From 597a9a2b4b18323c20538008cd3ded85de76e9fa Mon Sep 17 00:00:00 2001 From: Peter Maydell Date: Mon, 22 Jan 2024 16:36:06 +0000 Subject: [PATCH] system/vl.c: Fix handling of '-serial none -serial something' MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Currently if the user passes multiple -serial options on the command line, we mostly treat those as applying to the different serial devices in order, so that for example -serial stdio -serial file:filename will connect the first serial port to stdio and the second to the named file. The exception to this is the '-serial none' serial device type. This means "don't allocate this serial device", but a bug means that following -serial options are not correctly handled, so that -serial none -serial stdio has the unexpected effect that stdio is connected to the first serial port, not the second. This is a very long-standing bug that dates back at least as far as commit 998bbd74b9d81 from 2009. Make the 'none' serial type move forward in the indexing of serial devices like all the other serial types, so that any subsequent -serial options are correctly handled. Note that if your commandline mistakenly had a '-serial none' that was being overridden by a following '-serial something' option, you should delete the unnecessary '-serial none'. This will give you the same behaviour as before, on QEMU versions both with and without this bug fix. Cc: qemu-stable@nongnu.org Reported-by: Bohdan Kostiv Signed-off-by: Peter Maydell Reviewed-by: Daniel P. Berrangé Reviewed-by: Richard Henderson Message-id: 20240122163607.459769-2-peter.maydell@linaro.org Fixes: 998bbd74b9d81 ("default devices: core code & serial lines") Signed-off-by: Peter Maydell (cherry picked from commit d2019a9d0c34a4fdcb5b5df550d73040dc0637d9) Signed-off-by: Michael Tokarev --- softmmu/vl.c | 22 +++++++++++++--------- 1 file changed, 13 insertions(+), 9 deletions(-) diff --git a/softmmu/vl.c b/softmmu/vl.c index ce88869618..ab4394c53d 100644 --- a/softmmu/vl.c +++ b/softmmu/vl.c @@ -1363,18 +1363,22 @@ static void qemu_create_default_devices(void) static int serial_parse(const char *devname) { int index = num_serial_hds; - char label[32]; - if (strcmp(devname, "none") == 0) - return 0; - snprintf(label, sizeof(label), "serial%d", index); serial_hds = g_renew(Chardev *, serial_hds, index + 1); - serial_hds[index] = qemu_chr_new_mux_mon(label, devname, NULL); - if (!serial_hds[index]) { - error_report("could not connect serial device" - " to character backend '%s'", devname); - return -1; + if (strcmp(devname, "none") == 0) { + /* Don't allocate a serial device for this index */ + serial_hds[index] = NULL; + } else { + char label[32]; + snprintf(label, sizeof(label), "serial%d", index); + + serial_hds[index] = qemu_chr_new_mux_mon(label, devname, NULL); + if (!serial_hds[index]) { + error_report("could not connect serial device" + " to character backend '%s'", devname); + return -1; + } } num_serial_hds++; return 0;