Re: [edk2-devel] [PATCH v3 13/39] UefiCpuPkg: Add CpuMmuLib.h to UefiCpuPkg

["Ni, Ray" <ray.ni@intel.com>]

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Thanks. I think we are aligned. Looking forward to your v4 patch.

Thanks,
Ray
From: devel@edk2.groups.io <devel@edk2.groups.io> On Behalf Of Chao Li
Sent: Friday, December 8, 2023 10:10 AM
To: Ni, Ray <ray.ni@intel.com>; devel@edk2.groups.io
Cc: Dong, Eric <eric.dong@intel.com>; Kumar, Rahul R <rahul.r.kumar@intel.com>; Gerd Hoffmann <kraxel@redhat.com>; Leif Lindholm <quic_llindhol@quicinc.com>; Ard Biesheuvel <ardb+tianocore@kernel.org>; Sami Mujawar <sami.mujawar@arm.com>; Sunil V L <sunilvl@ventanamicro.com>; Warkentin, Andrei <andrei.warkentin@intel.com>
Subject: Re: [edk2-devel] [PATCH v3 13/39] UefiCpuPkg: Add CpuMmuLib.h to UefiCpuPkg


Hi Ray,

Do you think this plan is OK? If possible, I will submit the V4 today.

Thanks,
Chao
On 2023/12/5 20:27, Chao Li wrote:

Hi Ray,
On 2023/12/5 16:27, Ni, Ray wrote:


Thanks,
Ray
From: devel@edk2.groups.io<mailto:devel@edk2.groups.io> <devel@edk2.groups.io><mailto:devel@edk2.groups.io> On Behalf Of Chao Li
Sent: Monday, December 4, 2023 3:32 PM
To: devel@edk2.groups.io<mailto:devel@edk2.groups.io>; Ni, Ray <ray.ni@intel.com><mailto:ray.ni@intel.com>
Cc: Dong, Eric <eric.dong@intel.com><mailto:eric.dong@intel.com>; Kumar, Rahul R <rahul.r.kumar@intel.com><mailto:rahul.r.kumar@intel.com>; Gerd Hoffmann <kraxel@redhat.com><mailto:kraxel@redhat.com>; Leif Lindholm <quic_llindhol@quicinc.com><mailto:quic_llindhol@quicinc.com>; Ard Biesheuvel <ardb+tianocore@kernel.org><mailto:ardb+tianocore@kernel.org>; Sami Mujawar <sami.mujawar@arm.com><mailto:sami.mujawar@arm.com>; Sunil V L <sunilvl@ventanamicro.com><mailto:sunilvl@ventanamicro.com>; Warkentin, Andrei <andrei.warkentin@intel.com><mailto:andrei.warkentin@intel.com>
Subject: Re: [edk2-devel] [PATCH v3 13/39] UefiCpuPkg: Add CpuMmuLib.h to UefiCpuPkg


Hi Ray,

For this patch, I checked again and here are my opinions:

  1.  (Set|Get)MemoryRegionAttribute is difficult to merge together, because the parameters between the tow APIs are not similar. So I suggest they be independent.

[Ray] What I mean is to merge SetMemoryRegion(NonExec|ReadOly) to SetMemoryRegionAttribute(). Similarly, GetXXX can be merged as well. What’s your opinion?
Ok, I already said it in point 2, other APIs will be removed.


  1.  The EfiAttributeConverse, GetMemoryRegionAttribute, SetMemoryRegionAttributes and ConfigureMemoryManagementUnit will be retained and other APIs will be removed. Because the functions expressed by other APIs can be completed though the retained API.

[Ray] I didn’t notice EfiAttributeConverse(). I guess callers may not need to know the architectural specific attributes. So EfiAttributeConverse() might be not needed as a public API.
I agree, the EfiAttributeCoverse() complete by caller or as a private API.


  1.  You pointed out MEMORY_REGION_DESCRIPTOR have no one to construct it, do I need add a new API to construct it? Could it be named GetMemoryMapPolicy and accept a parameter with MEMORY_REGION_DESCRIPTOR** ?

[Ray] So the GetMemoryRegionAttribute() and SetMemoryRegionAttributes() are performed on the active translation table. ConfigureMemoryManagementUint() is to create a translation table with a list of memory attributes. How about the following idea?

[Ray] (Set|Get)MemoryRegionAttribute() are performed on a translation table buffer. And caller calls SetMemoryRegionAttribute() to modify the translation table buffer supplied as the parameter. With this, ConfigureMemoryManagementUnit() is not needed.

Ah, I think you may have some misunderstanding, the ConfigureMemoryManagementUint is a function that to initialize the MMU. The MEMORY_REGION_DESCRIPTOR will created by the private API, and then the caller will call the ConfigureMemoryManagementUnit to initialize the MMU first(may be fill the static page tables and so on).

But I thought about it again and it seems you are right, the ConfigureMemoryManagementUnit and discrptor creater as the public APIs are not appropriate. They are more suitable as some private APIs.

So, (Get|Set)MemoryRegionAttribute() will be the public APIs and the parameters will be the same with this change?

Hope to hear from you! :)

Thanks,
Chao
On 2023/11/30 10:25, Chao Li wrote:

Hi Ray,

Thanks for review, here are some of my thoughts:
On 2023/11/30 08:59, Ni, Ray wrote:

Chao,

Since the lib class is so general, I'd like to understand more details to make sure it can properly fit into any CPU arch.



In X86, cache setting is through MSRs and Page tables, and memory access control (read-only, not-present, non-executable) is through page tables.
Let me understand, 'cache setting' means does it access a certain address(probably a memory address) via cache? If so, I'd say the 'cache setting' should be a part of attributes.



This CpuMmuLib is to provide both services. How does LoongArch64 manage the cache settings and memory access control?

Is it proper to combine both services into one lib?
In LoongArch64, cache settings and memory access control are performed via page tables. Please check the patch 14 of this series.



If the backend silicon IP is the same one that supports the "one" lib design, can we refine the lib API a bit?
Yes, I think Attribute's instance family can be bear the memory access and cache setting. So what are you suggestions if we improve the lib API?



We have (Set|Get)MemoryRegionAttribute() and (Set|Clear)MemoryRegion(NoExec|ReadOnly). Can we merge them together?
Do you means the (Set|Get) merge together(differentiate Get or Set operations by parameters)? If so, I think it's OK, but maybe some existing instances will be modified together.



And the API ConfigureMemoryManagementUint() accepts MEMORY_REGION_DESCRIPTOR but none of other APIs helps to construct the descriptor.
Yes, currently, no one helps construct MEMORY_REGION_DESCRIPTOR. I think the construction of descriptors is not part of the API, it should be the localized or private when I design them. Do I need to add an API to construct descripters?



It seems to me the MmuLib is simply a combination of different random APIs.

It's not a well-designed library class.



We need more discussion to make it be able to be accommodated by other archs in future, at least by figuring out the path of X86, ARM.
Yes, the APIs looks like so fragmented and we should improve them. So we should talk more about this API, thanks.



Thanks,

Ray

-----Original Message-----

From: Chao Li <lichao@loongson.cn><mailto:lichao@loongson.cn>

Sent: Friday, November 17, 2023 6:00 PM

To: devel@edk2.groups.io<mailto:devel@edk2.groups.io>

Cc: Dong, Eric <eric.dong@intel.com><mailto:eric.dong@intel.com>; Ni, Ray <ray.ni@intel.com><mailto:ray.ni@intel.com>; Kumar,

Rahul R <rahul.r.kumar@intel.com><mailto:rahul.r.kumar@intel.com>; Gerd Hoffmann <kraxel@redhat.com><mailto:kraxel@redhat.com>;

Leif Lindholm <quic_llindhol@quicinc.com><mailto:quic_llindhol@quicinc.com>; Ard Biesheuvel

<ardb+tianocore@kernel.org><mailto:ardb+tianocore@kernel.org>; Sami Mujawar <sami.mujawar@arm.com><mailto:sami.mujawar@arm.com>;

Sunil V L <sunilvl@ventanamicro.com><mailto:sunilvl@ventanamicro.com>; Warkentin, Andrei

<andrei.warkentin@intel.com><mailto:andrei.warkentin@intel.com>

Subject: [PATCH v3 13/39] UefiCpuPkg: Add CpuMmuLib.h to UefiCpuPkg



Add a new header file CpuMmuLib.h, whitch is referenced from

ArmPkg/Include/Library/ArmMmuLib.h. Currently, only support for

LoongArch64 is added, and more architectures can be accommodated in the

future.



BZ: https://bugzilla.tianocore.org/show_bug.cgi?id=4584



Cc: Eric Dong <eric.dong@intel.com><mailto:eric.dong@intel.com>

Cc: Ray Ni <ray.ni@intel.com><mailto:ray.ni@intel.com>

Cc: Rahul Kumar <rahul1.kumar@intel.com><mailto:rahul1.kumar@intel.com>

Cc: Gerd Hoffmann <kraxel@redhat.com><mailto:kraxel@redhat.com>

Cc: Leif Lindholm <quic_llindhol@quicinc.com><mailto:quic_llindhol@quicinc.com>

Cc: Ard Biesheuvel <ardb+tianocore@kernel.org><mailto:ardb+tianocore@kernel.org>

Cc: Sami Mujawar <sami.mujawar@arm.com><mailto:sami.mujawar@arm.com>

Cc: Sunil V L <sunilvl@ventanamicro.com><mailto:sunilvl@ventanamicro.com>

Cc: Andrei Warkentin <andrei.warkentin@intel.com><mailto:andrei.warkentin@intel.com>

Signed-off-by: Chao Li <lichao@loongson.cn><mailto:lichao@loongson.cn>

---

 UefiCpuPkg/Include/Library/CpuMmuLib.h | 155

+++++++++++++++++++++++++

 UefiCpuPkg/UefiCpuPkg.dec              |   4 +

 2 files changed, 159 insertions(+)

 create mode 100644 UefiCpuPkg/Include/Library/CpuMmuLib.h



diff --git a/UefiCpuPkg/Include/Library/CpuMmuLib.h

b/UefiCpuPkg/Include/Library/CpuMmuLib.h

new file mode 100644

index 0000000000..23b2fe34ac

--- /dev/null

+++ b/UefiCpuPkg/Include/Library/CpuMmuLib.h

@@ -0,0 +1,155 @@

+/** @file

+

+  Copyright (c) 2023 Loongson Technology Corporation Limited. All rights

reserved.<BR>

+

+  SPDX-License-Identifier: BSD-2-Clause-Patent

+

+**/

+

+#ifndef CPU_MMU_LIB_H_

+#define CPU_MMU_LIB_H_

+

+#include <Uefi/UefiBaseType.h>

+

+#define EFI_MEMORY_CACHETYPE_MASK  (EFI_MEMORY_UC  | \

+                                    EFI_MEMORY_WC  | \

+                                    EFI_MEMORY_WT  | \

+                                    EFI_MEMORY_WB  | \

+                                    EFI_MEMORY_UCE   \

+                                    )

+

+typedef struct {

+  EFI_PHYSICAL_ADDRESS    PhysicalBase;

+  EFI_VIRTUAL_ADDRESS     VirtualBase;

+  UINTN                   Length;

+  UINTN                   Attributes;

+} MEMORY_REGION_DESCRIPTOR;

+

+/**

+  Converts EFI Attributes to corresponding architecture Attributes.

+

+  @param[in]  EfiAttributes     Efi Attributes.

+

+  @retval  Corresponding architecture attributes.

+**/

+UINTN

+EfiAttributeConverse (

+  IN UINTN  EfiAttributes

+  );

+

+/**

+  Finds the length and memory properties of the memory region

corresponding to the specified base address.

+

+  @param[in]  BaseAddress    To find the base address of the memory

region.

+  @param[in]  EndAddress     To find the end address of the memory

region.

+  @param[out]  RegionLength    The length of the memory region

found.

+  @param[out]  RegionAttributes    Properties of the memory region

found.

+

+  @retval  EFI_SUCCESS    The corresponding memory area was

successfully found

+           EFI_NOT_FOUND    No memory area found

+**/

+EFI_STATUS

+GetMemoryRegionAttribute (

+  IN     UINTN  BaseAddress,

+  IN     UINTN  EndAddress,

+  OUT    UINTN  *RegionLength,

+  OUT    UINTN  *RegionAttributes

+  );

+

+/**

+  Sets the Attributes  of the specified memory region

+

+  @param[in]  BaseAddress    The base address of the memory region

to set the Attributes.

+  @param[in]  Length         The length of the memory region to set

the Attributes.

+  @param[in]  Attributes     The Attributes to be set.

+  @param[in]  AttributeMask  Mask of memory attributes to take into

account.

+

+  @retval  EFI_SUCCESS    The Attributes was set successfully

+**/

+EFI_STATUS

+SetMemoryRegionAttributes (

+  IN EFI_PHYSICAL_ADDRESS  BaseAddress,

+  IN UINTN                 Length,

+  IN UINTN                 Attributes,

+  IN UINT64                AttributeMask

+  );

+

+/**

+  Sets the non-executable Attributes for the specified memory region

+

+  @param[in]  BaseAddress  The base address of the memory region to

set the Attributes.

+  @param[in]  Length       The length of the memory region to set the

Attributes.

+

+  @retval  EFI_SUCCESS    The Attributes was set successfully

+**/

+EFI_STATUS

+SetMemoryRegionNoExec (

+  IN  EFI_PHYSICAL_ADDRESS  BaseAddress,

+  IN  UINTN                 Length

+  );

+

+/**

+  Clears the non-executable Attributes for the specified memory region

+

+  @param[in]  BaseAddress  The base address of the memory region to

clear the Attributes.

+  @param[in]  Length       The length of the memory region to clear

the Attributes.

+

+  @retval  EFI_SUCCESS    The Attributes was clear successfully

+**/

+EFI_STATUS

+EFIAPI

+ClearMemoryRegionNoExec (

+  IN  EFI_PHYSICAL_ADDRESS  BaseAddress,

+  IN  UINT64                Length

+  );

+

+/**

+  Sets the read-only Attributes for the specified memory region

+

+  @param[in]  BaseAddress  The base address of the memory region to

set the Attributes.

+  @param[in]  Length       The length of the memory region to set the

Attributes.

+

+  @retval  EFI_SUCCESS    The Attributes was set successfully

+**/

+EFI_STATUS

+EFIAPI

+SetMemoryRegionReadOnly (

+  IN  EFI_PHYSICAL_ADDRESS  BaseAddress,

+  IN  UINT64                Length

+  );

+

+/**

+  Clears the read-only Attributes for the specified memory region

+

+  @param[in]  BaseAddress  The base address of the memory region to

clear the Attributes.

+  @param[in]  Length       The length of the memory region to clear

the Attributes.

+

+  @retval  EFI_SUCCESS    The Attributes was clear successfully

+**/

+EFI_STATUS

+EFIAPI

+ClearMemoryRegionReadOnly (

+  IN  EFI_PHYSICAL_ADDRESS  BaseAddress,

+  IN  UINT64                Length

+  );

+

+/**

+  Create a page table and initialize the memory management unit(MMU).

+

+  @param[in]  MemoryTable           A pointer to a memory ragion

table.

+  @param[out] TranslationTableBase  A pointer to a translation table base

address.

+  @param[out] TranslationTableSize  A pointer to a translation table base

size.

+

+  @retval  EFI_SUCCESS                Configure MMU successfully.

+           EFI_INVALID_PARAMETER      MemoryTable is NULL.

+           EFI_UNSUPPORTED            Out of memory space or

size not aligned.

+**/

+EFI_STATUS

+EFIAPI

+ConfigureMemoryManagementUint (

+  IN  MEMORY_REGION_DESCRIPTOR  *MemoryTable,

+  OUT VOID                      **TranslationTableBase OPTIONAL,

+  OUT UINTN                     *TranslationTableSize  OPTIONAL

+  );

+

+#endif // CPU_MMU_LIB_H_

diff --git a/UefiCpuPkg/UefiCpuPkg.dec b/UefiCpuPkg/UefiCpuPkg.dec

index 154b1d06fe..150beae981 100644

--- a/UefiCpuPkg/UefiCpuPkg.dec

+++ b/UefiCpuPkg/UefiCpuPkg.dec

@@ -62,6 +62,10 @@

   ##  @libraryclass  Provides function for manipulating x86 paging

structures.

   CpuPageTableLib|Include/Library/CpuPageTableLib.h



+[LibraryClasses.LoongArch64]

+  ##  @libraryclass  Provides macros and functions for the memory

management unit.

+  CpuMmuLib|Include/Library/CpuMmuLib.h

+

   ## @libraryclass   Provides functions for manipulating smram savestate

registers.

   MmSaveStateLib|Include/Library/MmSaveStateLib.h



--

2.27.0





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