patch "virt: acrn: Do hcall_destroy_vm() before resource release" added to char-misc-linus

This is a note to let you know that I've just added the patch titled

virt: acrn: Do hcall_destroy_vm() before resource release

to my char-misc git tree which can be found at
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc.git
in the char-misc-linus branch.

The patch will show up in the next release of the linux-next tree (usually sometime within the next 24 hours during the week.)

The patch will hopefully also be merged in Linus's tree for the next -rc kernel release.

If you have any questions about this process, please let me know.

From 4c4c1257b844ffe5d0933684e612f92c4b78e120 Mon Sep 17 00:00:00 2001
From: Shuo Liu <[email protected]>
Date: Thu, 22 Jul 2021 14:27:36 +0800
Subject: 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.

---
 drivers/virt/acrn/vm.c | 16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)

index 0d002a355a93..fbc9f1042000 100644
@@ -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);

2.32.0