[Qemu-devel] [PATCH v4 0/3] Fix hotplug of PCI passthrought device on Xen

[Qemu-devel] [PATCH v4 0/3] Fix hotplug of PCI passthrought device on Xen

[Anthony PERARD]

Adding PCI passthrough before the guest start works fine (broken in 2.9 but now
fixed), but hotplug does not work anymore.

Anthony PERARD (3):
  hw/acpi: Limit hotplug to root bus on legacy mode
  hw/acpi: Move acpi_set_pci_info to pcihp
  Revert "ACPI: don't call acpi_pcihp_device_plug_cb on xen"

 hw/acpi/pcihp.c       | 40 +++++++++++++++++++++++++++++++++++++++-
 hw/acpi/piix4.c       | 11 +++--------
 hw/i386/acpi-build.c  | 32 --------------------------------
 stubs/Makefile.objs   |  1 +
 stubs/pci-host-piix.c |  6 ++++++
 5 files changed, 49 insertions(+), 41 deletions(-)
 create mode 100644 stubs/pci-host-piix.c

-- 
Anthony PERARD

[Qemu-devel] [PATCH v4 1/3] hw/acpi: Limit hotplug to root bus on legacy mode

[Anthony PERARD]

Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>
---
New patch in V3
---
 hw/acpi/pcihp.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/hw/acpi/pcihp.c b/hw/acpi/pcihp.c
index c420a388ea..9db3c2eaf2 100644
--- a/hw/acpi/pcihp.c
+++ b/hw/acpi/pcihp.c
@@ -273,7 +273,7 @@ static void pci_write(void *opaque, hwaddr addr, uint64_t data,
                       addr, data);
         break;
     case PCI_SEL_BASE:
-        s->hotplug_select = data;
+        s->hotplug_select = s->legacy_piix ? ACPI_PCIHP_BSEL_DEFAULT : data;
         ACPI_PCIHP_DPRINTF("pcisel write %" HWADDR_PRIx " <== %" PRIu64 "\n",
                       addr, data);
     default:
-- 
Anthony PERARD

[Qemu-devel] [PATCH v4 2/3] hw/acpi: Move acpi_set_pci_info to pcihp

[Anthony PERARD]

HW part of ACPI PCI hotplug in QEMU depends on ACPI_PCIHP_PROP_BSEL
being set on a PCI bus that supports ACPI hotplug. It should work
regardless of the source of ACPI tables (QEMU generator/legacy SeaBIOS/Xen).
So move ACPI_PCIHP_PROP_BSEL initialization into HW ACPI implementation
part from QEMU's ACPI table generator.

To do PCI passthrough with Xen, the property ACPI_PCIHP_PROP_BSEL needs
to be set, but this was done only when ACPI tables are built which is
not needed for a Xen guest. The need for the property starts with commit
"pc: pcihp: avoid adding ACPI_PCIHP_PROP_BSEL twice"
(f0c9d64a68b776374ec4732424a3e27753ce37b6).

Adding find_i440fx into stubs so that mips-softmmu target can be built.

Reported-by: Sander Eikelenboom <linux@eikelenboom.it>
Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>

---
Changes in V4:
  - call acpi_set_pci_info only once
  - Add a stub of find_i440fx (for mips_softmmu target)

Changes in V3:
  - move acpi_set_pci_info to pcihp instead

Changes in V2:
  - check for acpi_enabled before calling acpi_set_pci_info.
  - set the property on the root bus only.
---
 hw/acpi/pcihp.c       | 38 ++++++++++++++++++++++++++++++++++++++
 hw/i386/acpi-build.c  | 32 --------------------------------
 stubs/Makefile.objs   |  1 +
 stubs/pci-host-piix.c |  6 ++++++
 4 files changed, 45 insertions(+), 32 deletions(-)
 create mode 100644 stubs/pci-host-piix.c

diff --git a/hw/acpi/pcihp.c b/hw/acpi/pcihp.c
index 9db3c2eaf2..7da51c0569 100644
--- a/hw/acpi/pcihp.c
+++ b/hw/acpi/pcihp.c
@@ -75,6 +75,43 @@ static int acpi_pcihp_get_bsel(PCIBus *bus)
     }
 }
 
+/* Assign BSEL property to all buses.  In the future, this can be changed
+ * to only assign to buses that support hotplug.
+ */
+static void *acpi_set_bsel(PCIBus *bus, void *opaque)
+{
+    unsigned *bsel_alloc = opaque;
+    unsigned *bus_bsel;
+
+    if (qbus_is_hotpluggable(BUS(bus))) {
+        bus_bsel = g_malloc(sizeof *bus_bsel);
+
+        *bus_bsel = (*bsel_alloc)++;
+        object_property_add_uint32_ptr(OBJECT(bus), ACPI_PCIHP_PROP_BSEL,
+                                       bus_bsel, &error_abort);
+    }
+
+    return bsel_alloc;
+}
+
+static void acpi_set_pci_info(void)
+{
+    static bool bsel_is_set;
+    PCIBus *bus;
+    unsigned bsel_alloc = ACPI_PCIHP_BSEL_DEFAULT;
+
+    if (bsel_is_set) {
+        return;
+    }
+    bsel_is_set = true;
+
+    bus = find_i440fx(); /* TODO: Q35 support */
+    if (bus) {
+        /* Scan all PCI buses. Set property to enable acpi based hotplug. */
+        pci_for_each_bus_depth_first(bus, acpi_set_bsel, NULL, &bsel_alloc);
+    }
+}
+
 static void acpi_pcihp_test_hotplug_bus(PCIBus *bus, void *opaque)
 {
     AcpiPciHpFind *find = opaque;
@@ -177,6 +214,7 @@ static void acpi_pcihp_update(AcpiPciHpState *s)
 
 void acpi_pcihp_reset(AcpiPciHpState *s)
 {
+    acpi_set_pci_info();
     acpi_pcihp_update(s);
 }
 
diff --git a/hw/i386/acpi-build.c b/hw/i386/acpi-build.c
index 98dd424678..4d19d91e1b 100644
--- a/hw/i386/acpi-build.c
+++ b/hw/i386/acpi-build.c
@@ -493,36 +493,6 @@ build_madt(GArray *table_data, BIOSLinker *linker, PCMachineState *pcms)
                  table_data->len - madt_start, 1, NULL, NULL);
 }
 
-/* Assign BSEL property to all buses.  In the future, this can be changed
- * to only assign to buses that support hotplug.
- */
-static void *acpi_set_bsel(PCIBus *bus, void *opaque)
-{
-    unsigned *bsel_alloc = opaque;
-    unsigned *bus_bsel;
-
-    if (qbus_is_hotpluggable(BUS(bus))) {
-        bus_bsel = g_malloc(sizeof *bus_bsel);
-
-        *bus_bsel = (*bsel_alloc)++;
-        object_property_add_uint32_ptr(OBJECT(bus), ACPI_PCIHP_PROP_BSEL,
-                                       bus_bsel, &error_abort);
-    }
-
-    return bsel_alloc;
-}
-
-static void acpi_set_pci_info(void)
-{
-    PCIBus *bus = find_i440fx(); /* TODO: Q35 support */
-    unsigned bsel_alloc = ACPI_PCIHP_BSEL_DEFAULT;
-
-    if (bus) {
-        /* Scan all PCI buses. Set property to enable acpi based hotplug. */
-        pci_for_each_bus_depth_first(bus, acpi_set_bsel, NULL, &bsel_alloc);
-    }
-}
-
 static void build_append_pcihp_notify_entry(Aml *method, int slot)
 {
     Aml *if_ctx;
@@ -2888,8 +2858,6 @@ void acpi_setup(void)
 
     build_state = g_malloc0(sizeof *build_state);
 
-    acpi_set_pci_info();
-
     acpi_build_tables_init(&tables);
     acpi_build(&tables, MACHINE(pcms));
 
diff --git a/stubs/Makefile.objs b/stubs/Makefile.objs
index e69c217aff..4a33495911 100644
--- a/stubs/Makefile.objs
+++ b/stubs/Makefile.objs
@@ -40,3 +40,4 @@ stub-obj-y += pc_madt_cpu_entry.o
 stub-obj-y += vmgenid.o
 stub-obj-y += xen-common.o
 stub-obj-y += xen-hvm.o
+stub-obj-y += pci-host-piix.o
diff --git a/stubs/pci-host-piix.c b/stubs/pci-host-piix.c
new file mode 100644
index 0000000000..6ed81b1f21
--- /dev/null
+++ b/stubs/pci-host-piix.c
@@ -0,0 +1,6 @@
+#include "qemu/osdep.h"
+#include "hw/i386/pc.h"
+PCIBus *find_i440fx(void)
+{
+    return NULL;
+}
-- 
Anthony PERARD

[Qemu-devel] [PATCH v4 3/3] Revert "ACPI: don't call acpi_pcihp_device_plug_cb on xen"

[Anthony PERARD]

This reverts commit 153eba4726dfa1bdfc31d1fe973b2a61b9035492.

This patch prevents PCI passthrough hotplug on Xen. Even if the Xen tool
stack prepares its own ACPI tables, we still rely on QEMU for hotplug
ACPI notifications.

The original issue is fixed by the two previous patch:
  hw/acpi: Limit hotplug to root bus on legacy mode
  hw/acpi: Move acpi_set_pci_info to pcihp

Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>
---
CC: Stefano Stabellini <sstabellini@kernel.org>
CC: Bruce Rogers <brogers@suse.com>
---
 hw/acpi/piix4.c | 11 +++--------
 1 file changed, 3 insertions(+), 8 deletions(-)

diff --git a/hw/acpi/piix4.c b/hw/acpi/piix4.c
index f276967365..f4fd5907b8 100644
--- a/hw/acpi/piix4.c
+++ b/hw/acpi/piix4.c
@@ -385,10 +385,7 @@ static void piix4_device_plug_cb(HotplugHandler *hotplug_dev,
                                 dev, errp);
         }
     } else if (object_dynamic_cast(OBJECT(dev), TYPE_PCI_DEVICE)) {
-        if (!xen_enabled()) {
-            acpi_pcihp_device_plug_cb(hotplug_dev, &s->acpi_pci_hotplug, dev,
-                                      errp);
-        }
+        acpi_pcihp_device_plug_cb(hotplug_dev, &s->acpi_pci_hotplug, dev, errp);
     } else if (object_dynamic_cast(OBJECT(dev), TYPE_CPU)) {
         if (s->cpu_hotplug_legacy) {
             legacy_acpi_cpu_plug_cb(hotplug_dev, &s->gpe_cpu, dev, errp);
@@ -411,10 +408,8 @@ static void piix4_device_unplug_request_cb(HotplugHandler *hotplug_dev,
         acpi_memory_unplug_request_cb(hotplug_dev, &s->acpi_memory_hotplug,
                                       dev, errp);
     } else if (object_dynamic_cast(OBJECT(dev), TYPE_PCI_DEVICE)) {
-        if (!xen_enabled()) {
-            acpi_pcihp_device_unplug_cb(hotplug_dev, &s->acpi_pci_hotplug, dev,
-                                        errp);
-        }
+        acpi_pcihp_device_unplug_cb(hotplug_dev, &s->acpi_pci_hotplug, dev,
+                                    errp);
     } else if (object_dynamic_cast(OBJECT(dev), TYPE_CPU) &&
                !s->cpu_hotplug_legacy) {
         acpi_cpu_unplug_request_cb(hotplug_dev, &s->cpuhp_state, dev, errp);
-- 
Anthony PERARD