[Qemu-devel] [PATCH 1/6] acpi_piix4: Disallow write to up/down PCI hotplug registers

[Alex Williamson <alex.williamson@redhat.com>]

These are never written.

Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
---

 hw/acpi_piix4.c |   45 +++++++++++++--------------------------------
 1 files changed, 13 insertions(+), 32 deletions(-)

diff --git a/hw/acpi_piix4.c b/hw/acpi_piix4.c
index 30d37f9..5960b7f 100644
--- a/hw/acpi_piix4.c
+++ b/hw/acpi_piix4.c
@@ -41,7 +41,8 @@
 #define GPE_BASE 0xafe0
 #define PROC_BASE 0xaf00
 #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
 
@@ -472,40 +473,22 @@ 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_updown_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;
+
+    if (addr == PCI_UP_BASE) {
+        val = s->pci0_status.up;
+    } else {
+        val = s->pci0_status.down;
     }
 
-    PIIX4_DPRINTF("pcihotplug read %x == %x\n", addr, val);
+    PIIX4_DPRINTF("pci %s read %x\n",
+                  (addr == PCI_UP_BASE) ? "up" : "down", val);
     return val;
 }
 
-static void pcihotplug_write(void *opaque, uint32_t addr, uint32_t val)
-{
-    struct pci_status *g = opaque;
-    switch (addr) {
-        case PCI_BASE:
-            g->up = val;
-            break;
-        case PCI_BASE + 4:
-            g->down = val;
-            break;
-   }
-
-    PIIX4_DPRINTF("pcihotplug write %x <== %d\n", addr, val);
-}
-
 static uint32_t pciej_read(void *opaque, uint32_t addr)
 {
     PIIX4_DPRINTF("pciej read %x\n", addr);
@@ -549,7 +532,6 @@ 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;
     int i = 0, cpus = smp_cpus;
 
     while (cpus > 0) {
@@ -564,8 +546,7 @@ static void piix4_acpi_system_hot_add_init(PCIBus *bus, PIIX4PMState *s)
     register_ioport_write(PROC_BASE, 32, 1, gpe_writeb, s);
     register_ioport_read(PROC_BASE, 32, 1,  gpe_readb, s);
 
-    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, 8, 4, pci_updown_read, s);
 
     register_ioport_write(PCI_EJ_BASE, 4, 4, pciej_write, bus);
     register_ioport_read(PCI_EJ_BASE, 4, 4,  pciej_read, bus);