From a73049953b7259a94d068c1b453a73b8905b1a6f Mon Sep 17 00:00:00 2001
From: David Woodhouse <dwmw@amazon.co.uk>
Date: Thu, 19 Oct 2023 12:56:42 +0100
Subject: [PATCH] xen-platform: unplug AHCI disks

To support Xen guests using the Q35 chipset, the unplug protocol needs
to also remove AHCI disks.

Make pci_xen_ide_unplug() more generic, iterating over the children
of the PCI device and destroying the "ide-hd" devices. That works the
same for both AHCI and IDE, as does the detection of the primary disk
as unit 0 on the bus named "ide.0".

Then pci_xen_ide_unplug() can be used for both AHCI and IDE devices.

Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Reviewed-by: Paul Durrant <paul@xen.org>
---
 hw/i386/xen/xen_platform.c | 76 ++++++++++++++++++++++++--------------
 1 file changed, 49 insertions(+), 27 deletions(-)

diff --git a/hw/i386/xen/xen_platform.c b/hw/i386/xen/xen_platform.c
index e2dd1b536a..ef7d3fc05f 100644
--- a/hw/i386/xen/xen_platform.c
+++ b/hw/i386/xen/xen_platform.c
@@ -169,39 +169,60 @@ static void pci_unplug_nics(PCIBus *bus)
  *
  * [1] https://xenbits.xen.org/gitweb/?p=xen.git;a=blob;f=docs/misc/hvm-emulated-unplug.pandoc
  */
-static void pci_xen_ide_unplug(PCIDevice *d, bool aux)
+struct ide_unplug_state {
+    bool aux;
+    int nr_unplugged;
+};
+
+static int ide_dev_unplug(DeviceState *dev, void *_st)
 {
-    DeviceState *dev = DEVICE(d);
-    PCIIDEState *pci_ide;
-    int i;
+    struct ide_unplug_state *st = _st;
     IDEDevice *idedev;
     IDEBus *idebus;
     BlockBackend *blk;
+    int unit;
 
-    pci_ide = PCI_IDE(dev);
-
-    for (i = aux ? 1 : 0; i < 4; i++) {
-        idebus = &pci_ide->bus[i / 2];
-        blk = idebus->ifs[i % 2].blk;
-
-        if (blk && idebus->ifs[i % 2].drive_kind != IDE_CD) {
-            if (!(i % 2)) {
-                idedev = idebus->master;
-            } else {
-                idedev = idebus->slave;
-            }
-
-            blk_drain(blk);
-            blk_flush(blk);
-
-            blk_detach_dev(blk, DEVICE(idedev));
-            idebus->ifs[i % 2].blk = NULL;
-            idedev->conf.blk = NULL;
-            monitor_remove_blk(blk);
-            blk_unref(blk);
-        }
+    idedev = IDE_DEVICE(object_dynamic_cast(OBJECT(dev), "ide-hd"));
+    if (!idedev) {
+        return 0;
+    }
+
+    idebus = IDE_BUS(qdev_get_parent_bus(dev));
+
+    unit = (idedev == idebus->slave);
+    assert(unit || idedev == idebus->master);
+
+    if (st->aux && !unit && !strcmp(BUS(idebus)->name, "ide.0")) {
+        return 0;
+    }
+
+    blk = idebus->ifs[unit].blk;
+    if (blk) {
+        blk_drain(blk);
+        blk_flush(blk);
+
+        blk_detach_dev(blk, DEVICE(idedev));
+        idebus->ifs[unit].blk = NULL;
+        idedev->conf.blk = NULL;
+        monitor_remove_blk(blk);
+        blk_unref(blk);
+    }
+
+    object_unparent(OBJECT(dev));
+    st->nr_unplugged++;
+
+    return 0;
+}
+
+static void pci_xen_ide_unplug(PCIDevice *d, bool aux)
+{
+    struct ide_unplug_state st = { aux, 0 };
+    DeviceState *dev = DEVICE(d);
+
+    qdev_walk_children(dev, NULL, NULL, ide_dev_unplug, NULL, &st);
+    if (st.nr_unplugged) {
+        pci_device_reset(d);
     }
-    pci_device_reset(d);
 }
 
 static void unplug_disks(PCIBus *b, PCIDevice *d, void *opaque)
@@ -216,6 +237,7 @@ static void unplug_disks(PCIBus *b, PCIDevice *d, void *opaque)
 
     switch (pci_get_word(d->config + PCI_CLASS_DEVICE)) {
     case PCI_CLASS_STORAGE_IDE:
+    case PCI_CLASS_STORAGE_SATA:
         pci_xen_ide_unplug(d, aux);
         break;