEM_MEM_TYPE:
-            return Q35_MEM_SPLIT_START;
-        default:
-            abort();
-    }
+    assert(is_mem_mapping_supported(GET_GLOBAL_STATE()->mem_mapping_type));
+    return GET_GLOBAL_STATE()->mem_mapping_low;
 }
 
 uint64_t get_mem_split_end(void){
-    switch(GET_GLOBAL_STATE()->mem_mapping_type){
-        case PC_PIIX_MEM_TYPE: 
-            return PC_PIXX_MEM_SPLIT_END;
-        case Q35_MEM_MEM_TYPE:
-            return Q35_MEM_SPLIT_END;
-        default:
-            abort();
-    }
+    assert(is_mem_mapping_supported(GET_GLOBAL_STATE()->mem_mapping_type));
+    assert(GET_GLOBAL_STATE()->mem_mapping_high != 0);
+    return GET_GLOBAL_STATE()->mem_mapping_high;
 }
 
 uint64_t address_to_ram_offset(uint64_t offset){
-    switch(GET_GLOBAL_STATE()->mem_mapping_type){
-        case PC_PIIX_MEM_LOW_TYPE:
-            if(offset >= PC_PIIX_LOW_MEM_SPLIT_START){
-                abort();
-            }
-            return offset;
-        case PC_PIIX_MEM_TYPE: 
-            return offset >= PC_PIXX_MEM_SPLIT_END ? (offset - PC_PIXX_MEM_SPLIT_END) + PC_PIIX_MEM_SPLIT_START : offset;
-        case Q35_MEM_MEM_TYPE:
-            return offset >= Q35_MEM_SPLIT_END ? (offset - Q35_MEM_SPLIT_END) + Q35_MEM_SPLIT_START : offset;
-        case Q35_MEM_MEM_LOW_TYPE:
-            if(offset >= Q35_LOW_MEM_SPLIT_START){
-                abort();
-            }
-            return offset;
-        default:
-            abort();
+    assert(is_mem_mapping_supported(GET_GLOBAL_STATE()->mem_mapping_type));
+    if(GET_GLOBAL_STATE()->mem_mapping_high == 0){
+        assert(offset <= GET_GLOBAL_STATE()->mem_mapping_low);
+        return offset;
+    }
+    else{
+        return offset >= GET_GLOBAL_STATE()->mem_mapping_high ? (offset - GET_GLOBAL_STATE()->mem_mapping_high) + GET_GLOBAL_STATE()->mem_mapping_low : offset;
     }
 }
 
 uint64_t ram_offset_to_address(uint64_t offset){
-    switch(GET_GLOBAL_STATE()->mem_mapping_type){
-        case PC_PIIX_MEM_LOW_TYPE:
-            if(offset >= PC_PIIX_LOW_MEM_SPLIT_START){
-                abort();
-            }
-            return offset;
-        case PC_PIIX_MEM_TYPE: 
-            return offset >= PC_PIIX_MEM_SPLIT_START ? (offset - PC_PIIX_MEM_SPLIT_START) + PC_PIXX_MEM_SPLIT_END : offset;;
-        case Q35_MEM_MEM_TYPE:
-            return offset >= Q35_MEM_SPLIT_START ? (offset - Q35_MEM_SPLIT_START) + Q35_MEM_SPLIT_END : offset;
-        case Q35_MEM_MEM_LOW_TYPE:
-            if(offset >= Q35_LOW_MEM_SPLIT_START){
-                abort();
-            }
-            return offset;
-        default:
-            abort();
+
+    assert(is_mem_mapping_supported(GET_GLOBAL_STATE()->mem_mapping_type));
+    if(GET_GLOBAL_STATE()->mem_mapping_high == 0){
+        assert(offset <= GET_GLOBAL_STATE()->mem_mapping_low);
+        return offset;
+    }
+    else{
+        return offset >= GET_GLOBAL_STATE()->mem_mapping_low ? (offset - GET_GLOBAL_STATE()->mem_mapping_low) + GET_GLOBAL_STATE()->mem_mapping_high : offset;
     }
 }
diff --git a/nyx/mem_split.h b/nyx/mem_split.h
index 12b933c5ae..d178e9b5e8 100644
--- a/nyx/mem_split.h
+++ b/nyx/mem_split.h
@@ -6,9 +6,7 @@
 
 typedef enum MemSplitType {
     MEM_SPLIT_TYPE_INVALID,
-    PC_PIIX_MEM_LOW_TYPE,
     PC_PIIX_MEM_TYPE,
-    Q35_MEM_MEM_LOW_TYPE,
     Q35_MEM_MEM_TYPE,
 } MemSplitType;
 
diff --git a/nyx/state/state.c b/nyx/state/state.c
index bd5a2b6dc4..da97952cbe 100644
--- a/nyx/state/state.c
+++ b/nyx/state/state.c
@@ -120,7 +120,8 @@ void state_init_global(void)
     global_state.mem_mapping_type = MEM_SPLIT_TYPE_INVALID;
 
     global_state.sharedir = sharedir_new();
-
+    global_state.mem_mapping_low = 0;
+    global_state.mem_mapping_high = 0;
 
     global_state.shared_bitmap_fd        = 0;
     global_state.shared_bitmap_size      = 0;
diff --git a/nyx/state/state.h b/nyx/state/state.h
index 7da8c3f720..ae6c1ddcc2 100644
--- a/nyx/state/state.h
+++ b/nyx/state/state.h
@@ -139,6 +139,8 @@ typedef struct qemu_nyx_state_s {
     bool set_agent_config_done;
 
     MemSplitType mem_mapping_type;
+    uint64_t mem_mapping_low;
+    uint64_t mem_mapping_high;
 
     /* capabilites */
     uint8_t  cap_timeout_detection;