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qemu/pc-bios/s390-ccw/virtio-scsi.c
Thomas Huth 605751b5a5 pc-bios/s390-ccw: Do not bail out early if not finding a SCSI disk 
In case the user did not specify a boot device, we want to continue
looking for other devices if there are no valid SCSI disks on a virtio-
scsi controller. As a first step, do not panic in this case and let
the control flow carry the error to the upper functions instead.

Message-Id: <20200806105349.632-6-thuth@redhat.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>
2020-10-06 19:36:50 +02:00

433 lines
14 KiB
C
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/*
* Virtio-SCSI implementation for s390 machine loader for qemu
*
* Copyright 2015 IBM Corp.
* Author: Eugene "jno" Dvurechenski <jno@linux.vnet.ibm.com>
*
* This work is licensed under the terms of the GNU GPL, version 2 or (at
* your option) any later version. See the COPYING file in the top-level
* directory.
*/
#include "libc.h"
#include "s390-ccw.h"
#include "virtio.h"
#include "scsi.h"
#include "virtio-scsi.h"
#include "s390-time.h"
#include "helper.h"
static ScsiDevice default_scsi_device;
static VirtioScsiCmdReq req;
static VirtioScsiCmdResp resp;
static uint8_t scsi_inquiry_std_response[256];
static ScsiInquiryEvpdPages scsi_inquiry_evpd_pages_response;
static ScsiInquiryEvpdBl scsi_inquiry_evpd_bl_response;
static inline void vs_assert(bool term, const char **msgs)
{
if (!term) {
int i = 0;
sclp_print("\n! ");
while (msgs[i]) {
sclp_print(msgs[i++]);
}
panic(" !\n");
}
}
static void virtio_scsi_verify_response(VirtioScsiCmdResp *resp,
const char *title)
{
const char *mr[] = {
title, ": response ", virtio_scsi_response_msg(resp), 0
};
const char *ms[] = {
title,
CDB_STATUS_VALID(resp->status) ? ": " : ": invalid ",
scsi_cdb_status_msg(resp->status),
resp->status == CDB_STATUS_CHECK_CONDITION ? " " : 0,
resp->sense_len ? scsi_cdb_asc_msg(resp->sense)
: "no sense data",
scsi_sense_response(resp->sense) == 0x70 ? ", sure" : "?",
0
};
vs_assert(resp->response == VIRTIO_SCSI_S_OK, mr);
vs_assert(resp->status == CDB_STATUS_GOOD, ms);
}
static void prepare_request(VDev *vdev, const void *cdb, int cdb_size,
void *data, uint32_t data_size)
{
const ScsiDevice *sdev = vdev->scsi_device;
memset(&req, 0, sizeof(req));
req.lun = make_lun(sdev->channel, sdev->target, sdev->lun);
memcpy(&req.cdb, cdb, cdb_size);
memset(&resp, 0, sizeof(resp));
resp.status = 0xff; /* set invalid */
resp.response = 0xff; /* */
if (data && data_size) {
memset(data, 0, data_size);
}
}
static inline void vs_io_assert(bool term, const char *msg)
{
if (!term) {
virtio_scsi_verify_response(&resp, msg);
}
}
static void vs_run(const char *title, VirtioCmd *cmd, VDev *vdev,
const void *cdb, int cdb_size,
void *data, uint32_t data_size)
{
prepare_request(vdev, cdb, cdb_size, data, data_size);
vs_io_assert(virtio_run(vdev, VR_REQUEST, cmd) == 0, title);
}
/* SCSI protocol implementation routines */
static bool scsi_inquiry(VDev *vdev, uint8_t evpd, uint8_t page,
void *data, uint32_t data_size)
{
ScsiCdbInquiry cdb = {
.command = 0x12,
.b1 = evpd,
.b2 = page,
.alloc_len = data_size < 65535 ? data_size : 65535,
};
VirtioCmd inquiry[] = {
{ &req, sizeof(req), VRING_DESC_F_NEXT },
{ &resp, sizeof(resp), VRING_DESC_F_WRITE | VRING_DESC_F_NEXT },
{ data, data_size, VRING_DESC_F_WRITE },
};
vs_run("inquiry", inquiry, vdev, &cdb, sizeof(cdb), data, data_size);
return virtio_scsi_response_ok(&resp);
}
static bool scsi_test_unit_ready(VDev *vdev)
{
ScsiCdbTestUnitReady cdb = {
.command = 0x00,
};
VirtioCmd test_unit_ready[] = {
{ &req, sizeof(req), VRING_DESC_F_NEXT },
{ &resp, sizeof(resp), VRING_DESC_F_WRITE },
};
prepare_request(vdev, &cdb, sizeof(cdb), 0, 0);
virtio_run(vdev, VR_REQUEST, test_unit_ready); /* ignore errors here */
return virtio_scsi_response_ok(&resp);
}
static bool scsi_report_luns(VDev *vdev, void *data, uint32_t data_size)
{
ScsiCdbReportLuns cdb = {
.command = 0xa0,
.select_report = 0x02, /* REPORT ALL */
.alloc_len = data_size,
};
VirtioCmd report_luns[] = {
{ &req, sizeof(req), VRING_DESC_F_NEXT },
{ &resp, sizeof(resp), VRING_DESC_F_WRITE | VRING_DESC_F_NEXT },
{ data, data_size, VRING_DESC_F_WRITE },
};
vs_run("report luns", report_luns,
vdev, &cdb, sizeof(cdb), data, data_size);
return virtio_scsi_response_ok(&resp);
}
static bool scsi_read_10(VDev *vdev,
ulong sector, int sectors, void *data,
unsigned int data_size)
{
ScsiCdbRead10 cdb = {
.command = 0x28,
.lba = sector,
.xfer_length = sectors,
};
VirtioCmd read_10[] = {
{ &req, sizeof(req), VRING_DESC_F_NEXT },
{ &resp, sizeof(resp), VRING_DESC_F_WRITE | VRING_DESC_F_NEXT },
{ data, data_size, VRING_DESC_F_WRITE },
};
debug_print_int("read_10 sector", sector);
debug_print_int("read_10 sectors", sectors);
vs_run("read(10)", read_10, vdev, &cdb, sizeof(cdb), data, data_size);
return virtio_scsi_response_ok(&resp);
}
static bool scsi_read_capacity(VDev *vdev,
void *data, uint32_t data_size)
{
ScsiCdbReadCapacity16 cdb = {
.command = 0x9e, /* SERVICE_ACTION_IN_16 */
.service_action = 0x10, /* SA_READ_CAPACITY */
.alloc_len = data_size,
};
VirtioCmd read_capacity_16[] = {
{ &req, sizeof(req), VRING_DESC_F_NEXT },
{ &resp, sizeof(resp), VRING_DESC_F_WRITE | VRING_DESC_F_NEXT },
{ data, data_size, VRING_DESC_F_WRITE },
};
vs_run("read capacity", read_capacity_16,
vdev, &cdb, sizeof(cdb), data, data_size);
return virtio_scsi_response_ok(&resp);
}
/* virtio-scsi routines */
/*
* Tries to locate a SCSI device and and adds the information for the found
* device to the vdev->scsi_device structure.
* Returns 0 if SCSI device could be located, or a error code < 0 otherwise
*/
static int virtio_scsi_locate_device(VDev *vdev)
{
const uint16_t channel = 0; /* again, it's what QEMU does */
uint16_t target;
static uint8_t data[16 + 8 * 63];
ScsiLunReport *r = (void *) data;
ScsiDevice *sdev = vdev->scsi_device;
int i, luns;
/* QEMU has hardcoded channel #0 in many places.
* If this hardcoded value is ever changed, we'll need to add code for
* vdev->config.scsi.max_channel != 0 here.
*/
debug_print_int("config.scsi.max_channel", vdev->config.scsi.max_channel);
debug_print_int("config.scsi.max_target ", vdev->config.scsi.max_target);
debug_print_int("config.scsi.max_lun ", vdev->config.scsi.max_lun);
debug_print_int("config.scsi.max_sectors", vdev->config.scsi.max_sectors);
if (vdev->scsi_device_selected) {
sdev->channel = vdev->selected_scsi_device.channel;
sdev->target = vdev->selected_scsi_device.target;
sdev->lun = vdev->selected_scsi_device.lun;
IPL_check(sdev->channel == 0, "non-zero channel requested");
IPL_check(sdev->target <= vdev->config.scsi.max_target, "target# high");
IPL_check(sdev->lun <= vdev->config.scsi.max_lun, "LUN# high");
return 0;
}
for (target = 0; target <= vdev->config.scsi.max_target; target++) {
sdev->channel = channel;
sdev->target = target;
sdev->lun = 0; /* LUN has to be 0 for REPORT LUNS */
if (!scsi_report_luns(vdev, data, sizeof(data))) {
if (resp.response == VIRTIO_SCSI_S_BAD_TARGET) {
continue;
}
print_int("target", target);
virtio_scsi_verify_response(&resp, "SCSI cannot report LUNs");
}
if (r->lun_list_len == 0) {
print_int("no LUNs for target", target);
continue;
}
luns = r->lun_list_len / 8;
debug_print_int("LUNs reported", luns);
if (luns == 1) {
/* There is no ",lun=#" arg for -device or ",lun=0" given.
* Hence, the only LUN reported.
* Usually, it's 0.
*/
sdev->lun = r->lun[0].v16[0]; /* it's returned this way */
debug_print_int("Have to use LUN", sdev->lun);
return 0; /* we have to use this device */
}
for (i = 0; i < luns; i++) {
if (r->lun[i].v64) {
/* Look for non-zero LUN - we have where to choose from */
sdev->lun = r->lun[i].v16[0];
debug_print_int("Will use LUN", sdev->lun);
return 0; /* we have found a device */
}
}
}
sclp_print("Warning: Could not locate a usable virtio-scsi device\n");
return -ENODEV;
}
int virtio_scsi_read_many(VDev *vdev,
ulong sector, void *load_addr, int sec_num)
{
int sector_count;
int f = vdev->blk_factor;
unsigned int data_size;
unsigned int max_transfer = MIN_NON_ZERO(vdev->config.scsi.max_sectors,
vdev->max_transfer);
do {
sector_count = MIN_NON_ZERO(sec_num, max_transfer);
data_size = sector_count * virtio_get_block_size() * f;
if (!scsi_read_10(vdev, sector * f, sector_count * f, load_addr,
data_size)) {
virtio_scsi_verify_response(&resp, "virtio-scsi:read_many");
}
load_addr += data_size;
sector += sector_count;
sec_num -= sector_count;
} while (sec_num > 0);
return 0;
}
static bool virtio_scsi_inquiry_response_is_cdrom(void *data)
{
const ScsiInquiryStd *response = data;
const int resp_data_fmt = response->b3 & 0x0f;
int i;
IPL_check(resp_data_fmt == 2, "Wrong INQUIRY response format");
if (resp_data_fmt != 2) {
return false; /* cannot decode */
}
if ((response->peripheral_qdt & 0x1f) == SCSI_INQ_RDT_CDROM) {
return true;
}
for (i = 0; i < sizeof(response->prod_id); i++) {
if (response->prod_id[i] != QEMU_CDROM_SIGNATURE[i]) {
return false;
}
}
return true;
}
static void scsi_parse_capacity_report(void *data,
uint64_t *last_lba, uint32_t *lb_len)
{
ScsiReadCapacity16Data *p = data;
if (last_lba) {
*last_lba = p->ret_lba;
}
if (lb_len) {
*lb_len = p->lb_len;
}
}
int virtio_scsi_setup(VDev *vdev)
{
int retry_test_unit_ready = 3;
uint8_t data[256];
uint32_t data_size = sizeof(data);
ScsiInquiryEvpdPages *evpd = &scsi_inquiry_evpd_pages_response;
ScsiInquiryEvpdBl *evpd_bl = &scsi_inquiry_evpd_bl_response;
int i, ret;
vdev->scsi_device = &default_scsi_device;
ret = virtio_scsi_locate_device(vdev);
if (ret < 0) {
return ret;
}
/* We have to "ping" the device before it becomes readable */
while (!scsi_test_unit_ready(vdev)) {
if (!virtio_scsi_response_ok(&resp)) {
uint8_t code = resp.sense[0] & SCSI_SENSE_CODE_MASK;
uint8_t sense_key = resp.sense[2] & SCSI_SENSE_KEY_MASK;
IPL_assert(resp.sense_len != 0, "virtio-scsi:setup: no SENSE data");
IPL_assert(retry_test_unit_ready && code == 0x70 &&
sense_key == SCSI_SENSE_KEY_UNIT_ATTENTION,
"virtio-scsi:setup: cannot retry");
/* retry on CHECK_CONDITION/UNIT_ATTENTION as it
* may not designate a real error, but it may be
* a result of device reset, etc.
*/
retry_test_unit_ready--;
sleep(1);
continue;
}
virtio_scsi_verify_response(&resp, "virtio-scsi:setup");
}
/* read and cache SCSI INQUIRY response */
if (!scsi_inquiry(vdev,
SCSI_INQUIRY_STANDARD,
SCSI_INQUIRY_STANDARD_NONE,
scsi_inquiry_std_response,
sizeof(scsi_inquiry_std_response))) {
virtio_scsi_verify_response(&resp, "virtio-scsi:setup:inquiry");
}
if (virtio_scsi_inquiry_response_is_cdrom(scsi_inquiry_std_response)) {
sclp_print("SCSI CD-ROM detected.\n");
vdev->is_cdrom = true;
vdev->scsi_block_size = VIRTIO_ISO_BLOCK_SIZE;
}
if (!scsi_inquiry(vdev,
SCSI_INQUIRY_EVPD,
SCSI_INQUIRY_EVPD_SUPPORTED_PAGES,
evpd,
sizeof(*evpd))) {
virtio_scsi_verify_response(&resp, "virtio-scsi:setup:supported_pages");
}
debug_print_int("EVPD length", evpd->page_length);
for (i = 0; i <= evpd->page_length; i++) {
debug_print_int("supported EVPD page", evpd->byte[i]);
if (evpd->byte[i] != SCSI_INQUIRY_EVPD_BLOCK_LIMITS) {
continue;
}
if (!scsi_inquiry(vdev,
SCSI_INQUIRY_EVPD,
SCSI_INQUIRY_EVPD_BLOCK_LIMITS,
evpd_bl,
sizeof(*evpd_bl))) {
virtio_scsi_verify_response(&resp, "virtio-scsi:setup:blocklimits");
}
debug_print_int("max transfer", evpd_bl->max_transfer);
vdev->max_transfer = evpd_bl->max_transfer;
}
/*
* The host sg driver will often be unhappy with particularly large
* I/Os that exceed the block iovec limits. Let's enforce something
* reasonable, despite what the device configuration tells us.
*/
vdev->max_transfer = MIN_NON_ZERO(VIRTIO_SCSI_MAX_SECTORS,
vdev->max_transfer);
if (!scsi_read_capacity(vdev, data, data_size)) {
virtio_scsi_verify_response(&resp, "virtio-scsi:setup:read_capacity");
}
scsi_parse_capacity_report(data, &vdev->scsi_last_block,
(uint32_t *) &vdev->scsi_block_size);
return 0;
}
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