[Qemu-devel] [PATCH v4 24/54] plugins: implement helpers for resolving hwaddr

["Alex Bennée" <alex.bennee@linaro.org>]

We need to keep a local per-cpu copy of the data as other threads may
be running. We use a automatically growing array and re-use the space
for subsequent queries.

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
---
 accel/tcg/cputlb.c      | 32 ++++++++++++++++++++++++++
 include/exec/exec-all.h | 17 ++++++++++++++
 include/qemu/plugin.h   |  6 +++++
 plugins/api.c           | 50 +++++++++++++++++++++++++++++++++--------
 4 files changed, 96 insertions(+), 9 deletions(-)

diff --git a/accel/tcg/cputlb.c b/accel/tcg/cputlb.c
index f7c0290639c..f37e89c806d 100644
--- a/accel/tcg/cputlb.c
+++ b/accel/tcg/cputlb.c
@@ -1130,6 +1130,38 @@ void *tlb_vaddr_to_host(CPUArchState *env, abi_ptr addr,
     return (void *)((uintptr_t)addr + entry->addend);
 }
 
+
+#ifdef CONFIG_PLUGIN
+/*
+ * Perform a TLB lookup and populate the qemu_plugin_hwaddr structure.
+ * This should be a hot path as we will have just looked this path up
+ * in the softmmu lookup code (or helper). We don't handle re-fills or
+ * checking the victim table. This is purely informational.
+ */
+
+bool tlb_plugin_lookup(CPUState *cpu, target_ulong addr, int mmu_idx,
+                       bool is_store, struct qemu_plugin_hwaddr *data)
+{
+    CPUArchState *env = cpu->env_ptr;
+    CPUTLBEntry *tlbe = tlb_entry(env, mmu_idx, addr);
+    target_ulong tlb_addr = is_store ? tlb_addr_write(tlbe) : tlbe->addr_read;
+
+    if (tlb_hit(tlb_addr, addr)) {
+        if (tlb_addr & TLB_MMIO) {
+            data->hostaddr = 0;
+            data->is_io = true;
+            /* XXX: lookup device */
+        } else {
+            data->hostaddr = addr + tlbe->addend;
+            data->is_io = false;
+        }
+        return true;
+    }
+    return false;
+}
+
+#endif
+
 /* Probe for a read-modify-write atomic operation.  Do not allow unaligned
  * operations, or io operations to proceed.  Return the host address.  */
 static void *atomic_mmu_lookup(CPUArchState *env, target_ulong addr,
diff --git a/include/exec/exec-all.h b/include/exec/exec-all.h
index 90045e77c1f..c42626e35b1 100644
--- a/include/exec/exec-all.h
+++ b/include/exec/exec-all.h
@@ -262,6 +262,17 @@ void tlb_set_page(CPUState *cpu, target_ulong vaddr,
                   int mmu_idx, target_ulong size);
 void probe_write(CPUArchState *env, target_ulong addr, int size, int mmu_idx,
                  uintptr_t retaddr);
+
+/**
+ * tlb_plugin_lookup: query last TLB lookup
+ * @cpu: cpu environment
+ *
+ * This function can be used directly after a memory operation to
+ * query information about the access. It is used by the plugin
+ * infrastructure to expose more information about the address.
+ */
+bool tlb_plugin_lookup(CPUState *cpu, target_ulong addr, int mmu_idx,
+                       bool is_store, struct qemu_plugin_hwaddr *data);
 #else
 static inline void tlb_init(CPUState *cpu)
 {
@@ -311,6 +322,12 @@ static inline void tlb_flush_by_mmuidx_all_cpus_synced(CPUState *cpu,
                                                        uint16_t idxmap)
 {
 }
+static inline bool tlb_plugin_lookup(CPUState *cpu, target_ulong addr,
+                                     int mmu_idx, bool is_store,
+                                     struct qemu_plugin_hwaddr *data)
+{
+    return false;
+}
 #endif
 
 #define CODE_GEN_ALIGN           16 /* must be >= of the size of a icache line */
diff --git a/include/qemu/plugin.h b/include/qemu/plugin.h
index 3c46a241669..657345df60c 100644
--- a/include/qemu/plugin.h
+++ b/include/qemu/plugin.h
@@ -182,6 +182,12 @@ struct qemu_plugin_insn *qemu_plugin_tb_insn_get(struct qemu_plugin_tb *tb)
     return insn;
 }
 
+struct qemu_plugin_hwaddr {
+    uint64_t hostaddr;
+    bool is_io;
+};
+
+
 #ifdef CONFIG_PLUGIN
 
 void qemu_plugin_vcpu_init_hook(CPUState *cpu);
diff --git a/plugins/api.c b/plugins/api.c
index 586bb8789f1..4b3ac9e31fb 100644
--- a/plugins/api.c
+++ b/plugins/api.c
@@ -39,7 +39,7 @@
 #include "cpu.h"
 #include "sysemu/sysemu.h"
 #include "tcg/tcg.h"
-#include "trace/mem-internal.h" /* mem_info macros */
+#include "exec/exec-all.h"
 #include "plugin.h"
 #ifndef CONFIG_USER_ONLY
 #include "hw/boards.h"
@@ -240,11 +240,42 @@ bool qemu_plugin_mem_is_store(qemu_plugin_meminfo_t info)
  * Virtual Memory queries
  */
 
+#ifdef CONFIG_SOFTMMU
+static GArray *hwaddr_refs;
+
+struct qemu_plugin_hwaddr *qemu_plugin_get_hwaddr(qemu_plugin_meminfo_t info,
+                                                  uint64_t vaddr)
+{
+    CPUState *cpu = current_cpu;
+    unsigned int mmu_idx = info >> TRACE_MEM_MMU_SHIFT;
+    struct qemu_plugin_hwaddr *hwaddr;
+
+    /* Ensure we have memory allocated for this work */
+    if (!hwaddr_refs) {
+        hwaddr_refs = g_array_sized_new(false, true,
+                                        sizeof(struct qemu_plugin_hwaddr),
+                                        cpu->cpu_index + 1);
+    } else if (cpu->cpu_index >= hwaddr_refs->len) {
+        hwaddr_refs = g_array_set_size(hwaddr_refs, cpu->cpu_index + 1);
+    }
+
+    hwaddr = &g_array_index(hwaddr_refs, struct qemu_plugin_hwaddr,
+                            cpu->cpu_index);
+
+    if (!tlb_plugin_lookup(cpu, vaddr, mmu_idx,
+                           info & TRACE_MEM_ST, hwaddr)) {
+        return NULL;
+    }
+
+    return hwaddr;
+}
+#else
 struct qemu_plugin_hwaddr *qemu_plugin_get_hwaddr(qemu_plugin_meminfo_t info,
                                                   uint64_t vaddr)
 {
     return NULL;
 }
+#endif
 
 bool qemu_plugin_hwaddr_is_io(struct qemu_plugin_hwaddr *hwaddr)
 {
@@ -253,14 +284,15 @@ bool qemu_plugin_hwaddr_is_io(struct qemu_plugin_hwaddr *hwaddr)
 
 uint64_t qemu_plugin_hwaddr_to_raddr(const struct qemu_plugin_hwaddr *haddr)
 {
-#if 0 /* XXX FIXME should be SOFTMMU */
-    ram_addr_t ram_addr;
-
-    g_assert(haddr);
-    ram_addr = qemu_ram_addr_from_host(haddr);
-    if (ram_addr == RAM_ADDR_INVALID) {
-        error_report("Bad ram pointer %p", haddr);
-        abort();
+#ifdef CONFIG_SOFTMMU
+    ram_addr_t ram_addr = 0;
+
+    if (haddr && !haddr->is_io) {
+        ram_addr = qemu_ram_addr_from_host((void *) haddr->hostaddr);
+        if (ram_addr == RAM_ADDR_INVALID) {
+            error_report("Bad ram pointer %"PRIx64"", haddr->hostaddr);
+            abort();
+        }
     }
     return ram_addr;
 #else
-- 
2.20.1