commit ae4d2eb273b167dad748ea4249720319240b1ac2
author Paul Durrant <paul.durrant@citrix.com> Tue Jan 24 14:05:47 2017 +0000
committer Stefano Stabellini <sstabellini@kernel.org> Fri Jan 27 15:23:29 2017 -0800
tree 29daef99af3e9563fd9ad480289e864101bd78af
parent 090fa1c8c837ebabf8c199031e0f9a9bcdf26814

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>

hw/i386/xen/xen_platform.c

diff --git a/hw/i386/xen/xen_platform.c b/hw/i386/xen/xen_platform.c
index 7d41ebb..6010f35 100644
--- a/hw/i386/xen/xen_platform.c
+++ b/hw/i386/xen/xen_platform.c
@@ -107,8 +107,12 @@
     pci_for_each_device(bus, 0, unplug_nic, NULL);
 }
 
-static void unplug_disks(PCIBus *b, PCIDevice *d, void *o)
+static void unplug_disks(PCIBus *b, PCIDevice *d, void *opaque)
 {
+    uint32_t flags = *(uint32_t *)opaque;
+    bool aux = (flags & UNPLUG_AUX_IDE_DISKS) &&
+        !(flags & UNPLUG_ALL_DISKS);
+
     /* We have to ignore passthrough devices */
     if (!strcmp(d->name, "xen-pci-passthrough")) {
         return;
@@ -116,12 +120,14 @@
 
     switch (pci_get_word(d->config + PCI_CLASS_DEVICE)) {
     case PCI_CLASS_STORAGE_IDE:
-        pci_piix3_xen_ide_unplug(DEVICE(d));
+        pci_piix3_xen_ide_unplug(DEVICE(d), aux);
         break;
 
     case PCI_CLASS_STORAGE_SCSI:
     case PCI_CLASS_STORAGE_EXPRESS:
-        object_unparent(OBJECT(d));
+        if (!aux) {
+            object_unparent(OBJECT(d));
+        }
         break;
 
     default:
@@ -129,9 +135,9 @@
     }
 }
 
-static void pci_unplug_disks(PCIBus *bus)
+static void pci_unplug_disks(PCIBus *bus, uint32_t flags)
 {
-    pci_for_each_device(bus, 0, unplug_disks, NULL);
+    pci_for_each_device(bus, 0, unplug_disks, &flags);
 }
 
 static void platform_fixed_ioport_writew(void *opaque, uint32_t addr, uint32_t val)
@@ -144,17 +150,14 @@
         /* Unplug devices.  Value is a bitmask of which devices to
            unplug, with bit 0 the disk devices, bit 1 the network
            devices, and bit 2 the non-primary-master IDE devices. */
-        if (val & UNPLUG_ALL_DISKS) {
+        if (val & (UNPLUG_ALL_DISKS | UNPLUG_AUX_IDE_DISKS)) {
             DPRINTF("unplug disks\n");
-            pci_unplug_disks(pci_dev->bus);
+            pci_unplug_disks(pci_dev->bus, val);
         }
         if (val & UNPLUG_ALL_NICS) {
             DPRINTF("unplug nics\n");
             pci_unplug_nics(pci_dev->bus);
         }
-        if (val & UNPLUG_AUX_IDE_DISKS) {
-            DPRINTF("unplug auxiliary disks not supported\n");
-        }
         break;
     }
     case 2:
@@ -335,14 +338,14 @@
              * If VMDP was to control both disk and LAN it would use 4.
              * If it controlled just disk or just LAN, it would use 8 below.
              */
-            pci_unplug_disks(pci_dev->bus);
+            pci_unplug_disks(pci_dev->bus, UNPLUG_ALL_DISKS);
             pci_unplug_nics(pci_dev->bus);
         }
         break;
     case 8:
         switch (val) {
         case 1:
-            pci_unplug_disks(pci_dev->bus);
+            pci_unplug_disks(pci_dev->bus, UNPLUG_ALL_DISKS);
             break;
         case 2:
             pci_unplug_nics(pci_dev->bus);