[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
[Qemu-devel] [PATCH v6 wave 1 2/4] fw-cfg: turn FW_CFG_FILE_SLOTS into a
From: |
Laszlo Ersek |
Subject: |
[Qemu-devel] [PATCH v6 wave 1 2/4] fw-cfg: turn FW_CFG_FILE_SLOTS into a device property |
Date: |
Thu, 12 Jan 2017 19:24:15 +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 FWCfgState.file_slots (and matching device property).
Make the following changes:
- Replace the FW_CFG_FILE_SLOTS macro with FW_CFG_FILE_SLOTS_MIN (minimum
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 FW_CFG_FILE_SLOTS_MIN. 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>
Acked-by: Gabriel Somlo <address@hidden>
Tested-by: Gabriel Somlo <address@hidden>
---
Notes:
v6:
- rename the "file_slots" property to "x-file-slots" [Eduardo, Michael]
- pick up Gabriel's A-b and T-b
v5:
- change the type of "FWCfgState.file_slots" to "uint16_t" [Igor]
- same for the retval of the trivial wrapper function
fw_cfg_file_slots(), and for the corresponding "file_slots" device
properties
- preserve the fw_cfg_file_slots() wrapper func (Igor was okay with it
in the end)
- rename FW_CFG_FILE_SLOTS_TRAD to FW_CFG_FILE_SLOTS_MIN
- Remove explicit qdev_prop_set_uint32() calls from fw_cfg_init_io_dma()
and fw_cfg_init_mem_wide(), but set the property default to
FW_CFG_FILE_SLOTS_MIN (0x10). This is the main change relative to v4;
the idea is that per-board opt-in shouldn't be necessary for an
increased file_slots count *in addition to* selecting a 2.9 machine
type. [Igor]
- delay the now-unused FW_CFG_FILE_SLOTS_DFLT macro to a later patch
v4:
- 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 | 71 +++++++++++++++++++++++++++++++++++++-----
3 files changed, 65 insertions(+), 11 deletions(-)
diff --git a/docs/specs/fw_cfg.txt b/docs/specs/fw_cfg.txt
index a19e2adbe1c6..9373bbc64743 100644
--- a/docs/specs/fw_cfg.txt
+++ b/docs/specs/fw_cfg.txt
@@ -156,7 +156,7 @@ Selector Reg. Range Usage
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_MIN) (see fw_cfg.h).
= Guest-side DMA Interface =
diff --git a/include/hw/nvram/fw_cfg_keys.h b/include/hw/nvram/fw_cfg_keys.h
index 0f3e871884c0..b6919451f5bd 100644
--- a/include/hw/nvram/fw_cfg_keys.h
+++ b/include/hw/nvram/fw_cfg_keys.h
@@ -29,8 +29,7 @@
#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_MIN 0x10
#define FW_CFG_WRITE_CHANNEL 0x4000
#define FW_CFG_ARCH_LOCAL 0x8000
diff --git a/hw/nvram/fw_cfg.c b/hw/nvram/fw_cfg.c
index e0145c11a19b..bf75ef71d57e 100644
--- a/hw/nvram/fw_cfg.c
+++ b/hw/nvram/fw_cfg.c
@@ -33,6 +33,7 @@
#include "qemu/error-report.h"
#include "qemu/config-file.h"
#include "qemu/cutils.h"
+#include "qapi/error.h"
#define FW_CFG_NAME "fw_cfg"
#define FW_CFG_PATH "/machine/" FW_CFG_NAME
@@ -71,8 +72,9 @@ struct FWCfgState {
SysBusDevice parent_obj;
/*< public >*/
- FWCfgEntry entries[2][FW_CFG_MAX_ENTRY];
- int entry_order[FW_CFG_MAX_ENTRY];
+ uint16_t file_slots;
+ FWCfgEntry *entries[2];
+ int *entry_order;
FWCfgFiles *files;
uint16_t cur_entry;
uint32_t cur_offset;
@@ -257,13 +259,24 @@ static void fw_cfg_write(FWCfgState *s, uint8_t value)
/* nothing, write support removed in QEMU v2.4+ */
}
+static inline uint16_t fw_cfg_file_slots(const FWCfgState *s)
+{
+ return s->file_slots;
+}
+
+/* Note: this function returns an exclusive limit. */
+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 {
@@ -610,7 +623,7 @@ static void fw_cfg_add_bytes_read_callback(FWCfgState *s,
uint16_t key,
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;
@@ -628,7 +641,7 @@ static void *fw_cfg_modify_bytes_read(FWCfgState *s,
uint16_t key,
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;
@@ -777,13 +790,13 @@ void fw_cfg_add_file_callback(FWCfgState *s, const char
*filename,
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) {
@@ -857,7 +870,7 @@ void *fw_cfg_modify_file(FWCfgState *s, const char
*filename,
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) {
@@ -1014,12 +1027,38 @@ static const TypeInfo fw_cfg_info = {
.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_MIN) {
+ error_setg(errp, "\"file_slots\" must be at least 0x%x",
+ FW_CFG_FILE_SLOTS_MIN);
+ 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_UINT16("x-file-slots", FWCfgIoState, parent_obj.file_slots,
+ FW_CFG_FILE_SLOTS_MIN),
DEFINE_PROP_END_OF_LIST(),
};
@@ -1027,6 +1066,13 @@ 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
@@ -1063,6 +1109,8 @@ 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_UINT16("x-file-slots", FWCfgMemState, parent_obj.file_slots,
+ FW_CFG_FILE_SLOTS_MIN),
DEFINE_PROP_END_OF_LIST(),
};
@@ -1071,6 +1119,13 @@ 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);
--
2.9.3