From 2bde9b3ec8bdf60788e9e2ce8c07a2f8d6003dbd Mon Sep 17 00:00:00 2001 From: Cédric Le Goater Date: Thu, 18 Apr 2019 12:39:41 +0200 Subject: KVM: Introduce a 'release' method for KVM devices When a P9 sPAPR VM boots, the CAS negotiation process determines which interrupt mode to use (XICS legacy or XIVE native) and invokes a machine reset to activate the chosen mode. To be able to switch from one interrupt mode to another, we introduce the capability to release a KVM device without destroying the VM. The KVM device interface is extended with a new 'release' method which is called when the file descriptor of the device is closed. Once 'release' is called, the 'destroy' method will not be called anymore as the device is removed from the device list of the VM. Cc: Paolo Bonzini Signed-off-by: Cédric Le Goater Reviewed-by: David Gibson Signed-off-by: Paul Mackerras --- virt/kvm/kvm_main.c | 13 +++++++++++++ 1 file changed, 13 insertions(+) (limited to 'virt') diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index ea2018ae1cd7..ea2619d5ca98 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -2938,6 +2938,19 @@ static int kvm_device_release(struct inode *inode, struct file *filp) struct kvm_device *dev = filp->private_data; struct kvm *kvm = dev->kvm; + if (!dev) + return -ENODEV; + + if (dev->kvm != kvm) + return -EPERM; + + if (dev->ops->release) { + mutex_lock(&kvm->lock); + list_del(&dev->vm_node); + dev->ops->release(dev); + mutex_unlock(&kvm->lock); + } + kvm_put_kvm(kvm); return 0; } -- cgit v1.2.3-55-g7522