commit 80b14b5b32cb0a98234283daf9b5a6643e1a1ef3
author Izik Eidus <izike@qumranet.com> Thu Oct 25 11:54:04 2007 +0200
committer Avi Kivity <avi@qumranet.com> Wed Jan 30 17:52:55 2008 +0200
tree 1abf719d18e5bcbb6ba7fd5b517bb70ebb8b1776
parent 5f43238d036fb30e73563e81e42d9c6f1de5551a

KVM: Unmap kernel-allocated memory on slot destruction

kvm_vm_ioctl_set_memory_region() is able to remove memory in addition to
adding it.  Therefore when using kernel swapping support for old userspaces,
we need to munmap the memory if the user request to remove it

Signed-off-by: Izik Eidus <izike@qumranet.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>

drivers/kvm/kvm.h

diff --git a/drivers/kvm/kvm.h b/drivers/kvm/kvm.h
index f7181a4..12de42c 100644
--- a/drivers/kvm/kvm.h
+++ b/drivers/kvm/kvm.h
@@ -353,6 +353,7 @@
 	unsigned long *rmap;
 	unsigned long *dirty_bitmap;
 	unsigned long userspace_addr;
+	int user_alloc;
 };
 
 struct kvm {

drivers/kvm/kvm_main.c

diff --git a/drivers/kvm/kvm_main.c b/drivers/kvm/kvm_main.c
index 453e98e..ab2c77c 100644
--- a/drivers/kvm/kvm_main.c
+++ b/drivers/kvm/kvm_main.c
@@ -713,6 +713,7 @@
 
 		memset(new.rmap, 0, npages * sizeof(*new.rmap));
 
+		new.user_alloc = user_alloc;
 		if (user_alloc)
 			new.userspace_addr = mem->userspace_addr;
 		else {
@@ -727,6 +728,19 @@
 			if (IS_ERR((void *)new.userspace_addr))
 				goto out_unlock;
 		}
+	} else {
+		if (!old.user_alloc && old.rmap) {
+			int ret;
+
+			down_write(&current->mm->mmap_sem);
+			ret = do_munmap(current->mm, old.userspace_addr,
+					old.npages * PAGE_SIZE);
+			up_write(&current->mm->mmap_sem);
+			if (ret < 0)
+				printk(KERN_WARNING
+				       "kvm_vm_ioctl_set_memory_region: "
+				       "failed to munmap memory\n");
+		}
 	}
 
 	/* Allocate page dirty bitmap if needed */