[Qemu-devel] [RFC 16/38] aie: add module for Atomic Instruction Emulation

[Emilio G. Cota]

Signed-off-by: Emilio G. Cota <address@hidden>
---
 Makefile.target    |  1 +
 aie.c              | 57 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 include/qemu/aie.h | 49 ++++++++++++++++++++++++++++++++++++++++++++++
 translate-all.c    |  2 ++
 4 files changed, 109 insertions(+)
 create mode 100644 aie.c
 create mode 100644 include/qemu/aie.h

diff --git a/Makefile.target b/Makefile.target
index 3e7aafd..840e257 100644
--- a/Makefile.target
+++ b/Makefile.target
@@ -85,6 +85,7 @@ all: $(PROGS) stap
 #########################################################
 # cpu emulator library
 obj-y = exec.o translate-all.o cpu-exec.o
+obj-y += aie.o
 obj-y += tcg/tcg.o tcg/tcg-op.o tcg/optimize.o
 obj-$(CONFIG_TCG_INTERPRETER) += tci.o
 obj-$(CONFIG_TCG_INTERPRETER) += disas/tci.o
diff --git a/aie.c b/aie.c
new file mode 100644
index 0000000..588c02b
--- /dev/null
+++ b/aie.c
@@ -0,0 +1,57 @@
+/*
+ * Atomic instruction emulation (AIE).
+ * This applies to LL/SC and higher-order atomic instructions.
+ * More info:
+ *   http://en.wikipedia.org/wiki/Load-link/store-conditional
+ */
+#include "qemu-common.h"
+#include "qemu/radix-tree.h"
+#include "qemu/thread.h"
+#include "qemu/aie.h"
+
+#if defined(CONFIG_USER_ONLY)
+# define AIE_FULL_ADDR_BITS  TARGET_VIRT_ADDR_SPACE_BITS
+#else
+#if HOST_LONG_BITS < TARGET_PHYS_ADDR_SPACE_BITS
+/* in this case QEMU restricts the maximum RAM size to fit in the host */
+# define AIE_FULL_ADDR_BITS  HOST_LONG_BITS
+#else
+# define AIE_FULL_ADDR_BITS  TARGET_PHYS_ADDR_SPACE_BITS
+#endif
+#endif /* CONFIG_USER_ONLY */
+
+#define AIE_ADDR_BITS  (AIE_FULL_ADDR_BITS - AIE_DISCARD_BITS)
+#define AIE_RADIX     8
+
+QemuRadixTree aie_rtree;
+unsigned long *aie_bm;
+
+static void *aie_entry_init(unsigned long index)
+{
+    AIEEntry *entry;
+
+    entry = qemu_memalign(64, sizeof(*entry));
+    qemu_spin_init(&entry->lock);
+    entry->bm_set = false;
+    return entry;
+}
+
+AIEEntry *aie_entry_get_lock(hwaddr paddr)
+{
+    aie_addr_t idx = to_aie(paddr);
+    AIEEntry *e;
+
+    e = qemu_radix_tree_find_alloc(&aie_rtree, idx, aie_entry_init, 
qemu_vfree);
+    qemu_spin_lock(&e->lock);
+    if (!e->bm_set) {
+        set_bit_atomic(idx & (AIE_BM_NR_ITEMS - 1), aie_bm);
+        e->bm_set = true;
+    }
+    return e;
+}
+
+void aie_init(void)
+{
+    qemu_radix_tree_init(&aie_rtree, AIE_ADDR_BITS, AIE_RADIX);
+    aie_bm = bitmap_new(AIE_BM_NR_ITEMS);
+}
diff --git a/include/qemu/aie.h b/include/qemu/aie.h
new file mode 100644
index 0000000..667f36c
--- /dev/null
+++ b/include/qemu/aie.h
@@ -0,0 +1,49 @@
+/*
+ * Atomic instruction emulation (AIE)
+ */
+#ifndef AIE_H
+#define AIE_H
+
+#include "qemu/radix-tree.h"
+#include "qemu/thread.h"
+#include "qemu/bitops.h"
+
+#include "exec/hwaddr.h"
+
+typedef hwaddr aie_addr_t;
+
+typedef struct AIEEntry AIEEntry;
+
+struct AIEEntry {
+    union {
+        struct {
+            QemuSpin lock;
+            bool bm_set;
+        };
+        uint8_t pad[64];
+    };
+} __attribute((aligned(64)));
+
+#define AIE_DISCARD_BITS 6
+
+#define AIE_BM_BITS     21
+#define AIE_BM_NR_ITEMS BIT(AIE_BM_BITS)
+
+extern QemuRadixTree aie_rtree;
+extern unsigned long *aie_bm;
+
+static inline aie_addr_t to_aie(hwaddr paddr)
+{
+    return paddr >> AIE_DISCARD_BITS;
+}
+
+void aie_init(void);
+
+AIEEntry *aie_entry_get_lock(hwaddr addr);
+
+static inline bool aie_entry_exists(hwaddr addr)
+{
+    return test_bit(to_aie(addr) & (AIE_BM_NR_ITEMS - 1), aie_bm);
+}
+
+#endif /* AIE_H */
diff --git a/translate-all.c b/translate-all.c
index b873d5c..f07547e 100644
--- a/translate-all.c
+++ b/translate-all.c
@@ -62,6 +62,7 @@
 #include "translate-all.h"
 #include "qemu/bitmap.h"
 #include "qemu/timer.h"
+#include "qemu/aie.h"
 
 //#define DEBUG_TB_INVALIDATE
 //#define DEBUG_FLUSH
@@ -730,6 +731,7 @@ void tcg_exec_init(unsigned long tb_size)
     tcg_ctx.code_gen_ptr = tcg_ctx.code_gen_buffer;
     tcg_register_jit(tcg_ctx.code_gen_buffer, tcg_ctx.code_gen_buffer_size);
     page_init();
+    aie_init();
 #if !defined(CONFIG_USER_ONLY) || !defined(CONFIG_USE_GUEST_BASE)
     /* There's no guest base to take into account, so go ahead and
        initialize the prologue now.  */
-- 
1.9.1