[edk2-devel] UefiCpuPkg/PiSmmCpuDxeSmm: don't free page table pages that are required to handle current page fault
Krzysztof Rusocki
krzysztof.rusocki at intel.com
Mon Aug 5 21:57:32 UTC 2019
From: Damian Nikodem <damian.nikodem at intel.com>
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 at intel.com>
Cc: Eric Dong <eric.dong at intel.com>
Cc: Ray Ni <ray.ni at intel.com>
Cc: Jian J Wang <jian.j.wang at intel.com>
Cc: Laszlo Ersek <lersek at redhat.com>
Cc: Krzysztof Rusocki <krzysztof.rusocki at intel.com>
diff --git a/UefiCpuPkg/PiSmmCpuDxeSmm/X64/PageTbl.c b/UefiCpuPkg/PiSmmCpuDxeSmm/X64/PageTbl.c
index a3b62f7787..f11323f439 100644
--- a/UefiCpuPkg/PiSmmCpuDxeSmm/X64/PageTbl.c
+++ b/UefiCpuPkg/PiSmmCpuDxeSmm/X64/PageTbl.c
@@ -543,6 +543,11 @@ ReclaimPages (
UINT64 *ReleasePageAddress;
IA32_CR4 Cr4;
BOOLEAN Enable5LevelPaging;
+ UINT64 PFAddress;
+ UINT64 PFAddressPml5Index;
+ UINT64 PFAddressPml4Index;
+ UINT64 PFAddressPdptIndex;
+ UINT64 PFAddressPdtIndex;
Pml4 = NULL;
Pdpt = NULL;
@@ -554,6 +559,11 @@ 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);
@@ -628,40 +638,46 @@ ReclaimPages (
// we will find the entry has the smallest access record value
//
PDPTEIgnore = TRUE;
- Acc = GetAndUpdateAccNum (Pdt + PdtIndex);
+ if (PdtIndex != PFAddressPdtIndex || PdptIndex != PFAddressPdptIndex ||
+ Pml4Index != PFAddressPml4Index || Pml5Index != PFAddressPml5Index) {
+ Acc = GetAndUpdateAccNum (Pdt + PdtIndex);
+ if (Acc < MinAcc) {
+ //
+ // If the PD entry has the smallest access record value,
+ // save the Page address to be released
+ //
+ MinAcc = Acc;
+ MinPml5 = Pml5Index;
+ MinPml4 = Pml4Index;
+ MinPdpt = PdptIndex;
+ MinPdt = PdtIndex;
+ ReleasePageAddress = Pdt + PdtIndex;
+ }
+ }
+ }
+ }
+ 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) {
//
- // If the PD entry has the smallest access record value,
+ // If the PDPT entry has the smallest access record value,
// save the Page address to be released
//
MinAcc = Acc;
MinPml5 = Pml5Index;
MinPml4 = Pml4Index;
MinPdpt = PdptIndex;
- MinPdt = PdtIndex;
- ReleasePageAddress = Pdt + PdtIndex;
+ MinPdt = (UINTN)-1;
+ ReleasePageAddress = Pdpt + PdptIndex;
}
}
}
- 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
- //
- Acc = GetAndUpdateAccNum (Pdpt + PdptIndex);
- if (Acc < MinAcc) {
- //
- // If the PDPT entry has the smallest access record value,
- // save the Page address to be released
- //
- MinAcc = Acc;
- MinPml5 = Pml5Index;
- MinPml4 = Pml4Index;
- MinPdpt = PdptIndex;
- MinPdt = (UINTN)-1;
- ReleasePageAddress = Pdpt + PdptIndex;
- }
- }
}
}
if (!PML4EIgnore) {
@@ -669,18 +685,20 @@ ReclaimPages (
// If PML4 entry has no the PDPT entry pointer to 2 MByte pages,
// it should only has the entries point to 1 GByte Pages
//
- Acc = GetAndUpdateAccNum (Pml4 + Pml4Index);
- if (Acc < MinAcc) {
- //
- // If the PML4 entry has the smallest access record value,
- // save the Page address to be released
- //
- MinAcc = Acc;
- MinPml5 = Pml5Index;
- MinPml4 = Pml4Index;
- MinPdpt = (UINTN)-1;
- MinPdt = (UINTN)-1;
- ReleasePageAddress = Pml4 + Pml4Index;
+ if (Pml4Index != PFAddressPml4Index || Pml5Index != PFAddressPml5Index) {
+ Acc = GetAndUpdateAccNum (Pml4 + Pml4Index);
+ if (Acc < MinAcc) {
+ //
+ // If the PML4 entry has the smallest access record value,
+ // save the Page address to be released
+ //
+ MinAcc = Acc;
+ MinPml5 = Pml5Index;
+ MinPml4 = Pml4Index;
+ MinPdpt = (UINTN)-1;
+ MinPdt = (UINTN)-1;
+ ReleasePageAddress = Pml4 + Pml4Index;
+ }
}
}
}
@@ -708,7 +726,8 @@ 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
@@ -724,7 +743,7 @@ 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) {
@@ -732,7 +751,7 @@ 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
@@ -745,7 +764,7 @@ ReclaimPages (
//
// Update the sub-entries filed in PML4 entry and exit
//
- SetSubEntriesNum (Pml4 + MinPml4, SubEntriesNum - 1);
+ SetSubEntriesNum (Pml4 + MinPml4, (SubEntriesNum - 1) & 0x1FF);
break;
}
//
@@ -918,7 +937,7 @@ 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
--------------------------------------------------------------------
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