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authorOliver Upton <oupton@google.com>2022-07-20 09:22:51 +0000
committerPaolo Bonzini <pbonzini@redhat.com>2022-08-10 15:08:28 -0400
commitb74ed7a68ec183403763571a54ca3dcc24cf19eb (patch)
treeda5f990836a9302e0f91cecc870ee7a70fc1db96 /virt/kvm
parent59f82aad5940ffd0fedfe07ff755168722193d56 (diff)
downloadlinux-b74ed7a68ec183403763571a54ca3dcc24cf19eb.tar.bz2
KVM: Actually create debugfs in kvm_create_vm()
Doing debugfs creation after vm creation leaves things in a quasi-initialized state for a while. This is further complicated by the fact that we tear down debugfs from kvm_destroy_vm(). Align debugfs and stats init/destroy with the vm init/destroy pattern to avoid any headaches. Note the fix for a benign mistake in error handling for calls to kvm_arch_create_vm_debugfs() rolled in. Since all implementations of the function return 0 unconditionally it isn't actually a bug at the moment. Lastly, tear down debugfs/stats data in the kvm_create_vm_debugfs() error path. Previously it was safe to assume that kvm_destroy_vm() would take out the garbage, that is no longer the case. Signed-off-by: Oliver Upton <oupton@google.com> Message-Id: <20220720092259.3491733-6-oliver.upton@linux.dev> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'virt/kvm')
-rw-r--r--virt/kvm/kvm_main.c36
1 files changed, 19 insertions, 17 deletions
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 8e08f66ddbd4..515dfe9d3bcf 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -1028,7 +1028,7 @@ static int kvm_create_vm_debugfs(struct kvm *kvm, const char *fdname)
char dir_name[ITOA_MAX_LEN * 2];
struct kvm_stat_data *stat_data;
const struct _kvm_stats_desc *pdesc;
- int i, ret;
+ int i, ret = -ENOMEM;
int kvm_debugfs_num_entries = kvm_vm_stats_header.num_desc +
kvm_vcpu_stats_header.num_desc;
@@ -1054,13 +1054,13 @@ static int kvm_create_vm_debugfs(struct kvm *kvm, const char *fdname)
sizeof(*kvm->debugfs_stat_data),
GFP_KERNEL_ACCOUNT);
if (!kvm->debugfs_stat_data)
- return -ENOMEM;
+ goto out_err;
for (i = 0; i < kvm_vm_stats_header.num_desc; ++i) {
pdesc = &kvm_vm_stats_desc[i];
stat_data = kzalloc(sizeof(*stat_data), GFP_KERNEL_ACCOUNT);
if (!stat_data)
- return -ENOMEM;
+ goto out_err;
stat_data->kvm = kvm;
stat_data->desc = pdesc;
@@ -1075,7 +1075,7 @@ static int kvm_create_vm_debugfs(struct kvm *kvm, const char *fdname)
pdesc = &kvm_vcpu_stats_desc[i];
stat_data = kzalloc(sizeof(*stat_data), GFP_KERNEL_ACCOUNT);
if (!stat_data)
- return -ENOMEM;
+ goto out_err;
stat_data->kvm = kvm;
stat_data->desc = pdesc;
@@ -1087,12 +1087,13 @@ static int kvm_create_vm_debugfs(struct kvm *kvm, const char *fdname)
}
ret = kvm_arch_create_vm_debugfs(kvm);
- if (ret) {
- kvm_destroy_vm_debugfs(kvm);
- return i;
- }
+ if (ret)
+ goto out_err;
return 0;
+out_err:
+ kvm_destroy_vm_debugfs(kvm);
+ return ret;
}
/*
@@ -1123,7 +1124,7 @@ int __weak kvm_arch_create_vm_debugfs(struct kvm *kvm)
return 0;
}
-static struct kvm *kvm_create_vm(unsigned long type)
+static struct kvm *kvm_create_vm(unsigned long type, const char *fdname)
{
struct kvm *kvm = kvm_arch_alloc_vm();
struct kvm_memslots *slots;
@@ -1212,7 +1213,7 @@ static struct kvm *kvm_create_vm(unsigned long type)
r = kvm_arch_post_init_vm(kvm);
if (r)
- goto out_err;
+ goto out_err_mmu_notifier;
mutex_lock(&kvm_lock);
list_add(&kvm->vm_list, &vm_list);
@@ -1228,12 +1229,18 @@ static struct kvm *kvm_create_vm(unsigned long type)
*/
if (!try_module_get(kvm_chardev_ops.owner)) {
r = -ENODEV;
- goto out_err;
+ goto out_err_mmu_notifier;
}
+ r = kvm_create_vm_debugfs(kvm, fdname);
+ if (r)
+ goto out_err;
+
return kvm;
out_err:
+ module_put(kvm_chardev_ops.owner);
+out_err_mmu_notifier:
#if defined(CONFIG_MMU_NOTIFIER) && defined(KVM_ARCH_WANT_MMU_NOTIFIER)
if (kvm->mmu_notifier.ops)
mmu_notifier_unregister(&kvm->mmu_notifier, current->mm);
@@ -4900,7 +4907,7 @@ static int kvm_dev_ioctl_create_vm(unsigned long type)
snprintf(fdname, sizeof(fdname), "%d", fd);
- kvm = kvm_create_vm(type);
+ kvm = kvm_create_vm(type, fdname);
if (IS_ERR(kvm)) {
r = PTR_ERR(kvm);
goto put_fd;
@@ -4923,11 +4930,6 @@ static int kvm_dev_ioctl_create_vm(unsigned long type)
* cases it will be called by the final fput(file) and will take
* care of doing kvm_put_kvm(kvm).
*/
- if (kvm_create_vm_debugfs(kvm, fdname) < 0) {
- fput(file);
- r = -ENOMEM;
- goto put_fd;
- }
kvm_uevent_notify_change(KVM_EVENT_CREATE_VM, kvm);
fd_install(fd, file);