From 7b1257946080b63421a8dc59c7b3dfd67997c643 Mon Sep 17 00:00:00 2001 From: Keir Fraser Date: Tue, 29 Jan 2008 15:18:27 +0000 Subject: minios: Fix bug when blkfront reading into zero-mapped buffer by just poking the page. No need to use virtual_to_mfn() for the ring since that is a real page. Signed-off-by: Samuel Thibault --- extras/mini-os/blkfront.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) (limited to 'extras/mini-os/blkfront.c') diff --git a/extras/mini-os/blkfront.c b/extras/mini-os/blkfront.c index 7fff105635..0c77d6d1e4 100644 --- a/extras/mini-os/blkfront.c +++ b/extras/mini-os/blkfront.c @@ -88,7 +88,7 @@ struct blkfront_dev *init_blkfront(char *nodename, uint64_t *sectors, unsigned * SHARED_RING_INIT(s); FRONT_RING_INIT(&dev->ring, s, PAGE_SIZE); - dev->ring_ref = gnttab_grant_access(0,virtual_to_mfn(s),0); + dev->ring_ref = gnttab_grant_access(0,virt_to_mfn(s),0); evtchn_alloc_unbound_t op; op.dom = DOMID_SELF; @@ -274,6 +274,11 @@ void blkfront_aio(struct blkfront_aiocb *aiocbp, int write) for (j = 0; j < n; j++) { uintptr_t data = start + j * PAGE_SIZE; + if (!write) { + /* Trigger CoW if needed */ + *(char*)data = 0; + barrier(); + } aiocbp->gref[j] = req->seg[j].gref = gnttab_grant_access(0, virtual_to_mfn(data), write); req->seg[j].first_sect = 0; -- cgit v1.2.3