It is not advisable to execute an object_dynamic_cast() to poke into
bus->qbus.parent and follow it up with a C cast into the PnvPHB type we
think we got.
A better way is to access the PnvPHB object via a QOM macro accessing
the existing parent links of the DeviceState. For a given
pnv-phb3/4-root-port 'dev', dev->parent_bus will give us the PHB bus,
and dev->parent_bus->parent is the PHB. Use the adequate QOM macro to
assert the type, and keep the NULL check in case we didn't get the
object we were expecting.
Signed-off-by: Daniel Henrique Barboza <danielhb413@gmail.com>
---
hw/pci-host/pnv_phb3.c | 10 +++++++---
hw/pci-host/pnv_phb4.c | 10 +++++++---
2 files changed, 14 insertions(+), 6 deletions(-)
diff --git a/hw/pci-host/pnv_phb3.c b/hw/pci-host/pnv_phb3.c
index 4ba660f8b9..5e7f827415 100644
--- a/hw/pci-host/pnv_phb3.c
+++ b/hw/pci-host/pnv_phb3.c
@@ -1139,12 +1139,16 @@ static void pnv_phb3_root_port_realize(DeviceState *dev, Error **errp)
{
PCIERootPortClass *rpc = PCIE_ROOT_PORT_GET_CLASS(dev);
PCIDevice *pci = PCI_DEVICE(dev);
- PCIBus *bus = pci_get_bus(pci);
PnvPHB3 *phb = NULL;
Error *local_err = NULL;
- phb = (PnvPHB3 *) object_dynamic_cast(OBJECT(bus->qbus.parent),
- TYPE_PNV_PHB3);
+ /*
+ * dev->parent_bus gives access to the pnv-phb-root bus.
+ * The PnvPHB3 is the owner (parent) of the bus.
+ */
+ if (dev->parent_bus) {
+ phb = PNV_PHB3(dev->parent_bus->parent);
+ }
if (!phb) {
error_setg(errp,
diff --git a/hw/pci-host/pnv_phb4.c b/hw/pci-host/pnv_phb4.c
index ffd9d8a947..a0ee52e820 100644
--- a/hw/pci-host/pnv_phb4.c
+++ b/hw/pci-host/pnv_phb4.c
@@ -1782,12 +1782,16 @@ static void pnv_phb4_root_port_realize(DeviceState *dev, Error **errp)
{
PCIERootPortClass *rpc = PCIE_ROOT_PORT_GET_CLASS(dev);
PCIDevice *pci = PCI_DEVICE(dev);
- PCIBus *bus = pci_get_bus(pci);
PnvPHB4 *phb = NULL;
Error *local_err = NULL;
- phb = (PnvPHB4 *) object_dynamic_cast(OBJECT(bus->qbus.parent),
- TYPE_PNV_PHB4);
+ /*
+ * dev->parent_bus gives access to the pnv-phb-root bus.
+ * The PnvPHB4 is the owner (parent) of the bus.
+ */
+ if (dev->parent_bus) {
+ phb = PNV_PHB4(dev->parent_bus->parent);
+ }
if (!phb) {
error_setg(errp, "%s must be connected to pnv-phb4 buses", dev->id);
--
2.36.1On 18/06/2022 12:01, Daniel Henrique Barboza wrote:
> It is not advisable to execute an object_dynamic_cast() to poke into
> bus->qbus.parent and follow it up with a C cast into the PnvPHB type we
> think we got.
>
> A better way is to access the PnvPHB object via a QOM macro accessing
> the existing parent links of the DeviceState. For a given
> pnv-phb3/4-root-port 'dev', dev->parent_bus will give us the PHB bus,
> and dev->parent_bus->parent is the PHB. Use the adequate QOM macro to
> assert the type, and keep the NULL check in case we didn't get the
> object we were expecting.
>
> Signed-off-by: Daniel Henrique Barboza <danielhb413@gmail.com>
> ---
> hw/pci-host/pnv_phb3.c | 10 +++++++---
> hw/pci-host/pnv_phb4.c | 10 +++++++---
> 2 files changed, 14 insertions(+), 6 deletions(-)
>
> diff --git a/hw/pci-host/pnv_phb3.c b/hw/pci-host/pnv_phb3.c
> index 4ba660f8b9..5e7f827415 100644
> --- a/hw/pci-host/pnv_phb3.c
> +++ b/hw/pci-host/pnv_phb3.c
> @@ -1139,12 +1139,16 @@ static void pnv_phb3_root_port_realize(DeviceState *dev, Error **errp)
> {
> PCIERootPortClass *rpc = PCIE_ROOT_PORT_GET_CLASS(dev);
> PCIDevice *pci = PCI_DEVICE(dev);
> - PCIBus *bus = pci_get_bus(pci);
> PnvPHB3 *phb = NULL;
> Error *local_err = NULL;
>
> - phb = (PnvPHB3 *) object_dynamic_cast(OBJECT(bus->qbus.parent),
> - TYPE_PNV_PHB3);
> + /*
> + * dev->parent_bus gives access to the pnv-phb-root bus.
> + * The PnvPHB3 is the owner (parent) of the bus.
> + */
> + if (dev->parent_bus) {
Here dev->parent_bus shouldn't be accessed directly: you should use
qdev_get_parent_bus() instead.
> + phb = PNV_PHB3(dev->parent_bus->parent);
> + }
This one is a bit trickier, since part of the qdev design is that devices should only
be aware of their immediate bus, and not the device parenting that bus i.e.
dev->parent_bus->parent shouldn't be allowed.
What is really needed here is to use QOM links (or embed the device as a suitable QOM
child) to get the PHB reference which I imagine will be changed as part of the
follow-up series. So I think this can be left as-is for now, and fixed later.
> if (!phb) {
> error_setg(errp,
> diff --git a/hw/pci-host/pnv_phb4.c b/hw/pci-host/pnv_phb4.c
> index ffd9d8a947..a0ee52e820 100644
> --- a/hw/pci-host/pnv_phb4.c
> +++ b/hw/pci-host/pnv_phb4.c
> @@ -1782,12 +1782,16 @@ static void pnv_phb4_root_port_realize(DeviceState *dev, Error **errp)
> {
> PCIERootPortClass *rpc = PCIE_ROOT_PORT_GET_CLASS(dev);
> PCIDevice *pci = PCI_DEVICE(dev);
> - PCIBus *bus = pci_get_bus(pci);
> PnvPHB4 *phb = NULL;
> Error *local_err = NULL;
>
> - phb = (PnvPHB4 *) object_dynamic_cast(OBJECT(bus->qbus.parent),
> - TYPE_PNV_PHB4);
> + /*
> + * dev->parent_bus gives access to the pnv-phb-root bus.
> + * The PnvPHB4 is the owner (parent) of the bus.
> + */
> + if (dev->parent_bus) {
> + phb = PNV_PHB4(dev->parent_bus->parent);
> + }
>
> if (!phb) {
> error_setg(errp, "%s must be connected to pnv-phb4 buses", dev->id);
I've had a quick look over the rest of the series and from what I can see this is
definitely heading in the right direction :)
ATB,
Mark.
On 6/20/22 04:27, Mark Cave-Ayland wrote:
> On 18/06/2022 12:01, Daniel Henrique Barboza wrote:
>
>> It is not advisable to execute an object_dynamic_cast() to poke into
>> bus->qbus.parent and follow it up with a C cast into the PnvPHB type we
>> think we got.
>>
>> A better way is to access the PnvPHB object via a QOM macro accessing
>> the existing parent links of the DeviceState. For a given
>> pnv-phb3/4-root-port 'dev', dev->parent_bus will give us the PHB bus,
>> and dev->parent_bus->parent is the PHB. Use the adequate QOM macro to
>> assert the type, and keep the NULL check in case we didn't get the
>> object we were expecting.
>>
>> Signed-off-by: Daniel Henrique Barboza <danielhb413@gmail.com>
>> ---
>> hw/pci-host/pnv_phb3.c | 10 +++++++---
>> hw/pci-host/pnv_phb4.c | 10 +++++++---
>> 2 files changed, 14 insertions(+), 6 deletions(-)
>>
>> diff --git a/hw/pci-host/pnv_phb3.c b/hw/pci-host/pnv_phb3.c
>> index 4ba660f8b9..5e7f827415 100644
>> --- a/hw/pci-host/pnv_phb3.c
>> +++ b/hw/pci-host/pnv_phb3.c
>> @@ -1139,12 +1139,16 @@ static void pnv_phb3_root_port_realize(DeviceState *dev, Error **errp)
>> {
>> PCIERootPortClass *rpc = PCIE_ROOT_PORT_GET_CLASS(dev);
>> PCIDevice *pci = PCI_DEVICE(dev);
>> - PCIBus *bus = pci_get_bus(pci);
>> PnvPHB3 *phb = NULL;
>> Error *local_err = NULL;
>> - phb = (PnvPHB3 *) object_dynamic_cast(OBJECT(bus->qbus.parent),
>> - TYPE_PNV_PHB3);
>> + /*
>> + * dev->parent_bus gives access to the pnv-phb-root bus.
>> + * The PnvPHB3 is the owner (parent) of the bus.
>> + */
>> + if (dev->parent_bus) {
>
> Here dev->parent_bus shouldn't be accessed directly: you should use qdev_get_parent_bus() instead.
>
>> + phb = PNV_PHB3(dev->parent_bus->parent);
>> + }
>
> This one is a bit trickier, since part of the qdev design is that devices should only be aware of their immediate bus, and not the device parenting that bus i.e. dev->parent_bus->parent shouldn't be allowed.
>
> What is really needed here is to use QOM links (or embed the device as a suitable QOM child) to get the PHB reference which I imagine will be changed as part of the follow-up series. So I think this can be left as-is for now, and fixed later.
In the previous patch (2) I've put the root port as a child of the bus,
giving us this hierarchy:
/pnv-phb3[0] (pnv-phb3) <====== PHB
/lsi (ics)
/msi (phb3-msi)
/msi32[0] (memory-region)
/msi64[0] (memory-region)
/pbcq (pnv-pbcq)
(...)
/phb3_iommu[0] (pnv-phb3-iommu-memory-region)
/pnv-phb3-root.0 (pnv-phb3-root) <=== bus
/pnv-phb3-root-port[0] (pnv-phb3-root-port) <==== root-port
/bus master container[0] (memory-region)
/bus master[0] (memory-region)
/pci_bridge_io[0] (memory-region)
/pci_bridge_io[1] (memory-region)
/pci_bridge_mem[0] (memory-region)
/pci_bridge_pci[0] (memory-region)
/pci_bridge_pref_mem[0] (memory-region)
/pci_bridge_vga_io_hi[0] (memory-region)
/pci_bridge_vga_io_lo[0] (memory-region)
/pci_bridge_vga_mem[0] (memory-region)
/pcie.0 (PCIE)
I did it like this instead of the PHB for no particular reason. If the root port of
other PHBs are located as a direct child of the PHB I can change it.
All that said, thinking more about it, since I need to access the PHB just
to set "chassis" and "slot" of the device, and I'm already setting a QOM
parent for it, I guess I'll just set that before root_port_realize() and spare us
from having to accessing the parent of the parent bus of the root_port.
Thanks,
Daniel
>
>> if (!phb) {
>> error_setg(errp,
>> diff --git a/hw/pci-host/pnv_phb4.c b/hw/pci-host/pnv_phb4.c
>> index ffd9d8a947..a0ee52e820 100644
>> --- a/hw/pci-host/pnv_phb4.c
>> +++ b/hw/pci-host/pnv_phb4.c
>> @@ -1782,12 +1782,16 @@ static void pnv_phb4_root_port_realize(DeviceState *dev, Error **errp)
>> {
>> PCIERootPortClass *rpc = PCIE_ROOT_PORT_GET_CLASS(dev);
>> PCIDevice *pci = PCI_DEVICE(dev);
>> - PCIBus *bus = pci_get_bus(pci);
>> PnvPHB4 *phb = NULL;
>> Error *local_err = NULL;
>> - phb = (PnvPHB4 *) object_dynamic_cast(OBJECT(bus->qbus.parent),
>> - TYPE_PNV_PHB4);
>> + /*
>> + * dev->parent_bus gives access to the pnv-phb-root bus.
>> + * The PnvPHB4 is the owner (parent) of the bus.
>> + */
>> + if (dev->parent_bus) {
>> + phb = PNV_PHB4(dev->parent_bus->parent);
>> + }
>> if (!phb) {
>> error_setg(errp, "%s must be connected to pnv-phb4 buses", dev->id);
>
> I've had a quick look over the rest of the series and from what I can see this is definitely heading in the right direction :)
>
>
> ATB,
>
> Mark.
© 2016 - 2026 Red Hat, Inc.