[SeaBIOS] [PATCH v2] block: add NVMe boot support

Kevin O'Connor kevin at koconnor.net
Sat Feb 11 18:11:39 CET 2017


On Wed, Feb 01, 2017 at 09:55:33AM +0100, Julian Stecklina wrote:
> This patch enables SeaBIOS to boot from NVMe. Finding namespaces and
> basic I/O works. Testing has been done in qemu and so far it works with
> Grub, syslinux, and the FreeBSD loader. You need a recent Qemu (>=
> 2.7.0), because older versions have buggy NVMe support.
> 
> The NVMe code is currently only enabled on Qemu due to lack of testing
> on real hardware.
> 
> Signed-off-by: Julian Stecklina <jsteckli at amazon.de>

Thanks Julian.  I have some comments below - most of them minor.
However, the use of panic() in a driver is a blocker - we don't want
any drivers to use panic as its use could cause a machine to be
inoperable.

[...]
> --- /dev/null
> +++ b/src/hw/nvme.c
> @@ -0,0 +1,651 @@
> +// Low level NVMe disk access
> +//
> +// Copyright 2017 Amazon.com, Inc. or its affiliates.
> +//
> +// This file may be distributed under the terms of the GNU LGPLv3 license.
> +
> +#include "blockcmd.h"
> +#include "fw/paravirt.h" // runningOnQEMU
> +#include "malloc.h" // malloc_high
> +#include "output.h" // dprintf
> +#include "pci.h"
> +#include "pci_ids.h" // PCI_CLASS_STORAGE_NVME
> +#include "pci_regs.h" // PCI_BASE_ADDRESS_0
> +#include "pcidevice.h" // foreachpci
> +#include "stacks.h" // yield
> +#include "std/disk.h" // DISK_RET_
> +#include "string.h" // memset
> +#include "util.h" // boot_add_hd
> +#include "x86.h" // readl
> +
> +#include "nvme.h"
> +#include "nvme-int.h"
> +
> +static void *
> +zalloc_page_aligned(void *(*memalign)(u32 /* align */, u32 /* size */),
> +                    u32 size)
> +{
> +    void *res = memalign(NVME_PAGE_SIZE, size);
> +    if (res) memset(res, 0, size);
> +    return res;
> +}

memalign_high() and memalign_tmp() are thin wrappers around _malloc()
- see malloc.h.  Instead of passing pointers to these thin wrapper
functions it would be preferable to pass the malloc zone and call
_malloc() directly.

> +
> +static void
> +nvme_init_queue_common(struct nvme_ctrl *ctrl, struct nvme_queue *q, u16 q_idx,
> +                       u16 length)
> +{
> +    memset(q, 0, sizeof(*q));
> +    q->dbl = (u32 *)((char *)ctrl->reg + 0x1000 + q_idx * ctrl->doorbell_stride);
> +    dprintf(3, " q %p q_idx %u dbl %p\n", q, q_idx, q->dbl);
> +    q->mask = length - 1;
> +}
> +
> +static void
> +nvme_init_sq(struct nvme_ctrl *ctrl, struct nvme_sq *sq, u16 q_idx, u16 length,
> +             struct nvme_cq *cq)
> +{
> +    nvme_init_queue_common(ctrl, &sq->common, q_idx, length);
> +    sq->sqe = zalloc_page_aligned(memalign_high, sizeof(*sq->sqe) * length);
> +    dprintf(3, "sq %p q_idx %u sqe %p\n", sq, q_idx, sq->sqe);
> +    sq->cq   = cq;
> +    sq->head = 0;
> +    sq->tail = 0;
> +}
> +
> +static void
> +nvme_init_cq(struct nvme_ctrl *ctrl, struct nvme_cq *cq, u16 q_idx, u16 length)
> +{
> +    nvme_init_queue_common(ctrl, &cq->common, q_idx, length);
> +    cq->cqe = zalloc_page_aligned(memalign_high, sizeof(*cq->cqe) * length);
> +
> +    cq->head = 0;
> +
> +    /* All CQE phase bits are initialized to zero. This means initially we wait
> +       for the host controller to set these to 1. */
> +    cq->phase = 1;
> +}
> +
> +static int
> +nvme_poll_cq(struct nvme_cq *cq)
> +{
> +    u32 dw3 = readl(&cq->cqe[cq->head].dword[3]);
> +    return (!!(dw3 & NVME_CQE_DW3_P) == cq->phase);
> +}
> +
> +static int
> +nvme_is_cqe_success(struct nvme_cqe const *cqe)
> +{
> +    return (cqe->status & 0xFF) >> 1 == 0;
> +}
> +
> +
> +static struct nvme_cqe
> +nvme_error_cqe(void)
> +{
> +    struct nvme_cqe r;
> +
> +    /* 0xFF is a vendor specific status code != success. Should be okay for
> +       indicating failure. */
> +    memset(&r, 0xFF, sizeof(r));
> +    return r;
> +}
> +
> +static struct nvme_cqe
> +nvme_consume_cqe(struct nvme_sq *sq)
> +{
> +    struct nvme_cq *cq = sq->cq;
> +
> +    if (!nvme_poll_cq(cq)) {
> +        /* Cannot consume a completion queue entry, if there is none ready. */
> +        return nvme_error_cqe();
> +    }
> +
> +    struct nvme_cqe *cqe = &cq->cqe[cq->head];
> +    u16 cq_next_head = (cq->head + 1) & cq->common.mask;
> +    dprintf(4, "cq %p head %u -> %u\n", cq, cq->head, cq_next_head);
> +    if (cq_next_head < cq->head) {
> +        dprintf(3, "cq %p wrap\n", cq);
> +        cq->phase = ~cq->phase;
> +    }
> +    cq->head = cq_next_head;
> +
> +    /* Update the submission queue head. */
> +    if (cqe->sq_head != sq->head) {
> +        sq->head = cqe->sq_head;
> +        dprintf(4, "sq %p advanced to %u\n", sq, cqe->sq_head);
> +    }
> +
> +    /* Tell the controller that we consumed the completion. */
> +    writel(cq->common.dbl, cq->head);
> +
> +    return *cqe;
> +}
> +
> +static struct nvme_cqe
> +nvme_wait(struct nvme_sq *sq)
> +{
> +    static const unsigned nvme_timeout = 500 /* ms */;
> +    u32 to = timer_calc(nvme_timeout);
> +    while (!nvme_poll_cq(sq->cq)) {
> +        yield();
> +
> +        if (timer_check(to)) {
> +            warn_timeout();
> +            return nvme_error_cqe();
> +        }
> +    }
> +
> +    return nvme_consume_cqe(sq);
> +}
> +
> +/* Returns the next submission queue entry (or NULL if the queue is full). It
> +   also fills out Command Dword 0 and clears the rest. */
> +static struct nvme_sqe *
> +nvme_get_next_sqe(struct nvme_sq *sq, u8 opc, void *metadata, void *data)
> +{
> +    if (((sq->head + 1) & sq->common.mask) == sq->tail) {
> +        dprintf(3, "submission queue is full");
> +        return NULL;
> +    }
> +
> +    struct nvme_sqe *sqe = &sq->sqe[sq->tail];
> +    dprintf(4, "sq %p next_sqe %u\n", sq, sq->tail);
> +
> +    memset(sqe, 0, sizeof(*sqe));
> +    sqe->cdw0 = opc | (sq->tail << 16 /* CID */);
> +    sqe->mptr = (u32)metadata;
> +    sqe->dptr_prp1 = (u32)data;
> +
> +    if (sqe->dptr_prp1 & (NVME_PAGE_SIZE - 1)) {
> +        /* Data buffer not page aligned. */
> +        panic("data buffer not page aligned: %p\n", data);
> +        warn_internalerror();

Can't call panic().

> +    }
> +
> +    return sqe;
> +}
> +
> +/* Call this after you've filled out an sqe that you've got from nvme_get_next_sqe. */
> +static void
> +nvme_commit_sqe(struct nvme_sq *sq)
> +{
> +    dprintf(4, "sq %p commit_sqe %u\n", sq, sq->tail);
> +    sq->tail = (sq->tail + 1) & sq->common.mask;
> +    writel(sq->common.dbl, sq->tail);
> +}
> +
> +/* Perform an identify command on the admin queue and return the resulting
> +   buffer. This may be a NULL pointer, if something failed. This function
> +   cannot be used after initialization, because it uses buffers in tmp zone. */
> +static union nvme_identify *
> +nvme_admin_identify(struct nvme_ctrl *ctrl, u8 cns, u32 nsid)
> +{
> +    union nvme_identify *identify_buf = zalloc_page_aligned(memalign_tmp, 4096);
> +    if (!identify_buf) {
> +        /* Could not allocate identify buffer. */
> +        warn_internalerror();
> +        return NULL;
> +    }
> +
> +    struct nvme_sqe *cmd_identify;
> +    cmd_identify = nvme_get_next_sqe(&ctrl->admin_sq,
> +                                     NVME_SQE_OPC_ADMIN_IDENTIFY, NULL,
> +                                     identify_buf);
> +
> +    if (!cmd_identify) { panic("admin queue full\n"); }

Can't call panic().

> +
> +    cmd_identify->nsid = nsid;
> +    cmd_identify->dword[10] = cns;
> +
> +    nvme_commit_sqe(&ctrl->admin_sq);
> +
> +    struct nvme_cqe cqe = nvme_wait(&ctrl->admin_sq);
> +
> +    if (!nvme_is_cqe_success(&cqe)) {
> +        free(identify_buf);
> +        return NULL;
> +    }
> +
> +    return identify_buf;
> +}
> +
> +static struct nvme_identify_ctrl *
> +nvme_admin_identify_ctrl(struct nvme_ctrl *ctrl)
> +{
> +    return &nvme_admin_identify(ctrl, NVME_ADMIN_IDENTIFY_CNS_ID_CTRL, 0)->ctrl;
> +}
> +
> +static struct nvme_identify_ns_list *
> +nvme_admin_identify_get_ns_list(struct nvme_ctrl *ctrl)
> +{
> +    return &nvme_admin_identify(ctrl, NVME_ADMIN_IDENTIFY_CNS_GET_NS_LIST,
> +                                0)->ns_list;
> +}
> +
> +static struct nvme_identify_ns *
> +nvme_admin_identify_ns(struct nvme_ctrl *ctrl, u32 ns_id)
> +{
> +    return &nvme_admin_identify(ctrl, NVME_ADMIN_IDENTIFY_CNS_ID_NS,
> +                                ns_id)->ns;
> +}
> +
> +static void
> +nvme_probe_ns(struct nvme_ctrl *ctrl, struct nvme_namespace *ns, u32 ns_id)
> +{
> +    ns->ctrl  = ctrl;
> +    ns->ns_id = ns_id;
> +
> +    struct nvme_identify_ns *id = nvme_admin_identify_ns(ctrl, ns_id);
> +    if (!id) {
> +        dprintf(2, "NVMe couldn't identify namespace %u.\n", ns_id);
> +        goto free_buffer;
> +    }
> +
> +    u8 current_lba_format = id->flbas & 0xF;
> +    if (current_lba_format > id->nlbaf) {
> +        dprintf(2, "NVMe NS %u: current LBA format %u is beyond what the "
> +                " namespace supports (%u)?\n",
> +                ns_id, current_lba_format, id->nlbaf + 1);
> +        goto free_buffer;
> +    }
> +
> +    ns->lba_count = id->nsze;
> +
> +    struct nvme_lba_format *fmt = &id->lbaf[current_lba_format];
> +
> +    ns->block_size    = 1U << fmt->lbads;
> +    ns->metadata_size = fmt->ms;
> +
> +    if (ns->block_size > NVME_PAGE_SIZE) {
> +        /* If we see devices that trigger this path, we need to increase our
> +           buffer size. */
> +        warn_internalerror();
> +        goto free_buffer;
> +    }
> +
> +    ns->drive.cntl_id   = ns - ctrl->ns;
> +    ns->drive.removable = 0;
> +    ns->drive.type      = DTYPE_NVME;
> +    ns->drive.blksize   = ns->block_size;
> +    ns->drive.sectors   = ns->lba_count;
> +
> +    ns->dma_buffer = zalloc_page_aligned(memalign_high, NVME_PAGE_SIZE);
> +
> +    char *desc = znprintf(MAXDESCSIZE, "NVMe NS %u: %llu MiB (%llu %u-byte "
> +                          "blocks + %u-byte metadata)\n",
> +                          ns_id, (ns->lba_count * ns->block_size) >> 20,
> +                          ns->lba_count, ns->block_size, ns->metadata_size);
> +
> +    dprintf(3, "%s", desc);
> +    boot_add_hd(&ns->drive, desc, bootprio_find_pci_device(ctrl->pci));
> +
> + free_buffer:
> +    free (id);
> + }
> +
> +/* Returns 0 on success. */
> +static int
> +nvme_create_io_cq(struct nvme_ctrl *ctrl, struct nvme_cq *cq, u16 q_idx)
> +{
> +    struct nvme_sqe *cmd_create_cq;
> +
> +    nvme_init_cq(ctrl, cq, q_idx, NVME_PAGE_SIZE / sizeof(struct nvme_cqe));
> +    cmd_create_cq = nvme_get_next_sqe(&ctrl->admin_sq,
> +                                      NVME_SQE_OPC_ADMIN_CREATE_IO_CQ, NULL,
> +                                      cq->cqe);
> +    if (!cmd_create_cq) {
> +        return -1;
> +    }
> +
> +    cmd_create_cq->dword[10] = (cq->common.mask << 16) | (q_idx >> 1);
> +    cmd_create_cq->dword[11] = 1 /* physically contiguous */;
> +
> +    nvme_commit_sqe(&ctrl->admin_sq);
> +
> +    struct nvme_cqe cqe = nvme_wait(&ctrl->admin_sq);
> +
> +    if (!nvme_is_cqe_success(&cqe)) {
> +        dprintf(2, "create io cq failed: %08x %08x %08x %08x\n",
> +                cqe.dword[0], cqe.dword[1], cqe.dword[2], cqe.dword[3]);
> +
> +        return -1;
> +    }
> +
> +    return 0;
> +}
> +
> +/* Returns 0 on success. */
> +static int
> +nvme_create_io_sq(struct nvme_ctrl *ctrl, struct nvme_sq *sq, u16 q_idx, struct nvme_cq *cq)
> +{
> +    struct nvme_sqe *cmd_create_sq;
> +
> +    nvme_init_sq(ctrl, sq, q_idx, NVME_PAGE_SIZE / sizeof(struct nvme_cqe), cq);
> +    cmd_create_sq = nvme_get_next_sqe(&ctrl->admin_sq,
> +                                      NVME_SQE_OPC_ADMIN_CREATE_IO_SQ, NULL,
> +                                      sq->sqe);
> +    if (!cmd_create_sq) {
> +        return -1;
> +    }
> +
> +    cmd_create_sq->dword[10] = (sq->common.mask << 16) | (q_idx >> 1);
> +    cmd_create_sq->dword[11] = (q_idx >> 1) << 16 | 1 /* contiguous */;
> +    dprintf(3, "sq %p create dword10 %08x dword11 %08x\n", sq,
> +            cmd_create_sq->dword[10], cmd_create_sq->dword[11]);
> +
> +    nvme_commit_sqe(&ctrl->admin_sq);
> +
> +    struct nvme_cqe cqe = nvme_wait(&ctrl->admin_sq);
> +
> +    if (!nvme_is_cqe_success(&cqe)) {
> +        dprintf(2, "create io sq failed: %08x %08x %08x %08x\n",
> +                cqe.dword[0], cqe.dword[1], cqe.dword[2], cqe.dword[3]);
> +        return -1;
> +    }
> +
> +    return 0;
> +}
> +
> +/* Reads count sectors into buf. Returns DISK_RET_*. The buffer cannot cross
> +   page boundaries. */
> +static int
> +nvme_io_readwrite(struct nvme_namespace *ns, u64 lba, char *buf, u16 count,
> +                  int write)
> +{
> +    u32 buf_addr = (u32)buf;
> +
> +    if ((buf_addr & 0x3) ||
> +        ((buf_addr & ~(NVME_PAGE_SIZE - 1)) !=
> +         ((buf_addr + ns->block_size * count - 1) & ~(NVME_PAGE_SIZE - 1)))) {
> +        /* Buffer is misaligned or crosses page boundary */
> +        warn_internalerror();
> +        return DISK_RET_EBADTRACK;
> +    }
> +
> +    struct nvme_sqe *io_read = nvme_get_next_sqe(&ns->ctrl->io_sq,
> +                                                 write ? NVME_SQE_OPC_IO_WRITE
> +                                                       : NVME_SQE_OPC_IO_READ,
> +                                                 NULL, buf);
> +    io_read->nsid = ns->ns_id;
> +    io_read->dword[10] = (u32)lba;
> +    io_read->dword[11] = (u32)(lba >> 32);
> +    io_read->dword[12] = (1U << 31 /* limited retry */) | (count - 1);
> +
> +    nvme_commit_sqe(&ns->ctrl->io_sq);
> +
> +    struct nvme_cqe cqe = nvme_wait(&ns->ctrl->io_sq);
> +
> +    if (!nvme_is_cqe_success(&cqe)) {
> +        dprintf(2, "read io: %08x %08x %08x %08x\n",
> +                cqe.dword[0], cqe.dword[1], cqe.dword[2], cqe.dword[3]);
> +
> +        return DISK_RET_EBADTRACK;
> +    }
> +
> +    return DISK_RET_SUCCESS;
> +}
> +
> +
> +static int
> +nvme_create_io_queues(struct nvme_ctrl *ctrl)
> +{
> +    if (nvme_create_io_cq(ctrl, &ctrl->io_cq, 3))
> +        return -1;
> +
> +    if (nvme_create_io_sq(ctrl, &ctrl->io_sq, 2, &ctrl->io_cq))
> +        return -1;
> +
> +    return 0;
> +}
> +
> +/* Waits for CSTS.RDY to match rdy. Returns 0 on success. */
> +static int
> +nvme_wait_csts_rdy(struct nvme_ctrl *ctrl, unsigned rdy)
> +{
> +    u32 const max_to = 500 /* ms */ * ((ctrl->reg->cap >> 24) & 0xFFU);
> +    u32 to = timer_calc(max_to);
> +    u32 csts;
> +
> +    while (rdy != ((csts = ctrl->reg->csts) & NVME_CSTS_RDY)) {
> +        yield();
> +
> +        if (csts & NVME_CSTS_FATAL) {
> +            dprintf(3, "NVMe fatal error during controller shutdown\n");
> +            return -1;
> +        }
> +
> +        if (timer_check(to)) {
> +            warn_timeout();
> +            return -1;
> +        }
> +    }
> +
> +    return 0;
> +}
> +
> +static void
> +nvme_controller_enable(struct nvme_ctrl *ctrl)
> +{
> +    pci_enable_busmaster(ctrl->pci);
> +
> +    /* Turn the controller off. */
> +    ctrl->reg->cc = 0;
> +    if (nvme_wait_csts_rdy(ctrl, 0)) {
> +        dprintf(2, "NVMe fatal error during controller shutdown\n");
> +        return;
> +    }
> +
> +    ctrl->doorbell_stride = 4U << ((ctrl->reg->cap >> 32) & 0xF);
> +
> +    nvme_init_cq(ctrl, &ctrl->admin_cq, 1,
> +                 NVME_PAGE_SIZE / sizeof(struct nvme_cqe));
> +
> +    nvme_init_sq(ctrl, &ctrl->admin_sq, 0,
> +                 NVME_PAGE_SIZE / sizeof(struct nvme_sqe), &ctrl->admin_cq);
> +
> +    ctrl->reg->aqa = ctrl->admin_cq.common.mask << 16
> +        | ctrl->admin_sq.common.mask;
> +
> +    /* Create the admin queue pair */
> +    if (!ctrl->admin_sq.sqe || !ctrl->admin_cq.cqe) goto out_of_memory;
> +
> +    ctrl->reg->asq = (u32)ctrl->admin_sq.sqe;
> +    ctrl->reg->acq = (u32)ctrl->admin_cq.cqe;
> +
> +    dprintf(3, "  admin submission queue: %p\n", ctrl->admin_sq.sqe);
> +    dprintf(3, "  admin completion queue: %p\n", ctrl->admin_cq.cqe);
> +
> +    ctrl->reg->cc = NVME_CC_EN | (NVME_CQE_SIZE_LOG << 20)
> +        | (NVME_SQE_SIZE_LOG << 16 /* IOSQES */);
> +
> +    if (nvme_wait_csts_rdy(ctrl, 1)) {
> +        dprintf(2, "NVMe fatal error while enabling controller\n");
> +        return;

Shouldn't this free the allocated memory on failure (ie, goto failed)?

> +    }
> +    /* The admin queue is set up and the controller is ready. Let's figure out
> +       what namespaces we have. */
> +
> +    struct nvme_identify_ctrl *identify = nvme_admin_identify_ctrl(ctrl);
> +
> +    if (!identify) {
> +        dprintf(2, "NVMe couldn't identify controller.\n");
> +        goto failed;
> +    }
> +
> +    /* TODO Print model/serial info. */
> +    dprintf(3, "NVMe has %u namespace%s.\n",
> +            identify->nn, (identify->nn == 1) ? "" : "s");
> +
> +    ctrl->ns_count = identify->nn;
> +    free(identify);
> +
> +    if ((ctrl->ns_count == 0) || nvme_create_io_queues(ctrl)) {
> +        /* No point to continue, if the controller says it doesn't have
> +           namespaces or we couldn't create I/O queues. */
> +        goto failed;
> +    }
> +
> +    ctrl->ns = malloc_fseg(sizeof(*ctrl->ns) * ctrl->ns_count);
> +    if (!ctrl->ns) goto out_of_memory;
> +    memset(ctrl->ns, 0, sizeof(*ctrl->ns) * ctrl->ns_count);
> +
> +    struct nvme_identify_ns_list *ns_list = nvme_admin_identify_get_ns_list(ctrl);
> +    if (!ns_list) {
> +        dprintf(2, "NVMe couldn't get namespace list.\n");
> +        goto failed;
> +    }
> +
> +    /* Populate namespace IDs */
> +    int ns_idx;
> +    for (ns_idx = 0;
> +         ns_idx < ARRAY_SIZE(ns_list->ns_id)
> +             && ns_idx < ctrl->ns_count
> +             && ns_list->ns_id[ns_idx];
> +         ns_idx++) {
> +        nvme_probe_ns(ctrl, &ctrl->ns[ns_idx], ns_list->ns_id[ns_idx]);
> +    }
> +
> +    free(ns_list);
> +
> +    /* If for some reason the namespace list gives us fewer namespaces, we just
> +       go along. */
> +    if (ns_idx != ctrl->ns_count) {
> +        dprintf(2, "NVMe namespace list has only %u namespaces?\n", ns_idx);
> +        ctrl->ns_count = ns_idx;
> +    }
> +
> +    dprintf(3, "NVMe initialization complete!\n");
> +    return;
> +
> + out_of_memory:
> +    warn_noalloc();
> + failed:
> +    free(ctrl->admin_sq.sqe);
> +    free(ctrl->admin_cq.cqe);
> +    free(ctrl->ns);
> +    return;
> +}
> +
> +/* Initialize an NVMe controller and detect its drives. */
> +static void
> +nvme_controller_setup(void *opaque)
> +{
> +    struct pci_device *pci = opaque;
> +
> +    if (create_bounce_buf() < 0)
> +        return;

The bounce buffer isn't used anywhere in the code, so it's not
necessary to create it.

> +
> +    struct nvme_reg volatile *reg = pci_enable_membar(pci, PCI_BASE_ADDRESS_0);
> +    if (!reg)
> +        return;
> +
> +    u32 version = reg->vs;
> +    dprintf(3, "Found NVMe controller with version %u.%u.%u.\n",
> +            version >> 16, (version >> 8) & 0xFF, version & 0xFF);
> +    dprintf(3, "  Capabilities %016llx\n", reg->cap);
> +
> +    if (version < 0x00010100U) {
> +        dprintf(3, "Need at least 1.1.0! Skipping.\n");
> +        return;
> +    }
> +
> +    if (~reg->cap & NVME_CAP_CSS_NVME) {
> +        dprintf(3, "Controller doesn't speak NVMe command set. Skipping.\n");
> +        return;
> +    }
> +
> +    struct nvme_ctrl *ctrl = malloc_high(sizeof(*ctrl));
> +    if (!ctrl) {
> +        warn_noalloc();
> +        return;
> +    }
> +
> +    memset(ctrl, 0, sizeof(*ctrl));
> +
> +    ctrl->reg = reg;
> +    ctrl->pci = pci;
> +
> +    nvme_controller_enable(ctrl);

Shouldn't ctrl be free'd on failure?

> +}
> +
> +// Locate and init NVMe controllers
> +static void
> +nvme_scan(void)
> +{
> +    // Scan PCI bus for ATA adapters
> +    struct pci_device *pci;
> +
> +    foreachpci(pci) {
> +        if (pci->class != PCI_CLASS_STORAGE_NVME)
> +            continue;
> +        if (pci->prog_if != 2 /* as of NVM 1.0e */) {
> +            dprintf(3, "Found incompatble NVMe: prog-if=%02x\n", pci->prog_if);
> +            continue;
> +        }
> +
> +        run_thread(nvme_controller_setup, pci);
> +    }
> +}
> +
> +static int
> +nvme_cmd_readwrite(struct nvme_namespace *ns, struct disk_op_s *op, int write)
> +{
> +    int res = DISK_RET_SUCCESS;
> +    u16 const max_blocks = NVME_PAGE_SIZE / ns->block_size;
> +    u16 i;
> +
> +    for (i = 0; i < op->count || res != DISK_RET_SUCCESS;) {
> +        u16 blocks_remaining = op->count - i;
> +        u16 blocks = blocks_remaining < max_blocks ? blocks_remaining
> +                                                   : max_blocks;
> +        char *op_buf = op->buf_fl + i * ns->block_size;
> +
> +        if (write) {
> +            memcpy(ns->dma_buffer, op_buf, blocks * ns->block_size);
> +        }
> +
> +        res = nvme_io_readwrite(ns, op->lba + i, ns->dma_buffer, blocks, write);
> +        dprintf(3, "ns %u %s lba %llu+%u: %d\n", ns->ns_id, write ? "write"
> +                                                                  : "read",
> +                op->lba + i, blocks, res);
> +
> +        if (!write && res == DISK_RET_SUCCESS) {
> +            memcpy(op_buf, ns->dma_buffer, blocks * ns->block_size);
> +        }
> +
> +        i += blocks;
> +    }
> +
> +    return res;
> +}
> +
> +int
> +nvme_process_op(struct disk_op_s *op)
> +{
> +    if (!CONFIG_NVME || !runningOnQEMU())
> +        return DISK_RET_SUCCESS;
> +
> +    struct nvme_namespace *ns = container_of(op->drive_gf, struct nvme_namespace,
> +                                             drive);
> +
> +    switch (op->command) {
> +    case CMD_READ:
> +    case CMD_WRITE:
> +        return nvme_cmd_readwrite(ns, op, op->command == CMD_WRITE);
> +    default:
> +        return default_process_op(op);
> +    }
> +}
> +
> +void
> +nvme_setup(void)
> +{
> +    ASSERT32FLAT();
> +    if (!CONFIG_NVME)
> +        return;

With the driver set to require QEMU_HARDWARE, this test should be:
  if (!CONFIG_NVME || !runningOnQEMU()) return;
to make sure the code is actually running on QEMU.

> +
> +    dprintf(3, "init nvme\n");
> +    nvme_scan();
> +}
> +
> +/* EOF */

-Kevin



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