These calls are not the same in general: the former will dequeue the
page if it is enqueued, while the latter will just leave it alone. But,
all existing uses of the former apply to unmanaged pages, which are
never enqueued in the first place. No functional change intended.
Reviewed by: kib
MFC after: 1 week
Sponsored by: Netflix
Differential Revision: https://reviews.freebsd.org/D20470
The type represents byte offset in the vm_object_t data space, which
does not span negative offsets in FreeBSD VM. The change matches byte
offset signess with the unsignedness of the vm_pindex_t which
represents the type of the page indexes in the objects.
This allows to remove the UOFF_TO_IDX() macro which was used when we
have to forcibly interpret the type as unsigned anyway. Also it fixes
a lot of implicit bugs in the device drivers d_mmap methods.
Reviewed by: alc, markj (previous version)
Tested by: pho
MFC after: 2 weeks
Sponsored by: The FreeBSD Foundation
Current interface to the gntdev in FreeBSD is wrong, and mostly worked
out of luck before the PTI FreeBSD fixes, when kernel and user-space
where sharing the same page tables.
On FreeBSD ioctls have the size of the passed struct encoded in the
ioctl number, because the generic ioctl handler in the OS takes care
of copying the data from user-space to kernel space, and then calls
the device specific ioctl handler. Thus using ioctl structs with
variable sizes is not possible.
The fix is to turn the array of structs at the end of
ioctl_gntdev_alloc_gref and ioctl_gntdev_map_grant_ref into pointers,
that can be properly accessed from the kernel gntdev driver using the
copyin/copyout functions. Note that this is exactly how it's done for
the privcmd driver.
Sponsored by: Citrix Systems R&D
vm_map_lookup_done should only be called when the gntdev has finished poking at
the entry.
Reported by: alc
Reviewed by: alc
MFC after: 1 week
Sponsored by: Citrix Systems R&D
The Xen grant table device treats the mmap offset parameter as an unsigned
type, and as so it must use the newly introduced UOFF_TO_IDX.
Sponsored by: Citrix Systems R&D
MFC after: 2 weeks
X-MFC-with: r313690
A grant-table user-space device will allow user-space applications to map
and share grants (Xen way to share memory) among Xen domains. This grant
table user-space device has been tested with the QEMU Qdisk Xen backed.
Submitted by: jaggi
Reviewed by: royger
Differential review: https://reviews.freebsd.org/D7293
