From 30a25f277821a1c8a168f6f3050721aa13f44b8d Mon Sep 17 00:00:00 2001 From: Zhou Jianfeng Date: Fri, 2 Feb 2024 22:20:09 +0800 Subject: UefiCpuPkg: Reduce and optimize access to attribute This commit is to reduce and optimize access to attribute in CpuPageTableLib. Unreasonable writing to attribute of page table may leads to expection. The assembly code for C code Pnle->Bits.Present = Attribute->Bits.Present looks like: and dword [rcx], 0xfffffffe and eax, 0x1 or [rcx], eax In case Pnle->Bits.Present and Attribute->Bits.Present is 1, Pnle->Bits.Present will be set to 0 for short time(2 instructions) which is unexpected. If some other core is accessing the page, it may leads to expection. This change reduce and optimize access to attribute of page table, attribute of page table is set only when it need to be changed. Signed-off-by: Zhou Jianfeng Reviewed-by: Ray Ni Reviewed-by: Jiaxin Wu Cc: Laszlo Ersek Cc: Rahul Kumar Cc: Gerd Hoffmann --- .../Library/CpuPageTableLib/CpuPageTableMap.c | 86 +++++++++++++--------- 1 file changed, 53 insertions(+), 33 deletions(-) (limited to 'UefiCpuPkg') diff --git a/UefiCpuPkg/Library/CpuPageTableLib/CpuPageTableMap.c b/UefiCpuPkg/Library/CpuPageTableLib/CpuPageTableMap.c index 36b2c4e6a3..ae4caf8dfe 100644 --- a/UefiCpuPkg/Library/CpuPageTableLib/CpuPageTableMap.c +++ b/UefiCpuPkg/Library/CpuPageTableLib/CpuPageTableMap.c @@ -26,52 +26,59 @@ PageTableLibSetPte4K ( IN IA32_MAP_ATTRIBUTE *Mask ) { + IA32_PTE_4K LocalPte4K; + + LocalPte4K.Uint64 = Pte4K->Uint64; if (Mask->Bits.PageTableBaseAddressLow || Mask->Bits.PageTableBaseAddressHigh) { - Pte4K->Uint64 = (IA32_MAP_ATTRIBUTE_PAGE_TABLE_BASE_ADDRESS (Attribute) + Offset) | (Pte4K->Uint64 & ~IA32_PE_BASE_ADDRESS_MASK_40); + LocalPte4K.Uint64 = (IA32_MAP_ATTRIBUTE_PAGE_TABLE_BASE_ADDRESS (Attribute) + Offset) | (Pte4K->Uint64 & ~IA32_PE_BASE_ADDRESS_MASK_40); } if (Mask->Bits.Present) { - Pte4K->Bits.Present = Attribute->Bits.Present; + LocalPte4K.Bits.Present = Attribute->Bits.Present; } if (Mask->Bits.ReadWrite) { - Pte4K->Bits.ReadWrite = Attribute->Bits.ReadWrite; + LocalPte4K.Bits.ReadWrite = Attribute->Bits.ReadWrite; } if (Mask->Bits.UserSupervisor) { - Pte4K->Bits.UserSupervisor = Attribute->Bits.UserSupervisor; + LocalPte4K.Bits.UserSupervisor = Attribute->Bits.UserSupervisor; } if (Mask->Bits.WriteThrough) { - Pte4K->Bits.WriteThrough = Attribute->Bits.WriteThrough; + LocalPte4K.Bits.WriteThrough = Attribute->Bits.WriteThrough; } if (Mask->Bits.CacheDisabled) { - Pte4K->Bits.CacheDisabled = Attribute->Bits.CacheDisabled; + LocalPte4K.Bits.CacheDisabled = Attribute->Bits.CacheDisabled; } if (Mask->Bits.Accessed) { - Pte4K->Bits.Accessed = Attribute->Bits.Accessed; + LocalPte4K.Bits.Accessed = Attribute->Bits.Accessed; } if (Mask->Bits.Dirty) { - Pte4K->Bits.Dirty = Attribute->Bits.Dirty; + LocalPte4K.Bits.Dirty = Attribute->Bits.Dirty; } if (Mask->Bits.Pat) { - Pte4K->Bits.Pat = Attribute->Bits.Pat; + LocalPte4K.Bits.Pat = Attribute->Bits.Pat; } if (Mask->Bits.Global) { - Pte4K->Bits.Global = Attribute->Bits.Global; + LocalPte4K.Bits.Global = Attribute->Bits.Global; } if (Mask->Bits.ProtectionKey) { - Pte4K->Bits.ProtectionKey = Attribute->Bits.ProtectionKey; + LocalPte4K.Bits.ProtectionKey = Attribute->Bits.ProtectionKey; } if (Mask->Bits.Nx) { - Pte4K->Bits.Nx = Attribute->Bits.Nx; + LocalPte4K.Bits.Nx = Attribute->Bits.Nx; + } + + if (Pte4K->Uint64 != LocalPte4K.Uint64) { + Pte4K->Uint64 = LocalPte4K.Uint64; } } @@ -93,54 +100,61 @@ PageTableLibSetPleB ( IN IA32_MAP_ATTRIBUTE *Mask ) { + IA32_PAGE_LEAF_ENTRY_BIG_PAGESIZE LocalPleB; + + LocalPleB.Uint64 = PleB->Uint64; if (Mask->Bits.PageTableBaseAddressLow || Mask->Bits.PageTableBaseAddressHigh) { - PleB->Uint64 = (IA32_MAP_ATTRIBUTE_PAGE_TABLE_BASE_ADDRESS (Attribute) + Offset) | (PleB->Uint64 & ~IA32_PE_BASE_ADDRESS_MASK_39); + LocalPleB.Uint64 = (IA32_MAP_ATTRIBUTE_PAGE_TABLE_BASE_ADDRESS (Attribute) + Offset) | (PleB->Uint64 & ~IA32_PE_BASE_ADDRESS_MASK_39); } - PleB->Bits.MustBeOne = 1; + LocalPleB.Bits.MustBeOne = 1; if (Mask->Bits.Present) { - PleB->Bits.Present = Attribute->Bits.Present; + LocalPleB.Bits.Present = Attribute->Bits.Present; } if (Mask->Bits.ReadWrite) { - PleB->Bits.ReadWrite = Attribute->Bits.ReadWrite; + LocalPleB.Bits.ReadWrite = Attribute->Bits.ReadWrite; } if (Mask->Bits.UserSupervisor) { - PleB->Bits.UserSupervisor = Attribute->Bits.UserSupervisor; + LocalPleB.Bits.UserSupervisor = Attribute->Bits.UserSupervisor; } if (Mask->Bits.WriteThrough) { - PleB->Bits.WriteThrough = Attribute->Bits.WriteThrough; + LocalPleB.Bits.WriteThrough = Attribute->Bits.WriteThrough; } if (Mask->Bits.CacheDisabled) { - PleB->Bits.CacheDisabled = Attribute->Bits.CacheDisabled; + LocalPleB.Bits.CacheDisabled = Attribute->Bits.CacheDisabled; } if (Mask->Bits.Accessed) { - PleB->Bits.Accessed = Attribute->Bits.Accessed; + LocalPleB.Bits.Accessed = Attribute->Bits.Accessed; } if (Mask->Bits.Dirty) { - PleB->Bits.Dirty = Attribute->Bits.Dirty; + LocalPleB.Bits.Dirty = Attribute->Bits.Dirty; } if (Mask->Bits.Pat) { - PleB->Bits.Pat = Attribute->Bits.Pat; + LocalPleB.Bits.Pat = Attribute->Bits.Pat; } if (Mask->Bits.Global) { - PleB->Bits.Global = Attribute->Bits.Global; + LocalPleB.Bits.Global = Attribute->Bits.Global; } if (Mask->Bits.ProtectionKey) { - PleB->Bits.ProtectionKey = Attribute->Bits.ProtectionKey; + LocalPleB.Bits.ProtectionKey = Attribute->Bits.ProtectionKey; } if (Mask->Bits.Nx) { - PleB->Bits.Nx = Attribute->Bits.Nx; + LocalPleB.Bits.Nx = Attribute->Bits.Nx; + } + + if (PleB->Uint64 != LocalPleB.Uint64) { + PleB->Uint64 = LocalPleB.Uint64; } } @@ -186,24 +200,27 @@ PageTableLibSetPnle ( IN IA32_MAP_ATTRIBUTE *Mask ) { + IA32_PAGE_NON_LEAF_ENTRY LocalPnle; + + LocalPnle.Uint64 = Pnle->Uint64; if (Mask->Bits.Present) { - Pnle->Bits.Present = Attribute->Bits.Present; + LocalPnle.Bits.Present = Attribute->Bits.Present; } if (Mask->Bits.ReadWrite) { - Pnle->Bits.ReadWrite = Attribute->Bits.ReadWrite; + LocalPnle.Bits.ReadWrite = Attribute->Bits.ReadWrite; } if (Mask->Bits.UserSupervisor) { - Pnle->Bits.UserSupervisor = Attribute->Bits.UserSupervisor; + LocalPnle.Bits.UserSupervisor = Attribute->Bits.UserSupervisor; } if (Mask->Bits.Nx) { - Pnle->Bits.Nx = Attribute->Bits.Nx; + LocalPnle.Bits.Nx = Attribute->Bits.Nx; } - Pnle->Bits.Accessed = 0; - Pnle->Bits.MustBeZero = 0; + LocalPnle.Bits.Accessed = 0; + LocalPnle.Bits.MustBeZero = 0; // // Set the attributes (WT, CD, A) to 0. @@ -211,8 +228,11 @@ PageTableLibSetPnle ( // So, it implictly requires PAT[0] is Write Back. // Create a new parameter if caller requires to use a different memory type for accessing page directories. // - Pnle->Bits.WriteThrough = 0; - Pnle->Bits.CacheDisabled = 0; + LocalPnle.Bits.WriteThrough = 0; + LocalPnle.Bits.CacheDisabled = 0; + if (Pnle->Uint64 != LocalPnle.Uint64) { + Pnle->Uint64 = LocalPnle.Uint64; + } } /** -- cgit v1.2.3