commit cd8dbb13cfa36be06d1e54d97856dd0a7072845f
author Travis Geiselbrecht <travisg@google.com> Thu Aug 16 17:15:29 2018 -0700
committer Travis Geiselbrecht <travisg@google.com> Mon Aug 20 11:51:59 2018 -0700
tree 2384ffe427fd7c916dae8568946158b19ab9cf0b
parent bb8e7343dff10f457ba57cc67e7e30f16b5367ed

WIP [kernel][vm][vmalloc] pull all of the vmalloc/vmfree allocations out of a dedicated VMAR

Change-Id: I8c84327c802d48b50358167e9b22084b770f2e3b

kernel/vm/include/vm/vmalloc.h

diff --git a/kernel/vm/include/vm/vmalloc.h b/kernel/vm/include/vm/vmalloc.h
index e3dfe0a..8c1385a 100644
--- a/kernel/vm/include/vm/vmalloc.h
+++ b/kernel/vm/include/vm/vmalloc.h
@@ -16,4 +16,6 @@
 void* vmalloc(size_t len, const char* name);
 void vmfree(void* ptr);
 
+void vmalloc_init(void);
+
 __END_CDECLS

kernel/vm/vm.cpp

diff --git a/kernel/vm/vm.cpp b/kernel/vm/vm.cpp
index e9ffaac..2bc9e78 100644
--- a/kernel/vm/vm.cpp
+++ b/kernel/vm/vm.cpp
@@ -23,6 +23,7 @@
 #include <vm/pmm.h>
 #include <vm/vm.h>
 #include <vm/vm_aspace.h>
+#include <vm/vmalloc.h>
 #include <zircon/types.h>
 
 #define LOCAL_TRACE MAX(VM_GLOBAL_TRACE, 0)
@@ -177,6 +178,8 @@
     ASSERT(status == ZX_OK);
     LTRACEF("VM: aspace random padding size: %#" PRIxPTR "\n", random_size);
 #endif
+
+    vmalloc_init();
 }
 
 paddr_t vaddr_to_paddr(const void* ptr) {

kernel/vm/vmalloc.cpp

diff --git a/kernel/vm/vmalloc.cpp b/kernel/vm/vmalloc.cpp
index 6723abc..b39caba 100644
--- a/kernel/vm/vmalloc.cpp
+++ b/kernel/vm/vmalloc.cpp
@@ -8,21 +8,59 @@
 
 #include <trace.h>
 #include <vm/vm_aspace.h>
+#include <vm/vm_object_paged.h>
+
+#define LOCAL_TRACE 0
 
 static const uint kArchRwFlags = ARCH_MMU_FLAG_PERM_READ | ARCH_MMU_FLAG_PERM_WRITE;
+static fbl::RefPtr<VmAddressRegion> vmalloc_vmar;
 
-void* vmalloc(size_t len, const char* name) {
-    void* ptr;
-    zx_status_t status = VmAspace::kernel_aspace()->Alloc(name ? name : "vmalloc",
-            len, &ptr, 0, VmAspace::VMM_FLAG_COMMIT, kArchRwFlags);
+// the power of 2 size of the vmar used for vmalloc mappings
+static const size_t vmalloc_vmar_shift = 30; // 1GB
+
+void* vmalloc(size_t len, const char* _name) {
+    const char* name = _name ? _name : "vmalloc";
+
+    // Create a VMO for our allocation
+    fbl::RefPtr<VmObject> vmo;
+    zx_status_t status = VmObjectPaged::Create(
+        PMM_ALLOC_FLAG_ANY, 0u, len, &vmo);
     if (status != ZX_OK) {
+        TRACEF("vmalloc: failed to allocate vmo of size %zu\n", len);
         return nullptr;
     }
+    vmo->set_name(name, strlen(name));
+
+    auto vmo_size = vmo->size();
+
+    // create a mapping with random placement into the vmalloc region
+    fbl::RefPtr<VmMapping> mapping;
+    status = vmalloc_vmar->CreateVmMapping(0, vmo_size, 0,
+                                          0,
+                                          fbl::move(vmo), 0,
+                                          kArchRwFlags,
+                                          name,
+                                          &mapping);
+    if (status != ZX_OK)
+        return nullptr;
+
+    // fault in all the pages so we dont demand fault in the allocation
+    status = mapping->MapRange(0, vmo_size, true);
+    if (status != ZX_OK) {
+        mapping->Destroy();
+        return nullptr;
+    }
+
+    void* ptr = reinterpret_cast<void*>(mapping->base());
+
+    LTRACEF("returning %p for size %zu\n", ptr, len);
 
     return ptr;
 }
 
 void vmfree(void* ptr) {
+    LTRACEF("ptr %p\n", ptr);
+
     vaddr_t va = reinterpret_cast<vaddr_t>(ptr);
 
     DEBUG_ASSERT(is_kernel_address(va));
@@ -33,3 +71,12 @@
     }
 }
 
+void vmalloc_init() {
+    auto root_vmar = VmAspace::kernel_aspace()->RootVmar()->as_vm_address_region();
+
+    zx_status_t status = root_vmar->CreateSubVmar(0,
+            (1ULL << vmalloc_vmar_shift), vmalloc_vmar_shift,
+            VMAR_FLAG_CAN_MAP_READ | VMAR_FLAG_CAN_MAP_WRITE,
+            "vmalloc vmar", &vmalloc_vmar);
+    ASSERT(status == ZX_OK);
+}