[Xen-devel] [Patch V2 03/15] xen: don't build mfn tree if tools don't need it

[Juergen Gross <jgross@xxxxxxxx>]

In case the Xen tools indicate they don't need the p2m 3 level tree
as they support the virtual mapped linear p2m list, just omit building
the tree.

Signed-off-by: Juergen Gross <jgross@xxxxxxxx>
---
 arch/x86/xen/p2m.c | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/arch/x86/xen/p2m.c b/arch/x86/xen/p2m.c
index 703f803..6f80cd3 100644
--- a/arch/x86/xen/p2m.c
+++ b/arch/x86/xen/p2m.c
@@ -198,7 +198,8 @@ void __ref xen_build_mfn_list_list(void)
        unsigned int level, topidx, mididx;
        unsigned long *mid_mfn_p;
 
-       if (xen_feature(XENFEAT_auto_translated_physmap))
+       if (xen_feature(XENFEAT_auto_translated_physmap) ||
+           xen_start_info->flags & SIF_VIRT_P2M_4TOOLS)
                return;
 
        /* Pre-initialize p2m_top_mfn to be completely missing */
@@ -259,8 +260,11 @@ void xen_setup_mfn_list_list(void)
 
        BUG_ON(HYPERVISOR_shared_info == &xen_dummy_shared_info);
 
-       HYPERVISOR_shared_info->arch.pfn_to_mfn_frame_list_list =
-               virt_to_mfn(p2m_top_mfn);
+       if (xen_start_info->flags & SIF_VIRT_P2M_4TOOLS)
+               HYPERVISOR_shared_info->arch.pfn_to_mfn_frame_list_list = ~0UL;
+       else
+               HYPERVISOR_shared_info->arch.pfn_to_mfn_frame_list_list =
+                       virt_to_mfn(p2m_top_mfn);
        HYPERVISOR_shared_info->arch.max_pfn = xen_max_p2m_pfn;
        HYPERVISOR_shared_info->arch.p2m_generation = 0;
        HYPERVISOR_shared_info->arch.p2m_vaddr = (unsigned long)xen_p2m_addr;
-- 
2.1.4


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