vm: add context to Pool.Create()

Enable external abortion of the instance creation process. This is
especially useful for the qemu case where we retry the creation/boot up
to 1000 times, which can take significant time (e.g. it timeouts
syz-cluster pods on unstable kernels).

The context can be further propagated to WaitForSSH, but that requires
another quite significant vm/ refactoring.

1 files changed, 4 insertions, 1 deletions

diff --git a/vm/qemu/qemu.go b/vm/qemu/qemu.go
index 3bf546aa2..63598d4bb 100644
--- a/vm/qemu/qemu.go
+++ b/vm/qemu/qemu.go
@@ -324,7 +324,7 @@ func (pool *Pool) Count() int {
 	return pool.cfg.Count
 }
 
-func (pool *Pool) Create(workdir string, index int) (vmimpl.Instance, error) {
+func (pool *Pool) Create(ctx context.Context, workdir string, index int) (vmimpl.Instance, error) {
 	sshkey := pool.env.SSHKey
 	sshuser := pool.env.SSHUser
 	if pool.env.Image == "9p" {
@@ -341,6 +341,9 @@ func (pool *Pool) Create(workdir string, index int) (vmimpl.Instance, error) {
 	}
 
 	for i := 0; ; i++ {
+		if err := ctx.Err(); err != nil {
+			return nil, err
+		}
 		inst, err := pool.ctor(workdir, sshkey, sshuser, index)
 		if err == nil {
 			return inst, nil