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author | Rusty Russell <rusty@rustcorp.com.au> | 2007-10-22 11:24:21 +1000 |
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committer | Rusty Russell <rusty@rustcorp.com.au> | 2007-10-23 15:49:56 +1000 |
commit | 19f1537b7b8a9a82665db3ad8210a9d954d13acd (patch) | |
tree | 793c1f8763350012caa521a55c5778b1c633b7e5 /arch/x86/lguest | |
parent | 15045275c32bf6d15d32c2eca8157be9c0ba6e45 (diff) | |
download | linux-3.10-19f1537b7b8a9a82665db3ad8210a9d954d13acd.tar.gz linux-3.10-19f1537b7b8a9a82665db3ad8210a9d954d13acd.tar.bz2 linux-3.10-19f1537b7b8a9a82665db3ad8210a9d954d13acd.zip |
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 <rusty@rustcorp.com.au>
Diffstat (limited to 'arch/x86/lguest')
-rw-r--r-- | arch/x86/lguest/Kconfig | 5 | ||||
-rw-r--r-- | arch/x86/lguest/boot.c | 21 |
2 files changed, 26 insertions, 0 deletions
diff --git a/arch/x86/lguest/Kconfig b/arch/x86/lguest/Kconfig index 44dccfd845f..c4dffbeea5e 100644 --- a/arch/x86/lguest/Kconfig +++ b/arch/x86/lguest/Kconfig @@ -2,8 +2,13 @@ config LGUEST_GUEST bool "Lguest guest support" select PARAVIRT depends on !X86_PAE + select VIRTIO select VIRTIO_RING + select VIRTIO_CONSOLE help Lguest is a tiny in-kernel hypervisor. Selecting this will allow your kernel to boot under lguest. This option will increase your kernel size by about 6k. If in doubt, say N. + + If you say Y here, make sure you say Y (or M) to the virtio block + and net drivers which lguest needs. diff --git a/arch/x86/lguest/boot.c b/arch/x86/lguest/boot.c index 959aeebb02f..495e46a1f11 100644 --- a/arch/x86/lguest/boot.c +++ b/arch/x86/lguest/boot.c @@ -55,6 +55,7 @@ #include <linux/clockchips.h> #include <linux/lguest.h> #include <linux/lguest_launcher.h> +#include <linux/virtio_console.h> #include <asm/paravirt.h> #include <asm/param.h> #include <asm/page.h> @@ -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; |