Allow limiting the amount of log output sent. Allow up to 1 MiB.
In case the guest log buffer is larger than 1 MiB limit the output
instead of throwing an error.
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
---
hw/uefi/ovmf-log.c | 42 ++++++++++++++++++++++++++++++++++--------
hmp-commands-info.hx | 4 ++--
qapi/machine.json | 5 +++++
3 files changed, 41 insertions(+), 10 deletions(-)
diff --git a/hw/uefi/ovmf-log.c b/hw/uefi/ovmf-log.c
index fe8acbd19236..98ebb0209491 100644
--- a/hw/uefi/ovmf-log.c
+++ b/hw/uefi/ovmf-log.c
@@ -18,6 +18,7 @@
#include "qapi/error.h"
#include "qapi/type-helpers.h"
#include "qapi/qapi-commands-machine.h"
+#include "qobject/qdict.h"
/* ----------------------------------------------------------------------- */
@@ -164,7 +165,8 @@ static void handle_ovmf_log_range(GString *out,
}
}
-FirmwareLog *qmp_query_firmware_log(Error **errp)
+FirmwareLog *qmp_query_firmware_log(bool have_max_size, uint64_t max_size,
+ Error **errp)
{
MEM_DEBUG_LOG_HDR header;
dma_addr_t offset, base;
@@ -184,18 +186,40 @@ FirmwareLog *qmp_query_firmware_log(Error **errp)
return NULL;
}
- if (header.DebugLogSize > MiB) {
- /* default size is 128k (32 pages), allow up to 1M */
- error_setg(errp, "firmware log: log buffer is too big");
- return NULL;
- }
-
if (header.DebugLogHeadOffset > header.DebugLogSize ||
header.DebugLogTailOffset > header.DebugLogSize) {
error_setg(errp, "firmware log buffer header is invalid");
return NULL;
}
+ if (have_max_size) {
+ if (max_size > MiB) {
+ error_setg(errp, "parameter 'max-size' exceeds 1MiB");
+ return NULL;
+ }
+ } else {
+ max_size = MiB;
+ }
+
+ /* adjust header.DebugLogHeadOffset so we return at most maxsize bytes */
+ if (header.DebugLogHeadOffset > header.DebugLogTailOffset) {
+ /* wrap around */
+ if (header.DebugLogTailOffset > max_size) {
+ header.DebugLogHeadOffset = header.DebugLogTailOffset - max_size;
+ } else {
+ uint64_t max_chunk = max_size - header.DebugLogTailOffset;
+ if (header.DebugLogSize > max_chunk &&
+ header.DebugLogHeadOffset < header.DebugLogSize - max_chunk) {
+ header.DebugLogHeadOffset = header.DebugLogSize - max_chunk;
+ }
+ }
+ } else {
+ if (header.DebugLogTailOffset > max_size &&
+ header.DebugLogHeadOffset < header.DebugLogTailOffset - max_size) {
+ header.DebugLogHeadOffset = header.DebugLogTailOffset - max_size;
+ }
+ }
+
base = offset + header.HeaderSize;
if (header.DebugLogHeadOffset > header.DebugLogTailOffset) {
/* wrap around */
@@ -239,8 +263,10 @@ void hmp_info_firmware_log(Monitor *mon, const QDict *qdict)
Error *err = NULL;
FirmwareLog *log;
gsize log_len;
+ int64_t maxsize;
- log = qmp_query_firmware_log(&err);
+ maxsize = qdict_get_try_int(qdict, "max-size", -1);
+ log = qmp_query_firmware_log(maxsize != -1, (uint64_t)maxsize, &err);
if (err) {
hmp_handle_error(mon, err);
return;
diff --git a/hmp-commands-info.hx b/hmp-commands-info.hx
index 33cf740bbc1b..2a7f5810d706 100644
--- a/hmp-commands-info.hx
+++ b/hmp-commands-info.hx
@@ -998,8 +998,8 @@ ERST
{
.name = "firmware-log",
- .args_type = "",
- .params = "",
+ .args_type = "max-size:o?",
+ .params = "[max-size]",
.help = "show the firmware (ovmf) debug log",
.cmd = hmp_info_firmware_log,
},
diff --git a/qapi/machine.json b/qapi/machine.json
index 96133e5c71cf..c6dc6fe69b5c 100644
--- a/qapi/machine.json
+++ b/qapi/machine.json
@@ -1858,9 +1858,14 @@
#
# Find firmware memory log buffer in guest memory, return content.
#
+# @max-size: limit the amount of log data returned. Up to 1 MiB of
+# log data is allowed. In case the amount of log data is
+# larger than @max-size the tail of the log is returned.
+#
# Since: 10.2
##
{ 'command': 'query-firmware-log',
+ 'data': { '*max-size': 'size' },
'returns': 'FirmwareLog' }
##
--
2.51.0