@@ -259,7 +259,6 @@ static int get_paged_frame(unsigned long gfn, unsigned long *frame,
struct domain *rd)
{
int rc = GNTST_okay;
-#if defined(P2M_PAGED_TYPES) || defined(P2M_SHARED_TYPES)
p2m_type_t p2mt;
*page = get_page_from_gfn(rd, gfn, &p2mt,
@@ -267,26 +266,20 @@ static int get_paged_frame(unsigned long gfn, unsigned long *frame,
if ( !(*page) )
{
*frame = mfn_x(INVALID_MFN);
+#if defined(P2M_SHARED_TYPES)
if ( p2m_is_shared(p2mt) )
return GNTST_eagain;
+#endif
+#if defined(P2M_PAGES_TYPES)
if ( p2m_is_paging(p2mt) )
{
p2m_mem_paging_populate(rd, gfn);
return GNTST_eagain;
}
+#endif
return GNTST_bad_page;
}
*frame = page_to_mfn(*page);
-#else
- *frame = mfn_x(gfn_to_mfn(rd, _gfn(gfn)));
- *page = mfn_valid(_mfn(*frame)) ? mfn_to_page(*frame) : NULL;
- if ( (!(*page)) || (!get_page(*page, rd)) )
- {
- *frame = mfn_x(INVALID_MFN);
- *page = NULL;
- rc = GNTST_bad_page;
- }
-#endif
return rc;
}
The implementation of get_page_frame is currently different whether the architecture support sharing memory or paging memory. Both version are extremely similar so it is possible to consolidate in a single implementation. The check for shared/paged memory are gated with the respective ifdef. Potentially, dummy p2m_is_shared/p2m_is_paging could be implemented for Arm. Signed-off-by: Julien Grall <julien.grall@arm.com> --- Cc: Andrew Cooper <andrew.cooper3@citrix.com> Cc: George Dunlap <George.Dunlap@eu.citrix.com> Cc: Ian Jackson <ian.jackson@eu.citrix.com> Cc: Jan Beulich <jbeulich@suse.com> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: Stefano Stabellini <sstabellini@kernel.org> Cc: Tim Deegan <tim@xen.org> Cc: Wei Liu <wei.liu2@citrix.com> get_page_from_gfn will be able to get reference on foreign page and as per my understanding will allow to grant page on foreign memory. This was not allowed with a simple get_page(...) on the ARM implementation (no sharing nor paging supprot) but is allowed on the x86 implementation due to get_page_from_gfn. On x86, foreign pages are currently only allowed for PVH dom0, so I think it is not a big deal for now. On Arm, foreign pages can be present on any domain. So this patch would permit grant on foreing pages. So I would like to check whether it would be valid to grant a mapping on foreign pages? If not, I could add a check if ( p2m_is_foreign(...) ) return GTNST_bad_page. --- xen/common/grant_table.c | 15 ++++----------- 1 file changed, 4 insertions(+), 11 deletions(-)