[PATCH v2 3/9] xen/x86: make "earlyprintk=xen" work better for PVH Dom0
STALE1831d
LANDED: 7 (7M)
From: Jan Beulich <hidden>
Date: 2021-09-30 12:17:51
Also in:
lkml, xen-devel
1 review trailer; landed in mainline as adf330a7cd64 on 2021-10-05.
The xen_hvm_early_write() path better wouldn't be taken in this case; while port 0xE9 can be used, the hypercall path is quite a bit more efficient. Put that first, as it may also work for DomU-s (see also xen_raw_console_write()). While there also bail from the function when the first domU_write_console() failed - later ones aren't going to succeed. Signed-off-by: Jan Beulich <redacted> Reviewed-by: Juergen Gross <jgross@suse.com>
--- a/drivers/tty/hvc/hvc_xen.c
+++ b/drivers/tty/hvc/hvc_xen.c@@ -632,17 +632,16 @@ static void xenboot_write_console(struct unsigned int linelen, off = 0; const char *pos; + if (dom0_write_console(0, string, len) >= 0) + return; + if (!xen_pv_domain()) { xen_hvm_early_write(0, string, len); return; } - dom0_write_console(0, string, len); - - if (xen_initial_domain()) + if (domU_write_console(0, "(early) ", 8) < 0) return; - - domU_write_console(0, "(early) ", 8); while (off < len && NULL != (pos = strchr(string+off, '\n'))) { linelen = pos-string+off; if (off + linelen > len)