Re: [PATCH v2] MdeModulePkg/NonDiscoverablePciDeviceDxe: Allow partial FreeBuffer


Jeff Brasen
 

Adding Leif/Ard to CC incase they have any comments on this patch.

Thanks
Jeff

-----Original Message-----
From: Jeff Brasen
Sent: Friday, June 17, 2022 9:39 AM
To: devel@edk2.groups.io
Cc: hao.a.wu@...; ray.ni@...
Subject: RE: [PATCH v2] MdeModulePkg/NonDiscoverablePciDeviceDxe:
Allow partial FreeBuffer

Any thoughts on this patch?

-----Original Message-----
From: Jeff Brasen <jbrasen@...>
Sent: Monday, February 14, 2022 11:46 AM
To: devel@edk2.groups.io
Cc: hao.a.wu@...; ray.ni@...; Jeff Brasen
<jbrasen@...>
Subject: [PATCH v2] MdeModulePkg/NonDiscoverablePciDeviceDxe: Allow
partial FreeBuffer

Add support for partial free of non cached buffers.
If a request for less than the full size is requested new allocations
for the remaining head and tail of the buffer are added to the list.
Added verification that Buffer is EFI_PAGE_SIZE aligned.
The XHCI driver does this if the page size for the controller is >4KB.

Signed-off-by: Jeff Brasen <jbrasen@...>
---
.../NonDiscoverablePciDeviceIo.c | 53 ++++++++++++++++++-
1 file changed, 51 insertions(+), 2 deletions(-)

diff --git
a/MdeModulePkg/Bus/Pci/NonDiscoverablePciDeviceDxe/NonDiscoverable
PciDeviceIo.c
b/MdeModulePkg/Bus/Pci/NonDiscoverablePciDeviceDxe/NonDiscoverable
PciDeviceIo.c
index c1c5c6267c..77809cfedf 100644
---
a/MdeModulePkg/Bus/Pci/NonDiscoverablePciDeviceDxe/NonDiscoverable
PciDeviceIo.c
+++
b/MdeModulePkg/Bus/Pci/NonDiscoverablePciDeviceDxe/NonDiscoverable
Pc
+++ iDeviceIo.c
@@ -960,12 +960,23 @@ NonCoherentPciIoFreeBuffer (
LIST_ENTRY *Entry;
EFI_STATUS Status;
NON_DISCOVERABLE_DEVICE_UNCACHED_ALLOCATION *Alloc;
+ NON_DISCOVERABLE_DEVICE_UNCACHED_ALLOCATION *AllocHead;
+ NON_DISCOVERABLE_DEVICE_UNCACHED_ALLOCATION *AllocTail;
BOOLEAN Found;
+ UINTN StartPages;
+ UINTN EndPages;
+
+ if (HostAddress != ALIGN_POINTER (HostAddress, EFI_PAGE_SIZE)) {
+ ASSERT_EFI_ERROR (EFI_INVALID_PARAMETER);
+ return EFI_INVALID_PARAMETER;
+ }

Dev = NON_DISCOVERABLE_PCI_DEVICE_FROM_PCI_IO (This);

Found = FALSE;
Alloc = NULL;
+ AllocHead = NULL;
+ AllocTail = NULL;

//
// Find the uncached allocation list entry associated @@ -976,9
+987,13 @@ NonCoherentPciIoFreeBuffer (
Entry = Entry->ForwardLink)
{
Alloc = BASE_CR (Entry,
NON_DISCOVERABLE_DEVICE_UNCACHED_ALLOCATION, List);
- if ((Alloc->HostAddress == HostAddress) && (Alloc->NumPages ==
Pages))
{
+ StartPages = 0;
+ if (Alloc->HostAddress < HostAddress) {
+ StartPages = (HostAddress - Alloc->HostAddress) / EFI_PAGE_SIZE;
+ }
+ if ((Alloc->HostAddress <= HostAddress) && (Alloc->NumPages >=
+ (Pages + StartPages))) {
//
- // We are freeing the exact allocation we were given
+ // We are freeing at least part of what we were given
// before by AllocateBuffer()
//
Found = TRUE;
@@ -991,7 +1006,41 @@ NonCoherentPciIoFreeBuffer (
return EFI_NOT_FOUND;
}

+ EndPages = Alloc->NumPages - (Pages + StartPages);
+
+ if (StartPages != 0) {
+ AllocHead = AllocatePool (sizeof *AllocHead);
+ if (AllocHead == NULL) {
+ return EFI_OUT_OF_RESOURCES;
+ }
+
+ AllocHead->HostAddress = Alloc->HostAddress;
+ AllocHead->NumPages = StartPages;
+ AllocHead->Attributes = Alloc->Attributes; }
+
+ if (EndPages != 0) {
+ AllocTail = AllocatePool (sizeof *AllocTail);
+ if (AllocTail == NULL) {
+ return EFI_OUT_OF_RESOURCES;
+ }
+
+ AllocTail->HostAddress = Alloc->HostAddress + ((Pages +
+ StartPages) *
EFI_PAGE_SIZE);
+ AllocTail->NumPages = EndPages;
+ AllocTail->Attributes = Alloc->Attributes; }
+
RemoveEntryList (&Alloc->List);
+ //
+ // Record this new sub allocations in the linked list, so we //
+ can restore the memory space attributes later // if (AllocHead !=
+ NULL) {
+ InsertHeadList (&Dev->UncachedAllocationList, &AllocHead->List);
+ } if (AllocTail != NULL) {
+ InsertHeadList (&Dev->UncachedAllocationList, &AllocTail->List);
+ }

Status = gDS->SetMemorySpaceAttributes (
(EFI_PHYSICAL_ADDRESS)(UINTN)HostAddress,
--
2.17.1

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