virt: acrn: Do hcall_destroy_vm() before resource release

The ACRN hypervisor has scenarios which could run a real-time guest VM.
The real-time guest VM occupies dedicated CPU cores, be assigned with
dedicated PCI devices. It can run without the Service VM after boot up.
hcall_destroy_vm() returns failure when a real-time guest VM refuses.
The clearing of flag ACRN_VM_FLAG_DESTROYED causes some kernel resource
double-freed in a later acrn_vm_destroy().

Do hcall_destroy_vm() before resource release to drop this chance to
destroy the VM if hypercall fails.

Fixes: 9c5137aedd11 ("virt: acrn: Introduce VM management interfaces")
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Shuo Liu <shuo.a.liu@intel.com>
Signed-off-by: Fei Li <fei1.li@intel.com>
Link: https://lore.kernel.org/r/20210722062736.15050-1-fei1.li@intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/virt/acrn/vm.c b/drivers/virt/acrn/vm.c
index 0d002a3..fbc9f10 100644 (file)
--- a/drivers/virt/acrn/vm.c
+++ b/drivers/virt/acrn/vm.c
@@ -64,6 +64,14 @@ int acrn_vm_destroy(struct acrn_vm *vm)
            test_and_set_bit(ACRN_VM_FLAG_DESTROYED, &vm->flags))
                return 0;
 
+       ret = hcall_destroy_vm(vm->vmid);
+       if (ret < 0) {
+               dev_err(acrn_dev.this_device,
+                       "Failed to destroy VM %u\n", vm->vmid);
+               clear_bit(ACRN_VM_FLAG_DESTROYED, &vm->flags);
+               return ret;
+       }
+
        /* Remove from global VM list */
        write_lock_bh(&acrn_vm_list_lock);
        list_del_init(&vm->list);
@@ -78,14 +86,6 @@ int acrn_vm_destroy(struct acrn_vm *vm)
                vm->monitor_page = NULL;
        }
 
-       ret = hcall_destroy_vm(vm->vmid);
-       if (ret < 0) {
-               dev_err(acrn_dev.this_device,
-                       "Failed to destroy VM %u\n", vm->vmid);
-               clear_bit(ACRN_VM_FLAG_DESTROYED, &vm->flags);
-               return ret;
-       }
-
        acrn_vm_all_ram_unmap(vm);
 
        dev_dbg(acrn_dev.this_device, "VM %u destroyed.\n", vm->vmid);