acpi_piix4: Disallow write to up/down PCI hotplug registers

The write side of these registers is never used and actually can't be
used as defined because any read/modify/write sequence from the guest
potentially races with qemu.  Drop the write support and define these
as read-only registers.

Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
This commit is contained in:
Alex Williamson 2012-04-05 11:07:08 -06:00 committed by Michael S. Tsirkin
parent 2ba1d381c2
commit ba737541ed
2 changed files with 15 additions and 31 deletions

View file

@ -15,14 +15,14 @@ PCI slot injection notification pending (IO port 0xae00-0xae03, 4-byte access):
Slot injection notification pending. One bit per slot.
Read by ACPI BIOS GPE.1 handler to notify OS of injection
events.
events. Read-only.
PCI slot removal notification (IO port 0xae04-0xae07, 4-byte access):
-----------------------------------------------------
Slot removal notification pending. One bit per slot.
Read by ACPI BIOS GPE.1 handler to notify OS of removal
events.
events. Read-only.
PCI device eject (IO port 0xae08-0xae0b, 4-byte access):
----------------------------------------

View file

@ -40,7 +40,8 @@
#define GPE_BASE 0xafe0
#define GPE_LEN 4
#define PCI_BASE 0xae00
#define PCI_UP_BASE 0xae00
#define PCI_DOWN_BASE 0xae04
#define PCI_EJ_BASE 0xae08
#define PCI_RMV_BASE 0xae0c
@ -448,38 +449,22 @@ static void gpe_writeb(void *opaque, uint32_t addr, uint32_t val)
PIIX4_DPRINTF("gpe write %x <== %d\n", addr, val);
}
static uint32_t pcihotplug_read(void *opaque, uint32_t addr)
static uint32_t pci_up_read(void *opaque, uint32_t addr)
{
uint32_t val = 0;
struct pci_status *g = opaque;
switch (addr) {
case PCI_BASE:
val = g->up;
break;
case PCI_BASE + 4:
val = g->down;
break;
default:
break;
}
PIIX4PMState *s = opaque;
uint32_t val = s->pci0_status.up;
PIIX4_DPRINTF("pcihotplug read %x == %x\n", addr, val);
PIIX4_DPRINTF("pci_up_read %x\n", val);
return val;
}
static void pcihotplug_write(void *opaque, uint32_t addr, uint32_t val)
static uint32_t pci_down_read(void *opaque, uint32_t addr)
{
struct pci_status *g = opaque;
switch (addr) {
case PCI_BASE:
g->up = val;
break;
case PCI_BASE + 4:
g->down = val;
break;
}
PIIX4PMState *s = opaque;
uint32_t val = s->pci0_status.down;
PIIX4_DPRINTF("pcihotplug write %x <== %d\n", addr, val);
PIIX4_DPRINTF("pci_down_read %x\n", val);
return val;
}
static uint32_t pciej_read(void *opaque, uint32_t addr)
@ -523,14 +508,13 @@ static int piix4_device_hotplug(DeviceState *qdev, PCIDevice *dev,
static void piix4_acpi_system_hot_add_init(PCIBus *bus, PIIX4PMState *s)
{
struct pci_status *pci0_status = &s->pci0_status;
register_ioport_write(GPE_BASE, GPE_LEN, 1, gpe_writeb, s);
register_ioport_read(GPE_BASE, GPE_LEN, 1, gpe_readb, s);
acpi_gpe_blk(&s->ar, GPE_BASE);
register_ioport_write(PCI_BASE, 8, 4, pcihotplug_write, pci0_status);
register_ioport_read(PCI_BASE, 8, 4, pcihotplug_read, pci0_status);
register_ioport_read(PCI_UP_BASE, 4, 4, pci_up_read, s);
register_ioport_read(PCI_DOWN_BASE, 4, 4, pci_down_read, s);
register_ioport_write(PCI_EJ_BASE, 4, 4, pciej_write, bus);
register_ioport_read(PCI_EJ_BASE, 4, 4, pciej_read, bus);