xen-platform: add missing disk unplug option

The Xen HVM unplug protocol [1] specifies a mechanism to allow guests to
request unplug of 'aux' disks (which is stated to mean all IDE disks,
except the primary master). This patch adds support for that unplug request.

NOTE: The semantics of what happens if unplug of all disks and 'aux' disks
      is simultaneously requests is not clear. The patch makes that
      assumption that an 'all' request overrides an 'aux' request.

[1] http://xenbits.xen.org/gitweb/?p=xen.git;a=blob;f=docs/misc/hvm-emulated-unplug.markdown

Signed-off-by: Paul Durrant <paul.durrant@citrix.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
----
Cc: Stefano Stabellini <sstabellini@kernel.org>
Cc: Anthony Perard <anthony.perard@citrix.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Eduardo Habkost <ehabkost@redhat.com>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: John Snow <jsnow@redhat.com>

1 files changed, 2 insertions, 2 deletions

diff --git a/hw/ide/piix.c b/hw/ide/piix.c
index d5777fd..7e2d767 100644
--- a/hw/ide/piix.c
+++ b/hw/ide/piix.c
@@ -165,7 +165,7 @@ static void pci_piix_ide_realize(PCIDevice *dev, Error **errp)
     pci_piix_init_ports(d);
 }
 
-int pci_piix3_xen_ide_unplug(DeviceState *dev)
+int pci_piix3_xen_ide_unplug(DeviceState *dev, bool aux)
 {
     PCIIDEState *pci_ide;
     DriveInfo *di;
@@ -174,7 +174,7 @@ int pci_piix3_xen_ide_unplug(DeviceState *dev)
 
     pci_ide = PCI_IDE(dev);
 
-    for (i = 0; i < 4; i++) {
+    for (i = aux ? 1 : 0; i < 4; i++) {
         di = drive_get_by_index(IF_IDE, i);
         if (di != NULL && !di->media_cd) {
             BlockBackend *blk = blk_by_legacy_dinfo(di);