[RFC,v1,02/22] cpu-common: add debug version of physical memory read/write

Commit Message

Brijesh Singh Sept. 13, 2016, 2:47 p.m. UTC

The patch adds the following new APIs:
- cpu_physical_memory_read_debug
- cpu_physical_memory_write_debug

These API's can be used when reading/writing guest physical memory for
debugging purposes. In next patch will update the hmp monitor memory
dump commands (xp, info mem, info tlb etc) to use this API instead of
cpu_physical_memory_read() to access the guest physical memory.

The idea behind this patch is that in case of SEV-enabled guest we
need a method to identify whether the memory access is for debug
purposes.

If all the debug access requests are done through these API's then
we can create/set special sev specific MemTxAttrs to indicate that
RAM access is for debugg purposes and use SEV debug commands to
read and write guest memory for debug purposes.

Signed-off-by: Brijesh Singh <[e-mail]>
---
 exec.c                    |   10 ++++++++++
 include/exec/cpu-common.h |   12 ++++++++++++
 2 files changed, 22 insertions(+)

Patch

diff --git a/exec.c b/exec.c
index d0f45b4..604bd05 100644
--- a/exec.c
+++ b/exec.c
@@ -3768,6 +3768,16 @@  void stq_be_phys(AddressSpace *as, hwaddr addr, uint64_t val)
     address_space_stq_be(as, addr, val, MEMTXATTRS_UNSPECIFIED, NULL);
 }
 
+void cpu_physical_memory_rw_debug(hwaddr addr, uint8_t *buf,
+                                  int len, int is_write)
+{
+    MemTxAttrs attrs;
+
+    attrs = MEMTXATTRS_UNSPECIFIED;
+
+    address_space_rw(&address_space_memory, addr, attrs, buf, len, is_write);
+}
+
 /* virtual memory access for debug (includes writing to ROM) */
 int cpu_memory_rw_debug(CPUState *cpu, target_ulong addr,
                         uint8_t *buf, int len, int is_write)
diff --git a/include/exec/cpu-common.h b/include/exec/cpu-common.h
index 952bcfe..1ebd9aa 100644
--- a/include/exec/cpu-common.h
+++ b/include/exec/cpu-common.h
@@ -61,6 +61,8 @@  const char *qemu_ram_get_idstr(RAMBlock *rb);
 
 void cpu_physical_memory_rw(hwaddr addr, uint8_t *buf,
                             int len, int is_write);
+void cpu_physical_memory_rw_debug(hwaddr addr, uint8_t *buf,
+                                  int len, int is_write);
 static inline void cpu_physical_memory_read(hwaddr addr,
                                             void *buf, int len)
 {
@@ -71,6 +73,16 @@  static inline void cpu_physical_memory_write(hwaddr addr,
 {
     cpu_physical_memory_rw(addr, (void *)buf, len, 1);
 }
+static inline void cpu_physical_memory_read_debug(hwaddr addr,
+                                                  void *buf, int len)
+{
+    cpu_physical_memory_rw_debug(addr, buf, len, 0);
+}
+static inline void cpu_physical_memory_write_debug(hwaddr addr,
+                                                   const void *buf, int len)
+{
+    cpu_physical_memory_rw_debug(addr, (void *)buf, len, 1);
+}
 void *cpu_physical_memory_map(hwaddr addr,
                               hwaddr *plen,
                               int is_write);