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[Qemu-devel] [PATCH v4 2/7] fw-cfg: turn FW_CFG_FILE_SLOTS into a device
From: |
Laszlo Ersek |
Subject: |
[Qemu-devel] [PATCH v4 2/7] fw-cfg: turn FW_CFG_FILE_SLOTS into a device property |
Date: |
Thu, 1 Dec 2016 18:06:19 +0100 |
We'd like to raise the value of FW_CFG_FILE_SLOTS. Doing it naively could
lead to problems with backward migration: a more recent QEMU (running an
older machine type) would allow the guest, in fw_cfg_select(), to select a
high key value that is unavailable in the same machine type implemented by
the older (target) QEMU. On the target host, fw_cfg_data_read() for
example could dereference nonexistent entries.
As first step, size the FWCfgState.entries[*] and FWCfgState.entry_order
arrays dynamically. All three array sizes will be influenced by the new
field (and device property) FWCfgState.file_slots.
Make the following changes:
- Replace the FW_CFG_FILE_SLOTS macro with FW_CFG_FILE_SLOTS_TRAD
(traditional count of fw_cfg file slots) in the header file. The value
remains 0x10.
- Replace all uses of FW_CFG_FILE_SLOTS with a helper function called
fw_cfg_file_slots(), returning the new property.
- Eliminate the macro FW_CFG_MAX_ENTRY, and replace all its uses with a
helper function called fw_cfg_max_entry().
- In the MMIO- and IO-mapped realize functions both, allocate all three
arrays dynamically, based on the new property.
- The new property defaults to 0x20; however at the moment we forcibly set
it to FW_CFG_FILE_SLOTS_TRAD on all code paths available to board code
(namely in the fw_cfg_init_io_dma() and fw_cfg_init_mem_wide() helper
functions). This is going to be customized in the following patches.
Cc: "Gabriel L. Somlo" <address@hidden>
Cc: "Michael S. Tsirkin" <address@hidden>
Cc: Gerd Hoffmann <address@hidden>
Cc: Igor Mammedov <address@hidden>
Cc: Paolo Bonzini <address@hidden>
Signed-off-by: Laszlo Ersek <address@hidden>
---
Notes:
I know that upstream doesn't care about backward migration, but some
downstreams might.
docs/specs/fw_cfg.txt | 2 +-
include/hw/nvram/fw_cfg_keys.h | 3 +-
hw/nvram/fw_cfg.c | 85 ++++++++++++++++++++++++++++++++++++++----
3 files changed, 79 insertions(+), 11 deletions(-)
diff --git a/docs/specs/fw_cfg.txt b/docs/specs/fw_cfg.txt
index a19e2adbe1c6..84e2978706f5 100644
--- a/docs/specs/fw_cfg.txt
+++ b/docs/specs/fw_cfg.txt
@@ -154,11 +154,11 @@ Selector Reg. Range Usage
0x8000 - 0xbfff Arch. Specific (0x0000 - 0x3fff, generally RO, possibly RW
through the DMA interface in QEMU v2.9+)
0xc000 - 0xffff Arch. Specific (0x0000 - 0x3fff, RW, ignored in v2.4+)
In practice, the number of allowed firmware configuration items is given
-by the value of FW_CFG_MAX_ENTRY (see fw_cfg.h).
+by the value (FW_CFG_FILE_FIRST + FW_CFG_FILE_SLOTS_TRAD) (see fw_cfg.h).
= Guest-side DMA Interface =
If bit 1 of the feature bitmap is set, the DMA interface is present. This does
not replace the existing fw_cfg interface, it is an add-on. This interface
diff --git a/include/hw/nvram/fw_cfg_keys.h b/include/hw/nvram/fw_cfg_keys.h
index 0f3e871884c0..627589793671 100644
--- a/include/hw/nvram/fw_cfg_keys.h
+++ b/include/hw/nvram/fw_cfg_keys.h
@@ -27,12 +27,11 @@
#define FW_CFG_SETUP_SIZE 0x17
#define FW_CFG_SETUP_DATA 0x18
#define FW_CFG_FILE_DIR 0x19
#define FW_CFG_FILE_FIRST 0x20
-#define FW_CFG_FILE_SLOTS 0x10
-#define FW_CFG_MAX_ENTRY (FW_CFG_FILE_FIRST + FW_CFG_FILE_SLOTS)
+#define FW_CFG_FILE_SLOTS_TRAD 0x10
#define FW_CFG_WRITE_CHANNEL 0x4000
#define FW_CFG_ARCH_LOCAL 0x8000
#define FW_CFG_ENTRY_MASK (~(FW_CFG_WRITE_CHANNEL | FW_CFG_ARCH_LOCAL))
diff --git a/hw/nvram/fw_cfg.c b/hw/nvram/fw_cfg.c
index e0145c11a19b..2e1441c09750 100644
--- a/hw/nvram/fw_cfg.c
+++ b/hw/nvram/fw_cfg.c
@@ -31,10 +31,13 @@
#include "hw/sysbus.h"
#include "trace.h"
#include "qemu/error-report.h"
#include "qemu/config-file.h"
#include "qemu/cutils.h"
+#include "qapi/error.h"
+
+#define FW_CFG_FILE_SLOTS_DFLT 0x20
#define FW_CFG_NAME "fw_cfg"
#define FW_CFG_PATH "/machine/" FW_CFG_NAME
#define TYPE_FW_CFG "fw_cfg"
@@ -69,12 +72,13 @@ typedef struct FWCfgEntry {
struct FWCfgState {
/*< private >*/
SysBusDevice parent_obj;
/*< public >*/
- FWCfgEntry entries[2][FW_CFG_MAX_ENTRY];
- int entry_order[FW_CFG_MAX_ENTRY];
+ uint32_t file_slots;
+ FWCfgEntry *entries[2];
+ int *entry_order;
FWCfgFiles *files;
uint16_t cur_entry;
uint32_t cur_offset;
Notifier machine_ready;
@@ -255,17 +259,27 @@ static void fw_cfg_reboot(FWCfgState *s)
static void fw_cfg_write(FWCfgState *s, uint8_t value)
{
/* nothing, write support removed in QEMU v2.4+ */
}
+static inline uint32_t fw_cfg_file_slots(const FWCfgState *s)
+{
+ return s->file_slots;
+}
+
+static inline uint32_t fw_cfg_max_entry(const FWCfgState *s)
+{
+ return FW_CFG_FILE_FIRST + fw_cfg_file_slots(s);
+}
+
static int fw_cfg_select(FWCfgState *s, uint16_t key)
{
int arch, ret;
FWCfgEntry *e;
s->cur_offset = 0;
- if ((key & FW_CFG_ENTRY_MASK) >= FW_CFG_MAX_ENTRY) {
+ if ((key & FW_CFG_ENTRY_MASK) >= fw_cfg_max_entry(s)) {
s->cur_entry = FW_CFG_INVALID;
ret = 0;
} else {
s->cur_entry = key;
ret = 1;
@@ -608,11 +622,11 @@ static void fw_cfg_add_bytes_read_callback(FWCfgState *s,
uint16_t key,
{
int arch = !!(key & FW_CFG_ARCH_LOCAL);
key &= FW_CFG_ENTRY_MASK;
- assert(key < FW_CFG_MAX_ENTRY && len < UINT32_MAX);
+ assert(key < fw_cfg_max_entry(s) && len < UINT32_MAX);
assert(s->entries[arch][key].data == NULL); /* avoid key conflict */
s->entries[arch][key].data = data;
s->entries[arch][key].len = (uint32_t)len;
s->entries[arch][key].read_callback = callback;
@@ -626,11 +640,11 @@ static void *fw_cfg_modify_bytes_read(FWCfgState *s,
uint16_t key,
void *ptr;
int arch = !!(key & FW_CFG_ARCH_LOCAL);
key &= FW_CFG_ENTRY_MASK;
- assert(key < FW_CFG_MAX_ENTRY && len < UINT32_MAX);
+ assert(key < fw_cfg_max_entry(s) && len < UINT32_MAX);
/* return the old data to the function caller, avoid memory leak */
ptr = s->entries[arch][key].data;
s->entries[arch][key].data = data;
s->entries[arch][key].len = len;
@@ -775,17 +789,17 @@ void fw_cfg_add_file_callback(FWCfgState *s, const char
*filename,
size_t dsize;
MachineClass *mc = MACHINE_GET_CLASS(qdev_get_machine());
int order = 0;
if (!s->files) {
- dsize = sizeof(uint32_t) + sizeof(FWCfgFile) * FW_CFG_FILE_SLOTS;
+ dsize = sizeof(uint32_t) + sizeof(FWCfgFile) * fw_cfg_file_slots(s);
s->files = g_malloc0(dsize);
fw_cfg_add_bytes(s, FW_CFG_FILE_DIR, s->files, dsize);
}
count = be32_to_cpu(s->files->count);
- assert(count < FW_CFG_FILE_SLOTS);
+ assert(count < fw_cfg_file_slots(s));
/* Find the insertion point. */
if (mc->legacy_fw_cfg_order) {
/*
* Sort by order. For files with the same order, we keep them
@@ -855,11 +869,11 @@ void *fw_cfg_modify_file(FWCfgState *s, const char
*filename,
void *ptr = NULL;
assert(s->files);
index = be32_to_cpu(s->files->count);
- assert(index < FW_CFG_FILE_SLOTS);
+ assert(index < fw_cfg_file_slots(s));
for (i = 0; i < index; i++) {
if (strcmp(filename, s->files->f[i].name) == 0) {
ptr = fw_cfg_modify_bytes_read(s, FW_CFG_FILE_FIRST + i,
data, len);
@@ -926,10 +940,16 @@ FWCfgState *fw_cfg_init_io_dma(uint32_t iobase, uint32_t
dma_iobase,
qdev_prop_set_uint32(dev, "dma_iobase", dma_iobase);
if (!dma_requested) {
qdev_prop_set_bit(dev, "dma_enabled", false);
}
+ /* Once we expose the "file_slots" property to callers of
+ * fw_cfg_init_io_dma(), the following setting should become conditional on
+ * the input parameter being lower than the current value of the property.
+ */
+ qdev_prop_set_uint32(dev, "file_slots", FW_CFG_FILE_SLOTS_TRAD);
+
fw_cfg_init1(dev);
s = FW_CFG(dev);
if (s->dma_enabled) {
/* 64 bits for the address field */
@@ -963,10 +983,17 @@ FWCfgState *fw_cfg_init_mem_wide(hwaddr ctl_addr,
qdev_prop_set_uint32(dev, "data_width", data_width);
if (!dma_requested) {
qdev_prop_set_bit(dev, "dma_enabled", false);
}
+ /* Once we expose the "file_slots" property to callers of
+ * fw_cfg_init_mem_wide(), the following setting should become conditional
+ * on the input parameter being lower than the current value of the
+ * property. Refer to fw_cfg_init_io_dma().
+ */
+ qdev_prop_set_uint32(dev, "file_slots", FW_CFG_FILE_SLOTS_TRAD);
+
fw_cfg_init1(dev);
sbd = SYS_BUS_DEVICE(dev);
sysbus_mmio_map(sbd, 0, ctl_addr);
sysbus_mmio_map(sbd, 1, data_addr);
@@ -1012,23 +1039,56 @@ static const TypeInfo fw_cfg_info = {
.abstract = true,
.instance_size = sizeof(FWCfgState),
.class_init = fw_cfg_class_init,
};
+static void fw_cfg_file_slots_allocate(FWCfgState *s, Error **errp)
+{
+ uint16_t file_slots_max;
+
+ if (fw_cfg_file_slots(s) < FW_CFG_FILE_SLOTS_TRAD) {
+ error_setg(errp, "\"file_slots\" must be at least 0x%x",
+ FW_CFG_FILE_SLOTS_TRAD);
+ return;
+ }
+
+ /* (UINT16_MAX & FW_CFG_ENTRY_MASK) is the highest inclusive selector value
+ * that we permit. The actual (exclusive) value coming from the
+ * configuration is (FW_CFG_FILE_FIRST + fw_cfg_file_slots(s)). */
+ file_slots_max = (UINT16_MAX & FW_CFG_ENTRY_MASK) - FW_CFG_FILE_FIRST + 1;
+ if (fw_cfg_file_slots(s) > file_slots_max) {
+ error_setg(errp, "\"file_slots\" must not exceed 0x%" PRIx16,
+ file_slots_max);
+ return;
+ }
+
+ s->entries[0] = g_new0(FWCfgEntry, fw_cfg_max_entry(s));
+ s->entries[1] = g_new0(FWCfgEntry, fw_cfg_max_entry(s));
+ s->entry_order = g_new0(int, fw_cfg_max_entry(s));
+}
static Property fw_cfg_io_properties[] = {
DEFINE_PROP_UINT32("iobase", FWCfgIoState, iobase, -1),
DEFINE_PROP_UINT32("dma_iobase", FWCfgIoState, dma_iobase, -1),
DEFINE_PROP_BOOL("dma_enabled", FWCfgIoState, parent_obj.dma_enabled,
true),
+ DEFINE_PROP_UINT32("file_slots", FWCfgIoState, parent_obj.file_slots,
+ FW_CFG_FILE_SLOTS_DFLT),
DEFINE_PROP_END_OF_LIST(),
};
static void fw_cfg_io_realize(DeviceState *dev, Error **errp)
{
FWCfgIoState *s = FW_CFG_IO(dev);
SysBusDevice *sbd = SYS_BUS_DEVICE(dev);
+ Error *local_err = NULL;
+
+ fw_cfg_file_slots_allocate(FW_CFG(s), &local_err);
+ if (local_err) {
+ error_propagate(errp, local_err);
+ return;
+ }
/* when using port i/o, the 8-bit data register ALWAYS overlaps
* with half of the 16-bit control register. Hence, the total size
* of the i/o region used is FW_CFG_CTL_SIZE */
memory_region_init_io(&s->comb_iomem, OBJECT(s), &fw_cfg_comb_mem_ops,
@@ -1061,18 +1121,27 @@ static const TypeInfo fw_cfg_io_info = {
static Property fw_cfg_mem_properties[] = {
DEFINE_PROP_UINT32("data_width", FWCfgMemState, data_width, -1),
DEFINE_PROP_BOOL("dma_enabled", FWCfgMemState, parent_obj.dma_enabled,
true),
+ DEFINE_PROP_UINT32("file_slots", FWCfgMemState, parent_obj.file_slots,
+ FW_CFG_FILE_SLOTS_DFLT),
DEFINE_PROP_END_OF_LIST(),
};
static void fw_cfg_mem_realize(DeviceState *dev, Error **errp)
{
FWCfgMemState *s = FW_CFG_MEM(dev);
SysBusDevice *sbd = SYS_BUS_DEVICE(dev);
const MemoryRegionOps *data_ops = &fw_cfg_data_mem_ops;
+ Error *local_err = NULL;
+
+ fw_cfg_file_slots_allocate(FW_CFG(s), &local_err);
+ if (local_err) {
+ error_propagate(errp, local_err);
+ return;
+ }
memory_region_init_io(&s->ctl_iomem, OBJECT(s), &fw_cfg_ctl_mem_ops,
FW_CFG(s), "fwcfg.ctl", FW_CFG_CTL_SIZE);
sysbus_init_mmio(sbd, &s->ctl_iomem);
--
2.9.2
[Qemu-devel] [PATCH v4 2/7] fw-cfg: turn FW_CFG_FILE_SLOTS into a device property,
Laszlo Ersek <=
Re: [Qemu-devel] [PATCH v4 2/7] fw-cfg: turn FW_CFG_FILE_SLOTS into a device property, Igor Mammedov, 2016/12/06
[Qemu-devel] [PATCH v4 4/7] hw/i386/pc: introduce 2.9 machine types with 0x20 fw_cfg file slots, Laszlo Ersek, 2016/12/01
[Qemu-devel] [PATCH v4 6/7] hw/isa/lpc_ich9: add broadcast SMI feature, Laszlo Ersek, 2016/12/01
[Qemu-devel] [PATCH v4 1/7] fw-cfg: support writeable blobs, Laszlo Ersek, 2016/12/01