diff --git a/tests/libqos/pci-pc.c b/tests/libqos/pci-pc.c
index 9600ed6..51dff8a 100644
--- a/tests/libqos/pci-pc.c
+++ b/tests/libqos/pci-pc.c
@@ -36,79 +36,64 @@ typedef struct QPCIBusPC
     uint16_t pci_iohole_alloc;
 } QPCIBusPC;
 
-static uint8_t qpci_pc_io_readb(QPCIBus *bus, void *addr)
+static uint8_t qpci_pc_pio_readb(QPCIBus *bus, uint32_t addr)
 {
-    uintptr_t port = (uintptr_t)addr;
-    uint8_t value;
-
-    if (port < 0x10000) {
-        value = inb(port);
-    } else {
-        value = readb(port);
-    }
-
-    return value;
+    return inb(addr);
 }
 
-static uint16_t qpci_pc_io_readw(QPCIBus *bus, void *addr)
+static uint8_t qpci_pc_mmio_readb(QPCIBus *bus, uint32_t addr)
 {
-    uintptr_t port = (uintptr_t)addr;
-    uint16_t value;
-
-    if (port < 0x10000) {
-        value = inw(port);
-    } else {
-        value = readw(port);
-    }
+    return readb(addr);
+}
 
-    return value;
+static void qpci_pc_pio_writeb(QPCIBus *bus, uint32_t addr, uint8_t val)
+{
+    outb(addr, val);
 }
 
-static uint32_t qpci_pc_io_readl(QPCIBus *bus, void *addr)
+static void qpci_pc_mmio_writeb(QPCIBus *bus, uint32_t addr, uint8_t val)
 {
-    uintptr_t port = (uintptr_t)addr;
-    uint32_t value;
+    writeb(addr, val);
+}
 
-    if (port < 0x10000) {
-        value = inl(port);
-    } else {
-        value = readl(port);
-    }
+static uint16_t qpci_pc_pio_readw(QPCIBus *bus, uint32_t addr)
+{
+    return inw(addr);
+}
 
-    return value;
+static uint16_t qpci_pc_mmio_readw(QPCIBus *bus, uint32_t addr)
+{
+    return readw(addr);
 }
 
-static void qpci_pc_io_writeb(QPCIBus *bus, void *addr, uint8_t value)
+static void qpci_pc_pio_writew(QPCIBus *bus, uint32_t addr, uint16_t val)
 {
-    uintptr_t port = (uintptr_t)addr;
+    outw(addr, val);
+}
 
-    if (port < 0x10000) {
-        outb(port, value);
-    } else {
-        writeb(port, value);
-    }
+static void qpci_pc_mmio_writew(QPCIBus *bus, uint32_t addr, uint16_t val)
+{
+    writew(addr, val);
 }
 
-static void qpci_pc_io_writew(QPCIBus *bus, void *addr, uint16_t value)
+static uint32_t qpci_pc_pio_readl(QPCIBus *bus, uint32_t addr)
 {
-    uintptr_t port = (uintptr_t)addr;
+    return inl(addr);
+}
 
-    if (port < 0x10000) {
-        outw(port, value);
-    } else {
-        writew(port, value);
-    }
+static uint32_t qpci_pc_mmio_readl(QPCIBus *bus, uint32_t addr)
+{
+    return readl(addr);
 }
 
-static void qpci_pc_io_writel(QPCIBus *bus, void *addr, uint32_t value)
+static void qpci_pc_pio_writel(QPCIBus *bus, uint32_t addr, uint32_t val)
 {
-    uintptr_t port = (uintptr_t)addr;
+    outl(addr, val);
+}
 
-    if (port < 0x10000) {
-        outl(port, value);
-    } else {
-        writel(port, value);
-    }
+static void qpci_pc_mmio_writel(QPCIBus *bus, uint32_t addr, uint32_t val)
+{
+    writel(addr, val);
 }
 
 static uint8_t qpci_pc_config_readb(QPCIBus *bus, int devfn, uint8_t offset)
@@ -218,13 +203,21 @@ QPCIBus *qpci_init_pc(QGuestAllocator *alloc)
 
     ret = g_malloc(sizeof(*ret));
 
-    ret->bus.io_readb = qpci_pc_io_readb;
-    ret->bus.io_readw = qpci_pc_io_readw;
-    ret->bus.io_readl = qpci_pc_io_readl;
+    ret->bus.pio_readb = qpci_pc_pio_readb;
+    ret->bus.pio_readw = qpci_pc_pio_readw;
+    ret->bus.pio_readl = qpci_pc_pio_readl;
+
+    ret->bus.pio_writeb = qpci_pc_pio_writeb;
+    ret->bus.pio_writew = qpci_pc_pio_writew;
+    ret->bus.pio_writel = qpci_pc_pio_writel;
+
+    ret->bus.mmio_readb = qpci_pc_mmio_readb;
+    ret->bus.mmio_readw = qpci_pc_mmio_readw;
+    ret->bus.mmio_readl = qpci_pc_mmio_readl;
 
-    ret->bus.io_writeb = qpci_pc_io_writeb;
-    ret->bus.io_writew = qpci_pc_io_writew;
-    ret->bus.io_writel = qpci_pc_io_writel;
+    ret->bus.mmio_writeb = qpci_pc_mmio_writeb;
+    ret->bus.mmio_writew = qpci_pc_mmio_writew;
+    ret->bus.mmio_writel = qpci_pc_mmio_writel;
 
     ret->bus.config_readb = qpci_pc_config_readb;
     ret->bus.config_readw = qpci_pc_config_readw;
diff --git a/tests/libqos/pci-spapr.c b/tests/libqos/pci-spapr.c
index 2eaaf91..2d26a94 100644
--- a/tests/libqos/pci-spapr.c
+++ b/tests/libqos/pci-spapr.c
@@ -50,78 +50,76 @@ typedef struct QPCIBusSPAPR {
  * so PCI accessors need to swap data endianness
  */
 
-static uint8_t qpci_spapr_io_readb(QPCIBus *bus, void *addr)
+static uint8_t qpci_spapr_pio_readb(QPCIBus *bus, uint32_t addr)
 {
     QPCIBusSPAPR *s = container_of(bus, QPCIBusSPAPR, bus);
-    uint64_t port = (uintptr_t)addr;
-    uint8_t v;
-    if (port < s->pio.size) {
-        v = readb(s->pio_cpu_base + port);
-    } else {
-        v = readb(s->mmio32_cpu_base + port);
-    }
-    return v;
+    return readb(s->pio_cpu_base + addr);
 }
 
-static uint16_t qpci_spapr_io_readw(QPCIBus *bus, void *addr)
+static uint8_t qpci_spapr_mmio32_readb(QPCIBus *bus, uint32_t addr)
 {
     QPCIBusSPAPR *s = container_of(bus, QPCIBusSPAPR, bus);
-    uint64_t port = (uintptr_t)addr;
-    uint16_t v;
-    if (port < s->pio.size) {
-        v = readw(s->pio_cpu_base + port);
-    } else {
-        v = readw(s->mmio32_cpu_base + port);
-    }
-    return bswap16(v);
+    return readb(s->mmio32_cpu_base + addr);
 }
 
-static uint32_t qpci_spapr_io_readl(QPCIBus *bus, void *addr)
+static void qpci_spapr_pio_writeb(QPCIBus *bus, uint32_t addr, uint8_t val)
 {
     QPCIBusSPAPR *s = container_of(bus, QPCIBusSPAPR, bus);
-    uint64_t port = (uintptr_t)addr;
-    uint32_t v;
-    if (port < s->pio.size) {
-        v = readl(s->pio_cpu_base + port);
-    } else {
-        v = readl(s->mmio32_cpu_base + port);
-    }
-    return bswap32(v);
+    writeb(s->pio_cpu_base + addr, val);
 }
 
-static void qpci_spapr_io_writeb(QPCIBus *bus, void *addr, uint8_t value)
+static void qpci_spapr_mmio32_writeb(QPCIBus *bus, uint32_t addr, uint8_t val)
 {
     QPCIBusSPAPR *s = container_of(bus, QPCIBusSPAPR, bus);
-    uint64_t port = (uintptr_t)addr;
-    if (port < s->pio.size) {
-        writeb(s->pio_cpu_base + port, value);
-    } else {
-        writeb(s->mmio32_cpu_base + port, value);
-    }
+    writeb(s->mmio32_cpu_base + addr, val);
 }
 
-static void qpci_spapr_io_writew(QPCIBus *bus, void *addr, uint16_t value)
+static uint16_t qpci_spapr_pio_readw(QPCIBus *bus, uint32_t addr)
 {
     QPCIBusSPAPR *s = container_of(bus, QPCIBusSPAPR, bus);
-    uint64_t port = (uintptr_t)addr;
-    value = bswap16(value);
-    if (port < s->pio.size) {
-        writew(s->pio_cpu_base + port, value);
-    } else {
-        writew(s->mmio32_cpu_base + port, value);
-    }
+    return bswap16(readw(s->pio_cpu_base + addr));
 }
 
-static void qpci_spapr_io_writel(QPCIBus *bus, void *addr, uint32_t value)
+static uint16_t qpci_spapr_mmio32_readw(QPCIBus *bus, uint32_t addr)
 {
     QPCIBusSPAPR *s = container_of(bus, QPCIBusSPAPR, bus);
-    uint64_t port = (uintptr_t)addr;
-    value = bswap32(value);
-    if (port < s->pio.size) {
-        writel(s->pio_cpu_base + port, value);
-    } else {
-        writel(s->mmio32_cpu_base + port, value);
-    }
+    return bswap16(readw(s->mmio32_cpu_base + addr));
+}
+
+static void qpci_spapr_pio_writew(QPCIBus *bus, uint32_t addr, uint16_t val)
+{
+    QPCIBusSPAPR *s = container_of(bus, QPCIBusSPAPR, bus);
+    writew(s->pio_cpu_base + addr, bswap16(val));
+}
+
+static void qpci_spapr_mmio32_writew(QPCIBus *bus, uint32_t addr, uint16_t val)
+{
+    QPCIBusSPAPR *s = container_of(bus, QPCIBusSPAPR, bus);
+    writew(s->mmio32_cpu_base + addr, bswap16(val));
+}
+
+static uint32_t qpci_spapr_pio_readl(QPCIBus *bus, uint32_t addr)
+{
+    QPCIBusSPAPR *s = container_of(bus, QPCIBusSPAPR, bus);
+    return bswap32(readl(s->pio_cpu_base + addr));
+}
+
+static uint32_t qpci_spapr_mmio32_readl(QPCIBus *bus, uint32_t addr)
+{
+    QPCIBusSPAPR *s = container_of(bus, QPCIBusSPAPR, bus);
+    return bswap32(readl(s->mmio32_cpu_base + addr));
+}
+
+static void qpci_spapr_pio_writel(QPCIBus *bus, uint32_t addr, uint32_t val)
+{
+    QPCIBusSPAPR *s = container_of(bus, QPCIBusSPAPR, bus);
+    writel(s->pio_cpu_base + addr, bswap32(val));
+}
+
+static void qpci_spapr_mmio32_writel(QPCIBus *bus, uint32_t addr, uint32_t val)
+{
+    QPCIBusSPAPR *s = container_of(bus, QPCIBusSPAPR, bus);
+    writel(s->mmio32_cpu_base + addr, bswap32(val));
 }
 
 static uint8_t qpci_spapr_config_readb(QPCIBus *bus, int devfn, uint8_t offset)
@@ -248,13 +246,21 @@ QPCIBus *qpci_init_spapr(QGuestAllocator *alloc)
 
     ret->alloc = alloc;
 
-    ret->bus.io_readb = qpci_spapr_io_readb;
-    ret->bus.io_readw = qpci_spapr_io_readw;
-    ret->bus.io_readl = qpci_spapr_io_readl;
+    ret->bus.pio_readb = qpci_spapr_pio_readb;
+    ret->bus.pio_readw = qpci_spapr_pio_readw;
+    ret->bus.pio_readl = qpci_spapr_pio_readl;
+
+    ret->bus.pio_writeb = qpci_spapr_pio_writeb;
+    ret->bus.pio_writew = qpci_spapr_pio_writew;
+    ret->bus.pio_writel = qpci_spapr_pio_writel;
+
+    ret->bus.mmio_readb = qpci_spapr_mmio32_readb;
+    ret->bus.mmio_readw = qpci_spapr_mmio32_readw;
+    ret->bus.mmio_readl = qpci_spapr_mmio32_readl;
 
-    ret->bus.io_writeb = qpci_spapr_io_writeb;
-    ret->bus.io_writew = qpci_spapr_io_writew;
-    ret->bus.io_writel = qpci_spapr_io_writel;
+    ret->bus.mmio_writeb = qpci_spapr_mmio32_writeb;
+    ret->bus.mmio_writew = qpci_spapr_mmio32_writew;
+    ret->bus.mmio_writel = qpci_spapr_mmio32_writel;
 
     ret->bus.config_readb = qpci_spapr_config_readb;
     ret->bus.config_readw = qpci_spapr_config_readw;
diff --git a/tests/libqos/pci.c b/tests/libqos/pci.c
index c3f3382..55b01df 100644
--- a/tests/libqos/pci.c
+++ b/tests/libqos/pci.c
@@ -224,33 +224,68 @@ void qpci_config_writel(QPCIDevice *dev, uint8_t offset, uint32_t value)
 
 uint8_t qpci_io_readb(QPCIDevice *dev, void *data)
 {
-    return dev->bus->io_readb(dev->bus, data);
+    uintptr_t addr = (uintptr_t)data;
+
+    if (addr < QPCI_PIO_LIMIT) {
+        return dev->bus->pio_readb(dev->bus, addr);
+    } else {
+        return dev->bus->mmio_readb(dev->bus, addr);
+    }
 }
 
 uint16_t qpci_io_readw(QPCIDevice *dev, void *data)
 {
-    return dev->bus->io_readw(dev->bus, data);
+    uintptr_t addr = (uintptr_t)data;
+
+    if (addr < QPCI_PIO_LIMIT) {
+        return dev->bus->pio_readw(dev->bus, addr);
+    } else {
+        return dev->bus->mmio_readw(dev->bus, addr);
+    }
 }
 
 uint32_t qpci_io_readl(QPCIDevice *dev, void *data)
 {
-    return dev->bus->io_readl(dev->bus, data);
-}
+    uintptr_t addr = (uintptr_t)data;
 
+    if (addr < QPCI_PIO_LIMIT) {
+        return dev->bus->pio_readl(dev->bus, addr);
+    } else {
+        return dev->bus->mmio_readl(dev->bus, addr);
+    }
+}
 
 void qpci_io_writeb(QPCIDevice *dev, void *data, uint8_t value)
 {
-    dev->bus->io_writeb(dev->bus, data, value);
+    uintptr_t addr = (uintptr_t)data;
+
+    if (addr < QPCI_PIO_LIMIT) {
+        dev->bus->pio_writeb(dev->bus, addr, value);
+    } else {
+        dev->bus->mmio_writeb(dev->bus, addr, value);
+    }
 }
 
 void qpci_io_writew(QPCIDevice *dev, void *data, uint16_t value)
 {
-    dev->bus->io_writew(dev->bus, data, value);
+    uintptr_t addr = (uintptr_t)data;
+
+    if (addr < QPCI_PIO_LIMIT) {
+        dev->bus->pio_writew(dev->bus, addr, value);
+    } else {
+        dev->bus->mmio_writew(dev->bus, addr, value);
+    }
 }
 
 void qpci_io_writel(QPCIDevice *dev, void *data, uint32_t value)
 {
-    dev->bus->io_writel(dev->bus, data, value);
+    uintptr_t addr = (uintptr_t)data;
+
+    if (addr < QPCI_PIO_LIMIT) {
+        dev->bus->pio_writel(dev->bus, addr, value);
+    } else {
+        dev->bus->mmio_writel(dev->bus, addr, value);
+    }
 }
 
 void *qpci_iomap(QPCIDevice *dev, int barno, uint64_t *sizeptr)
diff --git a/tests/libqos/pci.h b/tests/libqos/pci.h
index c06add8..72a2245 100644
--- a/tests/libqos/pci.h
+++ b/tests/libqos/pci.h
@@ -15,6 +15,8 @@
 
 #include "libqtest.h"
 
+#define QPCI_PIO_LIMIT    0x10000
+
 #define QPCI_DEVFN(dev, fn) (((dev) << 3) | (fn))
 
 typedef struct QPCIDevice QPCIDevice;
@@ -22,13 +24,21 @@ typedef struct QPCIBus QPCIBus;
 
 struct QPCIBus
 {
-    uint8_t (*io_readb)(QPCIBus *bus, void *addr);
-    uint16_t (*io_readw)(QPCIBus *bus, void *addr);
-    uint32_t (*io_readl)(QPCIBus *bus, void *addr);
+    uint8_t (*pio_readb)(QPCIBus *bus, uint32_t addr);
+    uint16_t (*pio_readw)(QPCIBus *bus, uint32_t addr);
+    uint32_t (*pio_readl)(QPCIBus *bus, uint32_t addr);
+
+    uint8_t (*mmio_readb)(QPCIBus *bus, uint32_t addr);
+    uint16_t (*mmio_readw)(QPCIBus *bus, uint32_t addr);
+    uint32_t (*mmio_readl)(QPCIBus *bus, uint32_t addr);
+
+    void (*pio_writeb)(QPCIBus *bus, uint32_t addr, uint8_t value);
+    void (*pio_writew)(QPCIBus *bus, uint32_t addr, uint16_t value);
+    void (*pio_writel)(QPCIBus *bus, uint32_t addr, uint32_t value);
 
-    void (*io_writeb)(QPCIBus *bus, void *addr, uint8_t value);
-    void (*io_writew)(QPCIBus *bus, void *addr, uint16_t value);
-    void (*io_writel)(QPCIBus *bus, void *addr, uint32_t value);
+    void (*mmio_writeb)(QPCIBus *bus, uint32_t addr, uint8_t value);
+    void (*mmio_writew)(QPCIBus *bus, uint32_t addr, uint16_t value);
+    void (*mmio_writel)(QPCIBus *bus, uint32_t addr, uint32_t value);
 
     uint8_t (*config_readb)(QPCIBus *bus, int devfn, uint8_t offset);
     uint16_t (*config_readw)(QPCIBus *bus, int devfn, uint8_t offset);
