From a4d7b75be034115d36b6a20db566eb8b11bacaf8 Mon Sep 17 00:00:00 2001 From: Stefano Stabellini Date: Thu, 25 Feb 2016 12:10:39 +0000 Subject: [PATCH] hvc_xen: make early_printk work with HVM guests Refactor the existing code in xen_raw_console_write to get the generic early_printk console work with HVM guests. Take the opportunity to replace the outb loop with a single outsb call to reduce the number of vmexit. Signed-off-by: Stefano Stabellini Reviewed-by: Boris Ostrovsky --- drivers/tty/hvc/hvc_xen.c | 27 ++++++++++++++++----------- 1 file changed, 16 insertions(+), 11 deletions(-) diff --git a/drivers/tty/hvc/hvc_xen.c b/drivers/tty/hvc/hvc_xen.c index f34dec1d588a..71784950048f 100644 --- a/drivers/tty/hvc/hvc_xen.c +++ b/drivers/tty/hvc/hvc_xen.c @@ -605,6 +605,16 @@ static int xen_cons_init(void) } console_initcall(xen_cons_init); +#ifdef CONFIG_X86 +static void xen_hvm_early_write(uint32_t vtermno, const char *str, int len) +{ + if (xen_cpuid_base()) + outsb(0xe9, str, len); +} +#else +static void xen_hvm_early_write(uint32_t vtermno, const char *str, int len) { } +#endif + #ifdef CONFIG_EARLY_PRINTK static int __init xenboot_setup_console(struct console *console, char *string) { @@ -624,8 +634,10 @@ static void xenboot_write_console(struct console *console, const char *string, unsigned int linelen, off = 0; const char *pos; - if (!xen_pv_domain()) + if (!xen_pv_domain()) { + xen_hvm_early_write(0, string, len); return; + } dom0_write_console(0, string, len); @@ -661,17 +673,10 @@ void xen_raw_console_write(const char *str) if (xen_domain()) { rc = dom0_write_console(0, str, len); -#ifdef CONFIG_X86 - if (rc == -ENOSYS && xen_hvm_domain()) - goto outb_print; - - } else if (xen_cpuid_base()) { - int i; -outb_print: - for (i = 0; i < len; i++) - outb(str[i], 0xe9); -#endif + if (rc != -ENOSYS || !xen_hvm_domain()) + return; } + xen_hvm_early_write(0, str, len); } void xen_raw_printk(const char *fmt, ...) -- 2.20.1