diff options
authorKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>2012-08-17 16:43:28 -0400
committerKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>2012-08-23 10:14:52 -0400
commitc96aae1f7f393387d160211f60398d58463a7e65 (patch)
parent250a41e0ecc433cdd553a364d0fc74c766425209 (diff)
xen/setup: Fix one-off error when adding for-balloon PFNs to the P2M.
When we are finished with return PFNs to the hypervisor, then populate it back, and also mark the E820 MMIO and E820 gaps as IDENTITY_FRAMEs, we then call P2M to set areas that can be used for ballooning. We were off by one, and ended up over-writting a P2M entry that most likely was an IDENTITY_FRAME. For example: 1-1 mapping on 40000->40200 1-1 mapping on bc558->bc5ac 1-1 mapping on bc5b4->bc8c5 1-1 mapping on bc8c6->bcb7c 1-1 mapping on bcd00->100000 Released 614 pages of unused memory Set 277889 page(s) to 1-1 mapping Populating 40200-40466 pfn range: 614 pages added => here we set from 40466 up to bc559 P2M tree to be INVALID_P2M_ENTRY. We should have done it up to bc558. The end result is that if anybody is trying to construct a PTE for PFN bc558 they end up with ~PAGE_PRESENT. CC: stable@vger.kernel.org Reported-by-and-Tested-by: Andre Przywara <andre.przywara@amd.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
1 files changed, 8 insertions, 1 deletions
diff --git a/arch/x86/xen/setup.c b/arch/x86/xen/setup.c
index ead85576d54a..d11ca11d14fc 100644
--- a/arch/x86/xen/setup.c
+++ b/arch/x86/xen/setup.c
@@ -78,9 +78,16 @@ static void __init xen_add_extra_mem(u64 start, u64 size)
memblock_reserve(start, size);
xen_max_p2m_pfn = PFN_DOWN(start + size);
+ for (pfn = PFN_DOWN(start); pfn < xen_max_p2m_pfn; pfn++) {
+ unsigned long mfn = pfn_to_mfn(pfn);
+ if (WARN(mfn == pfn, "Trying to over-write 1-1 mapping (pfn: %lx)\n", pfn))
+ continue;
+ WARN(mfn != INVALID_P2M_ENTRY, "Trying to remove %lx which has %lx mfn!\n",
+ pfn, mfn);
- for (pfn = PFN_DOWN(start); pfn <= xen_max_p2m_pfn; pfn++)
__set_phys_to_machine(pfn, INVALID_P2M_ENTRY);
+ }
static unsigned long __init xen_do_chunk(unsigned long start,