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| author | Rusty Russell <rusty@rustcorp.com.au> | 2008-08-26 07:19:27 +0200 |
|---|---|---|
| committer | Rusty Russell <rusty@rustcorp.com.au> | 2008-08-25 16:19:28 +0200 |
| commit | 1dc3e3bcbfe335843ec938bfdddb34d10f4dd278 (patch) | |
| tree | 8666189f7a285c8e4c6512784dff39971fefa30c /drivers/lguest/lguest_device.c | |
| parent | stop_machine: Remove deprecated stop_machine_run (diff) | |
| download | linux-1dc3e3bcbfe335843ec938bfdddb34d10f4dd278.tar.xz linux-1dc3e3bcbfe335843ec938bfdddb34d10f4dd278.zip | |
lguest: update commentry
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Diffstat (limited to 'drivers/lguest/lguest_device.c')
| -rw-r--r-- | drivers/lguest/lguest_device.c | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/drivers/lguest/lguest_device.c b/drivers/lguest/lguest_device.c index 37344aaee22f..a661bbdae3d6 100644 --- a/drivers/lguest/lguest_device.c +++ b/drivers/lguest/lguest_device.c @@ -98,6 +98,10 @@ static u32 lg_get_features(struct virtio_device *vdev) return features; } +/* The virtio core takes the features the Host offers, and copies the + * ones supported by the driver into the vdev->features array. Once + * that's all sorted out, this routine is called so we can tell the + * Host which features we understand and accept. */ static void lg_finalize_features(struct virtio_device *vdev) { unsigned int i, bits; @@ -108,6 +112,10 @@ static void lg_finalize_features(struct virtio_device *vdev) /* Give virtio_ring a chance to accept features. */ vring_transport_features(vdev); + /* The vdev->feature array is a Linux bitmask: this isn't the + * same as a the simple array of bits used by lguest devices + * for features. So we do this slow, manual conversion which is + * completely general. */ memset(out_features, 0, desc->feature_len); bits = min_t(unsigned, desc->feature_len, sizeof(vdev->features)) * 8; for (i = 0; i < bits; i++) { |