[Xen-devel] [rfc 4/4] ioemu: allow xend to specify the slot for pass-through devices

[Simon Horman <horms@xxxxxxxxxxxx>]

Currently a slot may be specified for a hot-plug device,
but not for a pass-through device that is inserted at boot time.
This patch adds support for the latter.

The syntax is:
     BUS:DEV.FUNC[@VSLOT]
e.g: 0000:00:1d:0@7

This may be important as recent changes that allow any free PCI
slot to be used for pass-through (and hotplug) may case pass-through
devices to be assigned in different locations to before. Amongst
other things, specifying the slot will allow users to move them
back, if there is a need.

There is also a xend portion of this patch, which will be posted separately.

Signed-off-by: Simon Horman <horms@xxxxxxxxxxxx>

--- 

Some implementation details

* Pass the slot parsed from xend to register_real_device().
  If none was passed, next_bdf() will supply AUTO_PHP_SLOT.

* Make use of the fact that __insert_to_pci_slot() is
  now indempotent and always call it in register_real_device()

* Change the error message int he case where __insert_to_pci_slot()
  fails to not refer to hot-plut. e_devfn will always
  be non-auto in the hotplug case as register_real_device() is
  called by power_on_php_slot() which is called by acpi_php_add()
  which is called by acpi_php_add(). acpi_php_add() handles
  calling __insert_to_pci_slot() and acpi_php_add() handles
  the case where the call failed, before calling power_on_php_slot().

* Remove PT_VIRT_DEVFN_AUTO, it is no longer used.

Index: ioemu-remote/hw/pass-through.c
===================================================================
--- ioemu-remote.orig/hw/pass-through.c 2009-03-20 21:34:06.000000000 +1100
+++ ioemu-remote/hw/pass-through.c      2009-03-20 21:35:25.000000000 +1100
@@ -3560,7 +3560,7 @@ static int pt_pmcsr_reg_restore(struct p
 }
 
 struct pt_dev * register_real_device(PCIBus *e_bus,
-        const char *e_dev_name, int e_devfn, uint8_t r_bus, uint8_t r_dev,
+        const char *e_dev_name, int e_slot, uint8_t r_bus, uint8_t r_dev,
         uint8_t r_func, uint32_t machine_irq, struct pci_access *pci_access,
         char *opt)
 {
@@ -3569,7 +3569,6 @@ struct pt_dev * register_real_device(PCI
     struct pci_dev *pci_dev;
     uint8_t e_device, e_intx;
     struct pci_config_cf8 machine_bdf;
-    int free_slot;
     char *key, *val;
     int msi_translate;
 
@@ -3592,15 +3591,10 @@ struct pt_dev * register_real_device(PCI
     pci_fill_info(pci_dev, PCI_FILL_IRQ | PCI_FILL_BASES | PCI_FILL_ROM_BASE | 
PCI_FILL_SIZES);
     pt_libpci_fixup(pci_dev);
 
-    if ( e_devfn == PT_VIRT_DEVFN_AUTO ) {
-        /*indicate a static assignment(not hotplug), so find a free PCI hot 
plug slot */
-        free_slot = __insert_to_pci_slot(r_bus, r_dev, r_func,
-                                         AUTO_PHP_SLOT, NULL);
-        if ( free_slot < 0 ) {
-            PT_LOG("Error: no free virtual PCI hot plug slot, thus no live 
migration.\n");
-            return NULL;
-        }
-        e_devfn = free_slot << 3;
+    e_slot = __insert_to_pci_slot(r_bus, r_dev, r_func, e_slot, NULL);
+    if ( e_slot < 0 ) {
+        PT_LOG("Error: no free virtual PCI slot\n");
+        return NULL;
     }
 
     msi_translate = direct_pci_msitranslate;
@@ -3633,7 +3627,7 @@ struct pt_dev * register_real_device(PCI
 
     /* Register device */
     assigned_device = (struct pt_dev *) pci_register_device(e_bus, e_dev_name,
-                                sizeof(struct pt_dev), e_devfn,
+                                sizeof(struct pt_dev), PCI_DEVFN(e_slot, 0),
                                 pt_pci_read_config, pt_pci_write_config);
     if ( assigned_device == NULL )
     {
@@ -3641,7 +3635,7 @@ struct pt_dev * register_real_device(PCI
         return NULL;
     }
 
-    dpci_infos.php_devs[PCI_SLOT(e_devfn)].pt_dev = assigned_device;
+    dpci_infos.php_devs[e_slot].pt_dev = assigned_device;
 
     assigned_device->pci_dev = pci_dev;
     assigned_device->msi_trans_cap = msi_translate;
@@ -3802,7 +3796,7 @@ int power_on_php_slot(int slot)
     pt_dev =
         register_real_device(dpci_infos.e_bus,
             "DIRECT PCI",
-            slot << 3,
+            slot,
             php_dev->r_bus,
             php_dev->r_dev,
             php_dev->r_func,
@@ -3862,7 +3856,7 @@ int pt_init(PCIBus *e_bus, const char *d
     while ( next_bdf(&direct_pci_p, &seg, &b, &d, &f, &opt, &s) )
     {
         /* Register real device with the emulated bus */
-        pt_dev = register_real_device(e_bus, "DIRECT PCI", PT_VIRT_DEVFN_AUTO,
+        pt_dev = register_real_device(e_bus, "DIRECT PCI", s,
             b, d, f, PT_MACHINE_IRQ_AUTO, pci_access, opt);
         if ( pt_dev == NULL )
         {
Index: ioemu-remote/hw/pass-through.h
===================================================================
--- ioemu-remote.orig/hw/pass-through.h 2009-03-20 21:24:13.000000000 +1100
+++ ioemu-remote/hw/pass-through.h      2009-03-20 21:35:25.000000000 +1100
@@ -39,7 +39,6 @@
 // #define PT_DEBUG_PCI_CONFIG_ACCESS
 
 #define PT_MACHINE_IRQ_AUTO (0xFFFFFFFF)
-#define PT_VIRT_DEVFN_AUTO  (-1)
 
 /* Misc PCI constants that should be moved to a separate library :) */
 #define PCI_CONFIG_SIZE         (256)

-- 

-- 
Simon Horman
  VA Linux Systems Japan K.K., Sydney, Australia Satellite Office
  H: www.vergenet.net/~horms/             W: www.valinux.co.jp/en


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