From 3203148917d035b09f71986ac2eaa19a352d6d9d Mon Sep 17 00:00:00 2001 From: Philippe Mathieu-Daudé Date: Thu, 14 May 2020 15:15:38 +0200 Subject: hw/nvram/fw_cfg: Add the FW_CFG_DATA_GENERATOR interface The FW_CFG_DATA_GENERATOR allows any object to produce blob of data consumable by the fw_cfg device. Reviewed-by: Laszlo Ersek Signed-off-by: Philippe Mathieu-Daudé Reviewed-by: Daniel P. Berrangé Message-Id: <20200623172726.21040-3-philmd@redhat.com> --- docs/specs/fw_cfg.txt | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) (limited to 'docs') diff --git a/docs/specs/fw_cfg.txt b/docs/specs/fw_cfg.txt index 8f1ebc66fa..bc16daa38a 100644 --- a/docs/specs/fw_cfg.txt +++ b/docs/specs/fw_cfg.txt @@ -219,7 +219,7 @@ To check the result, read the "control" field: = Externally Provided Items = -As of v2.4, "file" fw_cfg items (i.e., items with selector keys above +Since v2.4, "file" fw_cfg items (i.e., items with selector keys above FW_CFG_FILE_FIRST, and with a corresponding entry in the fw_cfg file directory structure) may be inserted via the QEMU command line, using the following syntax: @@ -230,6 +230,13 @@ Or -fw_cfg [name=],string= +Since v5.1, QEMU allows some objects to generate fw_cfg-specific content, +the content is then associated with a "file" item using the 'gen_id' option +in the command line, using the following syntax: + + -object ,id=,[generator-specific-options] \ + -fw_cfg [name=],gen_id= + See QEMU man page for more documentation. Using item_name with plain ASCII characters only is recommended. -- cgit v1.2.3-55-g7522 From f7d8afb16dceb780270960692b949329c8752ff2 Mon Sep 17 00:00:00 2001 From: Philippe Mathieu-Daudé Date: Tue, 19 May 2020 19:17:09 +0200 Subject: softmmu/vl: Allow -fw_cfg 'gen_id' option to use the 'etc/' namespace Names of user-provided fw_cfg items are supposed to start with "opt/". However FW_CFG_DATA_GENERATOR items are generated by QEMU, so allow the "etc/" namespace in this specific case. Reviewed-by: Laszlo Ersek Signed-off-by: Philippe Mathieu-Daudé Reviewed-by: Daniel P. Berrangé Message-Id: <20200623172726.21040-5-philmd@redhat.com> --- docs/specs/fw_cfg.txt | 4 ++++ softmmu/vl.c | 8 +++++++- 2 files changed, 11 insertions(+), 1 deletion(-) (limited to 'docs') diff --git a/docs/specs/fw_cfg.txt b/docs/specs/fw_cfg.txt index bc16daa38a..3e6d586f66 100644 --- a/docs/specs/fw_cfg.txt +++ b/docs/specs/fw_cfg.txt @@ -258,4 +258,8 @@ Prefix "opt/org.qemu/" is reserved for QEMU itself. Use of names not beginning with "opt/" is potentially dangerous and entirely unsupported. QEMU will warn if you try. +Use of names not beginning with "opt/" is tolerated with 'gen_id' (that +is, the warning is suppressed), but you must know exactly what you're +doing. + All externally provided fw_cfg items are read-only to the guest. diff --git a/softmmu/vl.c b/softmmu/vl.c index 13cada39d6..159f0352a9 100644 --- a/softmmu/vl.c +++ b/softmmu/vl.c @@ -2049,7 +2049,13 @@ static int parse_fw_cfg(void *opaque, QemuOpts *opts, Error **errp) FW_CFG_MAX_FILE_PATH - 1); return -1; } - if (strncmp(name, "opt/", 4) != 0) { + if (nonempty_str(gen_id)) { + /* + * In this particular case where the content is populated + * internally, the "etc/" namespace protection is relaxed, + * so do not emit a warning. + */ + } else if (strncmp(name, "opt/", 4) != 0) { warn_report("externally provided fw_cfg item names " "should be prefixed with \"opt/\""); } -- cgit v1.2.3-55-g7522