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| author | Julien Grall <julien.grall@citrix.com> | 2015-08-07 19:34:37 +0300 |
|---|---|---|
| committer | Julien Grall <julien.grall@citrix.com> | 2015-09-08 20:03:49 +0300 |
| commit | 0df4f266b3af90442bbeb5e685a84a80745beba0 (patch) | |
| tree | 6516dbebc85a0e204b1e619466b3fbff6d14c3f3 /drivers/tty | |
| parent | 5192b35de47e47a0f736fe30da199f32030680e7 (diff) | |
| download | linux-0df4f266b3af90442bbeb5e685a84a80745beba0.tar.xz | |
xen: Use correctly the Xen memory terminologies
Based on include/xen/mm.h [1], Linux is mistakenly using MFN when GFN
is meant, I suspect this is because the first support for Xen was for
PV. This resulted in some misimplementation of helpers on ARM and
confused developers about the expected behavior.
For instance, with pfn_to_mfn, we expect to get an MFN based on the name.
Although, if we look at the implementation on x86, it's returning a GFN.
For clarity and avoid new confusion, replace any reference to mfn with
gfn in any helpers used by PV drivers. The x86 code will still keep some
reference of pfn_to_mfn which may be used by all kind of guests
No changes as been made in the hypercall field, even
though they may be invalid, in order to keep the same as the defintion
in xen repo.
Note that page_to_mfn has been renamed to xen_page_to_gfn to avoid a
name to close to the KVM function gfn_to_page.
Take also the opportunity to simplify simple construction such
as pfn_to_mfn(page_to_pfn(page)) into xen_page_to_gfn. More complex clean up
will come in follow-up patches.
[1] http://xenbits.xen.org/gitweb/?p=xen.git;a=commitdiff;h=e758ed14f390342513405dd766e874934573e6cb
Signed-off-by: Julien Grall <julien.grall@citrix.com>
Reviewed-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Acked-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Diffstat (limited to 'drivers/tty')
| -rw-r--r-- | drivers/tty/hvc/hvc_xen.c | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/drivers/tty/hvc/hvc_xen.c b/drivers/tty/hvc/hvc_xen.c index a9d837f83ce8..efe5124a368d 100644 --- a/drivers/tty/hvc/hvc_xen.c +++ b/drivers/tty/hvc/hvc_xen.c @@ -265,7 +265,8 @@ static int xen_pv_console_init(void) return 0; } info->evtchn = xen_start_info->console.domU.evtchn; - info->intf = mfn_to_virt(xen_start_info->console.domU.mfn); + /* GFN == MFN for PV guest */ + info->intf = gfn_to_virt(xen_start_info->console.domU.mfn); info->vtermno = HVC_COOKIE; spin_lock(&xencons_lock); @@ -390,7 +391,7 @@ static int xencons_connect_backend(struct xenbus_device *dev, if (IS_ERR(info->hvc)) return PTR_ERR(info->hvc); if (xen_pv_domain()) - mfn = virt_to_mfn(info->intf); + mfn = virt_to_gfn(info->intf); else mfn = __pa(info->intf) >> PAGE_SHIFT; ret = gnttab_alloc_grant_references(1, &gref_head); |