[PATCH v2] plugins: Expose physical addresses instead of device offsets

* [PATCH v2] plugins: Expose physical addresses instead of device offsets
@ 2021-03-09 20:28 Aaron Lindsay
  2021-03-11 10:29 ` Alex Bennée
  0 siblings, 1 reply; 2+ messages in thread
From: Aaron Lindsay @ 2021-03-09 20:28 UTC (permalink / raw)
  To: qemu-devel, Peter Maydell, Alex Bennée
  Cc: cota, richard.henderson, Aaron Lindsay

This allows plugins to query for full virtual-to-physical address
translation for a given `qemu_plugin_hwaddr` and stops exposing the
offset within the device itself. As this change breaks the API,
QEMU_PLUGIN_VERSION is incremented.

Signed-off-by: Aaron Lindsay <aaron@os.amperecomputing.com>
---
 contrib/plugins/hotpages.c  |  2 +-
 contrib/plugins/hwprofile.c |  2 +-
 include/qemu/qemu-plugin.h  | 32 +++++++++++++++++++++++++-------
 plugins/api.c               | 17 ++++++++++++-----
 4 files changed, 39 insertions(+), 14 deletions(-)

diff --git a/contrib/plugins/hotpages.c b/contrib/plugins/hotpages.c
index eacc678eac..bf53267532 100644
--- a/contrib/plugins/hotpages.c
+++ b/contrib/plugins/hotpages.c
@@ -122,7 +122,7 @@ static void vcpu_haddr(unsigned int cpu_index, qemu_plugin_meminfo_t meminfo,
         }
     } else {
         if (hwaddr && !qemu_plugin_hwaddr_is_io(hwaddr)) {
-            page = (uint64_t) qemu_plugin_hwaddr_device_offset(hwaddr);
+            page = (uint64_t) qemu_plugin_hwaddr_phys_addr(hwaddr);
         } else {
             page = vaddr;
         }
diff --git a/contrib/plugins/hwprofile.c b/contrib/plugins/hwprofile.c
index 6dac1d5f85..faf216ac00 100644
--- a/contrib/plugins/hwprofile.c
+++ b/contrib/plugins/hwprofile.c
@@ -201,7 +201,7 @@ static void vcpu_haddr(unsigned int cpu_index, qemu_plugin_meminfo_t meminfo,
         return;
     } else {
         const char *name = qemu_plugin_hwaddr_device_name(hwaddr);
-        uint64_t off = qemu_plugin_hwaddr_device_offset(hwaddr);
+        uint64_t off = qemu_plugin_hwaddr_phys_addr(hwaddr);
         bool is_write = qemu_plugin_mem_is_store(meminfo);
         DeviceCounts *counts;
 
diff --git a/include/qemu/qemu-plugin.h b/include/qemu/qemu-plugin.h
index c66507fe8f..3303dce862 100644
--- a/include/qemu/qemu-plugin.h
+++ b/include/qemu/qemu-plugin.h
@@ -47,7 +47,7 @@ typedef uint64_t qemu_plugin_id_t;
 
 extern QEMU_PLUGIN_EXPORT int qemu_plugin_version;
 
-#define QEMU_PLUGIN_VERSION 0
+#define QEMU_PLUGIN_VERSION 1
 
 typedef struct {
     /* string describing architecture */
@@ -307,8 +307,8 @@ bool qemu_plugin_mem_is_sign_extended(qemu_plugin_meminfo_t info);
 bool qemu_plugin_mem_is_big_endian(qemu_plugin_meminfo_t info);
 bool qemu_plugin_mem_is_store(qemu_plugin_meminfo_t info);
 
-/*
- * qemu_plugin_get_hwaddr():
+/**
+ * qemu_plugin_get_hwaddr() - return handle for memory operation
  * @vaddr: the virtual address of the memory operation
  *
  * For system emulation returns a qemu_plugin_hwaddr handle to query
@@ -323,12 +323,30 @@ struct qemu_plugin_hwaddr *qemu_plugin_get_hwaddr(qemu_plugin_meminfo_t info,
                                                   uint64_t vaddr);
 
 /*
- * The following additional queries can be run on the hwaddr structure
- * to return information about it. For non-IO accesses the device
- * offset will be into the appropriate block of RAM.
+ * The following additional queries can be run on the hwaddr structure to
+ * return information about it - namely whether it is for an IO access and the
+ * physical address associated with the access.
+ */
+
+/**
+ * qemu_plugin_hwaddr_is_io() - query whether memory operation is IO
+ * @haddr: address handle from qemu_plugin_get_hwaddr()
+ *
+ * Returns true if the handle's memory operation is to memory-mapped IO, or
+ * false if it is to RAM
  */
 bool qemu_plugin_hwaddr_is_io(const struct qemu_plugin_hwaddr *haddr);
-uint64_t qemu_plugin_hwaddr_device_offset(const struct qemu_plugin_hwaddr *haddr);
+
+/**
+ * qemu_plugin_hwaddr_phys_addr() - query physical address for memory operation
+ * @haddr: address handle from qemu_plugin_get_hwaddr()
+ *
+ * Returns the physical address associated with the memory operation
+ *
+ * Note that the returned physical address may not be unique if you are dealing
+ * with multiple address spaces.
+ */
+uint64_t qemu_plugin_hwaddr_phys_addr(const struct qemu_plugin_hwaddr *haddr);
 
 /*
  * Returns a string representing the device. The string is valid for
diff --git a/plugins/api.c b/plugins/api.c
index 0b04380d57..3c7dc406e3 100644
--- a/plugins/api.c
+++ b/plugins/api.c
@@ -40,6 +40,7 @@
 #include "sysemu/sysemu.h"
 #include "tcg/tcg.h"
 #include "exec/exec-all.h"
+#include "exec/ram_addr.h"
 #include "disas/disas.h"
 #include "plugin.h"
 #ifndef CONFIG_USER_ONLY
@@ -298,19 +299,25 @@ bool qemu_plugin_hwaddr_is_io(const struct qemu_plugin_hwaddr *haddr)
 #endif
 }
 
-uint64_t qemu_plugin_hwaddr_device_offset(const struct qemu_plugin_hwaddr *haddr)
+uint64_t qemu_plugin_hwaddr_phys_addr(const struct qemu_plugin_hwaddr *haddr)
 {
 #ifdef CONFIG_SOFTMMU
     if (haddr) {
         if (!haddr->is_io) {
-            ram_addr_t ram_addr = qemu_ram_addr_from_host((void *) haddr->v.ram.hostaddr);
-            if (ram_addr == RAM_ADDR_INVALID) {
+            RAMBlock *block;
+            ram_addr_t offset;
+            void *hostaddr = (void *) haddr->v.ram.hostaddr;
+
+            block = qemu_ram_block_from_host(hostaddr, false, &offset);
+            if (!block) {
                 error_report("Bad ram pointer %"PRIx64"", haddr->v.ram.hostaddr);
                 abort();
             }
-            return ram_addr;
+
+            return block->offset + offset + block->mr->addr;
         } else {
-            return haddr->v.io.offset;
+            MemoryRegionSection *mrs = haddr->v.io.section;
+            return haddr->v.io.offset + mrs->mr->addr;
         }
     }
 #endif
-- 
2.17.1



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