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authorJulien Grall <julien.grall@citrix.com>2015-08-07 17:34:37 +0100
committerJulien Grall <julien.grall@citrix.com>2015-09-08 18:03:49 +0100
commit0df4f266b3af90442bbeb5e685a84a80745beba0 (patch)
tree6516dbebc85a0e204b1e619466b3fbff6d14c3f3 /drivers/tty/hvc
parent5192b35de47e47a0f736fe30da199f32030680e7 (diff)
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/hvc')
-rw-r--r--drivers/tty/hvc/hvc_xen.c5
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);