From 19f1537b7b8a9a82665db3ad8210a9d954d13acd Mon Sep 17 00:00:00 2001 From: Rusty Russell Date: Mon, 22 Oct 2007 11:24:21 +1000 Subject: Lguest support for Virtio This makes lguest able to use the virtio devices. We change the device descriptor page from a simple array to a variable length "type, config_len, status, config data..." format, and implement virtio_config_ops to read from that config data. We use the virtio ring implementation for an efficient Guest <-> Host virtqueue mechanism, and the new LHCALL_NOTIFY hypercall to kick the host when it changes. We also use LHCALL_NOTIFY on kernel addresses for very very early console output. We could have another hypercall, but this hack works quite well. Signed-off-by: Rusty Russell --- arch/x86/lguest/boot.c | 21 +++++++++++++++++++++ 1 file changed, 21 insertions(+) (limited to 'arch/x86/lguest/boot.c') diff --git a/arch/x86/lguest/boot.c b/arch/x86/lguest/boot.c index 959aeebb02f5..495e46a1f111 100644 --- a/arch/x86/lguest/boot.c +++ b/arch/x86/lguest/boot.c @@ -55,6 +55,7 @@ #include #include #include +#include #include #include #include @@ -849,6 +850,23 @@ static __init char *lguest_memory_setup(void) return "LGUEST"; } +/* Before virtqueues are set up, we use LHCALL_NOTIFY on normal memory to + * produce console output. */ +static __init int early_put_chars(u32 vtermno, const char *buf, int count) +{ + char scratch[17]; + unsigned int len = count; + + if (len > sizeof(scratch) - 1) + len = sizeof(scratch) - 1; + scratch[len] = '\0'; + memcpy(scratch, buf, len); + hcall(LHCALL_NOTIFY, __pa(scratch), 0, 0); + + /* This routine returns the number of bytes actually written. */ + return len; +} + /*G:050 * Patching (Powerfully Placating Performance Pedants) * @@ -1048,6 +1066,9 @@ __init void lguest_init(void *boot) * adapted for lguest's use. */ add_preferred_console("hvc", 0, NULL); + /* Register our very early console. */ + virtio_cons_early_init(early_put_chars); + /* Last of all, we set the power management poweroff hook to point to * the Guest routine to power off. */ pm_power_off = lguest_power_off; -- cgit v1.2.3