diff mbox series

[v2,3/6] hw/isa/piix: Wire up Xen PCI IRQ handling outside of PIIX3

Message ID 20230104144437.27479-4-shentey@gmail.com (mailing list archive)
State New, archived
Headers show
Series Resolve TYPE_PIIX3_XEN_DEVICE | expand

Commit Message

Bernhard Beschow Jan. 4, 2023, 2:44 p.m. UTC
xen_intx_set_irq() doesn't depend on PIIX state. In order to resolve
TYPE_PIIX3_XEN_DEVICE and in order to make Xen agnostic about the
precise south bridge being used, set up Xen's PCI IRQ handling of PIIX3
in the board.

Signed-off-by: Bernhard Beschow <shentey@gmail.com>
---
 hw/i386/pc_piix.c | 12 ++++++++++++
 hw/isa/piix.c     | 24 +-----------------------
 2 files changed, 13 insertions(+), 23 deletions(-)

Comments

Philippe Mathieu-Daudé Jan. 4, 2023, 3:18 p.m. UTC | #1
On 4/1/23 15:44, Bernhard Beschow wrote:
> xen_intx_set_irq() doesn't depend on PIIX state. In order to resolve
> TYPE_PIIX3_XEN_DEVICE and in order to make Xen agnostic about the
> precise south bridge being used, set up Xen's PCI IRQ handling of PIIX3
> in the board.
> 
> Signed-off-by: Bernhard Beschow <shentey@gmail.com>
> ---
>   hw/i386/pc_piix.c | 12 ++++++++++++
>   hw/isa/piix.c     | 24 +-----------------------
>   2 files changed, 13 insertions(+), 23 deletions(-)

Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
David Woodhouse Jan. 6, 2023, 5:35 p.m. UTC | #2
On Wed, 2023-01-04 at 15:44 +0100, Bernhard Beschow wrote:
> +        if (xen_enabled()) {

Could this perhaps be if (xen_mode != XEN_DISABLED) once we merge the
Xen-on-KVM series?
Chuck Zmudzinski Jan. 6, 2023, 5:46 p.m. UTC | #3
On 1/6/23 12:35 PM, David Woodhouse wrote:
> On Wed, 2023-01-04 at 15:44 +0100, Bernhard Beschow wrote:
>> +        if (xen_enabled()) {
> 
> Could this perhaps be if (xen_mode != XEN_DISABLED) once we merge the
> Xen-on-KVM series?

I am not an expert and just on here as a user/tester, but I think it
would depend on whether or not the Xen-on-KVM mode uses Xen PCI IRQ
handling or Linux/KVM PCI IRQ handling.

Chuck
Chuck Zmudzinski Jan. 6, 2023, 6:39 p.m. UTC | #4
On 1/6/23 12:46 PM, Chuck Zmudzinski wrote:
> On 1/6/23 12:35 PM, David Woodhouse wrote:
>> On Wed, 2023-01-04 at 15:44 +0100, Bernhard Beschow wrote:
>>> +        if (xen_enabled()) {
>> 
>> Could this perhaps be if (xen_mode != XEN_DISABLED) once we merge the
>> Xen-on-KVM series?
> 
> I am not an expert and just on here as a user/tester, but I think it
> would depend on whether or not the Xen-on-KVM mode uses Xen PCI IRQ
> handling or Linux/KVM PCI IRQ handling.
> 
> Chuck

I could try Bernhard's patches in a Xen-on-KVM configuration if that might help.
I would need help configuring the Xen-on-KVM mode to do it, though, because
I have never tried Xen-on-KVM before.

The test I could do would be to:

1) Test my Xen guest that uses the current PIIX3-xen device in the
Xen-on-KVM environment and get that working.

2) Apply Bernhard's patch series and see what, if anything, needs to
be done to make Bernhard's patch work in Xen-on-KVM. I have already
verified that Bernhard's patches work well with Xen on bare metal, so I
don't think we need to answer this question before going forward with
Bernhard's patches. This can be patched later to support Xen-on-KVM if
necessary as part of or in addition to the Xen-on-KVM series.

Chuck
Bernhard Beschow Jan. 7, 2023, 10:58 a.m. UTC | #5
Am 6. Januar 2023 17:35:18 UTC schrieb David Woodhouse <dwmw2@infradead.org>:
>On Wed, 2023-01-04 at 15:44 +0100, Bernhard Beschow wrote:
>> +        if (xen_enabled()) {
>
>Could this perhaps be if (xen_mode != XEN_DISABLED) once we merge the
>Xen-on-KVM series?

It's the same condition which selected TYPE_PIIX3_XEN_DEVICE until the last patch of this series. If you had to change this condition in your series then just perform the same change here instead.

Best regards,
Bernhard
diff mbox series

Patch

diff --git a/hw/i386/pc_piix.c b/hw/i386/pc_piix.c
index aacdb72b7c..792dcd3ce8 100644
--- a/hw/i386/pc_piix.c
+++ b/hw/i386/pc_piix.c
@@ -67,6 +67,7 @@ 
 #include "kvm/kvm-cpu.h"
 
 #define MAX_IDE_BUS 2
+#define XEN_IOAPIC_NUM_PIRQS 128ULL
 
 #ifdef CONFIG_IDE_ISA
 static const int ide_iobase[MAX_IDE_BUS] = { 0x1f0, 0x170 };
@@ -246,6 +247,17 @@  static void pc_init1(MachineState *machine,
                                  &error_abort);
         pci_realize_and_unref(pci_dev, pci_bus, &error_fatal);
 
+        if (xen_enabled()) {
+            /*
+             * Xen supports additional interrupt routes from the PCI devices to
+             * the IOAPIC: the four pins of each PCI device on the bus are also
+             * connected to the IOAPIC directly.
+             * These additional routes can be discovered through ACPI.
+             */
+            pci_bus_irqs(pci_bus, xen_intx_set_irq, pci_dev,
+                         XEN_IOAPIC_NUM_PIRQS);
+        }
+
         dev = DEVICE(object_resolve_path_component(OBJECT(pci_dev), "pic"));
         for (i = 0; i < ISA_NUM_IRQS; i++) {
             qdev_connect_gpio_out(dev, i, x86ms->gsi[i]);
diff --git a/hw/isa/piix.c b/hw/isa/piix.c
index 25707479eb..ac04781f46 100644
--- a/hw/isa/piix.c
+++ b/hw/isa/piix.c
@@ -38,8 +38,6 @@ 
 #include "migration/vmstate.h"
 #include "hw/acpi/acpi_aml_interface.h"
 
-#define XEN_IOAPIC_NUM_PIRQS    128ULL
-
 static void piix_set_irq_pic(PIIXState *piix, int pic_irq)
 {
     qemu_set_irq(piix->pic.in_irqs[pic_irq],
@@ -487,33 +485,13 @@  static const TypeInfo piix3_info = {
     .class_init    = piix3_class_init,
 };
 
-static void piix3_xen_realize(PCIDevice *dev, Error **errp)
-{
-    ERRP_GUARD();
-    PIIXState *piix3 = PIIX_PCI_DEVICE(dev);
-    PCIBus *pci_bus = pci_get_bus(dev);
-
-    piix3_realize(dev, errp);
-    if (*errp) {
-        return;
-    }
-
-    /*
-     * Xen supports additional interrupt routes from the PCI devices to
-     * the IOAPIC: the four pins of each PCI device on the bus are also
-     * connected to the IOAPIC directly.
-     * These additional routes can be discovered through ACPI.
-     */
-    pci_bus_irqs(pci_bus, xen_intx_set_irq, piix3, XEN_IOAPIC_NUM_PIRQS);
-}
-
 static void piix3_xen_class_init(ObjectClass *klass, void *data)
 {
     DeviceClass *dc = DEVICE_CLASS(klass);
     PCIDeviceClass *k = PCI_DEVICE_CLASS(klass);
 
     k->config_write = piix3_write_config_xen;
-    k->realize = piix3_xen_realize;
+    k->realize = piix3_realize;
     /* 82371SB PIIX3 PCI-to-ISA bridge (Step A1) */
     k->device_id = PCI_DEVICE_ID_INTEL_82371SB_0;
     dc->vmsd = &vmstate_piix3;