From nobody Fri Dec 27 18:50:20 2024 Delivered-To: importer@patchew.org Received-SPF: none (zoho.com: 198.145.21.10 is neither permitted nor denied by domain of lists.01.org) client-ip=198.145.21.10; envelope-from=edk2-devel-bounces@lists.01.org; helo=ml01.01.org; Authentication-Results: mx.zohomail.com; spf=none (zoho.com: 198.145.21.10 is neither permitted nor denied by domain of lists.01.org) smtp.mailfrom=edk2-devel-bounces@lists.01.org Return-Path: Received: from ml01.01.org (ml01.01.org [198.145.21.10]) by mx.zohomail.com with SMTPS id 1501709135156718.0860849919649; Wed, 2 Aug 2017 14:25:35 -0700 (PDT) Received: from [127.0.0.1] (localhost [IPv6:::1]) by ml01.01.org (Postfix) with ESMTP id 2283E209589F6; Wed, 2 Aug 2017 14:23:13 -0700 (PDT) Received: from mx1.redhat.com (mx1.redhat.com [209.132.183.28]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ml01.01.org (Postfix) with ESMTPS id 2F9DA209589D0 for ; Wed, 2 Aug 2017 14:23:11 -0700 (PDT) Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 9652983F40; Wed, 2 Aug 2017 21:25:21 +0000 (UTC) Received: from lacos-laptop-7.usersys.redhat.com (ovpn-116-47.phx2.redhat.com [10.3.116.47]) by smtp.corp.redhat.com (Postfix) with ESMTP id 1B4EF17B57; Wed, 2 Aug 2017 21:25:19 +0000 (UTC) X-Original-To: edk2-devel@lists.01.org DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com 9652983F40 Authentication-Results: ext-mx03.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com Authentication-Results: ext-mx03.extmail.prod.ext.phx2.redhat.com; spf=fail smtp.mailfrom=lersek@redhat.com From: Laszlo Ersek To: edk2-devel-01 Date: Wed, 2 Aug 2017 23:24:51 +0200 Message-Id: <20170802212453.19221-11-lersek@redhat.com> In-Reply-To: <20170802212453.19221-1-lersek@redhat.com> References: <20170802212453.19221-1-lersek@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.27]); Wed, 02 Aug 2017 21:25:21 +0000 (UTC) Subject: [edk2] [PATCH 10/12] OvmfPkg/IoMmuDxe: implement in-place decryption/encryption for Map/Unmap X-BeenThere: edk2-devel@lists.01.org X-Mailman-Version: 2.1.22 Precedence: list List-Id: EDK II Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Jordan Justen , Tom Lendacky , Ard Biesheuvel MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Errors-To: edk2-devel-bounces@lists.01.org Sender: "edk2-devel" X-ZohoMail: RSF_4 Z_629925259 SPT_0 Content-Type: text/plain; charset="utf-8" At the moment, we have the following distribution of actions between the IOMMU protocol member functions: - AllocateBuffer() allocates pages and clears the memory encryption mask. - FreeBuffer() re-sets the memory encryption mask, and deallocates pages. - Map() does nothing at all when BusMasterCommonBuffer[64] is requested (and AllocateBuffer() was called previously). Otherwise, Map() allocates pages, and clears the memory encryption mask. - Unmap() does nothing when cleaning up a BusMasterCommonBuffer[64] operation. Otherwise, Unmap() clears the encryption mask, and frees the pages. This is wrong: the AllocateBuffer() protocol member is not expected to produce a buffer that is immediately usable, and client code is required to call Map() unconditionally, even if BusMasterCommonBuffer[64] is the desired operation. Implement the right distribution of actions as follows: - AllocateBuffer() allocates pages and does not touch the encryption mask. - FreeBuffer() deallocates pages and does not touch the encryption mask. - Map() does not allocate pages when BusMasterCommonBuffer[64] is requested, and it allocates pages (bounce buffer) otherwise. Regardless of the BusMaster operation, Map() (and Map() only) clears the memory encryption mask. - Unmap() restores the encryption mask unconditionally. If the operation was BusMasterCommonBuffer[64], then Unmap() does not release the pages. Otherwise, the pages (bounce buffer) are released. This approach also ensures that Unmap() can be called from ExitBootServices() event handlers, for cleaning up BusMasterCommonBuffer[64] operations. (More specifically, for restoring the SEV encryption mask on any in-flight buffers, after resetting any referring devices.) ExitBootServices() event handlers must not change the UEFI memory map, thus any memory allocation or freeing in Unmap() would disqualify Unmap() from being called in such a context. Map()-ing and Unmap()-ing memory for a BusMasterCommonBuffer[64] operation effectively means in-place decryption and encryption in a SEV context. As an additional hurdle, section "7.10.8 Encrypt-in-Place" of AMD publication Nr.24593 implies that we need a separate temporary buffer for decryption and encryption that will eventually land in-place. Allocating said temporary buffer in the straightforward way would violate the above allocation/freeing restrictions on Map()/Unmap(), therefore pre-allocate this "stash buffer" too in AllocateBuffer(), and free it in FreeBuffer(). To completely rid Unmap() of dynamic memory impact, for BusMasterCommonBuffer[64] operations, we're going to rework the lifecycle of the MAP_INFO structures in a later patch. (The MemEncryptSevSetPageEncMask() call in Unmap() could theoretically allocate memory internally for page splitting, however this won't happen in practice: in Unmap() we only restore the memory encryption mask, and don't genuinely set it. Any page splitting will have occurred in Map()'s MemEncryptSevClearPageEncMask() call first.) Cc: Ard Biesheuvel Cc: Brijesh Singh Cc: Jordan Justen Cc: Tom Lendacky Contributed-under: TianoCore Contribution Agreement 1.0 Signed-off-by: Laszlo Ersek --- OvmfPkg/IoMmuDxe/AmdSevIoMmu.c | 242 +++++++++++++++----- 1 file changed, 185 insertions(+), 57 deletions(-) diff --git a/OvmfPkg/IoMmuDxe/AmdSevIoMmu.c b/OvmfPkg/IoMmuDxe/AmdSevIoMmu.c index 0a85ee6559e7..5049d19e9cb7 100644 --- a/OvmfPkg/IoMmuDxe/AmdSevIoMmu.c +++ b/OvmfPkg/IoMmuDxe/AmdSevIoMmu.c @@ -23,40 +23,64 @@ typedef struct { EDKII_IOMMU_OPERATION Operation; UINTN NumberOfBytes; UINTN NumberOfPages; EFI_PHYSICAL_ADDRESS CryptedAddress; EFI_PHYSICAL_ADDRESS PlainTextAddress; } MAP_INFO; =20 -#define NO_MAPPING (VOID *) (UINTN) -1 +#define COMMON_BUFFER_SIG SIGNATURE_64 ('C', 'M', 'N', 'B', 'U', 'F', 'F',= 'R') + +// +// The following structure enables Map() and Unmap() to perform in-place +// decryption and encryption, respectively, for BusMasterCommonBuffer[64] +// operations, without dynamic memory allocation or release. +// +// Both COMMON_BUFFER_HEADER and COMMON_BUFFER_HEADER.StashBuffer are allo= cated +// by AllocateBuffer() and released by FreeBuffer(). +// +#pragma pack (1) +typedef struct { + UINT64 Signature; + + // + // Always allocated from EfiBootServicesData type memory, and always + // encrypted. + // + VOID *StashBuffer; + + // + // Followed by the actual common buffer, starting at the next page. + // +} COMMON_BUFFER_HEADER; +#pragma pack () =20 /** Provides the controller-specific addresses required to access system mem= ory from a DMA bus master. On SEV guest, the DMA operations must be performe= d on shared buffer hence we allocate a bounce buffer to map the HostAddress t= o a DeviceAddress. The Encryption attribute is removed from the DeviceAddress buffer. =20 @param This The protocol instance pointer. @param Operation Indicates if the bus master is going to re= ad or write to system memory. @param HostAddress The system memory address to map to the PCI controller. @param NumberOfBytes On input the number of bytes to map. On ou= tput the number of bytes that were mapped. @param DeviceAddress The resulting map address for the bus mast= er PCI controller to use to access the hosts HostAddress. @param Mapping A resulting value to pass to Unmap(). =20 @retval EFI_SUCCESS The range was mapped for the returned NumberOfBytes. @retval EFI_UNSUPPORTED The HostAddress cannot be mapped as a comm= on buffer. @retval EFI_INVALID_PARAMETER One or more parameters are invalid. @retval EFI_OUT_OF_RESOURCES The request could not be completed due to a lack of resources. @retval EFI_DEVICE_ERROR The system hardware could not map the requ= ested address. =20 **/ @@ -65,157 +89,175 @@ EFIAPI IoMmuMap ( IN EDKII_IOMMU_PROTOCOL *This, IN EDKII_IOMMU_OPERATION Operation, IN VOID *HostAddress, IN OUT UINTN *NumberOfBytes, OUT EFI_PHYSICAL_ADDRESS *DeviceAddress, OUT VOID **Mapping ) { EFI_STATUS Status; MAP_INFO *MapInfo; EFI_ALLOCATE_TYPE AllocateType; + COMMON_BUFFER_HEADER *CommonBufferHeader; + VOID *DecryptionSource; =20 if (HostAddress =3D=3D NULL || NumberOfBytes =3D=3D NULL || DeviceAddres= s =3D=3D NULL || Mapping =3D=3D NULL) { return EFI_INVALID_PARAMETER; } =20 // // Allocate a MAP_INFO structure to remember the mapping when Unmap() is // called later. // MapInfo =3D AllocatePool (sizeof (MAP_INFO)); if (MapInfo =3D=3D NULL) { Status =3D EFI_OUT_OF_RESOURCES; goto Failed; } =20 // // Initialize the MAP_INFO structure, except the PlainTextAddress field // MapInfo->Operation =3D Operation; MapInfo->NumberOfBytes =3D *NumberOfBytes; MapInfo->NumberOfPages =3D EFI_SIZE_TO_PAGES (MapInfo->NumberOfBytes= ); MapInfo->CryptedAddress =3D (UINTN)HostAddress; =20 // // In the switch statement below, we point "MapInfo->PlainTextAddress" t= o the - // plaintext buffer, according to Operation. + // plaintext buffer, according to Operation. We also set "DecryptionSour= ce". // MapInfo->PlainTextAddress =3D MAX_ADDRESS; AllocateType =3D AllocateAnyPages; + DecryptionSource =3D (VOID *)(UINTN)MapInfo->CryptedAddress; switch (Operation) { // // For BusMasterRead[64] and BusMasterWrite[64] operations, a bounce buf= fer // is necessary regardless of whether the original (crypted) buffer cros= ses // the 4GB limit or not -- we have to allocate a separate plaintext buff= er. // The only variable is whether the plaintext buffer should be under 4GB. // case EdkiiIoMmuOperationBusMasterRead: case EdkiiIoMmuOperationBusMasterWrite: MapInfo->PlainTextAddress =3D BASE_4GB - 1; AllocateType =3D AllocateMaxAddress; // // fall through // case EdkiiIoMmuOperationBusMasterRead64: case EdkiiIoMmuOperationBusMasterWrite64: // // Allocate the implicit plaintext bounce buffer. // Status =3D gBS->AllocatePages ( AllocateType, EfiBootServicesData, MapInfo->NumberOfPages, &MapInfo->PlainTextAddress ); if (EFI_ERROR (Status)) { goto FreeMapInfo; } break; =20 // - // For BusMasterCommonBuffer[64] operations, a plaintext buffer has been - // allocated already, with AllocateBuffer(). We only check whether the - // address is low enough for the requested operation. + // For BusMasterCommonBuffer[64] operations, a to-be-plaintext buffer an= d a + // stash buffer (for in-place decryption) have been allocated already, w= ith + // AllocateBuffer(). We only check whether the address of the to-be-plai= ntext + // buffer is low enough for the requested operation. // case EdkiiIoMmuOperationBusMasterCommonBuffer: if ((MapInfo->CryptedAddress > BASE_4GB) || (EFI_PAGES_TO_SIZE (MapInfo->NumberOfPages) > BASE_4GB - MapInfo->CryptedAddress)) { // // CommonBuffer operations cannot be remapped. If the common buffer = is // above 4GB, then it is not possible to generate a mapping, so retu= rn an // error. // Status =3D EFI_UNSUPPORTED; goto FreeMapInfo; } // // fall through // case EdkiiIoMmuOperationBusMasterCommonBuffer64: // - // The buffer at MapInfo->CryptedAddress comes from AllocateBuffer(), - // and it is already decrypted. + // The buffer at MapInfo->CryptedAddress comes from AllocateBuffer(). // MapInfo->PlainTextAddress =3D MapInfo->CryptedAddress; - // - // Therefore no mapping is necessary. + // Stash the crypted data. // - *DeviceAddress =3D MapInfo->PlainTextAddress; - *Mapping =3D NO_MAPPING; - FreePool (MapInfo); - return EFI_SUCCESS; + CommonBufferHeader =3D (COMMON_BUFFER_HEADER *)( + (UINTN)MapInfo->CryptedAddress - EFI_PAGE_SIZE + ); + ASSERT (CommonBufferHeader->Signature =3D=3D COMMON_BUFFER_SIG); + CopyMem ( + CommonBufferHeader->StashBuffer, + (VOID *)(UINTN)MapInfo->CryptedAddress, + MapInfo->NumberOfBytes + ); + // + // Point "DecryptionSource" to the stash buffer so that we decrypt + // it to the original location, after the switch statement. + // + DecryptionSource =3D CommonBufferHeader->StashBuffer; + break; =20 default: // // Operation is invalid // Status =3D EFI_INVALID_PARAMETER; goto FreeMapInfo; } =20 // // Clear the memory encryption mask on the plaintext buffer. // Status =3D MemEncryptSevClearPageEncMask ( 0, MapInfo->PlainTextAddress, MapInfo->NumberOfPages, TRUE ); ASSERT_EFI_ERROR(Status); =20 // // If this is a read operation from the Bus Master's point of view, // then copy the contents of the real buffer into the mapped buffer // so the Bus Master can read the contents of the real buffer. // + // For BusMasterCommonBuffer[64] operations, the CopyMem() below will de= crypt + // the original data (from the stash buffer) back to the original locati= on. + // if (Operation =3D=3D EdkiiIoMmuOperationBusMasterRead || - Operation =3D=3D EdkiiIoMmuOperationBusMasterRead64) { + Operation =3D=3D EdkiiIoMmuOperationBusMasterRead64 || + Operation =3D=3D EdkiiIoMmuOperationBusMasterCommonBuffer || + Operation =3D=3D EdkiiIoMmuOperationBusMasterCommonBuffer64) { CopyMem ( (VOID *) (UINTN) MapInfo->PlainTextAddress, - (VOID *) (UINTN) MapInfo->CryptedAddress, + DecryptionSource, MapInfo->NumberOfBytes ); } =20 // // Populate output parameters. // *DeviceAddress =3D MapInfo->PlainTextAddress; *Mapping =3D MapInfo; =20 DEBUG (( DEBUG_VERBOSE, "%a PlainText 0x%Lx Crypted 0x%Lx Pages 0x%Lx Bytes 0x%Lx\n", __FUNCTION__, MapInfo->PlainTextAddress, MapInfo->CryptedAddress, (UINT64)MapInfo->NumberOfPages, (UINT64)MapInfo->NumberOfBytes )); =20 return EFI_SUCCESS; @@ -245,91 +287,129 @@ EFIAPI IoMmuUnmap ( IN EDKII_IOMMU_PROTOCOL *This, IN VOID *Mapping ) { MAP_INFO *MapInfo; EFI_STATUS Status; + COMMON_BUFFER_HEADER *CommonBufferHeader; + VOID *EncryptionTarget; =20 if (Mapping =3D=3D NULL) { return EFI_INVALID_PARAMETER; } =20 - // - // See if the Map() operation associated with this Unmap() required a ma= pping - // buffer. If a mapping buffer was not required, then this function simp= ly - // buffer. If a mapping buffer was not required, then this function simp= ly - // - if (Mapping =3D=3D NO_MAPPING) { - return EFI_SUCCESS; - } - MapInfo =3D (MAP_INFO *)Mapping; =20 // - // If this is a write operation from the Bus Master's point of view, - // then copy the contents of the mapped buffer into the real buffer - // so the processor can read the contents of the real buffer. + // For BusMasterWrite[64] operations and BusMasterCommonBuffer[64] opera= tions + // we have to encrypt the results, ultimately to the original place (i.e= ., + // "MapInfo->CryptedAddress"). // - if (MapInfo->Operation =3D=3D EdkiiIoMmuOperationBusMasterWrite || - MapInfo->Operation =3D=3D EdkiiIoMmuOperationBusMasterWrite64) { + // For BusMasterCommonBuffer[64] operations however, this encryption has= to + // land in-place, so divert the encryption to the stash buffer first. + // + EncryptionTarget =3D (VOID *)(UINTN)MapInfo->CryptedAddress; + + switch (MapInfo->Operation) { + case EdkiiIoMmuOperationBusMasterCommonBuffer: + case EdkiiIoMmuOperationBusMasterCommonBuffer64: + ASSERT (MapInfo->PlainTextAddress =3D=3D MapInfo->CryptedAddress); + + CommonBufferHeader =3D (COMMON_BUFFER_HEADER *)( + (UINTN)MapInfo->PlainTextAddress - EFI_PAGE_SIZE + ); + ASSERT (CommonBufferHeader->Signature =3D=3D COMMON_BUFFER_SIG); + EncryptionTarget =3D CommonBufferHeader->StashBuffer; + // + // fall through + // + + case EdkiiIoMmuOperationBusMasterWrite: + case EdkiiIoMmuOperationBusMasterWrite64: CopyMem ( - (VOID *) (UINTN) MapInfo->CryptedAddress, + EncryptionTarget, (VOID *) (UINTN) MapInfo->PlainTextAddress, MapInfo->NumberOfBytes ); + break; + + default: + // + // nothing to encrypt after BusMasterRead[64] operations + // + break; } =20 DEBUG (( DEBUG_VERBOSE, "%a PlainText 0x%Lx Crypted 0x%Lx Pages 0x%Lx Bytes 0x%Lx\n", __FUNCTION__, MapInfo->PlainTextAddress, MapInfo->CryptedAddress, (UINT64)MapInfo->NumberOfPages, (UINT64)MapInfo->NumberOfBytes )); + // - // Restore the memory encryption mask + // Restore the memory encryption mask on the area we used to hold the + // plaintext. // Status =3D MemEncryptSevSetPageEncMask ( 0, MapInfo->PlainTextAddress, MapInfo->NumberOfPages, TRUE ); ASSERT_EFI_ERROR(Status); - ZeroMem ( - (VOID*)(UINTN)MapInfo->PlainTextAddress, - EFI_PAGES_TO_SIZE (MapInfo->NumberOfPages) - ); =20 // - // Free the mapped buffer and the MAP_INFO structure. + // For BusMasterCommonBuffer[64] operations, copy the stashed data to the + // original (now encrypted) location. + // + // For all other operations, fill the late bounce buffer (which existed = as + // plaintext at some point) with zeros, and then release it. + // + if (MapInfo->Operation =3D=3D EdkiiIoMmuOperationBusMasterCommonBuffer || + MapInfo->Operation =3D=3D EdkiiIoMmuOperationBusMasterCommonBuffer64= ) { + CopyMem ( + (VOID *)(UINTN)MapInfo->CryptedAddress, + CommonBufferHeader->StashBuffer, + MapInfo->NumberOfBytes + ); + } else { + ZeroMem ( + (VOID *)(UINTN)MapInfo->PlainTextAddress, + EFI_PAGES_TO_SIZE (MapInfo->NumberOfPages) + ); + gBS->FreePages (MapInfo->PlainTextAddress, MapInfo->NumberOfPages); + } + + // + // Free the MAP_INFO structure. // - gBS->FreePages (MapInfo->PlainTextAddress, MapInfo->NumberOfPages); FreePool (Mapping); return EFI_SUCCESS; } =20 /** Allocates pages that are suitable for an OperationBusMasterCommonBuffer = or OperationBusMasterCommonBuffer64 mapping. =20 @param This The protocol instance pointer. @param Type This parameter is not used and must be ign= ored. @param MemoryType The type of memory to allocate, EfiBootServicesData or EfiRuntimeServicesD= ata. @param Pages The number of pages to allocate. @param HostAddress A pointer to store the base system memory address of the allocated range. @param Attributes The requested bit mask of attributes for t= he allocated range. =20 @retval EFI_SUCCESS The requested memory pages were allocated. @retval EFI_UNSUPPORTED Attributes is unsupported. The only legal attribute bits are MEMORY_WRITE_COMBINE and MEMORY_CACHED. @retval EFI_INVALID_PARAMETER One or more parameters are invalid. @retval EFI_OUT_OF_RESOURCES The memory pages could not be allocated. =20 **/ @@ -338,81 +418,116 @@ EFIAPI IoMmuAllocateBuffer ( IN EDKII_IOMMU_PROTOCOL *This, IN EFI_ALLOCATE_TYPE Type, IN EFI_MEMORY_TYPE MemoryType, IN UINTN Pages, IN OUT VOID **HostAddress, IN UINT64 Attributes ) { EFI_STATUS Status; EFI_PHYSICAL_ADDRESS PhysicalAddress; + VOID *StashBuffer; + UINTN CommonBufferPages; + COMMON_BUFFER_HEADER *CommonBufferHeader; =20 // // Validate Attributes // if ((Attributes & EDKII_IOMMU_ATTRIBUTE_INVALID_FOR_ALLOCATE_BUFFER) != =3D 0) { return EFI_UNSUPPORTED; } =20 // // Check for invalid inputs // if (HostAddress =3D=3D NULL) { return EFI_INVALID_PARAMETER; } =20 // // The only valid memory types are EfiBootServicesData and // EfiRuntimeServicesData // if (MemoryType !=3D EfiBootServicesData && MemoryType !=3D EfiRuntimeServicesData) { return EFI_INVALID_PARAMETER; } =20 + // + // We'll need a header page for the COMMON_BUFFER_HEADER structure. + // + if (Pages > MAX_UINTN - 1) { + return EFI_OUT_OF_RESOURCES; + } + CommonBufferPages =3D Pages + 1; + + // + // Allocate the stash in EfiBootServicesData type memory. + // + // Map() will temporarily save encrypted data in the stash for + // BusMasterCommonBuffer[64] operations, so the data can be decrypted to= the + // original location. + // + // Unmap() will temporarily save plaintext data in the stash for + // BusMasterCommonBuffer[64] operations, so the data can be encrypted to= the + // original location. + // + // StashBuffer always resides in encrypted memory. + // + StashBuffer =3D AllocatePages (Pages); + if (StashBuffer =3D=3D NULL) { + return EFI_OUT_OF_RESOURCES; + } + PhysicalAddress =3D (UINTN)-1; if ((Attributes & EDKII_IOMMU_ATTRIBUTE_DUAL_ADDRESS_CYCLE) =3D=3D 0) { // // Limit allocations to memory below 4GB // PhysicalAddress =3D SIZE_4GB - 1; } Status =3D gBS->AllocatePages ( AllocateMaxAddress, MemoryType, - Pages, + CommonBufferPages, &PhysicalAddress ); - if (!EFI_ERROR (Status)) { - *HostAddress =3D (VOID *) (UINTN) PhysicalAddress; - - // - // Clear memory encryption mask - // - Status =3D MemEncryptSevClearPageEncMask (0, PhysicalAddress, Pages, T= RUE); - ASSERT_EFI_ERROR(Status); + if (EFI_ERROR (Status)) { + goto FreeStashBuffer; } =20 + CommonBufferHeader =3D (VOID *)(UINTN)PhysicalAddress; + PhysicalAddress +=3D EFI_PAGE_SIZE; + + CommonBufferHeader->Signature =3D COMMON_BUFFER_SIG; + CommonBufferHeader->StashBuffer =3D StashBuffer; + + *HostAddress =3D (VOID *)(UINTN)PhysicalAddress; + DEBUG (( DEBUG_VERBOSE, "%a Address 0x%Lx Pages 0x%Lx\n", __FUNCTION__, PhysicalAddress, (UINT64)Pages )); + return EFI_SUCCESS; + +FreeStashBuffer: + FreePages (StashBuffer, Pages); return Status; } =20 /** Frees memory that was allocated with AllocateBuffer(). =20 @param This The protocol instance pointer. @param Pages The number of pages to free. @param HostAddress The base system memory address of the allo= cated range. =20 @retval EFI_SUCCESS The requested memory pages were freed. @retval EFI_INVALID_PARAMETER The memory range specified by HostAddress = and Pages was not allocated with AllocateBuffe= r(). =20 **/ @@ -421,79 +536,92 @@ EFIAPI IoMmuFreeBuffer ( IN EDKII_IOMMU_PROTOCOL *This, IN UINTN Pages, IN VOID *HostAddress ) { - EFI_STATUS Status; + UINTN CommonBufferPages; + COMMON_BUFFER_HEADER *CommonBufferHeader; + + CommonBufferPages =3D Pages + 1; + CommonBufferHeader =3D (COMMON_BUFFER_HEADER *)( + (UINTN)HostAddress - EFI_PAGE_SIZE + ); + + // + // Check the signature. + // + ASSERT (CommonBufferHeader->Signature =3D=3D COMMON_BUFFER_SIG); + if (CommonBufferHeader->Signature !=3D COMMON_BUFFER_SIG) { + return EFI_INVALID_PARAMETER; + } =20 // - // Set memory encryption mask + // Free the stash buffer. This buffer was always encrypted, so no need to + // zero it. // - Status =3D MemEncryptSevSetPageEncMask ( - 0, - (EFI_PHYSICAL_ADDRESS)(UINTN)HostAddress, - Pages, - TRUE - ); - ASSERT_EFI_ERROR(Status); - ZeroMem (HostAddress, EFI_PAGES_TO_SIZE (Pages)); + FreePages (CommonBufferHeader->StashBuffer, Pages); =20 DEBUG (( DEBUG_VERBOSE, "%a Address 0x%Lx Pages 0x%Lx\n", __FUNCTION__, (UINT64)(UINTN)HostAddress, (UINT64)Pages )); - return gBS->FreePages ((EFI_PHYSICAL_ADDRESS) (UINTN) HostAddress, Pages= ); + + // + // Release the common buffer itself. Unmap() has re-encrypted it in-plac= e, so + // no need to zero it. + // + return gBS->FreePages ((UINTN)CommonBufferHeader, CommonBufferPages); } =20 =20 /** Set IOMMU attribute for a system memory. =20 If the IOMMU protocol exists, the system memory cannot be used for DMA by default. =20 When a device requests a DMA access for a system memory, the device driver need use SetAttribute() to update the IOMMU attribute to request DMA access (read and/or write). =20 The DeviceHandle is used to identify which device submits the request. The IOMMU implementation need translate the device path to an IOMMU devi= ce ID, and set IOMMU hardware register accordingly. 1) DeviceHandle can be a standard PCI device. The memory for BusMasterRead need set EDKII_IOMMU_ACCESS_READ. The memory for BusMasterWrite need set EDKII_IOMMU_ACCESS_WRITE. The memory for BusMasterCommonBuffer need set EDKII_IOMMU_ACCESS_READ|EDKII_IOMMU_ACCESS_WRITE. After the memory is used, the memory need set 0 to keep it being protected. 2) DeviceHandle can be an ACPI device (ISA, I2C, SPI, etc). The memory for DMA access need set EDKII_IOMMU_ACCESS_READ and/or EDKII_IOMMU_ACCESS_WRITE. =20 @param[in] This The protocol instance pointer. @param[in] DeviceHandle The device who initiates the DMA access request. @param[in] Mapping The mapping value returned from Map(). @param[in] IoMmuAccess The IOMMU access. =20 @retval EFI_SUCCESS The IoMmuAccess is set for the memory ran= ge specified by DeviceAddress and Length. @retval EFI_INVALID_PARAMETER DeviceHandle is an invalid handle. @retval EFI_INVALID_PARAMETER Mapping is not a value that was returned = by Map(). @retval EFI_INVALID_PARAMETER IoMmuAccess specified an illegal combinat= ion of access. @retval EFI_UNSUPPORTED DeviceHandle is unknown by the IOMMU. @retval EFI_UNSUPPORTED The bit mask of IoMmuAccess is not suppor= ted by the IOMMU. @retval EFI_UNSUPPORTED The IOMMU does not support the memory ran= ge specified by Mapping. @retval EFI_OUT_OF_RESOURCES There are not enough resources available = to modify the IOMMU access. @retval EFI_DEVICE_ERROR The IOMMU device reported an error while attempting the operation. =20 **/ --=20 2.13.1.3.g8be5a757fa67 _______________________________________________ edk2-devel mailing list edk2-devel@lists.01.org https://lists.01.org/mailman/listinfo/edk2-devel