[21/26] KVM: PPC: Introduce kvm_tmp framework

Commit Message

Alexander Graf June 25, 2010, 11:25 p.m. UTC

None

Patch

diff --git a/arch/powerpc/kernel/kvm.c b/arch/powerpc/kernel/kvm.c
index b091f94..7e8fe6f 100644
--- a/arch/powerpc/kernel/kvm.c
+++ b/arch/powerpc/kernel/kvm.c
@@ -64,6 +64,8 @@ 
 #define KVM_INST_TLBSYNC	0x7c00046c
 
 static bool kvm_patching_worked = true;
+static char kvm_tmp[1024 * 1024];
+static int kvm_tmp_index;
 
 static void kvm_patch_ins_ld(u32 *inst, long addr, u32 rt)
 {
@@ -98,6 +100,23 @@  static void kvm_patch_ins_nop(u32 *inst)
 	*inst = KVM_INST_NOP;
 }
 
+static u32 *kvm_alloc(int len)
+{
+	u32 *p;
+
+	if ((kvm_tmp_index + len) > ARRAY_SIZE(kvm_tmp)) {
+		printk(KERN_ERR "KVM: No more space (%d + %d)\n",
+				kvm_tmp_index, len);
+		kvm_patching_worked = false;
+		return NULL;
+	}
+
+	p = (void*)&kvm_tmp[kvm_tmp_index];
+	kvm_tmp_index += len;
+
+	return p;
+}
+
 static void kvm_map_magic_page(void *data)
 {
 	kvm_hypercall2(KVM_HC_PPC_MAP_MAGIC_PAGE,
@@ -197,12 +216,27 @@  static void kvm_use_magic_page(void)
 		kvm_check_ins(p);
 }
 
+static void kvm_free_tmp(void)
+{
+	unsigned long start, end;
+
+	start = (ulong)&kvm_tmp[kvm_tmp_index + (PAGE_SIZE - 1)] & PAGE_MASK;
+	end = (ulong)&kvm_tmp[ARRAY_SIZE(kvm_tmp)] & PAGE_MASK;
+
+	/* Free the tmp space we don't need */
+	for (; start < end; start += PAGE_SIZE) {
+		ClearPageReserved(virt_to_page(start));
+		init_page_count(virt_to_page(start));
+		free_page(start);
+		totalram_pages++;
+	}
+}
+
 static int __init kvm_guest_init(void)
 {
-	char *p;
 
 	if (!kvm_para_available())
-		return 0;
+		goto free_tmp;
 
 	if (kvm_para_has_feature(KVM_FEATURE_MAGIC_PAGE))
 		kvm_use_magic_page();
@@ -210,6 +244,9 @@  static int __init kvm_guest_init(void)
 	printk(KERN_INFO "KVM: Live patching for a fast VM %s\n",
 			 kvm_patching_worked ? "worked" : "failed");
 
+free_tmp:
+	kvm_free_tmp();
+
 	return 0;
 }