diff mbox series

hw/ide/ahci: Check for PCI device once in ahci_init()

Message ID 20241121100152.65476-1-philmd@linaro.org
State New
Headers show
Series hw/ide/ahci: Check for PCI device once in ahci_init() | expand

Commit Message

Philippe Mathieu-Daudé Nov. 21, 2024, 10:01 a.m. UTC
object_dynamic_cast() is expensive; IRQ helpers are certainly
a bad place to call it. Since the device type won't change at
runtime, resolve it once when the AHCI context is initialized
in ahci_init().

Reported-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
---
 include/hw/ide/ahci.h |  2 +-
 hw/ide/ahci.c         | 17 +++++------------
 2 files changed, 6 insertions(+), 13 deletions(-)

Comments

Bernhard Beschow Dec. 3, 2024, 6:46 a.m. UTC | #1
Am 21. November 2024 10:01:52 UTC schrieb "Philippe Mathieu-Daudé" <philmd@linaro.org>:
>object_dynamic_cast() is expensive; IRQ helpers are certainly
>a bad place to call it. Since the device type won't change at
>runtime, resolve it once when the AHCI context is initialized
>in ahci_init().
>
>Reported-by: Peter Xu <peterx@redhat.com>
>Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
>---
> include/hw/ide/ahci.h |  2 +-
> hw/ide/ahci.c         | 17 +++++------------
> 2 files changed, 6 insertions(+), 13 deletions(-)
>
>diff --git a/include/hw/ide/ahci.h b/include/hw/ide/ahci.h
>index ba31e75ff9..f6d977610d 100644
>--- a/include/hw/ide/ahci.h
>+++ b/include/hw/ide/ahci.h
>@@ -37,7 +37,7 @@ typedef struct AHCIControlRegs {
> } AHCIControlRegs;
> 
> typedef struct AHCIState {
>-    DeviceState *container;
>+    PCIDevice *pci_dev;
> 
>     AHCIDevice *dev;
>     AHCIControlRegs control_regs;
>diff --git a/hw/ide/ahci.c b/hw/ide/ahci.c
>index 0eb24304ee..f2eb3b527b 100644
>--- a/hw/ide/ahci.c
>+++ b/hw/ide/ahci.c
>@@ -181,14 +181,10 @@ static uint32_t ahci_port_read(AHCIState *s, int port, int offset)
> 
> static void ahci_irq_raise(AHCIState *s)
> {
>-    DeviceState *dev_state = s->container;
>-    PCIDevice *pci_dev = (PCIDevice *) object_dynamic_cast(OBJECT(dev_state),
>-                                                           TYPE_PCI_DEVICE);
>-
>     trace_ahci_irq_raise(s);
> 
>-    if (pci_dev && msi_enabled(pci_dev)) {
>-        msi_notify(pci_dev, 0);
>+    if (s->pci_dev && msi_enabled(s->pci_dev)) {
>+        msi_notify(s->pci_dev, 0);
>     } else {
>         qemu_irq_raise(s->irq);
>     }
>@@ -196,13 +192,9 @@ static void ahci_irq_raise(AHCIState *s)
> 
> static void ahci_irq_lower(AHCIState *s)
> {
>-    DeviceState *dev_state = s->container;
>-    PCIDevice *pci_dev = (PCIDevice *) object_dynamic_cast(OBJECT(dev_state),
>-                                                           TYPE_PCI_DEVICE);
>-
>     trace_ahci_irq_lower(s);
> 
>-    if (!pci_dev || !msi_enabled(pci_dev)) {
>+    if (!s->pci_dev || !msi_enabled(s->pci_dev)) {
>         qemu_irq_lower(s->irq);
>     }
> }

By always triggering the "irq" property, it might be possible to push out the above two methods to the caller, i.e. the parent PCI device. This would make this device model independent from PCI, essentially turning it into an "IP block". At the same time this eliminates the need for the dynamic casts and AFAICS would also fix the missing PCI dependency in the Kconfig file. I could send a patch.

Best regards,
Bernhard

>@@ -1608,7 +1600,8 @@ static const IDEDMAOps ahci_dma_ops = {
> 
> void ahci_init(AHCIState *s, DeviceState *qdev)
> {
>-    s->container = qdev;
>+    s->pci_dev = (PCIDevice *)object_dynamic_cast(OBJECT(qdev), TYPE_PCI_DEVICE);
>+
>     /* XXX BAR size should be 1k, but that breaks, so bump it to 4k for now */
>     memory_region_init_io(&s->mem, OBJECT(qdev), &ahci_mem_ops, s,
>                           "ahci", AHCI_MEM_BAR_SIZE);
Philippe Mathieu-Daudé Dec. 3, 2024, 9:12 a.m. UTC | #2
On 3/12/24 07:46, Bernhard Beschow wrote:
> Am 21. November 2024 10:01:52 UTC schrieb "Philippe Mathieu-Daudé" <philmd@linaro.org>:
>> object_dynamic_cast() is expensive; IRQ helpers are certainly
>> a bad place to call it. Since the device type won't change at
>> runtime, resolve it once when the AHCI context is initialized
>> in ahci_init().
>>
>> Reported-by: Peter Xu <peterx@redhat.com>
>> Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
>> ---
>> include/hw/ide/ahci.h |  2 +-
>> hw/ide/ahci.c         | 17 +++++------------
>> 2 files changed, 6 insertions(+), 13 deletions(-)


>> @@ -196,13 +192,9 @@ static void ahci_irq_raise(AHCIState *s)
>>
>> static void ahci_irq_lower(AHCIState *s)
>> {
>> -    DeviceState *dev_state = s->container;
>> -    PCIDevice *pci_dev = (PCIDevice *) object_dynamic_cast(OBJECT(dev_state),
>> -                                                           TYPE_PCI_DEVICE);
>> -
>>      trace_ahci_irq_lower(s);
>>
>> -    if (!pci_dev || !msi_enabled(pci_dev)) {
>> +    if (!s->pci_dev || !msi_enabled(s->pci_dev)) {
>>          qemu_irq_lower(s->irq);
>>      }
>> }
> 
> By always triggering the "irq" property, it might be possible to push out the above two methods to the caller, i.e. the parent PCI device. This would make this device model independent from PCI, essentially turning it into an "IP block". At the same time this eliminates the need for the dynamic casts and AFAICS would also fix the missing PCI dependency in the Kconfig file. I could send a patch.

Oh. Please go ahead, that is appreciated!

> 
> Best regards,
> Bernhard
Bernhard Beschow Dec. 5, 2024, 11:49 a.m. UTC | #3
Am 3. Dezember 2024 09:12:08 UTC schrieb "Philippe Mathieu-Daudé" <philmd@linaro.org>:
>On 3/12/24 07:46, Bernhard Beschow wrote:
>> Am 21. November 2024 10:01:52 UTC schrieb "Philippe Mathieu-Daudé" <philmd@linaro.org>:
>>> object_dynamic_cast() is expensive; IRQ helpers are certainly
>>> a bad place to call it. Since the device type won't change at
>>> runtime, resolve it once when the AHCI context is initialized
>>> in ahci_init().
>>> 
>>> Reported-by: Peter Xu <peterx@redhat.com>
>>> Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
>>> ---
>>> include/hw/ide/ahci.h |  2 +-
>>> hw/ide/ahci.c         | 17 +++++------------
>>> 2 files changed, 6 insertions(+), 13 deletions(-)
>
>
>>> @@ -196,13 +192,9 @@ static void ahci_irq_raise(AHCIState *s)
>>> 
>>> static void ahci_irq_lower(AHCIState *s)
>>> {
>>> -    DeviceState *dev_state = s->container;
>>> -    PCIDevice *pci_dev = (PCIDevice *) object_dynamic_cast(OBJECT(dev_state),
>>> -                                                           TYPE_PCI_DEVICE);
>>> -
>>>      trace_ahci_irq_lower(s);
>>> 
>>> -    if (!pci_dev || !msi_enabled(pci_dev)) {
>>> +    if (!s->pci_dev || !msi_enabled(s->pci_dev)) {
>>>          qemu_irq_lower(s->irq);
>>>      }
>>> }
>> 
>> By always triggering the "irq" property, it might be possible to push out the above two methods to the caller, i.e. the parent PCI device. This would make this device model independent from PCI, essentially turning it into an "IP block". At the same time this eliminates the need for the dynamic casts and AFAICS would also fix the missing PCI dependency in the Kconfig file. I could send a patch.
>
>Oh. Please go ahead, that is appreciated!

Patch sent: <https://lore.kernel.org/qemu-devel/20241205114453.1848-1-shentey@gmail.com/>

Best regards,
Bernhard

>
>> 
>> Best regards,
>> Bernhard
diff mbox series

Patch

diff --git a/include/hw/ide/ahci.h b/include/hw/ide/ahci.h
index ba31e75ff9..f6d977610d 100644
--- a/include/hw/ide/ahci.h
+++ b/include/hw/ide/ahci.h
@@ -37,7 +37,7 @@  typedef struct AHCIControlRegs {
 } AHCIControlRegs;
 
 typedef struct AHCIState {
-    DeviceState *container;
+    PCIDevice *pci_dev;
 
     AHCIDevice *dev;
     AHCIControlRegs control_regs;
diff --git a/hw/ide/ahci.c b/hw/ide/ahci.c
index 0eb24304ee..f2eb3b527b 100644
--- a/hw/ide/ahci.c
+++ b/hw/ide/ahci.c
@@ -181,14 +181,10 @@  static uint32_t ahci_port_read(AHCIState *s, int port, int offset)
 
 static void ahci_irq_raise(AHCIState *s)
 {
-    DeviceState *dev_state = s->container;
-    PCIDevice *pci_dev = (PCIDevice *) object_dynamic_cast(OBJECT(dev_state),
-                                                           TYPE_PCI_DEVICE);
-
     trace_ahci_irq_raise(s);
 
-    if (pci_dev && msi_enabled(pci_dev)) {
-        msi_notify(pci_dev, 0);
+    if (s->pci_dev && msi_enabled(s->pci_dev)) {
+        msi_notify(s->pci_dev, 0);
     } else {
         qemu_irq_raise(s->irq);
     }
@@ -196,13 +192,9 @@  static void ahci_irq_raise(AHCIState *s)
 
 static void ahci_irq_lower(AHCIState *s)
 {
-    DeviceState *dev_state = s->container;
-    PCIDevice *pci_dev = (PCIDevice *) object_dynamic_cast(OBJECT(dev_state),
-                                                           TYPE_PCI_DEVICE);
-
     trace_ahci_irq_lower(s);
 
-    if (!pci_dev || !msi_enabled(pci_dev)) {
+    if (!s->pci_dev || !msi_enabled(s->pci_dev)) {
         qemu_irq_lower(s->irq);
     }
 }
@@ -1608,7 +1600,8 @@  static const IDEDMAOps ahci_dma_ops = {
 
 void ahci_init(AHCIState *s, DeviceState *qdev)
 {
-    s->container = qdev;
+    s->pci_dev = (PCIDevice *)object_dynamic_cast(OBJECT(qdev), TYPE_PCI_DEVICE);
+
     /* XXX BAR size should be 1k, but that breaks, so bump it to 4k for now */
     memory_region_init_io(&s->mem, OBJECT(qdev), &ahci_mem_ops, s,
                           "ahci", AHCI_MEM_BAR_SIZE);