virtio: use LGUEST_VRING_ALIGN instead of relying on pagesize
This doesn't really matter, since lguest is i386 only at the moment,
but we could actually choose a different value. (lguest doesn't have
a guarenteed ABI).
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
diff --git a/Documentation/lguest/lguest.c b/Documentation/lguest/lguest.c
index 8045206..aa2574c 100644
--- a/Documentation/lguest/lguest.c
+++ b/Documentation/lguest/lguest.c
@@ -1030,7 +1030,7 @@
/* Zero out the virtqueues. */
for (vq = dev->vq; vq; vq = vq->next) {
memset(vq->vring.desc, 0,
- vring_size(vq->config.num, getpagesize()));
+ vring_size(vq->config.num, LGUEST_VRING_ALIGN));
lg_last_avail(vq) = 0;
}
} else if (dev->desc->status & VIRTIO_CONFIG_S_FAILED) {
@@ -1211,7 +1211,7 @@
void *p;
/* First we need some memory for this virtqueue. */
- pages = (vring_size(num_descs, getpagesize()) + getpagesize() - 1)
+ pages = (vring_size(num_descs, LGUEST_VRING_ALIGN) + getpagesize() - 1)
/ getpagesize();
p = get_pages(pages);
@@ -1228,7 +1228,7 @@
vq->config.pfn = to_guest_phys(p) / getpagesize();
/* Initialize the vring. */
- vring_init(&vq->vring, num_descs, p, getpagesize());
+ vring_init(&vq->vring, num_descs, p, LGUEST_VRING_ALIGN);
/* Append virtqueue to this device's descriptor. We use
* device_config() to get the end of the device's current virtqueues;
diff --git a/drivers/lguest/lguest_device.c b/drivers/lguest/lguest_device.c
index a661bbd..f062dc5 100644
--- a/drivers/lguest/lguest_device.c
+++ b/drivers/lguest/lguest_device.c
@@ -250,7 +250,7 @@
/* Figure out how many pages the ring will take, and map that memory */
lvq->pages = lguest_map((unsigned long)lvq->config.pfn << PAGE_SHIFT,
DIV_ROUND_UP(vring_size(lvq->config.num,
- PAGE_SIZE),
+ LGUEST_VRING_ALIGN),
PAGE_SIZE));
if (!lvq->pages) {
err = -ENOMEM;
diff --git a/include/linux/lguest_launcher.h b/include/linux/lguest_launcher.h
index e7217dc..bd0eba7 100644
--- a/include/linux/lguest_launcher.h
+++ b/include/linux/lguest_launcher.h
@@ -59,4 +59,8 @@
LHREQ_IRQ, /* + irq */
LHREQ_BREAK, /* + on/off flag (on blocks until someone does off) */
};
+
+/* The alignment to use between consumer and producer parts of vring.
+ * x86 pagesize for historical reasons. */
+#define LGUEST_VRING_ALIGN 4096
#endif /* _LINUX_LGUEST_LAUNCHER */