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https://github.com/AuxXxilium/linux_dsm_epyc7002.git
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c29834584e
this patch uses the new hvc callback hvc_resize to set the window size which allows to change the tty size of hvc_console via a hvc_resize function. I have added a new feature bit VIRTIO_CONSOLE_F_SIZE. The driver will change the window size on tty open and via the config_changed callback of the transport. Currently lguest and kvm_s390 have not implemented this callback, but the callback can be implemented at a later point in time. Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
281 lines
8.1 KiB
C
281 lines
8.1 KiB
C
/*D:300
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* The Guest console driver
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*
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* Writing console drivers is one of the few remaining Dark Arts in Linux.
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* Fortunately for us, the path of virtual consoles has been well-trodden by
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* the PowerPC folks, who wrote "hvc_console.c" to generically support any
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* virtual console. We use that infrastructure which only requires us to write
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* the basic put_chars and get_chars functions and call the right register
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* functions.
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:*/
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/*M:002 The console can be flooded: while the Guest is processing input the
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* Host can send more. Buffering in the Host could alleviate this, but it is a
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* difficult problem in general. :*/
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/* Copyright (C) 2006, 2007 Rusty Russell, IBM Corporation
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*/
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#include <linux/err.h>
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#include <linux/init.h>
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#include <linux/virtio.h>
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#include <linux/virtio_console.h>
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#include "hvc_console.h"
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/*D:340 These represent our input and output console queues, and the virtio
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* operations for them. */
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static struct virtqueue *in_vq, *out_vq;
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static struct virtio_device *vdev;
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/* This is our input buffer, and how much data is left in it. */
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static unsigned int in_len;
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static char *in, *inbuf;
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/* The operations for our console. */
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static struct hv_ops virtio_cons;
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/* The hvc device */
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static struct hvc_struct *hvc;
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/*D:310 The put_chars() callback is pretty straightforward.
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*
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* We turn the characters into a scatter-gather list, add it to the output
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* queue and then kick the Host. Then we sit here waiting for it to finish:
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* inefficient in theory, but in practice implementations will do it
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* immediately (lguest's Launcher does). */
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static int put_chars(u32 vtermno, const char *buf, int count)
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{
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struct scatterlist sg[1];
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unsigned int len;
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/* This is a convenient routine to initialize a single-elem sg list */
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sg_init_one(sg, buf, count);
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/* add_buf wants a token to identify this buffer: we hand it any
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* non-NULL pointer, since there's only ever one buffer. */
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if (out_vq->vq_ops->add_buf(out_vq, sg, 1, 0, (void *)1) == 0) {
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/* Tell Host to go! */
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out_vq->vq_ops->kick(out_vq);
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/* Chill out until it's done with the buffer. */
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while (!out_vq->vq_ops->get_buf(out_vq, &len))
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cpu_relax();
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}
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/* We're expected to return the amount of data we wrote: all of it. */
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return count;
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}
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/* Create a scatter-gather list representing our input buffer and put it in the
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* queue. */
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static void add_inbuf(void)
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{
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struct scatterlist sg[1];
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sg_init_one(sg, inbuf, PAGE_SIZE);
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/* We should always be able to add one buffer to an empty queue. */
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if (in_vq->vq_ops->add_buf(in_vq, sg, 0, 1, inbuf) != 0)
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BUG();
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in_vq->vq_ops->kick(in_vq);
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}
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/*D:350 get_chars() is the callback from the hvc_console infrastructure when
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* an interrupt is received.
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*
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* Most of the code deals with the fact that the hvc_console() infrastructure
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* only asks us for 16 bytes at a time. We keep in_offset and in_used fields
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* for partially-filled buffers. */
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static int get_chars(u32 vtermno, char *buf, int count)
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{
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/* If we don't have an input queue yet, we can't get input. */
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BUG_ON(!in_vq);
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/* No buffer? Try to get one. */
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if (!in_len) {
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in = in_vq->vq_ops->get_buf(in_vq, &in_len);
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if (!in)
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return 0;
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}
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/* You want more than we have to give? Well, try wanting less! */
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if (in_len < count)
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count = in_len;
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/* Copy across to their buffer and increment offset. */
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memcpy(buf, in, count);
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in += count;
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in_len -= count;
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/* Finished? Re-register buffer so Host will use it again. */
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if (in_len == 0)
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add_inbuf();
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return count;
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}
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/*:*/
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/*D:320 Console drivers are initialized very early so boot messages can go out,
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* so we do things slightly differently from the generic virtio initialization
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* of the net and block drivers.
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*
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* At this stage, the console is output-only. It's too early to set up a
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* virtqueue, so we let the drivers do some boutique early-output thing. */
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int __init virtio_cons_early_init(int (*put_chars)(u32, const char *, int))
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{
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virtio_cons.put_chars = put_chars;
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return hvc_instantiate(0, 0, &virtio_cons);
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}
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/*
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* virtio console configuration. This supports:
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* - console resize
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*/
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static void virtcons_apply_config(struct virtio_device *dev)
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{
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struct winsize ws;
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if (virtio_has_feature(dev, VIRTIO_CONSOLE_F_SIZE)) {
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dev->config->get(dev,
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offsetof(struct virtio_console_config, cols),
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&ws.ws_col, sizeof(u16));
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dev->config->get(dev,
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offsetof(struct virtio_console_config, rows),
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&ws.ws_row, sizeof(u16));
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hvc_resize(hvc, ws);
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}
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}
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/*
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* we support only one console, the hvc struct is a global var
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* We set the configuration at this point, since we now have a tty
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*/
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static int notifier_add_vio(struct hvc_struct *hp, int data)
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{
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hp->irq_requested = 1;
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virtcons_apply_config(vdev);
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return 0;
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}
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static void notifier_del_vio(struct hvc_struct *hp, int data)
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{
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hp->irq_requested = 0;
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}
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static void hvc_handle_input(struct virtqueue *vq)
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{
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if (hvc_poll(hvc))
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hvc_kick();
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}
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/*D:370 Once we're further in boot, we get probed like any other virtio device.
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* At this stage we set up the output virtqueue.
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*
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* To set up and manage our virtual console, we call hvc_alloc(). Since we
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* never remove the console device we never need this pointer again.
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*
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* Finally we put our input buffer in the input queue, ready to receive. */
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static int __devinit virtcons_probe(struct virtio_device *dev)
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{
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int err;
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vdev = dev;
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/* This is the scratch page we use to receive console input */
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inbuf = kmalloc(PAGE_SIZE, GFP_KERNEL);
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if (!inbuf) {
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err = -ENOMEM;
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goto fail;
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}
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/* Find the input queue. */
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/* FIXME: This is why we want to wean off hvc: we do nothing
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* when input comes in. */
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in_vq = vdev->config->find_vq(vdev, 0, hvc_handle_input);
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if (IS_ERR(in_vq)) {
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err = PTR_ERR(in_vq);
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goto free;
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}
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out_vq = vdev->config->find_vq(vdev, 1, NULL);
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if (IS_ERR(out_vq)) {
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err = PTR_ERR(out_vq);
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goto free_in_vq;
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}
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/* Start using the new console output. */
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virtio_cons.get_chars = get_chars;
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virtio_cons.put_chars = put_chars;
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virtio_cons.notifier_add = notifier_add_vio;
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virtio_cons.notifier_del = notifier_del_vio;
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virtio_cons.notifier_hangup = notifier_del_vio;
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/* The first argument of hvc_alloc() is the virtual console number, so
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* we use zero. The second argument is the parameter for the
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* notification mechanism (like irq number). We currently leave this
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* as zero, virtqueues have implicit notifications.
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*
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* The third argument is a "struct hv_ops" containing the put_chars()
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* get_chars(), notifier_add() and notifier_del() pointers.
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* The final argument is the output buffer size: we can do any size,
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* so we put PAGE_SIZE here. */
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hvc = hvc_alloc(0, 0, &virtio_cons, PAGE_SIZE);
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if (IS_ERR(hvc)) {
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err = PTR_ERR(hvc);
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goto free_out_vq;
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}
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/* Register the input buffer the first time. */
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add_inbuf();
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return 0;
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free_out_vq:
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vdev->config->del_vq(out_vq);
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free_in_vq:
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vdev->config->del_vq(in_vq);
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free:
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kfree(inbuf);
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fail:
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return err;
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}
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static struct virtio_device_id id_table[] = {
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{ VIRTIO_ID_CONSOLE, VIRTIO_DEV_ANY_ID },
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{ 0 },
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};
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static unsigned int features[] = {
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VIRTIO_CONSOLE_F_SIZE,
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};
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static struct virtio_driver virtio_console = {
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.feature_table = features,
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.feature_table_size = ARRAY_SIZE(features),
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.driver.name = KBUILD_MODNAME,
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.driver.owner = THIS_MODULE,
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.id_table = id_table,
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.probe = virtcons_probe,
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.config_changed = virtcons_apply_config,
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};
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static int __init init(void)
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{
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return register_virtio_driver(&virtio_console);
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}
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module_init(init);
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MODULE_DEVICE_TABLE(virtio, id_table);
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MODULE_DESCRIPTION("Virtio console driver");
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MODULE_LICENSE("GPL");
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