Il 17/04/2013 19:54, Andrew Honig ha scritto:
>
> If userspace creates and destroys multiple VMs within the same process
> we leak 20k of memory in the userspace process context per VM. This
> patch frees the memory in kvm_arch_destroy_vm. If the process exits
> without closing the VM file descriptor or the file descriptor has been
> shared with another process then we don't need to free the memory.
>
> Signed-off-by: Andrew Honig <ahonig@xxxxxxxxxx>
> ---
> arch/x86/kvm/x86.c | 17 +++++++++++++++++
> 1 file changed, 17 insertions(+)
What about something like this (uncompiled/untested)
diff --git a/arch/ia64/kvm/kvm-ia64.c b/arch/ia64/kvm/kvm-ia64.c
index 8b3a9c0..6706134 100644
--- a/arch/ia64/kvm/kvm-ia64.c
+++ b/arch/ia64/kvm/kvm-ia64.c
@@ -1563,7 +1563,8 @@ int kvm_arch_vcpu_fault(struct kvm_vcpu *vcpu, struct vm_fault *vmf)
return VM_FAULT_SIGBUS;
}
-void kvm_arch_free_memslot(struct kvm_memory_slot *free,
+void kvm_arch_free_memslot(struct kvm *kvm,
+ struct kvm_memory_slot *free,
struct kvm_memory_slot *dont)
{
}
diff --git a/arch/powerpc/kvm/powerpc.c b/arch/powerpc/kvm/powerpc.c
index 4d213b8..a654580 100644
--- a/arch/powerpc/kvm/powerpc.c
+++ b/arch/powerpc/kvm/powerpc.c
@@ -299,7 +299,8 @@ long kvm_arch_dev_ioctl(struct file *filp,
return -EINVAL;
}
-void kvm_arch_free_memslot(struct kvm_memory_slot *free,
+void kvm_arch_free_memslot(struct kvm *kvm,
+ struct kvm_memory_slot *free,
struct kvm_memory_slot *dont)
{
if (!dont || free->arch.rmap != dont->arch.rmap) {
diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
index ecced9d..e2159c1 100644
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -912,7 +912,8 @@ int kvm_arch_vcpu_fault(struct kvm_vcpu *vcpu, struct vm_fault *vmf)
return VM_FAULT_SIGBUS;
}
-void kvm_arch_free_memslot(struct kvm_memory_slot *free,
+void kvm_arch_free_memslot(struct kvm *kvm,
+ struct kvm_memory_slot *free,
struct kvm_memory_slot *dont)
{
}
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 224a7e7..f9fa0d1 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -6357,11 +6367,26 @@ void kvm_arch_destroy_vm(struct kvm *kvm)
kfree(rcu_dereference_check(kvm->arch.apic_map, 1));
}
-void kvm_arch_free_memslot(struct kvm_memory_slot *free,
+void kvm_arch_free_memslot(struct kvm *kvm,
+ struct kvm_memory_slot *free,
struct kvm_memory_slot *dont)
{
int i;
+ if (current->mm == kvm->mm && free->user_alloc) {
+ if (!dont || !dont->user_alloc ||
+ free->userspace_addr != dont->userspace_addr) {
+ int ret;
+
+ ret = vm_munmap(free->userspace_addr,
+ free->npages * PAGE_SIZE);
+ if (ret < 0)
+ printk(KERN_WARNING
+ "kvm_vm_ioctl_set_memory_region: "
+ "failed to munmap memory\n");
+ }
+ }
+
for (i = 0; i < KVM_NR_PAGE_SIZES; ++i) {
if (!dont || free->arch.rmap[i] != dont->arch.rmap[i]) {
kvm_kvfree(free->arch.rmap[i]);
@@ -6453,7 +6478,7 @@ int kvm_arch_prepare_memory_region(struct kvm *kvm,
*x86 needs to handle !user_alloc case.
*/
if (!user_alloc) {
- if (npages && !old.npages) {
+ if (npages != old.npages) {
unsigned long userspace_addr;
userspace_addr = vm_mmap(NULL, 0,
@@ -6466,7 +6491,8 @@ int kvm_arch_prepare_memory_region(struct kvm *kvm,
return PTR_ERR((void *)userspace_addr);
memslot->userspace_addr = userspace_addr;
- }
+ } else
+ memslot->userspace_addr = old.userspace_addr;
}
@@ -6481,17 +6507,6 @@ void kvm_arch_commit_memory_region(struct kvm *kvm,
int nr_mmu_pages = 0, npages = mem->memory_size >> PAGE_SHIFT;
- if (!user_alloc && !old.user_alloc && old.npages && !npages) {
- int ret;
-
- ret = vm_munmap(old.userspace_addr,
- old.npages * PAGE_SIZE);
- if (ret < 0)
- printk(KERN_WARNING
- "kvm_vm_ioctl_set_memory_region: "
- "failed to munmap memory\n");
- }
-
if (!kvm->arch.n_requested_mmu_pages)
nr_mmu_pages = kvm_mmu_calculate_mmu_pages(kvm);
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index ecc5543..8f2a863 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -436,7 +436,8 @@ int kvm_set_memory_region(struct kvm *kvm,
int __kvm_set_memory_region(struct kvm *kvm,
struct kvm_userspace_memory_region *mem,
int user_alloc);
-void kvm_arch_free_memslot(struct kvm_memory_slot *free,
+void kvm_arch_free_memslot(struct kvm *kvm,
+ struct kvm_memory_slot *free,
struct kvm_memory_slot *dont);
int kvm_arch_create_memslot(struct kvm_memory_slot *slot, unsigned long npages);
int kvm_arch_prepare_memory_region(struct kvm *kvm,
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index be70035..ea63b9c 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -546,13 +546,14 @@ static void kvm_destroy_dirty_bitmap(struct kvm_memory_slot *memslot)
/*
* Free any memory in @free but not in @dont.
*/
-static void kvm_free_physmem_slot(struct kvm_memory_slot *free,
+static void kvm_free_physmem_slot(struct kvm *kvm,
+ struct kvm_memory_slot *free,
struct kvm_memory_slot *dont)
{
if (!dont || free->dirty_bitmap != dont->dirty_bitmap)
kvm_destroy_dirty_bitmap(free);
- kvm_arch_free_memslot(free, dont);
+ kvm_arch_free_memslot(kvm, free, dont);
free->npages = 0;
}
@@ -563,7 +564,7 @@ void kvm_free_physmem(struct kvm *kvm)
struct kvm_memory_slot *memslot;
kvm_for_each_memslot(memslot, slots)
- kvm_free_physmem_slot(memslot, NULL);
+ kvm_free_physmem_slot(kvm, memslot, NULL);
kfree(kvm->memslots);
}
@@ -851,13 +852,13 @@ int __kvm_set_memory_region(struct kvm *kvm,
kvm_arch_commit_memory_region(kvm, mem, old, user_alloc);
- kvm_free_physmem_slot(&old, &new);
+ kvm_free_physmem_slot(kvm, &old, &new);
kfree(old_memslots);
return 0;
out_free:
- kvm_free_physmem_slot(&new, &old);
+ kvm_free_physmem_slot(kvm, &new, &old);
out:
return r;
--
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