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hw/ide/ahci: Decouple from PCI

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In some adhoc profiling booting Linux VMs, it's observed that ahci_irq_lower()
can be a hot path (10000+ triggers until login prompt appears). Even though the
parent device never changes, this method re-determines whether the parent device
is a PCI device or not using the rather expensive object_dynamic_cast()
function. Avoid this overhead by pushing the interrupt handling to the parent
device, essentially turning AHCIState into an "IP block".

Note that this change also frees AHCIState from the PCI dependency which wasn't
reflected in Kconfig.

Reported-by: Peter Xu <peterx@redhat.com>
Inspired-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Bernhard Beschow <shentey@gmail.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-ID: <20241212110926.23548-2-shentey@gmail.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
This commit is contained in:
Bernhard Beschow 2024-12-05 12:44:53 +01:00 • committed by Philippe Mathieu-Daudé
parent c0179ead95
commit 8a4989f526
5 changed files with 21 additions and 42 deletions
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39
hw/ide/ahci.c
View file

@ -23,8 +23,6 @@
#include "qemu/osdep.h"
#include "hw/irq.h"
#include "hw/pci/msi.h"
#include "hw/pci/pci.h"
#include "hw/qdev-properties.h"
#include "migration/vmstate.h"
@ -34,8 +32,6 @@
#include "qemu/module.h"
#include "sysemu/block-backend.h"
#include "sysemu/dma.h"
#include "hw/ide/pci.h"
#include "hw/ide/ahci-pci.h"
#include "hw/ide/ahci-sysbus.h"
#include "ahci-internal.h"
#include "ide-internal.h"
@ -179,34 +175,6 @@ static uint32_t ahci_port_read(AHCIState *s, int port, int offset)
return val;
}
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);
} else {
qemu_irq_raise(s->irq);
}
}
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)) {
qemu_irq_lower(s->irq);
}
}
static void ahci_check_irq(AHCIState *s)
{
int i;
@ -222,9 +190,11 @@ static void ahci_check_irq(AHCIState *s)
trace_ahci_check_irq(s, old_irq, s->control_regs.irqstatus);
if (s->control_regs.irqstatus &&
(s->control_regs.ghc & HOST_CTL_IRQ_EN)) {
ahci_irq_raise(s);
trace_ahci_irq_raise(s);
qemu_irq_raise(s->irq);
} else {
ahci_irq_lower(s);
trace_ahci_irq_lower(s);
qemu_irq_lower(s->irq);
}
}
@ -1608,7 +1578,6 @@ static const IDEDMAOps ahci_dma_ops = {
void ahci_init(AHCIState *s, DeviceState *qdev)
{
s->container = qdev;
/* 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);