qemu-e2k/hw/ppc/pnv_pnor.c
Kevin Wolf 86b1cf3227 block: Separate blk_is_writable() and blk_supports_write_perm()
Currently, blk_is_read_only() tells whether a given BlockBackend can
only be used in read-only mode because its root node is read-only. Some
callers actually try to answer a slightly different question: Is the
BlockBackend configured to be writable, by taking write permissions on
the root node?

This can differ, for example, for CD-ROM devices which don't take write
permissions, but may be backed by a writable image file. scsi-cd allows
write requests to the drive if blk_is_read_only() returns false.
However, the write request will immediately run into an assertion
failure because the write permission is missing.

This patch introduces separate functions for both questions.
blk_supports_write_perm() answers the question whether the block
node/image file can support writable devices, whereas blk_is_writable()
tells whether the BlockBackend is currently configured to be writable.

All calls of blk_is_read_only() are converted to one of the two new
functions.

Fixes: https://bugs.launchpad.net/bugs/1906693
Cc: qemu-stable@nongnu.org
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Message-Id: <20210118123448.307825-2-kwolf@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2021-01-27 20:45:20 +01:00

143 lines
3.6 KiB
C

/*
* QEMU PowerNV PNOR simple model
*
* Copyright (c) 2015-2019, IBM Corporation.
*
* This code is licensed under the GPL version 2 or later. See the
* COPYING file in the top-level directory.
*/
#include "qemu/osdep.h"
#include "qapi/error.h"
#include "qemu/error-report.h"
#include "qemu/log.h"
#include "qemu/units.h"
#include "sysemu/block-backend.h"
#include "sysemu/blockdev.h"
#include "hw/loader.h"
#include "hw/ppc/pnv_pnor.h"
#include "hw/qdev-properties.h"
#include "hw/qdev-properties-system.h"
static uint64_t pnv_pnor_read(void *opaque, hwaddr addr, unsigned size)
{
PnvPnor *s = PNV_PNOR(opaque);
uint64_t ret = 0;
int i;
for (i = 0; i < size; i++) {
ret |= (uint64_t) s->storage[addr + i] << (8 * (size - i - 1));
}
return ret;
}
static void pnv_pnor_update(PnvPnor *s, int offset, int size)
{
int offset_end;
int ret;
if (s->blk) {
return;
}
offset_end = offset + size;
offset = QEMU_ALIGN_DOWN(offset, BDRV_SECTOR_SIZE);
offset_end = QEMU_ALIGN_UP(offset_end, BDRV_SECTOR_SIZE);
ret = blk_pwrite(s->blk, offset, s->storage + offset,
offset_end - offset, 0);
if (ret < 0) {
error_report("Could not update PNOR offset=0x%" PRIx32" : %s", offset,
strerror(-ret));
}
}
static void pnv_pnor_write(void *opaque, hwaddr addr, uint64_t data,
unsigned size)
{
PnvPnor *s = PNV_PNOR(opaque);
int i;
for (i = 0; i < size; i++) {
s->storage[addr + i] = (data >> (8 * (size - i - 1))) & 0xFF;
}
pnv_pnor_update(s, addr, size);
}
/*
* TODO: Check endianness: skiboot is BIG, Aspeed AHB is LITTLE, flash
* is BIG.
*/
static const MemoryRegionOps pnv_pnor_ops = {
.read = pnv_pnor_read,
.write = pnv_pnor_write,
.endianness = DEVICE_BIG_ENDIAN,
.valid = {
.min_access_size = 1,
.max_access_size = 4,
},
};
static void pnv_pnor_realize(DeviceState *dev, Error **errp)
{
PnvPnor *s = PNV_PNOR(dev);
int ret;
if (s->blk) {
uint64_t perm = BLK_PERM_CONSISTENT_READ |
(blk_supports_write_perm(s->blk) ? BLK_PERM_WRITE : 0);
ret = blk_set_perm(s->blk, perm, BLK_PERM_ALL, errp);
if (ret < 0) {
return;
}
s->size = blk_getlength(s->blk);
if (s->size <= 0) {
error_setg(errp, "failed to get flash size");
return;
}
s->storage = blk_blockalign(s->blk, s->size);
if (blk_pread(s->blk, 0, s->storage, s->size) != s->size) {
error_setg(errp, "failed to read the initial flash content");
return;
}
} else {
s->storage = blk_blockalign(NULL, s->size);
memset(s->storage, 0xFF, s->size);
}
memory_region_init_io(&s->mmio, OBJECT(s), &pnv_pnor_ops, s,
TYPE_PNV_PNOR, s->size);
}
static Property pnv_pnor_properties[] = {
DEFINE_PROP_INT64("size", PnvPnor, size, 128 * MiB),
DEFINE_PROP_DRIVE("drive", PnvPnor, blk),
DEFINE_PROP_END_OF_LIST(),
};
static void pnv_pnor_class_init(ObjectClass *klass, void *data)
{
DeviceClass *dc = DEVICE_CLASS(klass);
dc->realize = pnv_pnor_realize;
device_class_set_props(dc, pnv_pnor_properties);
}
static const TypeInfo pnv_pnor_info = {
.name = TYPE_PNV_PNOR,
.parent = TYPE_SYS_BUS_DEVICE,
.instance_size = sizeof(PnvPnor),
.class_init = pnv_pnor_class_init,
};
static void pnv_pnor_register_types(void)
{
type_register_static(&pnv_pnor_info);
}
type_init(pnv_pnor_register_types)