Re: [Qemu-devel] [PATCH 1 of 4] kvm-userpace: add virtio-console support

[Anthony Liguori <anthony@codemonkey.ws>]

Christian Ehrhardt wrote:
> # HG changeset patch
> # User Christian Ehrhardt <ehrhardt@linux.vnet.ibm.com>
> # Date 1231855865 -3600
> # Node ID 50f40bc14f793a5f4ce6d91c36a3f3b19b507d42
> # Parent  89ed96e77993639b89d41a1a113ccbef979adfb9
> kvm-userpace: add virtio-console support
>
> This patch adds the virtio console to qemu. This console can be found after the
> serial and parallel outputs as another virtual console. In the -nographic case
> it is redirected to the null output by default.
>
> Signed-off-by: Christian Ehrhardt <ehrhardt@linux.vnet.ibm.com>
>   

Please submit this against QEMU, not kvm-userspace.

Regards,

Anthony Liguori

> ---
>  Makefile.target     |    2
>  hw/virtio-console.c |  147 ++++++++++++++++++++++++++++++++++++++++++++++++++++
>  hw/virtio-console.h |   22 +++++++
>  sysemu.h            |    6 ++
>  vl.c                |   26 +++++++++
>  5 files changed, 202 insertions(+), 1 deletion(-)
>
> diff --git a/Makefile.target b/Makefile.target
> --- a/Makefile.target
> +++ b/Makefile.target
> @@ -559,7 +559,7 @@ OBJS=vl.o osdep.o monitor.o pci.o loader
>  OBJS=vl.o osdep.o monitor.o pci.o loader.o isa_mmio.o machine.o
>  # virtio has to be here due to weird dependency between PCI and virtio-net.
>  # need to fix this properly
> -OBJS+=virtio.o virtio-blk.o virtio-balloon.o virtio-net.o
> +OBJS+=virtio.o virtio-blk.o virtio-balloon.o virtio-net.o virtio-console.o
>  OBJS+=fw_cfg.o
>  ifdef CONFIG_KVM
>  OBJS+=kvm.o kvm-all.o
> diff --git a/hw/virtio-console.c b/hw/virtio-console.c
> new file mode 100644
> --- /dev/null
> +++ b/hw/virtio-console.c
> @@ -0,0 +1,147 @@
> +/*
> + * Virtio Console Device
> + *
> + * Copyright IBM, Corp. 2008
> + *
> + * Authors:
> + *  Christian Ehrhardt <ehrhardt@linux.vnet.ibm.com>
> + *
> + * This work is licensed under the terms of the GNU GPL, version 2.  See
> + * the COPYING file in the top-level directory.
> + *
> + */
> +
> +#include "hw.h"
> +#include "qemu-char.h"
> +#include "virtio.h"
> +#include "virtio-console.h"
> +
> +
> +typedef struct VirtIOConsole
> +{
> +    VirtIODevice vdev;
> +    VirtQueue *ivq, *dvq;
> +    CharDriverState *chr;
> +} VirtIOConsole;
> +
> +static VirtIOConsole *to_virtio_console(VirtIODevice *vdev)
> +{
> +    return (VirtIOConsole *)vdev;
> +}
> +
> +static void virtio_console_handle_output(VirtIODevice *vdev, VirtQueue *vq)
> +{
> +    VirtIOConsole *s = to_virtio_console(vdev);
> +    VirtQueueElement elem;
> +
> +    while (virtqueue_pop(vq, &elem)) {
> +        ssize_t len = 0;
> +        int d;
> +
> +        for (d=0; d < elem.out_num; d++)
> +            len += qemu_chr_write(s->chr, elem.out_sg[d].iov_base,elem.out_sg[d].iov_len);
> +        virtqueue_push(vq, &elem, len);
> +        virtio_notify(vdev, vq);
> +    }
> +}
> +
> +static void virtio_console_handle_input(VirtIODevice *vdev, VirtQueue *vq)
> +{
> +}
> +
> +static uint32_t virtio_console_get_features(VirtIODevice *vdev)
> +{
> +    return 0;
> +}
> +
> +static int vcon_can_read(void *opaque)
> +{
> +    VirtIOConsole *s = (VirtIOConsole *) opaque;
> +
> +    if (!virtio_queue_ready(s->ivq) ||
> +        !(s->vdev.status & VIRTIO_CONFIG_S_DRIVER_OK) ||
> +        virtio_queue_empty(s->ivq))
> +        return 0;
> +
> +    /* current implementations have a page sized buffer.
> +     * We fall back to a one byte per read if there is not enough room.
> +     * It would be cool to have a function that returns the available byte
> +     * instead of checking for a limit */
> +    if (virtqueue_avail_bytes(s->ivq, TARGET_PAGE_SIZE, 0))
> +        return TARGET_PAGE_SIZE;
> +    if (virtqueue_avail_bytes(s->ivq, 1, 0))
> +        return 1;
> +    return 0;
> +}
> +
> +static void vcon_read(void *opaque, const uint8_t *buf, int size)
> +{
> +    VirtIOConsole *s = (VirtIOConsole *) opaque;
> +    VirtQueueElement elem;
> +    int offset = 0;
> +
> +    /* The current kernel implementation has only one outstanding input
> +     * buffer of PAGE_SIZE. Nevertheless, this function is prepared to
> +     * handle multiple buffers with multiple sg element for input */
> +    while (offset < size) {
> +        int i = 0;
> +        if (!virtqueue_pop(s->ivq, &elem))
> +                break;
> +        while (offset < size && i < elem.in_num) {
> +            int len = MIN(elem.in_sg[i].iov_len, size - offset);
> +            memcpy(elem.in_sg[i].iov_base, buf + offset, len);
> +            offset += len;
> +            i++;
> +        }
> +        virtqueue_push(s->ivq, &elem, size);
> +    }
> +    virtio_notify(&s->vdev, s->ivq);
> +}
> +
> +static void vcon_event(void *opaque, int event)
> +{
> +    /* we will ignore any event for the time being */
> +}
> +
> +static void virtio_console_save(QEMUFile *f, void *opaque)
> +{
> +    VirtIOConsole *s = opaque;
> +
> +    virtio_save(&s->vdev, f);
> +}
> +
> +static int virtio_console_load(QEMUFile *f, void *opaque, int version_id)
> +{
> +    VirtIOConsole *s = opaque;
> +
> +    if (version_id != 1)
> +        return -EINVAL;
> +
> +    virtio_load(&s->vdev, f);
> +    return 0;
> +}
> +
> +void *virtio_console_init(PCIBus *bus, CharDriverState *chr)
> +{
> +    VirtIOConsole *s;
> +
> +    s = (VirtIOConsole *)virtio_init_pci(bus, "virtio-console",
> +                                         6900, 0x1003,
> +                                         0, VIRTIO_ID_CONSOLE,
> +                                         0x03, 0x80, 0x00,
> +                                         0, sizeof(VirtIOConsole));
> +    if (s == NULL)
> +        return NULL;
> +
> +    s->vdev.get_features = virtio_console_get_features;
> +
> +    s->ivq = virtio_add_queue(&s->vdev, 128, virtio_console_handle_input);
> +    s->dvq = virtio_add_queue(&s->vdev, 128, virtio_console_handle_output);
> +
> +    s->chr = chr;
> +    qemu_chr_add_handlers(chr, vcon_can_read, vcon_read, vcon_event, s);
> +
> +    register_savevm("virtio-console", -1, 1, virtio_console_save, virtio_console_load, s);
> +
> +    return &s->vdev;
> +}
> diff --git a/hw/virtio-console.h b/hw/virtio-console.h
> new file mode 100644
> --- /dev/null
> +++ b/hw/virtio-console.h
> @@ -0,0 +1,22 @@
> +/*
> + * Virtio Console Support
> + *
> + * Copyright IBM, Corp. 2008
> + *
> + * Authors:
> + *  Christian Ehrhardt <ehrhardt@linux.vnet.ibm.com>
> + *
> + * This work is licensed under the terms of the GNU GPL, version 2.  See
> + * the COPYING file in the top-level directory.
> + *
> + */
> +#ifndef _QEMU_VIRTIO_CONSOLE_H
> +#define _QEMU_VIRTIO_CONSOLE_H
> +
> +/* The ID for virtio console */
> +#define VIRTIO_ID_CONSOLE 3
> +
> +/* Creates a virtio console */
> +void *virtio_console_init(PCIBus *bus, CharDriverState *chr);
> +
> +#endif
> diff --git a/sysemu.h b/sysemu.h
> --- a/sysemu.h
> +++ b/sysemu.h
> @@ -158,6 +158,12 @@ extern CharDriverState *serial_hds[MAX_S
>  
>  extern CharDriverState *parallel_hds[MAX_PARALLEL_PORTS];
>  
> +/* virtio consoles */
> +
> +#define MAX_VIRTIO_CONSOLES 1
> +
> +extern CharDriverState *virtcon_hds[MAX_VIRTIO_CONSOLES];
> +
>  #define TFR(expr) do { if ((expr) != -1) break; } while (errno == EINTR)
>  
>  #ifdef NEED_CPU_H
> diff --git a/vl.c b/vl.c
> --- a/vl.c
> +++ b/vl.c
> @@ -209,6 +209,7 @@ int no_quit = 0;
>  int no_quit = 0;
>  CharDriverState *serial_hds[MAX_SERIAL_PORTS];
>  CharDriverState *parallel_hds[MAX_PARALLEL_PORTS];
> +CharDriverState *virtcon_hds[MAX_VIRTIO_CONSOLES];
>  #ifdef TARGET_I386
>  int win2k_install_hack = 0;
>  #endif
> @@ -4502,6 +4503,8 @@ int main(int argc, char **argv, char **e
>      int serial_device_index;
>      const char *parallel_devices[MAX_PARALLEL_PORTS];
>      int parallel_device_index;
> +    const char *virtio_consoles[MAX_VIRTIO_CONSOLES];
> +    int virtio_console_index;
>      const char *loadvm = NULL;
>      QEMUMachine *machine;
>      const char *cpu_model;
> @@ -4574,6 +4577,11 @@ int main(int argc, char **argv, char **e
>      for(i = 1; i < MAX_PARALLEL_PORTS; i++)
>          parallel_devices[i] = NULL;
>      parallel_device_index = 0;
> +
> +    virtio_consoles[0] = "vc:80Cx24C";
> +    for(i = 1; i < MAX_VIRTIO_CONSOLES; i++)
> +        virtio_consoles[i] = NULL;
> +    virtio_console_index = 0;
>  
>      usb_devices_index = 0;
>  
> @@ -5170,6 +5178,8 @@ int main(int argc, char **argv, char **e
>             parallel_devices[0] = "null";
>         if (strncmp(monitor_device, "vc", 2) == 0)
>             monitor_device = "stdio";
> +       if (virtio_console_index == 0)
> +           virtio_consoles[0] = "null";
>      }
>  
>  #ifndef _WIN32
> @@ -5464,6 +5474,22 @@ int main(int argc, char **argv, char **e
>          }
>      }
>  
> +    for(i = 0; i < MAX_VIRTIO_CONSOLES; i++) {
> +        const char *devname = virtio_consoles[i];
> +        if (devname && strcmp(devname, "none")) {
> +            char label[32];
> +            snprintf(label, sizeof(label), "virtcon%d", i);
> +            virtcon_hds[i] = qemu_chr_open(label, devname);
> +            if (!virtcon_hds[i]) {
> +                fprintf(stderr, "qemu: could not open virtio console '%s'\n",
> +                        devname);
> +                exit(1);
> +            }
> +            if (strstart(devname, "vc", 0))
> +                qemu_chr_printf(virtcon_hds[i], "virtio console%d\r\n", i);
> +        }
> +    }
> +
>      if (kvm_enabled()) {
>          int ret;
>  
>
>
>