Re: [PATCH V2] MdeModulePkg/Gcd: Filter gCpu->SetMemoryAttributes() calls

["Yao, Jiewen" <jiewen.yao@intel.com>]

Thanks.

Reviewed-by: Jiewen.yao@intel.com

> -----Original Message-----
> From: edk2-devel [mailto:edk2-devel-bounces@lists.01.org] On Behalf Of Star
> Zeng
> Sent: Wednesday, April 4, 2018 10:08 AM
> To: edk2-devel@lists.01.org
> Cc: Ni, Ruiyu <ruiyu.ni@intel.com>; Yi Li <phoenix.liyi@huawei.com>; Dong, Eric
> <eric.dong@intel.com>; Renhao Liang <liangrenhao@huawei.com>; Gao, Liming
> <liming.gao@intel.com>; Heyi Guo <heyi.guo@linaro.org>; Kinney, Michael D
> <michael.d.kinney@intel.com>; Zeng, Star <star.zeng@intel.com>
> Subject: [edk2] [PATCH V2] MdeModulePkg/Gcd: Filter
> gCpu->SetMemoryAttributes() calls
> 
> From: "Kinney, Michael D" <michael.d.kinney@intel.com>
> 
> This patch fixes an issue with VlvTbltDevicePkg introduced
> by commit 5b91bf82c67b586b9588cbe4bbffa1588f6b5926.
> 
> The history is as below.
> To support heap guard feature,
> 14dde9e903bb9a719ebb8f3381da72b19509bc36
> added support for SetMemorySpaceAttributes() to handle page attributes,
> but after that, a combination of CPU arch attributes and other attributes
> was not allowed anymore, for example, UC + RUNTIME. It is a regression.
> Then 5b91bf82c67b586b9588cbe4bbffa1588f6b5926 was to fix the regression,
> and we thought 0 CPU arch attributes may be used to clear CPU arch
> attributes, so 0 CPU arch attributes was allowed to be sent to
> gCpu->SetMemoryAttributes().
> 
> But some implementation of CPU driver may return error for 0 CPU arch
> attributes. That fails the case that caller just calls
> SetMemorySpaceAttributes() with none CPU arch attributes (for example,
> RUNTIME), and the purpose of the case is not to clear CPU arch attributes.
> 
> This patch filters the call to gCpu->SetMemoryAttributes()
> if the requested attributes is 0.  It also removes the #define
> INVALID_CPU_ARCH_ATTRIBUTES that is no longer used.
> 
> Cc: Heyi Guo <heyi.guo@linaro.org>
> Cc: Yi Li <phoenix.liyi@huawei.com>
> Cc: Renhao Liang <liangrenhao@huawei.com>
> Cc: Star Zeng <star.zeng@intel.com>
> Cc: Eric Dong <eric.dong@intel.com>
> Cc: Liming Gao <liming.gao@intel.com>
> Cc: Jian J Wang <jian.j.wang@intel.com>
> Cc: Ruiyu Ni <ruiyu.ni@intel.com>
> Signed-off-by: Michael D Kinney <michael.d.kinney@intel.com>
> Signed-off-by: Star Zeng <star.zeng@intel.com>
> Contributed-under: TianoCore Contribution Agreement 1.1
> ---
>  MdeModulePkg/Core/Dxe/Gcd/Gcd.c | 25 ++++++++++++++++++++++---
>  1 file changed, 22 insertions(+), 3 deletions(-)
> 
> diff --git a/MdeModulePkg/Core/Dxe/Gcd/Gcd.c
> b/MdeModulePkg/Core/Dxe/Gcd/Gcd.c
> index 907245a3f512..31ddf9c3bb51 100644
> --- a/MdeModulePkg/Core/Dxe/Gcd/Gcd.c
> +++ b/MdeModulePkg/Core/Dxe/Gcd/Gcd.c
> @@ -48,8 +48,6 @@ WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY
> KIND, EITHER EXPRESS OR IMPLIED.
>  #define NONEXCLUSIVE_MEMORY_ATTRIBUTES (EFI_MEMORY_XP |
> EFI_MEMORY_RP | \
>                                          EFI_MEMORY_RO)
> 
> -#define INVALID_CPU_ARCH_ATTRIBUTES   0xffffffff
> -
>  //
>  // Module Variables
>  //
> @@ -873,7 +871,21 @@ CoreConvertSpace (
>      // Call CPU Arch Protocol to attempt to set attributes on the range
>      //
>      CpuArchAttributes = ConverToCpuArchAttributes (Attributes);
> -    if (CpuArchAttributes != INVALID_CPU_ARCH_ATTRIBUTES) {
> +    //
> +    // CPU arch attributes include page attributes and cache attributes.
> +    // Only page attributes supports to be cleared, but not cache attributes.
> +    // Caller is expected to use GetMemorySpaceDescriptor() to get the current
> +    // attributes, AND/OR attributes, and then calls
> SetMemorySpaceAttributes()
> +    // to set the new attributes.
> +    // So 0 CPU arch attributes should not happen as memory should always
> have
> +    // a cache attribute (no matter UC or WB, etc).
> +    //
> +    // Here, 0 CPU arch attributes will be filtered to be compatible with the
> +    // case that caller just calls SetMemorySpaceAttributes() with none CPU
> +    // arch attributes (for example, RUNTIME) as the purpose of the case is not
> +    // to clear CPU arch attributes.
> +    //
> +    if (CpuArchAttributes != 0) {
>        if (gCpu == NULL) {
>          Status = EFI_NOT_AVAILABLE_YET;
>        } else {
> @@ -936,6 +948,13 @@ CoreConvertSpace (
>      // Set attributes operation
>      //
>      case GCD_SET_ATTRIBUTES_MEMORY_OPERATION:
> +      if (CpuArchAttributes == 0) {
> +        //
> +        // Keep original CPU arch attributes when caller just calls
> +        // SetMemorySpaceAttributes() with none CPU arch attributes (for
> example, RUNTIME).
> +        //
> +        Attributes |= (Entry->Attributes &
> (EXCLUSIVE_MEMORY_ATTRIBUTES | NONEXCLUSIVE_MEMORY_ATTRIBUTES));
> +      }
>        Entry->Attributes = Attributes;
>        break;
>      //
> --
> 2.7.0.windows.1
> 
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