/*H:430
* (iv) Switching page tables
*
* Now we've seen all the page table setting and manipulation, let's see
* what happens when the Guest changes page tables (ie. changes the top-level
* pgdir). This occurs on almost every context switch.
*/
void guest_new_pagetable(struct lg_cpu *cpu, unsigned long pgtable)
{
int newpgdir, repin = 0;
/*
* The very first time they call this, we're actually running without
* any page tables; we've been making it up. Throw them away now.
*/
if (unlikely(cpu->linear_pages)) {
release_all_pagetables(cpu->lg);
cpu->linear_pages = false;
/* Force allocation of a new pgdir. */
newpgdir = ARRAY_SIZE(cpu->lg->pgdirs);
} else {
/* Look to see if we have this one already. */
newpgdir = find_pgdir(cpu->lg, pgtable);
}
/*
* If not, we allocate or mug an existing one: if it's a fresh one,
* repin gets set to 1.
*/
if (newpgdir == ARRAY_SIZE(cpu->lg->pgdirs))
newpgdir = new_pgdir(cpu, pgtable, &repin);
/* Change the current pgd index to the new one. */
cpu->cpu_pgd = newpgdir;
/* If it was completely blank, we map in the Guest kernel stack */
if (repin)
pin_stack_pages(cpu);
}
/*
* We also throw away everything when a Guest tells us it's changed a kernel
* mapping. Since kernel mappings are in every page table, it's easiest to
* throw them all away. This traps the Guest in amber for a while as
* everything faults back in, but it's rare.
*/
void guest_pagetable_clear_all(struct lg_cpu *cpu)
{
release_all_pagetables(cpu->lg);
/* We need the Guest kernel stack mapped again. */
pin_stack_pages(cpu);
/* And we need Switcher allocated. */
if (!allocate_switcher_mapping(cpu))
kill_guest(cpu, "Cannot populate switcher mapping");
}
/* When a Guest dies, our cleanup is fairly simple. */
void free_guest_pagetable(struct lguest *lg)
{
unsigned int i;
/* Throw away all page table pages. */
release_all_pagetables(lg);
/* Now free the top levels: free_page() can handle 0 just fine. */
for (i = 0; i < ARRAY_SIZE(lg->pgdirs); i++)
free_page((long)lg->pgdirs[i].pgdir);
}
static void buffer_release(struct videobuf_queue *q, struct videobuf_buffer *vb)
{
struct file *file = q->priv_data;
struct saa7146_fh *fh = file->private_data;
struct saa7146_dev *dev = fh->dev;
struct saa7146_buf *buf = (struct saa7146_buf *)vb;
DEB_CAP("vbuf:%p\n", vb);
saa7146_dma_free(dev,q,buf);
release_all_pagetables(dev, buf);
}
/*H:500
* (vii) Setting up the page tables initially.
*
* When a Guest is first created, set initialize a shadow page table which
* we will populate on future faults. The Guest doesn't have any actual
* pagetables yet, so we set linear_pages to tell demand_page() to fake it
* for the moment.
*
* We do need the Switcher to be mapped at all times, so we allocate that
* part of the Guest page table here.
*/
int init_guest_pagetable(struct lguest *lg)
{
struct lg_cpu *cpu = &lg->cpus[0];
int allocated = 0;
/* lg (and lg->cpus[]) starts zeroed: this allocates a new pgdir */
cpu->cpu_pgd = new_pgdir(cpu, 0, &allocated);
if (!allocated)
return -ENOMEM;
/* We start with a linear mapping until the initialize. */
cpu->linear_pages = true;
/* Allocate the page tables for the Switcher. */
if (!allocate_switcher_mapping(cpu)) {
release_all_pagetables(lg);
return -ENOMEM;
}
return 0;
}
/*
* We also throw away everything when a Guest tells us it's changed a kernel
* mapping. Since kernel mappings are in every page table, it's easiest to
* throw them all away. This traps the Guest in amber for a while as
* everything faults back in, but it's rare.
*/
void guest_pagetable_clear_all(struct lg_cpu *cpu)
{
release_all_pagetables(cpu->lg);
/* We need the Guest kernel stack mapped again. */
pin_stack_pages(cpu);
}
static int buffer_prepare(struct videobuf_queue *q,
struct videobuf_buffer *vb, enum v4l2_field field)
{
struct file *file = q->priv_data;
struct saa7146_fh *fh = file->private_data;
struct saa7146_dev *dev = fh->dev;
struct saa7146_vv *vv = dev->vv_data;
struct saa7146_buf *buf = (struct saa7146_buf *)vb;
int size,err = 0;
DEB_CAP("vbuf:%p\n", vb);
/* sanity checks */
if (fh->video_fmt.width < 48 ||
fh->video_fmt.height < 32 ||
fh->video_fmt.width > vv->standard->h_max_out ||
fh->video_fmt.height > vv->standard->v_max_out) {
DEB_D("w (%d) / h (%d) out of bounds\n",
fh->video_fmt.width, fh->video_fmt.height);
return -EINVAL;
}
size = fh->video_fmt.sizeimage;
if (0 != buf->vb.baddr && buf->vb.bsize < size) {
DEB_D("size mismatch\n");
return -EINVAL;
}
DEB_CAP("buffer_prepare [size=%dx%d,bytes=%d,fields=%s]\n",
fh->video_fmt.width, fh->video_fmt.height,
size, v4l2_field_names[fh->video_fmt.field]);
if (buf->vb.width != fh->video_fmt.width ||
buf->vb.bytesperline != fh->video_fmt.bytesperline ||
buf->vb.height != fh->video_fmt.height ||
buf->vb.size != size ||
buf->vb.field != field ||
buf->vb.field != fh->video_fmt.field ||
buf->fmt != &fh->video_fmt) {
saa7146_dma_free(dev,q,buf);
}
if (VIDEOBUF_NEEDS_INIT == buf->vb.state) {
struct saa7146_format *sfmt;
buf->vb.bytesperline = fh->video_fmt.bytesperline;
buf->vb.width = fh->video_fmt.width;
buf->vb.height = fh->video_fmt.height;
buf->vb.size = size;
buf->vb.field = field;
buf->fmt = &fh->video_fmt;
buf->vb.field = fh->video_fmt.field;
sfmt = saa7146_format_by_fourcc(dev,buf->fmt->pixelformat);
release_all_pagetables(dev, buf);
if( 0 != IS_PLANAR(sfmt->trans)) {
saa7146_pgtable_alloc(dev->pci, &buf->pt[0]);
saa7146_pgtable_alloc(dev->pci, &buf->pt[1]);
saa7146_pgtable_alloc(dev->pci, &buf->pt[2]);
} else {
saa7146_pgtable_alloc(dev->pci, &buf->pt[0]);
}
err = videobuf_iolock(q,&buf->vb, &vv->ov_fb);
if (err)
goto oops;
err = saa7146_pgtable_build(dev,buf);
if (err)
goto oops;
}
buf->vb.state = VIDEOBUF_PREPARED;
buf->activate = buffer_activate;
return 0;
oops:
DEB_D("error out\n");
saa7146_dma_free(dev,q,buf);
return err;
}