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xen pvfb: Inhibit VM_IO flag to be set on vmalloc-ed framebuffers. 

In Xen-paravirt mode, VM_IO flag signifies that the page frame number (PFN)
is actually a machine frame number (MFN). This is correct for memory backed by
PCI devices, but wrong for memory allocated from System RAM where the PFN
!= MFN.

During page faults, pages with VM_IO, get assigned to special domain I/O
domain and as said, the PFN is interpreted as MFN. When Xen hypervisor
modifies the PTE it interprets the PFN as the MFN, complains and
fails the PTE modification.

The end result is an infinitive page fault in the domain.

Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
This commit is contained in:
Konrad Rzeszutek Wilk 2009-12-03 10:31:57 -05:00 committed by Jeremy Fitzhardinge
parent a9b5ff99c3
commit df11303c90
1 changed files with 1 additions and 1 deletions
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2
drivers/video/xen-fbfront.c
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@ -440,7 +440,7 @@ static int __devinit xenfb_probe(struct xenbus_device *dev,
fb_info->fix.type = FB_TYPE_PACKED_PIXELS;
fb_info->fix.accel = FB_ACCEL_NONE;
fb_info->flags = FBINFO_FLAG_DEFAULT;
fb_info->flags = FBINFO_FLAG_DEFAULT | FBINFO_VIRTFB;
ret = fb_alloc_cmap(&fb_info->cmap, 256, 0);
if (ret < 0) {