[Qemu-devel] [PATCH 5/6] hook cpu_register_physical_mem

[Glauber Costa <glommer@redhat.com>]

Since now we have our own memory read/write function, we don't
depend on all of tcg data structures anymore. So, instead of filling
them up, bypass it altogether by using kvm_set_phys mem alone.

To do that, we now have to provide our own way to get page
information given the address. (kvm_get_physical_page_desc)

Signed-off-by: Glauber Costa <glommer@redhat.com>
---
 exec.c    |   44 +++++++++++++++++++++++++++++---------------
 kvm-all.c |   13 +++++++++++++
 kvm.h     |    2 ++
 3 files changed, 44 insertions(+), 15 deletions(-)

diff --git a/exec.c b/exec.c
index 20ac972..f009e41 100644
--- a/exec.c
+++ b/exec.c
@@ -2260,14 +2260,8 @@ static void *subpage_init (target_phys_addr_t base, ram_addr_t *phys,
         }                                                               \
     } while (0)
 
-/* register physical memory. 'size' must be a multiple of the target
-   page size. If (phys_offset & ~TARGET_PAGE_MASK) != 0, then it is an
-   io memory page.  The address used when calling the IO function is
-   the offset from the start of the region, plus region_offset.  Both
-   start_region and regon_offset are rounded down to a page boundary
-   before calculating this offset.  This should not be a problem unless
-   the low bits of start_addr and region_offset differ.  */
-void cpu_register_physical_memory_offset(target_phys_addr_t start_addr,
+
+static void default_register_physical_memory_offset(target_phys_addr_t start_addr,
                                          ram_addr_t size,
                                          ram_addr_t phys_offset,
                                          ram_addr_t region_offset)
@@ -2285,8 +2279,6 @@ void cpu_register_physical_memory_offset(target_phys_addr_t start_addr,
         kqemu_set_phys_mem(start_addr, size, phys_offset);
     }
 #endif
-    if (kvm_enabled())
-        kvm_set_phys_mem(start_addr, size, phys_offset);
 
     region_offset &= TARGET_PAGE_MASK;
     size = (size + TARGET_PAGE_SIZE - 1) & TARGET_PAGE_MASK;
@@ -2353,15 +2345,37 @@ void cpu_register_physical_memory_offset(target_phys_addr_t start_addr,
     }
 }
 
+/* register physical memory. 'size' must be a multiple of the target
+   page size. If (phys_offset & ~TARGET_PAGE_MASK) != 0, then it is an
+   io memory page.  The address used when calling the IO function is
+   the offset from the start of the region, plus region_offset.  Both
+   start_region and regon_offset are rounded down to a page boundary
+   before calculating this offset.  This should not be a problem unless
+   the low bits of start_addr and region_offset differ.  */
+void cpu_register_physical_memory_offset(target_phys_addr_t start_addr,
+                                         ram_addr_t size,
+                                         ram_addr_t phys_offset,
+                                         ram_addr_t region_offset)
+{
+    if (kvm_enabled())
+        kvm_set_phys_mem(start_addr, size, phys_offset);
+    else
+        default_register_physical_memory_offset(start_addr, size, phys_offset, region_offset);
+}
+
 /* XXX: temporary until new memory mapping API */
 ram_addr_t cpu_get_physical_page_desc(target_phys_addr_t addr)
 {
-    PhysPageDesc *p;
+    if (kvm_enabled()) {
+        return kvm_get_physical_page_desc(addr);
+    } else {
+        PhysPageDesc *p;
 
-    p = phys_page_find(addr >> TARGET_PAGE_BITS);
-    if (!p)
-        return IO_MEM_UNASSIGNED;
-    return p->phys_offset;
+        p = phys_page_find(addr >> TARGET_PAGE_BITS);
+        if (!p)
+            return IO_MEM_UNASSIGNED;
+        return p->phys_offset;
+    }
 }
 
 void qemu_register_coalesced_mmio(target_phys_addr_t addr, ram_addr_t size)
diff --git a/kvm-all.c b/kvm-all.c
index 9cbb2f9..85f2922 100644
--- a/kvm-all.c
+++ b/kvm-all.c
@@ -709,3 +709,16 @@ void kvm_cpu_physical_memory_rw(target_phys_addr_t addr, uint8_t *buf,
             kvm_cpu_physical_memory_rw(addr + l, buf + l, len - l, is_write);
     }
 }
+
+ram_addr_t kvm_get_physical_page_desc(target_phys_addr_t addr)
+{
+
+    KVMSlot *mem;
+    KVMState *s = kvm_state;
+    mem = kvm_lookup_slot(s, addr);
+
+    if (!mem)
+        return IO_MEM_UNASSIGNED;
+    else
+        return (addr - mem->start_addr) + mem->phys_offset;
+}
diff --git a/kvm.h b/kvm.h
index e3e9ca0..776cfcf 100644
--- a/kvm.h
+++ b/kvm.h
@@ -51,6 +51,8 @@ int kvm_uncoalesce_mmio_region(target_phys_addr_t start, ram_addr_t size);
 
 void kvm_cpu_physical_memory_rw(target_phys_addr_t addr, uint8_t *buf,
                                 int len, int is_write);
+
+ram_addr_t kvm_get_physical_page_desc(target_phys_addr_t addr);
 /* internal API */
 
 struct KVMState;
-- 
1.5.6.5