[PATCH v3 5/8] Add memory hardware address read/write API

[Rowan Hart <rowanbhart@gmail.com>]

From: novafacing <rowanbhart@gmail.com>

Signed-off-by: novafacing <rowanbhart@gmail.com>
Signed-off-by: Rowan Hart <rowanbhart@gmail.com>
---
 include/qemu/qemu-plugin.h |  96 +++++++++++++++++++++++++++++++++++
 plugins/api.c              | 100 +++++++++++++++++++++++++++++++++++++
 2 files changed, 196 insertions(+)

diff --git a/include/qemu/qemu-plugin.h b/include/qemu/qemu-plugin.h
index eff8430b4a..d4f229abd9 100644
--- a/include/qemu/qemu-plugin.h
+++ b/include/qemu/qemu-plugin.h
@@ -1014,6 +1014,102 @@ QEMU_PLUGIN_API
 bool qemu_plugin_write_memory_vaddr(uint64_t addr,
                                    GByteArray *data);
 
+/**
+ * enum qemu_plugin_hwaddr_operation_result - result of a memory operation
+ *
+ * @QEMU_PLUGIN_HWADDR_OPERATION_OK: hwaddr operation succeeded
+ * @QEMU_PLUGIN_HWADDR_OPERATION_ERROR: unexpected error occurred
+ * @QEMU_PLUGIN_HWADDR_OPERATION_DEVICE_ERROR: error in memory device
+ * @QEMU_PLUGIN_HWADDR_OPERATION_ACCESS_DENIED: permission error
+ * @QEMU_PLUGIN_HWADDR_OPERATION_INVALID_ADDRESS: address was invalid
+ * @QEMU_PLUGIN_HWADDR_OPERATION_INVALID_ADDRESS_SPACE: invalid address space
+ */
+enum qemu_plugin_hwaddr_operation_result {
+    QEMU_PLUGIN_HWADDR_OPERATION_OK,
+    QEMU_PLUGIN_HWADDR_OPERATION_ERROR,
+    QEMU_PLUGIN_HWADDR_OPERATION_DEVICE_ERROR,
+    QEMU_PLUGIN_HWADDR_OPERATION_ACCESS_DENIED,
+    QEMU_PLUGIN_HWADDR_OPERATION_INVALID_ADDRESS,
+    QEMU_PLUGIN_HWADDR_OPERATION_INVALID_ADDRESS_SPACE,
+};
+
+/**
+ * qemu_plugin_read_memory_hwaddr() - read from memory using a hardware address
+ *
+ * @as_idx: The index of the address space to read from
+ * @addr: A physical address to read from
+ * @data: A byte array to store data into
+ * @len: The number of bytes to read, starting from @addr
+ *
+ * @len bytes of data is read starting at @addr and stored into @data. If @data
+ * is not large enough to hold @len bytes, it will be expanded to the necessary
+ * size, reallocating if necessary. @len must be greater than 0.
+ *
+ * This function does not ensure writes are flushed prior to reading, so
+ * callers should take care when calling this function in plugin callbacks to
+ * avoid attempting to read data which may not yet be written and should use
+ * the memory callback API instead.
+ *
+ * This function is only valid for softmmu targets.
+ *
+ * Returns a qemu_plugin_hwaddr_operation_result indicating the result of the
+ * operation.
+ */
+QEMU_PLUGIN_API
+enum qemu_plugin_hwaddr_operation_result
+qemu_plugin_read_memory_hwaddr(unsigned int as_idx, uint64_t addr,
+                                    GByteArray *data, size_t len);
+
+/**
+ * qemu_plugin_write_memory_hwaddr() - write to memory using a hardware address
+ *
+ * @as_idx: The index of the address space to write to
+ * @addr: A physical address to write to
+ * @data: A byte array containing the data to write
+ *
+ * The contents of @data will be written to memory starting at the hardware
+ * address @addr.
+ *
+ * This function does not guarantee consistency of writes, nor does it ensure
+ * that pending writes are flushed either before or after the write takes place,
+ * so callers should take care when calling this function in plugin callbacks to
+ * avoid depending on the existence of data written using this function which
+ * may be overwritten afterward. In addition, this function requires that the
+ * pages containing the address are not locked. Practically, this means that you
+ * should not write instruction memory in a current translation block inside a
+ * callback registered with qemu_plugin_register_vcpu_tb_trans_cb.
+ *
+ * You can, for example, write instruction memory in a current translation block
+ * in a callback registered with qemu_plugin_register_vcpu_tb_exec_cb, although
+ * be aware that the write will not be flushed until after the translation block
+ * has finished executing.  In general, this function should be used to write
+ * data memory or to patch code at a known address, not in a current translation
+ * block.
+ *
+ * This function is only valid for softmmu targets.
+ *
+ * Returns a qemu_plugin_hwaddr_operation_result indicating the result of the
+ * operation.
+ */
+QEMU_PLUGIN_API
+enum qemu_plugin_hwaddr_operation_result
+qemu_plugin_write_memory_hwaddr(unsigned int as_idx, uint64_t addr,
+                                     GByteArray *data);
+
+/**
+ * qemu_plugin_translate_vaddr() - translate a virtual address to a physical one
+ *
+ * @vaddr: virtual address to translate
+ * @hwaddr: pointer to store the physical address
+ *
+ * This function is only valid in vCPU context (i.e. in callbacks) and is only
+ * valid for softmmu targets.
+ *
+ * Returns true on success and false on failure.
+ */
+QEMU_PLUGIN_API
+bool qemu_plugin_translate_vaddr(uint64_t vaddr, uint64_t *hwaddr);
+
 /**
  * qemu_plugin_scoreboard_new() - alloc a new scoreboard
  *
diff --git a/plugins/api.c b/plugins/api.c
index 19c10bb39e..5983768783 100644
--- a/plugins/api.c
+++ b/plugins/api.c
@@ -569,6 +569,106 @@ bool qemu_plugin_write_memory_vaddr(uint64_t addr, GByteArray *data)
     return true;
 }
 
+enum qemu_plugin_hwaddr_operation_result
+qemu_plugin_read_memory_hwaddr(unsigned int as_idx, hwaddr addr,
+                               GByteArray *data, size_t len)
+{
+#ifdef CONFIG_SOFTMMU
+    CPUState *cpu = current_cpu;
+
+    if (len == 0 || as_idx >= cpu->cpu_ases_count) {
+        return QEMU_PLUGIN_HWADDR_OPERATION_INVALID_ADDRESS_SPACE;
+    }
+
+    g_byte_array_set_size(data, len);
+
+    AddressSpace *as = cpu_get_address_space(cpu, as_idx);
+
+    if (as == NULL) {
+        return QEMU_PLUGIN_HWADDR_OPERATION_INVALID_ADDRESS_SPACE;
+    }
+
+    MemTxResult res = address_space_rw(as, addr,
+                                       MEMTXATTRS_UNSPECIFIED, data->data,
+                                       data->len, false);
+
+    switch (res) {
+    case MEMTX_OK:
+        return QEMU_PLUGIN_HWADDR_OPERATION_OK;
+    case MEMTX_ERROR:
+        return QEMU_PLUGIN_HWADDR_OPERATION_DEVICE_ERROR;
+    case MEMTX_DECODE_ERROR:
+        return QEMU_PLUGIN_HWADDR_OPERATION_INVALID_ADDRESS;
+    case MEMTX_ACCESS_ERROR:
+        return QEMU_PLUGIN_HWADDR_OPERATION_ACCESS_DENIED;
+    default:
+        return QEMU_PLUGIN_HWADDR_OPERATION_ERROR;
+    }
+#else
+    return QEMU_PLUGIN_HWADDR_OPERATION_ERROR;
+#endif
+}
+
+enum qemu_plugin_hwaddr_operation_result
+qemu_plugin_write_memory_hwaddr(unsigned int as_idx, hwaddr addr, 
+                                GByteArray *data)
+{
+#ifdef CONFIG_SOFTMMU
+    CPUState *cpu = current_cpu;
+
+    if (data->len == 0 || as_idx >= cpu->cpu_ases_count) {
+        return QEMU_PLUGIN_HWADDR_OPERATION_INVALID_ADDRESS_SPACE;
+    }
+
+    AddressSpace *as = cpu_get_address_space(cpu, as_idx);
+
+    if (as == NULL) {
+        return QEMU_PLUGIN_HWADDR_OPERATION_INVALID_ADDRESS_SPACE;
+    }
+
+    qemu_plugin_outs("Got cpu address space...\n");
+
+    MemTxResult res = address_space_rw(as, addr,
+                                       MEMTXATTRS_UNSPECIFIED, data->data,
+                                       data->len, true);
+    switch (res) {
+    case MEMTX_OK:
+        return QEMU_PLUGIN_HWADDR_OPERATION_OK;
+    case MEMTX_ERROR:
+        return QEMU_PLUGIN_HWADDR_OPERATION_DEVICE_ERROR;
+    case MEMTX_DECODE_ERROR:
+        return QEMU_PLUGIN_HWADDR_OPERATION_INVALID_ADDRESS;
+    case MEMTX_ACCESS_ERROR:
+        return QEMU_PLUGIN_HWADDR_OPERATION_ACCESS_DENIED;
+    default:
+        return QEMU_PLUGIN_HWADDR_OPERATION_ERROR;
+    }
+#else
+    return QEMU_PLUGIN_HWADDR_OPERATION_ERROR;
+#endif
+}
+
+bool qemu_plugin_translate_vaddr(uint64_t vaddr, uint64_t *hwaddr)
+{
+#ifdef CONFIG_SOFTMMU
+    g_assert(current_cpu);
+
+    CPUState *cpu = current_cpu;
+
+    uint64_t res = cpu_get_phys_page_debug(cpu, vaddr);
+
+    if (res == (uint64_t)-1) {
+        return false;
+    }
+
+    *hwaddr = res | (vaddr & ~TARGET_PAGE_MASK);
+
+    return true;
+#else
+    return false;
+#endif
+}
+
 struct qemu_plugin_scoreboard *qemu_plugin_scoreboard_new(size_t element_size)
 {
     return plugin_scoreboard_new(element_size);
-- 
2.49.0