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KVM: Unmap kernel-allocated memory on slot destruction

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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>
This commit is contained in:
Izik Eidus 2007-10-25 11:54:04 +02:00 committed by Avi Kivity
parent 5f43238d03
commit 80b14b5b32
2 changed files with 15 additions and 0 deletions
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1
drivers/kvm/kvm.h
View File

@ -353,6 +353,7 @@ struct kvm_memory_slot {
unsigned long *rmap;
unsigned long *dirty_bitmap;
unsigned long userspace_addr;
int user_alloc;
};
struct kvm {

14
drivers/kvm/kvm_main.c
View File

@ -713,6 +713,7 @@ static int kvm_vm_ioctl_set_memory_region(struct kvm *kvm,
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 @@ static int kvm_vm_ioctl_set_memory_region(struct kvm *kvm,
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 */