Re: [PATCH v2] UefiCpuPkg/CpuDxe: Fix multiple entries of RT_CODE in memory map

[Laszlo Ersek <lersek@redhat.com>]

sorry about the late response

On 11/03/17 01:57, Jian J Wang wrote:
>> v2
>> a. Fix an issue which will cause setting capability failure if size is smaller
>>    than a page.
> 
> More than one entry of RT_CODE memory might cause boot problem for some
> old OSs. This patch will fix this issue to keep OS compatibility as much
> as possible.
> 
> More detailed information, please refer to
>     https://bugzilla.tianocore.org/show_bug.cgi?id=753
> 
> Cc: Eric Dong <eric.dong@intel.com>
> Cc: Jiewen Yao <jiewen.yao@intel.com>
> Cc: Laszlo Ersek <lersek@redhat.com>
> Contributed-under: TianoCore Contribution Agreement 1.1
> Signed-off-by: Jian J Wang <jian.j.wang@intel.com>
> ---
>  UefiCpuPkg/CpuDxe/CpuPageTable.c | 18 ++++++++++++++----
>  1 file changed, 14 insertions(+), 4 deletions(-)
> 
> diff --git a/UefiCpuPkg/CpuDxe/CpuPageTable.c b/UefiCpuPkg/CpuDxe/CpuPageTable.c
> index d312eb66f8..4a7827ebc9 100644
> --- a/UefiCpuPkg/CpuDxe/CpuPageTable.c
> +++ b/UefiCpuPkg/CpuDxe/CpuPageTable.c
> @@ -809,7 +809,9 @@ RefreshGcdMemoryAttributesFromPaging (
>    PageLength    = 0;
>  
>    for (Index = 0; Index < NumberOfDescriptors; Index++) {
> -    if (MemorySpaceMap[Index].GcdMemoryType == EfiGcdMemoryTypeNonExistent) {
> +    if (MemorySpaceMap[Index].GcdMemoryType == EfiGcdMemoryTypeNonExistent
> +        || (MemorySpaceMap[Index].BaseAddress & EFI_PAGE_MASK) != 0
> +        || (MemorySpaceMap[Index].Length & EFI_PAGE_MASK) != 0) {
>        continue;
>      }

When exactly do the new conditions match?

I thought the base addresses and the lengths in the GCD memory space map
are all page aligned. Is that not the case?

If these conditions are just a sanity check (i.e. we never expect them
to fire), then should we perpahs turn them into ASSERT()s?

>  
> @@ -829,6 +831,15 @@ RefreshGcdMemoryAttributesFromPaging (
>      // Sync real page attributes to GCD
>      BaseAddress       = MemorySpaceMap[Index].BaseAddress;
>      MemorySpaceLength = MemorySpaceMap[Index].Length;
> +    Capabilities      = MemorySpaceMap[Index].Capabilities |
> +                        EFI_MEMORY_PAGETYPE_MASK;
> +    Status = gDS->SetMemorySpaceCapabilities (
> +                    BaseAddress,
> +                    MemorySpaceLength,
> +                    Capabilities
> +                    );
> +    ASSERT_EFI_ERROR (Status);
> +

OK, so I guess we simply add EFI_MEMORY_PAGETYPE_MASK to the
capabilities of all memory space map entries that have a type different
from non-existent. We discussed it before and (apparently) it is
considered safe.

>      while (MemorySpaceLength > 0) {
>        if (PageLength == 0) {
>          PageEntry = GetPageTableEntry (&PagingContext, BaseAddress, &PageAttribute);
> @@ -846,7 +857,6 @@ RefreshGcdMemoryAttributesFromPaging (
>          if (Attributes != (MemorySpaceMap[Index].Attributes & EFI_MEMORY_PAGETYPE_MASK)) {
>            DoUpdate = TRUE;
>            Attributes |= (MemorySpaceMap[Index].Attributes & ~EFI_MEMORY_PAGETYPE_MASK);
> -          Capabilities = Attributes | MemorySpaceMap[Index].Capabilities;
>          } else {
>            DoUpdate = FALSE;
>          }
> @@ -854,8 +864,8 @@ RefreshGcdMemoryAttributesFromPaging (
>  
>        Length = MIN (PageLength, MemorySpaceLength);
>        if (DoUpdate) {
> -        gDS->SetMemorySpaceCapabilities (BaseAddress, Length, Capabilities);
> -        gDS->SetMemorySpaceAttributes (BaseAddress, Length, Attributes);
> +        Status = gDS->SetMemorySpaceAttributes (BaseAddress, Length, Attributes);
> +        ASSERT_EFI_ERROR (Status);
>          DEBUG ((DEBUG_INFO, "Update memory space attribute: [%02d] %016lx - %016lx (%08lx -> %08lx)\r\n",
>                               Index, BaseAddress, BaseAddress + Length - 1,
>                               MemorySpaceMap[Index].Attributes, Attributes));
> 

I'll let you decide about the EFI_PAGE_MASK conditions near the top.

Acked-by: Laszlo Ersek <lersek@redhat.com>

Thanks
Laszlo