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UefiCpuPkg/PiSmmCpuDxeSmm: don't free page table pages that are required to handle current page fault 

Reclaim may free page table pages that are required to handle current page
fault. This causes a page leak, and, after sufficent number of specific
page fault+reclaim pairs, we run out of reclaimable pages and hit:

ASSERT (MinAcc != (UINT64)-1);

To remedy, prevent pages essential to handling current page fault:
(1) from being considered as reclaim candidates (first reclaim phase)
(2) from being freed as part of "branch cleanup" (second reclaim phase)

Signed-off-by: Damian Nikodem <damian.nikodem@intel.com>
Cc: Eric Dong <eric.dong@intel.com>
Reviewed-by: Ray Ni <ray.ni@intel.com>
Reviewed-by: Jian J Wang <jian.j.wang@intel.com>
Cc: Laszlo Ersek <lersek@redhat.com>
Cc: Krzysztof Rusocki <krzysztof.rusocki@intel.com>
This commit is contained in:
Damian Nikodem 2019-08-20 01:48:45 +08:00 committed by Ray Ni
parent ada905ab5c
commit 4201098e97
1 changed files with 60 additions and 41 deletions
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29
UefiCpuPkg/PiSmmCpuDxeSmm/X64/PageTbl.c
View File

@ -544,6 +544,11 @@ ReclaimPages (
UINT64 *ReleasePageAddress;
IA32_CR4 Cr4;
BOOLEAN Enable5LevelPaging;
UINT64 PFAddress;
UINT64 PFAddressPml5Index;
UINT64 PFAddressPml4Index;
UINT64 PFAddressPdptIndex;
UINT64 PFAddressPdtIndex;
Pml4 = NULL;
Pdpt = NULL;
@ -555,6 +560,11 @@ ReclaimPages (
MinPdt = (UINTN)-1;
Acc = 0;
ReleasePageAddress = 0;
PFAddress = AsmReadCr2 ();
PFAddressPml5Index = BitFieldRead64 (PFAddress, 48, 48 + 8);
PFAddressPml4Index = BitFieldRead64 (PFAddress, 39, 39 + 8);
PFAddressPdptIndex = BitFieldRead64 (PFAddress, 30, 30 + 8);
PFAddressPdtIndex = BitFieldRead64 (PFAddress, 21, 21 + 8);
Cr4.UintN = AsmReadCr4 ();
Enable5LevelPaging = (BOOLEAN) (Cr4.Bits.LA57 == 1);
@ -629,6 +639,8 @@ ReclaimPages (
// we will find the entry has the smallest access record value
//
PDPTEIgnore = TRUE;
if (PdtIndex != PFAddressPdtIndex || PdptIndex != PFAddressPdptIndex ||
Pml4Index != PFAddressPml4Index || Pml5Index != PFAddressPml5Index) {
Acc = GetAndUpdateAccNum (Pdt + PdtIndex);
if (Acc < MinAcc) {
//
@ -644,11 +656,14 @@ ReclaimPages (
}
}
}
}
if (!PDPTEIgnore) {
//
// If this PDPT entry has no PDT entries pointer to 4 KByte pages,
// it should only has the entries point to 2 MByte Pages
//
if (PdptIndex != PFAddressPdptIndex || Pml4Index != PFAddressPml4Index ||
Pml5Index != PFAddressPml5Index) {
Acc = GetAndUpdateAccNum (Pdpt + PdptIndex);
if (Acc < MinAcc) {
//
@ -665,11 +680,13 @@ ReclaimPages (
}
}
}
}
if (!PML4EIgnore) {
//
// If PML4 entry has no the PDPT entry pointer to 2 MByte pages,
// it should only has the entries point to 1 GByte Pages
//
if (Pml4Index != PFAddressPml4Index || Pml5Index != PFAddressPml5Index) {
Acc = GetAndUpdateAccNum (Pml4 + Pml4Index);
if (Acc < MinAcc) {
//
@ -686,6 +703,7 @@ ReclaimPages (
}
}
}
}
//
// Make sure one PML4/PDPT/PD entry is selected
//
@ -709,7 +727,8 @@ ReclaimPages (
Pml4 = (UINT64 *) (UINTN) (Pml5[MinPml5] & gPhyMask);
Pdpt = (UINT64*)(UINTN)(Pml4[MinPml4] & ~mAddressEncMask & gPhyMask);
SubEntriesNum = GetSubEntriesNum(Pdpt + MinPdpt);
if (SubEntriesNum == 0) {
if (SubEntriesNum == 0 &&
(MinPdpt != PFAddressPdptIndex || MinPml4 != PFAddressPml4Index || MinPml5 != PFAddressPml5Index)) {
//
// Release the empty Page Directory table if there was no more 4 KByte Page Table entry
// clear the Page directory entry
@ -725,7 +744,7 @@ ReclaimPages (
//
// Update the sub-entries filed in PDPT entry and exit
//
SetSubEntriesNum (Pdpt + MinPdpt, SubEntriesNum - 1);
SetSubEntriesNum (Pdpt + MinPdpt, (SubEntriesNum - 1) & 0x1FF);
break;
}
if (MinPdpt != (UINTN)-1) {
@ -733,7 +752,7 @@ ReclaimPages (
// One 2MB Page Table is released or Page Directory table is released, check the PML4 entry
//
SubEntriesNum = GetSubEntriesNum (Pml4 + MinPml4);
if (SubEntriesNum == 0) {
if (SubEntriesNum == 0 && (MinPml4 != PFAddressPml4Index || MinPml5 != PFAddressPml5Index)) {
//
// Release the empty PML4 table if there was no more 1G KByte Page Table entry
// clear the Page directory entry
@ -746,7 +765,7 @@ ReclaimPages (
//
// Update the sub-entries filed in PML4 entry and exit
//
SetSubEntriesNum (Pml4 + MinPml4, SubEntriesNum - 1);
SetSubEntriesNum (Pml4 + MinPml4, (SubEntriesNum - 1) & 0x1FF);
break;
}
//
@ -919,7 +938,7 @@ SmiDefaultPFHandler (
PageTable[PTIndex] = ((PFAddress | mAddressEncMask) & gPhyMask & ~((1ull << EndBit) - 1)) |
PageAttribute | IA32_PG_A | PAGE_ATTRIBUTE_BITS;
if (UpperEntry != NULL) {
SetSubEntriesNum (UpperEntry, GetSubEntriesNum (UpperEntry) + 1);
SetSubEntriesNum (UpperEntry, (GetSubEntriesNum (UpperEntry) + 1) & 0x1FF);
}
//
// Get the next page address if we need to create more page tables