[dev][net][e1000] First stab at a working e1000 driver.

-Works against qemu's e1000 and e1000e driver. -Untested on real hardware yet.
2021-12-27 20:27:51 -08:00
parent b5a9c2d8b2
commit caafb3e2ad
6 changed files with 690 additions and 1 deletions
--- a/dev/net/e1000/e1000.cpp
+++ b/dev/net/e1000/e1000.cpp
@@ -0,0 +1,545 @@
+//
+// Copyright (c) 2021 Travis Geiselbrecht
+//
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file or at
+// https://opensource.org/licenses/MIT
+
+#include <lk/init.h>
+#include <lk/err.h>
+#include <lk/cpp.h>
+#include <lk/trace.h>
+#include <lk/list.h>
+#include <dev/bus/pci.h>
+#include <kernel/event.h>
+#include <kernel/thread.h>
+#include <kernel/vm.h>
+#include <lib/minip.h>
+#include <lib/pktbuf.h>
+#include <string.h>
+#include <platform/interrupts.h>
+#include <type_traits>
+
+#include "e1000_hw.h"
+
+#define LOCAL_TRACE 0
+
+class e1000;
+static e1000 *the_e; // XXX hack to remember the first e1000 seen and use for minip
+
+// list of known 8086:x e1000 devices to match against
+struct e1000_id_features {
+    uint16_t id;
+    bool e1000e;
+};
+
+const e1000_id_features e1000_ids[] = {
+    { 0x100c, false }, // 82544GC QEMU 'e1000-82544gc'
+    { 0x100e, false }, // 82540EM QEMU 'e1000'
+    { 0x100f, false }, // 82545EM QEMU 'e1000-82544em'
+    { 0x10d3, true }, // 82574L  QEMU 'e1000e'
+    { 0x1533, true }, // i210
+};
+
+// i210 ids
+// 0x1533
+// 0x1536
+// 0x1537
+// 0x1538
+
+
+class e1000 {
+public:
+    e1000();
+    ~e1000();
+
+    status_t init_device(pci_location_t loc, const e1000_id_features *id);
+
+    int tx(pktbuf_t *p);
+
+    bool is_e1000e() const { return id_feat_->e1000e; }
+
+private:
+    static const size_t rxring_len = 64;
+    static const size_t txring_len = 64;
+    static const size_t rxbuffer_len = 2048;
+
+    uint32_t read_reg(e1000_reg reg);
+    void write_reg(e1000_reg reg, uint32_t val);
+    uint16_t read_eeprom(uint8_t offset);
+
+    handler_return irq_handler();
+
+    void add_pktbuf_to_rxring(pktbuf_t *pkt);
+    void add_pktbuf_to_rxring_locked(pktbuf_t *pkt);
+
+    // main spinlock
+    spin_lock_t lock_ = SPIN_LOCK_INITIAL_VALUE;
+
+    // configuration
+    pci_location_t loc_ = {};
+    void *bar0_regs_ = nullptr;
+    uint8_t mac_addr_[6] = {};
+    const e1000_id_features *id_feat_ = nullptr;
+
+    // rx ring
+    rdesc *rxring_ = nullptr;
+    uint32_t rx_last_head_ = 0;
+    uint32_t rx_tail_ = 0;
+    pktbuf_t *rx_pktbuf_[rxring_len] = {};
+    uint8_t *rx_buf_ = nullptr; // rxbuffer_len * rxring_len byte buffer that rx_pktbuf[] points to
+
+    // rx worker thread
+    list_node rx_queue_ = LIST_INITIAL_VALUE(rx_queue_);
+    event_t rx_event_ = EVENT_INITIAL_VALUE(rx_event_, 0, EVENT_FLAG_AUTOUNSIGNAL);
+    thread_t *rx_worker_thread_ = nullptr;
+    int rx_worker_routine();
+
+    // tx ring
+    tdesc *txring_ = nullptr;
+    uint32_t tx_last_head_ = 0;
+    uint32_t tx_tail_ = 0;
+    pktbuf_t *tx_pktbuf_[txring_len] = {};
+};
+
+uint32_t e1000::read_reg(e1000_reg reg) {
+    volatile uint32_t *r = (volatile uint32_t *)((uintptr_t)bar0_regs_ + (size_t)reg);
+
+    return *r;
+}
+
+void e1000::write_reg(e1000_reg reg, uint32_t val) {
+    volatile uint32_t *r = (volatile uint32_t *)((uintptr_t)bar0_regs_ + (size_t)reg);
+
+    *r = val;
+}
+
+uint16_t e1000::read_eeprom(uint8_t offset) {
+    // 8257x+ seems to have a different EERD layout
+    uint32_t val;
+    if (is_e1000e()) {
+        write_reg(e1000_reg::EERD, (offset << 2) | 0x1); // data + start bit
+
+        // spin while bit 1 (DONE) is clear
+        while (((val = read_reg(e1000_reg::EERD)) & (1<<1)) == 0)
+            ;
+    } else {
+        write_reg(e1000_reg::EERD, (offset << 8) | 0x1); // data + start bit
+
+        // spin while bit 4 (DONE) is clear
+        while (((val = read_reg(e1000_reg::EERD)) & (1<<4)) == 0)
+            ;
+    }
+    return val >> 16;
+}
+
+e1000::e1000() = default;
+e1000::~e1000() {
+    // TODO: free resources
+}
+
+handler_return e1000::irq_handler() {
+    // read the interrupt cause register, which also auto clears all bits
+    auto icr = read_reg(e1000_reg::ICR);
+    if (!icr) {
+        return INT_NO_RESCHEDULE;
+    }
+
+    LTRACEF("icr %#x\n", icr);
+
+    AutoSpinLockNoIrqSave guard(&lock_);
+
+    handler_return ret = INT_NO_RESCHEDULE;
+
+    if (icr & (1<<0)) { // TXDW - transmit descriptor written back
+        PANIC_UNIMPLEMENTED;
+    }
+    if (icr & (1<<1)) { // TXQE - transmit queue empty
+        //PANIC_UNIMPLEMENTED;
+        // nothing to really do here
+    }
+    if (icr & (1<<6)) {
+        printf("e1000: RX OVERRUN\n");
+    }
+    if (icr & (1<<7)) { // RXTO - rx timer interrupt
+        // rx timer fired, packets are probably ready
+        auto rdh = read_reg(e1000_reg::RDH);
+        auto rdt = read_reg(e1000_reg::RDT);
+
+        while (rx_last_head_ != rdh) {
+            // copy the current rx descriptor locally for better cache performance
+            rdesc rxd;
+            copy(&rxd, rxring_ + rx_last_head_);
+
+            LTRACEF("last_head %#x RDH %#x RDT %#x\n", rx_last_head_, rdh, rdt);
+            if (LOCAL_TRACE) rxd.dump();
+
+            // recover the pktbuf we queued in this spot
+            DEBUG_ASSERT(rx_pktbuf_[rx_last_head_]);
+            DEBUG_ASSERT(pktbuf_data_phys(rx_pktbuf_[rx_last_head_]) == rxd.addr);
+            pktbuf_t *pkt = rx_pktbuf_[rx_last_head_];
+
+            bool consumed_pkt = false;
+            if (rxd.status & (1 << 0)) { // descriptor done, we own it now
+                if (rxd.status & (1<<1)) { // end of packet
+                    if (rxd.errors == 0) {
+                        // good packet, trim data len according to the rx descriptor
+                        pkt->dlen = rxd.length;
+                        pkt->flags |= PKTBUF_FLAG_EOF; // just to make sure
+
+                        // queue it in the rx queue
+                        list_add_tail(&rx_queue_, &pkt->list);
+
+                        // wake up the rx worker
+                        event_signal(&rx_event_, false);
+                        ret = INT_RESCHEDULE;
+                        consumed_pkt = true;
+                    }
+                }
+            }
+            if (!consumed_pkt) {
+                // TODO: return the pkt to the ring
+                add_pktbuf_to_rxring_locked(pkt);
+            }
+
+            rx_last_head_ = (rx_last_head_ + 1) % rxring_len;
+        }
+    }
+    return ret;
+}
+
+int e1000::rx_worker_routine() {
+    for (;;) {
+        event_wait(&rx_event_);
+
+        // pull some packets from the received queue
+        for (;;) {
+            pktbuf_t *p;
+
+            {
+                AutoSpinLock guard(&lock_);
+
+                p = list_remove_head_type(&rx_queue_, pktbuf_t, list);
+            }
+
+            if (!p) {
+                break; // nothing left in the queue, go back to waiting
+            }
+
+            if (LOCAL_TRACE) {
+                LTRACEF("got packet: ");
+                pktbuf_dump(p);
+            }
+
+            // push it up the stack
+            minip_rx_driver_callback(p);
+
+            // we own the pktbuf again
+
+            // set the data pointer to the start of the buffer and set dlen to 0
+            pktbuf_reset(p, 0);
+
+            // add it back to the rx ring at the current tail
+            add_pktbuf_to_rxring(p);
+        }
+    }
+
+    return 0;
+}
+
+int e1000::tx(pktbuf_t *p) {
+    LTRACE;
+    if (LOCAL_TRACE) {
+        pktbuf_dump(p);
+    }
+
+    // build a tx descriptor and stuff it in the tx ring
+    tdesc td = {};
+    td.addr = pktbuf_data_phys(p);
+    td.length = p->dlen;
+    td.cmd = (1<<0); // end of packet (EOP)
+    copy(&txring_[tx_tail_], &td);
+
+    // save a copy of the pktbuf in our list
+    tx_pktbuf_[tx_tail_] = p;
+
+    // bump tail forward
+    tx_tail_ = (tx_tail_ + 1) % txring_len;
+    write_reg(e1000_reg::TDT, tx_tail_);
+
+    LTRACEF("TDH %#x TDT %#x\n", read_reg(e1000_reg::TDH), read_reg(e1000_reg::TDT));
+
+    return NO_ERROR;
+}
+
+void e1000::add_pktbuf_to_rxring_locked(pktbuf_t *p) {
+    DEBUG_ASSERT(p);
+    DEBUG_ASSERT(p->dlen == 0);
+    DEBUG_ASSERT(p->blen == rxbuffer_len);
+
+    // add it to the next rxring entry at the tail
+    rdesc rd = {};
+    rd.addr = pktbuf_data_phys(p);
+    copy(&rxring_[rx_tail_], &rd);
+
+    // save a copy of the pktbuf in our list
+    rx_pktbuf_[rx_tail_] = p;
+
+    // bump tail forward
+    rx_tail_ = (rx_tail_ + 1) % rxring_len;
+    write_reg(e1000_reg::RDT, rx_tail_);
+
+    LTRACEF("after RDH %#x RDT %#x\n", read_reg(e1000_reg::RDH), read_reg(e1000_reg::RDT));
+}
+
+void e1000::add_pktbuf_to_rxring(pktbuf_t *pkt) {
+    AutoSpinLock guard(&lock_);
+
+    add_pktbuf_to_rxring_locked(pkt);
+}
+
+status_t e1000::init_device(pci_location_t loc, const e1000_id_features *id) {
+    loc_ = loc;
+    id_feat_ = id;
+
+    char str[14];
+    LTRACEF("pci location %s\n", pci_loc_string(loc_, str));
+
+    pci_bar_t bars[6];
+    size_t count;
+    status_t err = pci_bus_mgr_read_bars(loc_, bars, &count);
+    if (err != NO_ERROR) return err;
+    if (count < 2) {
+        return ERR_NOT_FOUND;
+    }
+
+    LTRACEF("e1000 BARS:\n");
+    if (LOCAL_TRACE) pci_dump_bars(bars, count);
+
+    if (!bars[0].valid) {
+        return ERR_NOT_FOUND;
+    }
+
+    pci_bus_mgr_enable_device(loc_);
+
+    // map bar 0, main memory mapped register interface, 128KB
+    err = vmm_alloc_physical(vmm_get_kernel_aspace(), "e1000_bar0", 128*1024, &bar0_regs_, 0,
+                             bars[0].addr, /* vmm_flags */ 0, ARCH_MMU_FLAG_UNCACHED_DEVICE);
+    if (err != NO_ERROR) {
+        return ERR_NOT_FOUND;
+    }
+
+    LTRACEF("bar 0 regs mapped to %p\n", bar0_regs_);
+
+    // read the mac address out of the eeprom
+    uint16_t tmp;
+    tmp = read_eeprom(0);
+    mac_addr_[0] = tmp & 0xff;
+    mac_addr_[1] = tmp >> 8;
+    tmp = read_eeprom(1);
+    mac_addr_[2] = tmp & 0xff;
+    mac_addr_[3] = tmp >> 8;
+    tmp = read_eeprom(2);
+    mac_addr_[4] = tmp & 0xff;
+    mac_addr_[5] = tmp >> 8;
+
+    printf("e1000: mac address %02x:%02x:%02x:%02x:%02x:%02x\n", mac_addr_[0], mac_addr_[1], mac_addr_[2],
+           mac_addr_[3], mac_addr_[4], mac_addr_[5]);
+
+    // allocate and map space for the rx and tx ring
+    err = vmm_alloc_contiguous(vmm_get_kernel_aspace(), "e1000 rxring", rxring_len * sizeof(rdesc), (void **)&rxring_, 0, 0, ARCH_MMU_FLAG_UNCACHED);
+    if (err != NO_ERROR) {
+        return ERR_NOT_FOUND;
+    }
+    memset(rxring_, 0, rxring_len * sizeof(rdesc));
+
+    paddr_t rxring_phys = vaddr_to_paddr(rxring_);
+    LTRACEF("rx ring at %p, physical %#lx\n", rxring_, rxring_phys);
+
+    err = vmm_alloc_contiguous(vmm_get_kernel_aspace(), "e1000 txring", txring_len * sizeof(tdesc), (void **)&txring_, 0, 0, ARCH_MMU_FLAG_UNCACHED);
+    if (err != NO_ERROR) {
+        return ERR_NOT_FOUND;
+    }
+    memset(txring_, 0, txring_len * sizeof(rdesc));
+
+    paddr_t txring_phys = vaddr_to_paddr(txring_);
+    LTRACEF("tx ring at %p, physical %#lx\n", txring_, txring_phys);
+
+    // allocate a large array of contiguous buffers to receive into
+    err = vmm_alloc_contiguous(vmm_get_kernel_aspace(), "e1000 rx buffers", rxring_len * rxbuffer_len, (void **)&rx_buf_, 0, 0, 0);
+    if (err != NO_ERROR) {
+        return ERR_NOT_FOUND;
+    }
+
+    // mask all IRQs
+    write_reg(e1000_reg::IMC, 0xffff);
+
+    // qemus 82574 emulation seems to want IAME to be set to auto-clear ICR bits.
+    if (is_e1000e()) {
+        auto ctrl_ext = read_reg(e1000_reg::CTL_EXT);
+        write_reg(e1000_reg::CTL_EXT, ctrl_ext | (1<<27)); // IAME - interrupt ack auto-mask
+        write_reg(e1000_reg::IAM, 0); // set such that no IMS bits are auto cleared
+    }
+
+    // set the interrupt treshold reg
+    const uint32_t irq_rate = 10000; // max 10k irqs/sec
+    write_reg(e1000_reg::ITR, 1000000 / irq_rate * 4);
+    if (is_e1000e()) {
+        write_reg(e1000_reg::EITR0, 1000000 / irq_rate * 4);
+        write_reg(e1000_reg::EITR1, 1000000 / irq_rate * 4);
+        write_reg(e1000_reg::EITR2, 1000000 / irq_rate * 4);
+        write_reg(e1000_reg::EITR3, 1000000 / irq_rate * 4);
+        write_reg(e1000_reg::EITR4, 1000000 / irq_rate * 4);
+    }
+
+    // set up minip's macaddr
+    // TODO: move to something smarter
+    minip_set_macaddr(mac_addr_);
+
+    // disable tx and rx
+    write_reg(e1000_reg::RCTL, 0);
+    write_reg(e1000_reg::TCTL, 0);
+
+    // irq handler lambda to get to inner method
+    auto irq_handler_wrapper = [](void *arg) -> handler_return {
+        e1000 *e = (e1000 *)arg;
+        return e->irq_handler();
+    };
+
+    // allocate a MSI interrupt
+    uint irq_base;
+    err = pci_bus_mgr_allocate_msi(loc_, 1, &irq_base);
+    if (err != NO_ERROR) {
+        // fall back to regular IRQs
+        err = pci_bus_mgr_allocate_irq(loc_, &irq_base);
+        if (err != NO_ERROR) {
+            printf("e1000: unable to allocate IRQ\n");
+            return err;
+        }
+        register_int_handler(irq_base, irq_handler_wrapper, this);
+    } else {
+        register_int_handler_msi(irq_base, irq_handler_wrapper, this, true);
+    }
+    LTRACEF("IRQ number %#x\n", irq_base);
+
+    unmask_interrupt(irq_base);
+
+    // set up the rx ring
+    write_reg(e1000_reg::RDBAL, rxring_phys & 0xffffffff);
+#if __INTPTR_WIDTH__ == 64
+    write_reg(e1000_reg::RDBAH, rxring_phys >> 32);
+#else
+    write_reg(e1000_reg::RDBAH, 0);
+#endif
+    write_reg(e1000_reg::RDLEN, rxring_len * sizeof(rdesc));
+    // set head and tail to 0
+    write_reg(e1000_reg::RDH, 0);
+    write_reg(e1000_reg::RDT, 0);
+
+    // disable receive delay timer and absolute delay timer
+    write_reg(e1000_reg::RDTR, 0);
+    write_reg(e1000_reg::RADV, 0);
+    // disable small packet detect
+    write_reg(e1000_reg::RSRPD, 0);
+
+    // set up the flow control thresholds
+    write_reg(e1000_reg::FCRTL, 0);
+    write_reg(e1000_reg::FCRTH, 0);
+
+    // fill the rx ring with pktbufs
+    rx_last_head_ = read_reg(e1000_reg::RDH);
+    rx_tail_ = read_reg(e1000_reg::RDT);
+    for (size_t i = 0; i < rxring_len - 1; i++) {
+        // construct a 2K pktbuf, pointing outo our rx_buf_ block of memory
+        auto *pkt = pktbuf_alloc_empty();
+        if (!pkt) {
+            break;
+        }
+        pktbuf_add_buffer(pkt, rx_buf_ + i * rxbuffer_len, rxbuffer_len, 0, 0, nullptr, nullptr);
+
+        add_pktbuf_to_rxring_locked(pkt);
+    }
+    //hexdump(rxring_, rxring_len * sizeof(rdesc));
+
+    // start rx worker thread
+    auto wrapper_lambda = [](void *arg) -> int {
+        e1000 *e = (e1000 *)arg;
+        return e->rx_worker_routine();
+    };
+    rx_worker_thread_ = thread_create("e1000 rx worker", wrapper_lambda, this, HIGH_PRIORITY, DEFAULT_STACK_SIZE);
+    thread_resume(rx_worker_thread_);
+
+    // start receiver
+    // enable RX, unicast permiscuous, multicast permiscuous, broadcast accept, BSIZE 2048
+    write_reg(e1000_reg::RCTL, (1<<1) | (1<<3) | (1<<4) | (1<<15) | (0<<16));
+
+    // unmask receive irq
+    auto ims = read_reg(e1000_reg::IMS);
+    write_reg(e1000_reg::IMS, ims | (1<<7) | (1<<6)); // RXO, RXTO
+
+    // set up the tx path
+    write_reg(e1000_reg::TDH, 0);
+    write_reg(e1000_reg::TDT, 0);
+    tx_last_head_ = 0;
+    tx_tail_ = 0;
+
+    // set up the tx ring
+    write_reg(e1000_reg::TDBAL, txring_phys & 0xffffffff);
+#if __INTPTR_WIDTH__ == 64
+    write_reg(e1000_reg::TDBAH, txring_phys >> 32);
+#else
+    write_reg(e1000_reg::TDBAH, 0);
+#endif
+    write_reg(e1000_reg::TDLEN, txring_len * sizeof(tdesc));
+
+    // enable the transmitter and appropriate irqs
+    write_reg(e1000_reg::TCTL, (1<<3) | (1<<1)); // short packet pad, tx enable
+
+    // unmask tx irq
+    ims = read_reg(e1000_reg::IMS);
+    write_reg(e1000_reg::IMS, ims | (1<<1) | (1<<0)); // transmit queue empty, tx descriptor write back
+
+    return NO_ERROR;
+}
+
+// XXX REMOVE HACK
+extern "C"
+int e1000_tx(pktbuf_t *p) {
+    if (the_e) {
+        the_e->tx(p);
+    }
+
+    return NO_ERROR;
+}
+
+static void e1000_init(uint level) {
+    LTRACE_ENTRY;
+
+    auto ac = lk::make_auto_call([]() { LTRACE_EXIT; });
+
+    // probe pci to find a device
+    for (auto id:  e1000_ids) {
+        for (size_t i = 0; ; i++) {
+            pci_location_t loc;
+            status_t err = pci_bus_mgr_find_device(&loc, id.id, 0x8086, i);
+            if (err != NO_ERROR) {
+                break;
+            }
+
+            // we maybe found one, create a new device and initialize it
+            auto e = new e1000;
+            err = e->init_device(loc, &id);
+            if (err != NO_ERROR) {
+                char str[14];
+                printf("e1000: device at %s failed to initialize\n", pci_loc_string(loc, str));
+                delete e;
+                continue;
+            }
+
+            // XXX first e1000 found is remembered
+            the_e = e;
+        }
+    }
+}
+
+LK_INIT_HOOK(e1000, &e1000_init, LK_INIT_LEVEL_PLATFORM + 1);
--- a/dev/net/e1000/e1000_hw.h
+++ b/dev/net/e1000/e1000_hw.h
@@ -0,0 +1,128 @@
+//
+// Copyright (c) 2021 Travis Geiselbrecht
+//
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file or at
+// https://opensource.org/licenses/MIT
+
+#pragma once
+
+#include <stdint.h>
+#include <stdio.h>
+
+// from 8254x Family SDM Table 13-2
+enum class e1000_reg {
+    // general
+    CTRL = 0x0,
+    STATUS = 0x8,
+    EECD = 0x10,
+    EERD = 0x14,
+    CTL_EXT = 0x18,
+    MDIC = 0x20,
+    FACL = 0x28,
+    FACH = 0x2c,
+    FCT = 0x30,
+    VET = 0x38,
+    FCTTV = 0x170,
+    TXCW = 0x178,
+    RXCW = 0x180,
+    LEDCTL = 0xe00,
+
+    // DMA
+    DMA = 0x1000,
+
+    // interrupt
+    ICR = 0xc0,
+    ITR = 0xc4,
+    IMS = 0xd0,
+    IMC = 0xd8,
+    IAM = 0xe0,
+    EITR0 = 0x1680, // e1000e only (i210)+
+    EITR1 = 0x1684,
+    EITR2 = 0x1688,
+    EITR3 = 0x168c,
+    EITR4 = 0x1690,
+
+    // receive
+    RCTL = 0x100,
+    FCRTL = 0x2160,
+    FCRTH = 0x2168,
+    RDBAL = 0x2800,
+    RDBAH = 0x2804,
+    RDLEN = 0x2808,
+    RDH = 0x2810,
+    RDT = 0x2818,
+    RDTR = 0x2820,
+    RADV = 0x282c,
+    RSRPD = 0x2c00,
+
+    // transmit
+    TCTL = 0x400,
+    TIPG = 0x410,
+    AIFS = 0x458,
+    TDBAL = 0x3800,
+    TDBAH = 0x3804,
+    TDLEN = 0x3808,
+    TDH = 0x3810,
+    TDT = 0x3818,
+    TIDV = 0x3820,
+
+    // tx dma
+    TXDMAC = 0x3000,
+    TXDCTL = 0x3828,
+    TADV = 0x382c,
+    TSPMT = 0x3830,
+
+    // rx dma
+    RXDCTL = 0x2828,
+    RXCSUM = 0x5000,
+};
+
+// receive descriptor
+struct rdesc {
+    uint64_t addr;
+    uint16_t length;
+    uint16_t checksum;
+    uint8_t status;
+    uint8_t errors;
+    uint16_t special;
+
+    void dump() {
+        printf("rdsec %p: addr %#llx len %hu cksum %#hx stat %#hhx err %#hhx spec %#hx\n",
+               this, addr, length, checksum, status, errors, special);
+    }
+
+};
+static_assert(sizeof(rdesc) == 16, "");
+
+// transmit descriptor (legacy)
+struct tdesc {
+    uint64_t addr;
+    uint16_t length;
+    uint8_t cso;
+    uint8_t cmd;
+    uint8_t sta_rsv;
+    uint8_t css;
+    uint16_t special;
+
+    void dump() {
+        printf("tdsec %p: addr %#llx len %hu cso %#hhx cmd %#hhx sta_rsv %#hhx css %#hhx spec %#hx\n",
+               this, addr, length, cso, cmd, sta_rsv, css, special);
+    }
+};
+static_assert(sizeof(tdesc) == 16, "");
+
+// efficient copy for rx/tx descriptors out/into uncached memory
+template <typename T>
+inline void copy(T *_dst, const T *_src) {
+    // only allow this for structs that are precisely 16 bytes long
+    static_assert(sizeof(T) == 16, "");
+
+    // treat as two 8 byte copies
+    uint64_t *dst = (uint64_t *)_dst;
+    const uint64_t *src = (uint64_t *)_src;
+
+    dst[0] = src[0];
+    dst[1] = src[1];
+}
+
--- a/dev/net/e1000/rules.mk
+++ b/dev/net/e1000/rules.mk
@@ -0,0 +1,10 @@
+LOCAL_DIR := $(GET_LOCAL_DIR)
+
+MODULE := $(LOCAL_DIR)
+
+MODULE_SRCS += $(LOCAL_DIR)/e1000.cpp
+
+MODULE_DEPS += dev/bus/pci
+MODULE_DEPS += lib/minip
+
+include make/module.mk
--- a/platform/pc/platform.c
+++ b/platform/pc/platform.c
@@ -296,4 +296,9 @@ void platform_init(void) {
 #endif

    platform_init_mmu_mappings();
+
+#if WITH_LIB_MINIP
+    extern int e1000_tx(pktbuf_t *p);
+    minip_init_dhcp(e1000_tx, 0);
+#endif
 }
--- a/platform/pc/rules.mk
+++ b/platform/pc/rules.mk
@@ -13,6 +13,7 @@ MODULE_DEPS += \

 ifneq ($(CPU),legacy)
 MODULE_DEPS += dev/bus/pci
+MODULE_DEPS += dev/net/e1000
 endif

 MODULE_SRCS += \
--- a/scripts/do-qemux86
+++ b/scripts/do-qemux86
@@ -110,7 +110,7 @@ if (( $DO_NET )); then
        exit 1
    fi
 else
-    ARGS+=" -nic none"
+    ARGS+=" -net none"
 fi

 $DIR/make-parallel $MAKE_VARS $PROJECT &&