Re: [PATCH 2/2] KVM: Fix kvm_free_physmem_slot memory leak.

[François Diakhate]

[Updated the patch taking your comments into account]

Make sure that kvm_free_physmem_slot also frees the VM memory
if it was allocated by the kernel.

Signed-off-by: François Diakhaté <[EMAIL PROTECTED]>
---
 arch/x86/kvm/x86.c  |   10 +++++-----
 virt/kvm/kvm_main.c |   18 ++++++++++++++----
 2 files changed, 19 insertions(+), 9 deletions(-)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 883c137..818220b 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -4179,13 +4179,13 @@ int kvm_arch_set_memory_region(struct kvm *kvm,
                if (npages && !old.rmap) {
                        unsigned long userspace_addr;

-                       down_write(&current->mm->mmap_sem);
+                       down_write(&kvm->mm->mmap_sem);
                        userspace_addr = do_mmap(NULL, 0,
                                                 npages * PAGE_SIZE,
                                                 PROT_READ | PROT_WRITE,
                                                 MAP_PRIVATE | MAP_ANONYMOUS,
                                                 0);
-                       up_write(&current->mm->mmap_sem);
+                       up_write(&kvm->mm->mmap_sem);

                        if (IS_ERR((void *)userspace_addr))
                                return PTR_ERR((void *)userspace_addr);
@@ -4198,10 +4198,10 @@ int kvm_arch_set_memory_region(struct kvm *kvm,
                        if (!old.user_alloc && old.rmap) {
                                int ret;

-                               down_write(&current->mm->mmap_sem);
-                               ret = do_munmap(current->mm, old.userspace_addr,
+                               down_write(&kvm->mm->mmap_sem);
+                               ret = do_munmap(kvm->mm, old.userspace_addr,
                                                old.npages * PAGE_SIZE);
-                               up_write(&current->mm->mmap_sem);
+                               up_write(&kvm->mm->mmap_sem);
                                if (ret < 0)
                                        printk(KERN_WARNING
                                       "kvm_vm_ioctl_set_memory_region: "
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index a87f45e..b420930 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -617,9 +617,19 @@ out:
 /*
  * 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->userspace_addr != dont->userspace_addr) {
+               struct kvm_userspace_memory_region mem = {
+                       .slot = memslot_id(kvm, free),
+                       .guest_phys_addr = free->base_gfn << PAGE_SHIFT,
+                       .memory_size = 0,
+                       .flags = 0,
+               };
+               kvm_arch_set_memory_region(kvm, &mem, *free, free->user_alloc);
+       }
+
        if (!dont || free->rmap != dont->rmap)
                vfree(free->rmap);

@@ -640,7 +650,7 @@ void kvm_free_physmem(struct kvm *kvm)
        int i;

        for (i = 0; i < kvm->nmemslots; ++i)
-               kvm_free_physmem_slot(&kvm->memslots[i], NULL);
+               kvm_free_physmem_slot(kvm, &kvm->memslots[i], NULL);
 }

 static void kvm_destroy_vm(struct kvm *kvm)
@@ -821,7 +831,7 @@ int __kvm_set_memory_region(struct kvm *kvm,
                goto out_free;
        }

-       kvm_free_physmem_slot(&old, &new);
+       kvm_free_physmem_slot(kvm, &old, &new);
 #ifdef CONFIG_DMAR
        /* map the pages in iommu page table */
        r = kvm_iommu_map_pages(kvm, base_gfn, npages);
@@ -831,7 +841,7 @@ int __kvm_set_memory_region(struct kvm *kvm,
        return 0;

 out_free:
-       kvm_free_physmem_slot(&new, &old);
+       kvm_free_physmem_slot(kvm, &new, &old);
 out:
        return r;

-- 
1.6.0.3