The purpose of writing CR3 in ConvertMemoryPageToNotPresent is just to flush TLB, because CR3 won't be changed in function ConvertMemoryPageToNotPresent. After ConvertMemoryPageToNotPresent, there is always a flush TLB function. Also, because ConvertMemoryPageToNotPresent in called in a loop, to improve performance, there is no need to flush TLB inside ConvertMemoryPageToNotPresent. Just flushing TLB after the loop is enough.
Cc: Ray Ni <ray...@intel.com> Cc: Laszlo Ersek <ler...@redhat.com> Cc: Rahul Kumar <rahul1.ku...@intel.com> Cc: Gerd Hoffmann <kra...@redhat.com> Signed-off-by: Zhiguang Liu <zhiguang....@intel.com> --- UefiCpuPkg/CpuMpPei/CpuPaging.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/UefiCpuPkg/CpuMpPei/CpuPaging.c b/UefiCpuPkg/CpuMpPei/CpuPaging.c index 15c7015fb8..b923d9b502 100644 --- a/UefiCpuPkg/CpuMpPei/CpuPaging.c +++ b/UefiCpuPkg/CpuMpPei/CpuPaging.c @@ -76,7 +76,8 @@ AllocatePageTableMemory ( /** This function modifies the page attributes for the memory region specified - by BaseAddress and Length to not present. + by BaseAddress and Length to not present. This function only change page + table, but not flush TLB. Caller have the responsbility to flush TLB. Caller should make sure BaseAddress and Length is at page boundary. @@ -167,7 +168,6 @@ ConvertMemoryPageToNotPresent ( } ASSERT_EFI_ERROR (Status); - AsmWriteCr3 (PageTable); return Status; } -- 2.31.1.windows.1 -=-=-=-=-=-=-=-=-=-=-=- Groups.io Links: You receive all messages sent to this group. View/Reply Online (#113929): https://edk2.groups.io/g/devel/message/113929 Mute This Topic: https://groups.io/mt/103781133/21656 Group Owner: devel+ow...@edk2.groups.io Unsubscribe: https://edk2.groups.io/g/devel/unsub [arch...@mail-archive.com] -=-=-=-=-=-=-=-=-=-=-=-
