xen/p2m: Create entries in the P2M_MFN trees's to track 1-1 mappings
.. when applicable. We need to track in the p2m_mfn and
p2m_mfn_p the MFNs and pointers, respectivly, for the P2M entries
that are allocated for the identity mappings. Without this,
a PV domain with an E820 that triggers the 1-1 mapping to kick in,
won't be able to be restored as the P2M won't have the identity
mappings.
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
diff --git a/arch/x86/xen/p2m.c b/arch/x86/xen/p2m.c
index 141eb0d..a01e653 100644
--- a/arch/x86/xen/p2m.c
+++ b/arch/x86/xen/p2m.c
@@ -522,11 +522,20 @@
/* Boundary cross-over for the edges: */
if (idx) {
unsigned long *p2m = extend_brk(PAGE_SIZE, PAGE_SIZE);
+ unsigned long *mid_mfn_p;
p2m_init(p2m);
p2m_top[topidx][mididx] = p2m;
+ /* For save/restore we need to MFN of the P2M saved */
+
+ mid_mfn_p = p2m_top_mfn_p[topidx];
+ WARN(mid_mfn_p[mididx] != virt_to_mfn(p2m_missing),
+ "P2M_TOP_P[%d][%d] != MFN of p2m_missing!\n",
+ topidx, mididx);
+ mid_mfn_p[mididx] = virt_to_mfn(p2m);
+
}
return idx != 0;
}
@@ -549,12 +558,29 @@
pfn += P2M_MID_PER_PAGE * P2M_PER_PAGE)
{
unsigned topidx = p2m_top_index(pfn);
- if (p2m_top[topidx] == p2m_mid_missing) {
- unsigned long **mid = extend_brk(PAGE_SIZE, PAGE_SIZE);
+ unsigned long *mid_mfn_p;
+ unsigned long **mid;
+
+ mid = p2m_top[topidx];
+ mid_mfn_p = p2m_top_mfn_p[topidx];
+ if (mid == p2m_mid_missing) {
+ mid = extend_brk(PAGE_SIZE, PAGE_SIZE);
p2m_mid_init(mid);
p2m_top[topidx] = mid;
+
+ BUG_ON(mid_mfn_p != p2m_mid_missing_mfn);
+ }
+ /* And the save/restore P2M tables.. */
+ if (mid_mfn_p == p2m_mid_missing_mfn) {
+ mid_mfn_p = extend_brk(PAGE_SIZE, PAGE_SIZE);
+ p2m_mid_mfn_init(mid_mfn_p);
+
+ p2m_top_mfn_p[topidx] = mid_mfn_p;
+ p2m_top_mfn[topidx] = virt_to_mfn(mid_mfn_p);
+ /* Note: we don't set mid_mfn_p[midix] here,
+ * look in __early_alloc_p2m */
}
}