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qemu/hw/ide/pci.c
Peter Maydell c1a6ae5145 hw/ide/pci: Remove dead code from bmdma_prepare_buf() 
Coverity notes that the code at the end of the loop in
bmdma_prepare_buf() is unreachable.  This is because in commit
9fbf0fa81f ("ide: remove hardcoded 2GiB transactional limit")
we removed the only codepath in the loop which could "break" out of
it, but didn't notice that this meant we should also remove the code
at the end of the loop.

Remove the dead code.

Resolves: Coverity CID 1547772
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
[PMD: Break and return once at EOF]
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20240805182419.22239-1-philmd@linaro.org>
2024-08-06 10:22:52 +02:00

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/*
* QEMU IDE Emulation: PCI Bus support.
*
* Copyright (c) 2003 Fabrice Bellard
* Copyright (c) 2006 Openedhand Ltd.
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
#include "qemu/osdep.h"
#include "hw/irq.h"
#include "hw/pci/pci.h"
#include "migration/vmstate.h"
#include "sysemu/dma.h"
#include "qemu/error-report.h"
#include "qemu/module.h"
#include "hw/ide/pci.h"
#include "ide-internal.h"
#include "trace.h"
#define BMDMA_PAGE_SIZE 4096
#define BM_MIGRATION_COMPAT_STATUS_BITS \
(IDE_RETRY_DMA | IDE_RETRY_PIO | \
IDE_RETRY_READ | IDE_RETRY_FLUSH)
static uint64_t pci_ide_status_read(void *opaque, hwaddr addr, unsigned size)
{
IDEBus *bus = opaque;
if (addr != 2 || size != 1) {
return ((uint64_t)1 << (size * 8)) - 1;
}
return ide_status_read(bus, addr + 2);
}
static void pci_ide_ctrl_write(void *opaque, hwaddr addr,
uint64_t data, unsigned size)
{
IDEBus *bus = opaque;
if (addr != 2 || size != 1) {
return;
}
ide_ctrl_write(bus, addr + 2, data);
}
const MemoryRegionOps pci_ide_cmd_le_ops = {
.read = pci_ide_status_read,
.write = pci_ide_ctrl_write,
.endianness = DEVICE_LITTLE_ENDIAN,
};
static uint64_t pci_ide_data_read(void *opaque, hwaddr addr, unsigned size)
{
IDEBus *bus = opaque;
if (size == 1) {
return ide_ioport_read(bus, addr);
} else if (addr == 0) {
if (size == 2) {
return ide_data_readw(bus, addr);
} else {
return ide_data_readl(bus, addr);
}
}
return ((uint64_t)1 << (size * 8)) - 1;
}
static void pci_ide_data_write(void *opaque, hwaddr addr,
uint64_t data, unsigned size)
{
IDEBus *bus = opaque;
if (size == 1) {
ide_ioport_write(bus, addr, data);
} else if (addr == 0) {
if (size == 2) {
ide_data_writew(bus, addr, data);
} else {
ide_data_writel(bus, addr, data);
}
}
}
const MemoryRegionOps pci_ide_data_le_ops = {
.read = pci_ide_data_read,
.write = pci_ide_data_write,
.endianness = DEVICE_LITTLE_ENDIAN,
};
void pci_ide_update_mode(PCIIDEState *s)
{
PCIDevice *d = PCI_DEVICE(s);
uint8_t mode = d->config[PCI_CLASS_PROG];
/*
* This function only configures the BARs/ioports for now: PCI IDE
* controllers must manage their own IRQ routing
*/
switch (mode & 0xf) {
case 0xa:
/* Both channels legacy mode */
/*
* TODO: according to the PCI IDE specification the BARs should
* be completely disabled, however Linux for the pegasos2
* machine stil accesses the BAR addresses after switching to legacy
* mode. Hence we leave them active for now.
*/
/* Clear interrupt pin */
pci_config_set_interrupt_pin(d->config, 0);
/* Add legacy IDE ports */
if (!s->bus[0].portio_list.owner) {
portio_list_init(&s->bus[0].portio_list, OBJECT(d),
ide_portio_list, &s->bus[0], "ide");
portio_list_add(&s->bus[0].portio_list,
pci_address_space_io(d), 0x1f0);
}
if (!s->bus[0].portio2_list.owner) {
portio_list_init(&s->bus[0].portio2_list, OBJECT(d),
ide_portio2_list, &s->bus[0], "ide");
portio_list_add(&s->bus[0].portio2_list,
pci_address_space_io(d), 0x3f6);
}
if (!s->bus[1].portio_list.owner) {
portio_list_init(&s->bus[1].portio_list, OBJECT(d),
ide_portio_list, &s->bus[1], "ide");
portio_list_add(&s->bus[1].portio_list,
pci_address_space_io(d), 0x170);
}
if (!s->bus[1].portio2_list.owner) {
portio_list_init(&s->bus[1].portio2_list, OBJECT(d),
ide_portio2_list, &s->bus[1], "ide");
portio_list_add(&s->bus[1].portio2_list,
pci_address_space_io(d), 0x376);
}
break;
case 0xf:
/* Both channels native mode */
/* Set interrupt pin */
pci_config_set_interrupt_pin(d->config, 1);
/* Remove legacy IDE ports */
if (s->bus[0].portio_list.owner) {
portio_list_del(&s->bus[0].portio_list);
portio_list_destroy(&s->bus[0].portio_list);
}
if (s->bus[0].portio2_list.owner) {
portio_list_del(&s->bus[0].portio2_list);
portio_list_destroy(&s->bus[0].portio2_list);
}
if (s->bus[1].portio_list.owner) {
portio_list_del(&s->bus[1].portio_list);
portio_list_destroy(&s->bus[1].portio_list);
}
if (s->bus[1].portio2_list.owner) {
portio_list_del(&s->bus[1].portio2_list);
portio_list_destroy(&s->bus[1].portio2_list);
}
break;
}
}
static IDEState *bmdma_active_if(BMDMAState *bmdma)
{
assert(bmdma->bus->retry_unit != (uint8_t)-1);
return bmdma->bus->ifs + bmdma->bus->retry_unit;
}
static void bmdma_start_dma(const IDEDMA *dma, IDEState *s,
BlockCompletionFunc *dma_cb)
{
BMDMAState *bm = DO_UPCAST(BMDMAState, dma, dma);
bm->dma_cb = dma_cb;
bm->cur_prd_last = 0;
bm->cur_prd_addr = 0;
bm->cur_prd_len = 0;
if (bm->status & BM_STATUS_DMAING) {
bm->dma_cb(bmdma_active_if(bm), 0);
}
}
/**
* Prepare an sglist based on available PRDs.
* @limit: How many bytes to prepare total.
*
* Returns the number of bytes prepared, -1 on error.
* IDEState.io_buffer_size will contain the number of bytes described
* by the PRDs, whether or not we added them to the sglist.
*/
static int32_t bmdma_prepare_buf(const IDEDMA *dma, int32_t limit)
{
BMDMAState *bm = DO_UPCAST(BMDMAState, dma, dma);
IDEState *s = bmdma_active_if(bm);
PCIDevice *pci_dev = PCI_DEVICE(bm->pci_dev);
struct {
uint32_t addr;
uint32_t size;
} prd;
int l, len;
pci_dma_sglist_init(&s->sg, pci_dev,
s->nsector / (BMDMA_PAGE_SIZE / BDRV_SECTOR_SIZE) + 1);
s->io_buffer_size = 0;
for(;;) {
if (bm->cur_prd_len == 0) {
/* end of table (with a fail safe of one page) */
if (bm->cur_prd_last ||
(bm->cur_addr - bm->addr) >= BMDMA_PAGE_SIZE) {
break;
}
pci_dma_read(pci_dev, bm->cur_addr, &prd, 8);
bm->cur_addr += 8;
prd.addr = le32_to_cpu(prd.addr);
prd.size = le32_to_cpu(prd.size);
len = prd.size & 0xfffe;
if (len == 0)
len = 0x10000;
bm->cur_prd_len = len;
bm->cur_prd_addr = prd.addr;
bm->cur_prd_last = (prd.size & 0x80000000);
}
l = bm->cur_prd_len;
if (l > 0) {
uint64_t sg_len;
/* Don't add extra bytes to the SGList; consume any remaining
* PRDs from the guest, but ignore them. */
sg_len = MIN(limit - s->sg.size, bm->cur_prd_len);
if (sg_len) {
qemu_sglist_add(&s->sg, bm->cur_prd_addr, sg_len);
}
bm->cur_prd_addr += l;
bm->cur_prd_len -= l;
s->io_buffer_size += l;
}
}
return s->sg.size;
}
/* return 0 if buffer completed */
static int bmdma_rw_buf(const IDEDMA *dma, bool is_write)
{
BMDMAState *bm = DO_UPCAST(BMDMAState, dma, dma);
IDEState *s = bmdma_active_if(bm);
PCIDevice *pci_dev = PCI_DEVICE(bm->pci_dev);
struct {
uint32_t addr;
uint32_t size;
} prd;
int l, len;
for(;;) {
l = s->io_buffer_size - s->io_buffer_index;
if (l <= 0)
break;
if (bm->cur_prd_len == 0) {
/* end of table (with a fail safe of one page) */
if (bm->cur_prd_last ||
(bm->cur_addr - bm->addr) >= BMDMA_PAGE_SIZE)
return 0;
pci_dma_read(pci_dev, bm->cur_addr, &prd, 8);
bm->cur_addr += 8;
prd.addr = le32_to_cpu(prd.addr);
prd.size = le32_to_cpu(prd.size);
len = prd.size & 0xfffe;
if (len == 0)
len = 0x10000;
bm->cur_prd_len = len;
bm->cur_prd_addr = prd.addr;
bm->cur_prd_last = (prd.size & 0x80000000);
}
if (l > bm->cur_prd_len)
l = bm->cur_prd_len;
if (l > 0) {
if (is_write) {
pci_dma_write(pci_dev, bm->cur_prd_addr,
s->io_buffer + s->io_buffer_index, l);
} else {
pci_dma_read(pci_dev, bm->cur_prd_addr,
s->io_buffer + s->io_buffer_index, l);
}
bm->cur_prd_addr += l;
bm->cur_prd_len -= l;
s->io_buffer_index += l;
}
}
return 1;
}
static void bmdma_set_inactive(const IDEDMA *dma, bool more)
{
BMDMAState *bm = DO_UPCAST(BMDMAState, dma, dma);
bm->dma_cb = NULL;
if (more) {
bm->status |= BM_STATUS_DMAING;
} else {
bm->status &= ~BM_STATUS_DMAING;
}
}
static void bmdma_restart_dma(const IDEDMA *dma)
{
BMDMAState *bm = DO_UPCAST(BMDMAState, dma, dma);
bm->cur_addr = bm->addr;
}
static void bmdma_cancel(BMDMAState *bm)
{
if (bm->status & BM_STATUS_DMAING) {
/* cancel DMA request */
bmdma_set_inactive(&bm->dma, false);
}
}
static void bmdma_reset(const IDEDMA *dma)
{
BMDMAState *bm = DO_UPCAST(BMDMAState, dma, dma);
trace_bmdma_reset();
bmdma_cancel(bm);
bm->cmd = 0;
bm->status = 0;
bm->addr = 0;
bm->cur_addr = 0;
bm->cur_prd_last = 0;
bm->cur_prd_addr = 0;
bm->cur_prd_len = 0;
}
static void bmdma_irq(void *opaque, int n, int level)
{
BMDMAState *bm = opaque;
if (!level) {
/* pass through lower */
qemu_set_irq(bm->irq, level);
return;
}
bm->status |= BM_STATUS_INT;
/* trigger the real irq */
qemu_set_irq(bm->irq, level);
}
void bmdma_cmd_writeb(BMDMAState *bm, uint32_t val)
{
trace_bmdma_cmd_writeb(val);
/* Ignore writes to SSBM if it keeps the old value */
if ((val & BM_CMD_START) != (bm->cmd & BM_CMD_START)) {
if (!(val & BM_CMD_START)) {
ide_cancel_dma_sync(ide_bus_active_if(bm->bus));
bm->status &= ~BM_STATUS_DMAING;
} else {
bm->cur_addr = bm->addr;
if (!(bm->status & BM_STATUS_DMAING)) {
bm->status |= BM_STATUS_DMAING;
/* start dma transfer if possible */
if (bm->dma_cb)
bm->dma_cb(bmdma_active_if(bm), 0);
}
}
}
bm->cmd = val & 0x09;
}
void bmdma_status_writeb(BMDMAState *bm, uint32_t val)
{
bm->status = (val & 0x60) | (bm->status & BM_STATUS_DMAING)
| (bm->status & ~val & (BM_STATUS_ERROR | BM_STATUS_INT));
}
static uint64_t bmdma_addr_read(void *opaque, hwaddr addr,
unsigned width)
{
BMDMAState *bm = opaque;
uint32_t mask = (1ULL << (width * 8)) - 1;
uint64_t data;
data = (bm->addr >> (addr * 8)) & mask;
trace_bmdma_addr_read(data);
return data;
}
static void bmdma_addr_write(void *opaque, hwaddr addr,
uint64_t data, unsigned width)
{
BMDMAState *bm = opaque;
int shift = addr * 8;
uint32_t mask = (1ULL << (width * 8)) - 1;
trace_bmdma_addr_write(data);
bm->addr &= ~(mask << shift);
bm->addr |= ((data & mask) << shift) & ~3;
}
MemoryRegionOps bmdma_addr_ioport_ops = {
.read = bmdma_addr_read,
.write = bmdma_addr_write,
.endianness = DEVICE_LITTLE_ENDIAN,
};
static bool ide_bmdma_current_needed(void *opaque)
{
BMDMAState *bm = opaque;
return (bm->cur_prd_len != 0);
}
static bool ide_bmdma_status_needed(void *opaque)
{
BMDMAState *bm = opaque;
/* Older versions abused some bits in the status register for internal
* error state. If any of these bits are set, we must add a subsection to
* transfer the real status register */
uint8_t abused_bits = BM_MIGRATION_COMPAT_STATUS_BITS;
return ((bm->status & abused_bits) != 0);
}
static int ide_bmdma_pre_save(void *opaque)
{
BMDMAState *bm = opaque;
uint8_t abused_bits = BM_MIGRATION_COMPAT_STATUS_BITS;
if (!(bm->status & BM_STATUS_DMAING) && bm->dma_cb) {
bm->bus->error_status =
ide_dma_cmd_to_retry(bmdma_active_if(bm)->dma_cmd);
}
bm->migration_retry_unit = bm->bus->retry_unit;
bm->migration_retry_sector_num = bm->bus->retry_sector_num;
bm->migration_retry_nsector = bm->bus->retry_nsector;
bm->migration_compat_status =
(bm->status & ~abused_bits) | (bm->bus->error_status & abused_bits);
return 0;
}
/* This function accesses bm->bus->error_status which is loaded only after
* BMDMA itself. This is why the function is called from ide_pci_post_load
* instead of being registered with VMState where it would run too early. */
static int ide_bmdma_post_load(void *opaque, int version_id)
{
BMDMAState *bm = opaque;
uint8_t abused_bits = BM_MIGRATION_COMPAT_STATUS_BITS;
if (bm->status == 0) {
bm->status = bm->migration_compat_status & ~abused_bits;
bm->bus->error_status |= bm->migration_compat_status & abused_bits;
}
if (bm->bus->error_status) {
bm->bus->retry_sector_num = bm->migration_retry_sector_num;
bm->bus->retry_nsector = bm->migration_retry_nsector;
bm->bus->retry_unit = bm->migration_retry_unit;
}
return 0;
}
static const VMStateDescription vmstate_bmdma_current = {
.name = "ide bmdma_current",
.version_id = 1,
.minimum_version_id = 1,
.needed = ide_bmdma_current_needed,
.fields = (const VMStateField[]) {
VMSTATE_UINT32(cur_addr, BMDMAState),
VMSTATE_UINT32(cur_prd_last, BMDMAState),
VMSTATE_UINT32(cur_prd_addr, BMDMAState),
VMSTATE_UINT32(cur_prd_len, BMDMAState),
VMSTATE_END_OF_LIST()
}
};
static const VMStateDescription vmstate_bmdma_status = {
.name ="ide bmdma/status",
.version_id = 1,
.minimum_version_id = 1,
.needed = ide_bmdma_status_needed,
.fields = (const VMStateField[]) {
VMSTATE_UINT8(status, BMDMAState),
VMSTATE_END_OF_LIST()
}
};
static const VMStateDescription vmstate_bmdma = {
.name = "ide bmdma",
.version_id = 3,
.minimum_version_id = 0,
.pre_save = ide_bmdma_pre_save,
.fields = (const VMStateField[]) {
VMSTATE_UINT8(cmd, BMDMAState),
VMSTATE_UINT8(migration_compat_status, BMDMAState),
VMSTATE_UINT32(addr, BMDMAState),
VMSTATE_INT64(migration_retry_sector_num, BMDMAState),
VMSTATE_UINT32(migration_retry_nsector, BMDMAState),
VMSTATE_UINT8(migration_retry_unit, BMDMAState),
VMSTATE_END_OF_LIST()
},
.subsections = (const VMStateDescription * const []) {
&vmstate_bmdma_current,
&vmstate_bmdma_status,
NULL
}
};
static int ide_pci_post_load(void *opaque, int version_id)
{
PCIIDEState *d = opaque;
int i;
for(i = 0; i < 2; i++) {
/* current versions always store 0/1, but older version
stored bigger values. We only need last bit */
d->bmdma[i].migration_retry_unit &= 1;
ide_bmdma_post_load(&d->bmdma[i], -1);
}
return 0;
}
const VMStateDescription vmstate_ide_pci = {
.name = "ide",
.version_id = 3,
.minimum_version_id = 0,
.post_load = ide_pci_post_load,
.fields = (const VMStateField[]) {
VMSTATE_PCI_DEVICE(parent_obj, PCIIDEState),
VMSTATE_STRUCT_ARRAY(bmdma, PCIIDEState, 2, 0,
vmstate_bmdma, BMDMAState),
VMSTATE_IDE_BUS_ARRAY(bus, PCIIDEState, 2),
VMSTATE_IDE_DRIVES(bus[0].ifs, PCIIDEState),
VMSTATE_IDE_DRIVES(bus[1].ifs, PCIIDEState),
VMSTATE_END_OF_LIST()
}
};
/* hd_table must contain 4 block drivers */
void pci_ide_create_devs(PCIDevice *dev)
{
PCIIDEState *d = PCI_IDE(dev);
DriveInfo *hd_table[2 * MAX_IDE_DEVS];
static const int bus[4] = { 0, 0, 1, 1 };
static const int unit[4] = { 0, 1, 0, 1 };
int i;
ide_drive_get(hd_table, ARRAY_SIZE(hd_table));
for (i = 0; i < 4; i++) {
if (hd_table[i]) {
ide_bus_create_drive(d->bus + bus[i], unit[i], hd_table[i]);
}
}
}
static const struct IDEDMAOps bmdma_ops = {
.start_dma = bmdma_start_dma,
.prepare_buf = bmdma_prepare_buf,
.rw_buf = bmdma_rw_buf,
.restart_dma = bmdma_restart_dma,
.set_inactive = bmdma_set_inactive,
.reset = bmdma_reset,
};
void bmdma_init(IDEBus *bus, BMDMAState *bm, PCIIDEState *d)
{
if (bus->dma == &bm->dma) {
return;
}
bm->dma.ops = &bmdma_ops;
bus->dma = &bm->dma;
bm->irq = bus->irq;
bus->irq = qemu_allocate_irq(bmdma_irq, bm, 0);
bm->bus = bus;
bm->pci_dev = d;
}
static void pci_ide_init(Object *obj)
{
PCIIDEState *d = PCI_IDE(obj);
qdev_init_gpio_out_named(DEVICE(d), d->isa_irq, "isa-irq",
ARRAY_SIZE(d->isa_irq));
}
static const TypeInfo pci_ide_type_info = {
.name = TYPE_PCI_IDE,
.parent = TYPE_PCI_DEVICE,
.instance_size = sizeof(PCIIDEState),
.instance_init = pci_ide_init,
.abstract = true,
.interfaces = (InterfaceInfo[]) {
{ INTERFACE_CONVENTIONAL_PCI_DEVICE },
{ },
},
};
static void pci_ide_register_types(void)
{
type_register_static(&pci_ide_type_info);
}
type_init(pci_ide_register_types)
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