diff --git a/kernel/Makefile b/kernel/Makefile
index eb55ffe4..e6182b23 100644
--- a/kernel/Makefile
+++ b/kernel/Makefile
@@ -118,6 +118,7 @@ net/fs.o \
 op-new.o \
 panic.o \
 partition.o \
+pci-mmio.o \
 pci.o \
 pipe.o \
 poll.o \
diff --git a/kernel/include/sortix/kernel/pci-mmio.h b/kernel/include/sortix/kernel/pci-mmio.h
new file mode 100644
index 00000000..8552c634
--- /dev/null
+++ b/kernel/include/sortix/kernel/pci-mmio.h
@@ -0,0 +1,40 @@
+/*******************************************************************************
+
+    Copyright(C) Jonas 'Sortie' Termansen 2014.
+
+    This file is part of Sortix.
+
+    Sortix is free software: you can redistribute it and/or modify it under the
+    terms of the GNU General Public License as published by the Free Software
+    Foundation, either version 3 of the License, or (at your option) any later
+    version.
+
+    Sortix is distributed in the hope that it will be useful, but WITHOUT ANY
+    WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+    FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
+    details.
+
+    You should have received a copy of the GNU General Public License along with
+    Sortix. If not, see <http://www.gnu.org/licenses/>.
+
+    sortix/kernel/pci-mmio.h
+    Functions for handling PCI devices.
+
+*******************************************************************************/
+
+#ifndef INCLUDE_SORTIX_KERNEL_PCI_MMIO_H
+#define INCLUDE_SORTIX_KERNEL_PCI_MMIO_H
+
+#include <sortix/kernel/addralloc.h>
+#include <sortix/kernel/pci.h>
+
+namespace Sortix {
+
+const int MAP_PCI_BAR_WRITE_COMBINE = 1 << 0;
+
+bool MapPCIBAR(addralloc_t* allocation, pcibar_t bar, int flags = 0);
+void UnmapPCIBar(addralloc_t* allocation);
+
+} // namespace Sortix
+
+#endif
diff --git a/kernel/pci-mmio.cpp b/kernel/pci-mmio.cpp
new file mode 100644
index 00000000..9c895048
--- /dev/null
+++ b/kernel/pci-mmio.cpp
@@ -0,0 +1,131 @@
+/*******************************************************************************
+
+    Copyright(C) Jonas 'Sortie' Termansen 2014.
+
+    This file is part of Sortix.
+
+    Sortix is free software: you can redistribute it and/or modify it under the
+    terms of the GNU General Public License as published by the Free Software
+    Foundation, either version 3 of the License, or (at your option) any later
+    version.
+
+    Sortix is distributed in the hope that it will be useful, but WITHOUT ANY
+    WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+    FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
+    details.
+
+    You should have received a copy of the GNU General Public License along with
+    Sortix. If not, see <http://www.gnu.org/licenses/>.
+
+    pci-mmio.cpp
+    Functions for handling PCI devices.
+
+*******************************************************************************/
+
+#include <assert.h>
+#include <errno.h>
+#include <stdint.h>
+#include <string.h>
+
+#include <sortix/mman.h>
+
+#include <sortix/kernel/addralloc.h>
+#include <sortix/kernel/memorymanagement.h>
+#include <sortix/kernel/pci.h>
+#include <sortix/kernel/pci-mmio.h>
+
+#if defined(__i386__) || defined(__x86_64__)
+#include "x86-family/memorymanagement.h"
+#endif
+
+namespace Sortix {
+
+bool MapPCIBAR(addralloc_t* allocation, pcibar_t bar, int flags)
+{
+	if ( !bar.is_mmio() )
+		return errno = EINVAL, false;
+
+	uint64_t phys_addr = bar.addr();
+	uint64_t phys_size = bar.size();
+
+	size_t addr_unalignment = phys_addr % Page::Size();
+	if ( addr_unalignment )
+	{
+		phys_addr -= addr_unalignment;
+		if ( (uint64_t) 0 - addr_unalignment <= phys_size )
+			return errno = EOVERFLOW, false;
+		phys_size += addr_unalignment;
+	}
+
+	size_t size_unalignment = phys_size % Page::Size();
+	if ( size_unalignment )
+	{
+		phys_size -= size_unalignment;
+		phys_size += Page::Size();
+		if ( phys_size == 0 )
+			return errno = EOVERFLOW, false;
+	}
+
+	if ( SIZE_MAX < phys_size )
+		return errno = EOVERFLOW, false;
+
+	size_t size = phys_size;
+
+	if ( !AllocateKernelAddress(allocation, size) )
+		return false;
+
+	for ( size_t i = 0; i < size; i += Page::Size() )
+	{
+		bool failure = false;
+
+		int prot = PROT_KWRITE | PROT_KREAD;
+		uint64_t physaddr = bar.addr() + i;
+		uintptr_t mapat = allocation->from + i;
+
+		if ( sizeof(void*) <= 4 && 0x100000000 <= physaddr )
+			errno = EOVERFLOW, failure = true;
+#if defined(__i386__) || defined(__x86_64__)
+		else if ( flags & MAP_PCI_BAR_WRITE_COMBINE )
+		{
+			const addr_t mtype = Memory::PAT_WC;
+			if ( !Memory::MapPAT(physaddr, mapat, prot, mtype) )
+				failure = true;
+		}
+#endif
+		else
+		{
+			if ( !Memory::Map(physaddr, mapat, prot) )
+				failure = true;
+		}
+
+		if ( failure )
+		{
+			for ( size_t n = 0; n < i; n += Page::Size() )
+				Memory::Unmap(allocation->from + n);
+			Memory::Flush();
+			FreeKernelAddress(allocation);
+			return false;
+		}
+	}
+
+	Memory::Flush();
+
+	allocation->from += addr_unalignment;
+	allocation->size = bar.size();
+
+	return true;
+}
+
+void UnmapPCIBar(addralloc_t* allocation)
+{
+	size_t unalignment = allocation->from % Page::Size();
+	allocation->from = Page::AlignDown(allocation->from);
+	allocation->size = Page::AlignUp(unalignment + allocation->size);
+	for ( size_t i = 0; i < allocation->size; i += Page::Size() )
+		Memory::Unmap(allocation->from + i);
+	Memory::Flush();
+	FreeKernelAddress(allocation);
+	memset(allocation, 0, sizeof(*allocation));
+}
+
+} // namespace Sortix