KVM: Use pci_store/load_saved_state() around VM device usage
Alex Williamson [Tue, 10 May 2011 16:02:39 +0000 (10:02 -0600)]
Store the device saved state so that we can reload the device back
to the original state when it's unassigned.  This has the benefit
that the state survives across pci_reset_function() calls via
the PCI sysfs reset interface while the VM is using the device.

Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Acked-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>

include/linux/kvm_host.h
virt/kvm/assigned-dev.c

index ab42855..9272db0 100644 (file)
@@ -513,6 +513,7 @@ struct kvm_assigned_dev_kernel {
        struct kvm *kvm;
        spinlock_t intx_lock;
        char irq_name[32];
+       struct pci_saved_state *pci_saved_state;
 };
 
 struct kvm_irq_mask_notifier {
index ae72ae6..6cc4b97 100644 (file)
@@ -197,8 +197,13 @@ static void kvm_free_assigned_device(struct kvm *kvm,
 {
        kvm_free_assigned_irq(kvm, assigned_dev);
 
-       __pci_reset_function(assigned_dev->dev);
-       pci_restore_state(assigned_dev->dev);
+       pci_reset_function(assigned_dev->dev);
+       if (pci_load_and_free_saved_state(assigned_dev->dev,
+                                         &assigned_dev->pci_saved_state))
+               printk(KERN_INFO "%s: Couldn't reload %s saved state\n",
+                      __func__, dev_name(&assigned_dev->dev->dev));
+       else
+               pci_restore_state(assigned_dev->dev);
 
        pci_release_regions(assigned_dev->dev);
        pci_disable_device(assigned_dev->dev);
@@ -516,7 +521,10 @@ static int kvm_vm_ioctl_assign_device(struct kvm *kvm,
 
        pci_reset_function(dev);
        pci_save_state(dev);
-
+       match->pci_saved_state = pci_store_saved_state(dev);
+       if (!match->pci_saved_state)
+               printk(KERN_DEBUG "%s: Couldn't store %s saved state\n",
+                      __func__, dev_name(&dev->dev));
        match->assigned_dev_id = assigned_dev->assigned_dev_id;
        match->host_segnr = assigned_dev->segnr;
        match->host_busnr = assigned_dev->busnr;
@@ -546,7 +554,9 @@ out:
        mutex_unlock(&kvm->lock);
        return r;
 out_list_del:
-       pci_restore_state(dev);
+       if (pci_load_and_free_saved_state(dev, &match->pci_saved_state))
+               printk(KERN_INFO "%s: Couldn't reload %s saved state\n",
+                      __func__, dev_name(&dev->dev));
        list_del(&match->list);
        pci_release_regions(dev);
 out_disable: