From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: 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 1050B21BC6A7F for ; Tue, 28 Mar 2017 01:12:21 -0700 (PDT) Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 665B2437F72; Tue, 28 Mar 2017 08:12:20 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com 665B2437F72 Authentication-Results: ext-mx05.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com Authentication-Results: ext-mx05.extmail.prod.ext.phx2.redhat.com; spf=pass smtp.mailfrom=lersek@redhat.com DKIM-Filter: OpenDKIM Filter v2.11.0 mx1.redhat.com 665B2437F72 Received: from lacos-laptop-7.usersys.redhat.com (ovpn-116-89.phx2.redhat.com [10.3.116.89]) by smtp.corp.redhat.com (Postfix) with ESMTP id 19FE5183AD; Tue, 28 Mar 2017 08:12:17 +0000 (UTC) To: Brijesh Singh References: <149013076154.27235.10725020825643505862.stgit@brijesh-build-machine> <149013081810.27235.18159090697032608822.stgit@brijesh-build-machine> <2443e42d-6b40-4bce-07cc-739690a5113a@redhat.com> Cc: "Kinney, Michael D" , "Justen, Jordan L" , edk2-devel@ml01.01.org, "Gao, Liming" , "Singh, Brijesh" , Leo Duran , Tom Lendacky From: Laszlo Ersek Message-ID: <47a1f04f-788d-5a1b-8cc8-c9a01ddf38b0@redhat.com> Date: Tue, 28 Mar 2017 10:12:16 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.8.0 MIME-Version: 1.0 In-Reply-To: X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.29]); Tue, 28 Mar 2017 08:12:20 +0000 (UTC) Subject: Re: [RFC PATCH v2 09/10] OvmfPkg/QemuFwCfgLib: Add Secure Encrypted Virtualization (SEV) support 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: , X-List-Received-Date: Tue, 28 Mar 2017 08:12:21 -0000 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit On 03/27/17 21:24, Brijesh Singh wrote: > On Mon, Mar 27, 2017 at 5:19 AM, Laszlo Ersek wrote: >> - regarding InternalQemuFwCfgDmaBytes(): would it be possible to hook >> the SEV-related tricks into the existent function, rather than >> copy+modify the entire function as InternalQemuFwCfgSevDmaBytes()? It >> seems to me that a conditional "prologue" and "epilogue" in >> InternalQemuFwCfgDmaBytes() could do the trick. >> >> > I wanted to reuse the existing function but I was not sure how do you > wanted me to handle static allocation of "Access" variable inside > the InternalQemuFwCfgDmaBytes() > > VOID > InternalQemuFwCfgDmaBytes ( > IN UINT32 Size, > IN OUT VOID *Buffer OPTIONAL, > IN UINT32 Control > ) > { > volatile FW_CFG_DMA_ACCESS Access; > UINT32 AccessHigh, AccessLow; > UINT32 Status; > > > The "Access" variable is statically allocated inside this function, The storage duration of "Access" is not "static", it is "automatic". (Put more colloquially, it is on the stack, it is not a global variable.) But, I do understand the point; for the SEV case, you need it to be dynamically allocated *and* exposed to the hypervisor, with InternalQemuFwCfgSevDmaAllocateBuffer(). So here's my suggestion: in the following (suggested) list of patches: - new interfaces in QemuFwCfgLibInternal.h - implementation of new APIs for SEC instance - implementation of new APIs for PEI instance - implementation of new APIs for DXE instance - call new APIs from common code the last part should actually be two patches (so not 5 but 6 patches in total). First, please modify InternalQemuFwCfgDmaBytes() so that it works through a pointer, but without other (functionality) changes: volatile FW_CFG_DMA_ACCESS LocalAccess; volatile FW_CFG_DMA_ACCESS *Access; Access = &LocalAccess; Second, add the SEV-specific prologue / epilogue that initially set the "Access" pointer differently, and finally free / unmap it. > in case > of SEV the Dma "Access" control variable need to be dynamically allocated > because hypervisor read/writes data into Access->status. > > I could convert Access into FW_CFG_DMA_ACCESS pointer for non SEV case and > then integerate the SEV specific changes inside the same function. Yes, that's the idea. > > I was just not sure which approach is prefrered hence decided to create a > new function for now and at least start the discussion. Thank you. Laszlo > > > > >> ... From skimming this patch, I think those are the only >> functionality-related comments I have at this point, beyond the remarks >> I made elsewhere in this series (like: line length, DEBUG_* macros, and >> so on). Please recheck all patches for those comments. >> >> > I will revist all the patches and fix those DEBUG_* macros. > > > >>> >>> diff --git a/OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgDxe.c >> b/OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgDxe.c >>> index ac05f4c..be8e945 100644 >>> --- a/OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgDxe.c >>> +++ b/OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgDxe.c >>> @@ -4,6 +4,7 @@ >>> >>> Copyright (C) 2013, Red Hat, Inc. >>> Copyright (c) 2011 - 2013, Intel Corporation. All rights reserved.
>>> + Copyright (c) 2017, Advanced Micro Devices. All rights reserved.
>>> >>> This program and the accompanying materials are licensed and made >> available >>> under the terms and conditions of the BSD License which accompanies >> this >>> @@ -14,14 +15,34 @@ >>> WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED. >>> **/ >>> >>> +#include "Uefi.h" >>> + >>> +#include >>> #include >>> #include >>> +#include >>> +#include >>> +#include >>> >>> #include "QemuFwCfgLibInternal.h" >>> >>> STATIC BOOLEAN mQemuFwCfgSupported = FALSE; >>> STATIC BOOLEAN mQemuFwCfgDmaSupported; >>> +STATIC BOOLEAN mQemuFwCfgSevIsEnabled = FALSE; >>> + >>> +/** >>> + Returns a boolean indicating whether the SEV is enabled >>> >>> + @retval TRUE SEV is enabled >>> + @retval FALSE SEV is not enabled >>> +**/ >>> +BOOLEAN >>> +InternalQemuFwCfgSevIsEnabled ( >>> + VOID >>> + ) >>> +{ >>> + return mQemuFwCfgSevIsEnabled; >>> +} >>> >>> /** >>> Returns a boolean indicating if the firmware configuration interface >>> @@ -79,6 +100,9 @@ QemuFwCfgInitialize ( >>> mQemuFwCfgDmaSupported = TRUE; >>> DEBUG ((DEBUG_INFO, "QemuFwCfg interface (DMA) is supported.\n")); >>> } >>> + >>> + mQemuFwCfgSevIsEnabled = MemEncryptSevIsEnabled (); >>> + >>> return RETURN_SUCCESS; >>> } >>> >>> @@ -114,3 +138,52 @@ InternalQemuFwCfgDmaIsAvailable ( >>> { >>> return mQemuFwCfgDmaSupported; >>> } >>> + >>> +/** >>> + Allocate a bounce buffer for SEV DMA. >>> + >> >> Please document that this function either succeeds or doesn't return. >> >>> + @param[in] NumPage Number of pages. >>> + @param[out] Buffer Allocated DMA Buffer pointer >>> + >>> +**/ >>> +VOID >>> +InternalQemuFwCfgSevDmaAllocateBuffer ( >>> + IN UINT32 NumPages, >>> + OUT VOID **Buffer >>> + ) >>> +{ >>> + EFI_STATUS Status; >>> + >>> + // >>> + // Allocate DMA bounce buffer >>> + // >>> + Status = BmDmaAllocateBuffer (TRUE, EfiBootServicesData, NumPages, >> Buffer); >>> + if (EFI_ERROR(Status)) { >>> + DEBUG ((EFI_D_ERROR, "SEV: Failed to allocate bounce buffer %d >> pages\n", NumPages)); >>> + ASSERT_EFI_ERROR (Status); >>> + CpuDeadLoop (); >>> + } >>> + >>> + DEBUG ((EFI_D_VERBOSE, "QemuFwCfgSevDma allocate buffer 0x%Lx Pages >> %d\n", (UINTN)Buffer, NumPages)); >>> +} >>> + >>> +/** >>> + Free the DMA buffer allocated using InternalQemuFwCfgSevDmaAllocat >> eBuffer >>> + >>> + @param[in] NumPage Number of pages. >>> + @param[in] Buffer DMA Buffer pointer >>> + >>> +**/ >>> +VOID >>> +InternalQemuFwCfgSevDmaFreeBuffer ( >>> + IN VOID *Buffer, >>> + IN UINT32 NumPages >>> + ) >>> +{ >>> + // >>> + // Free the bounce buffer >>> + // >>> + DEBUG ((EFI_D_VERBOSE, "QemuFwCfgSevDma free buffer 0x%Lx Pages >> %d\n", (UINTN)Buffer, NumPages)); >>> + BmDmaFreeBuffer (Buffer, NumPages); >>> +} >>> + >>> diff --git a/OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgDxeLib.inf >> b/OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgDxeLib.inf >>> index 346bb88..536887f 100644 >>> --- a/OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgDxeLib.inf >>> +++ b/OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgDxeLib.inf >>> @@ -47,4 +47,6 @@ >>> DebugLib >>> IoLib >>> MemoryAllocationLib >>> + MemEncryptSevLib >>> + BmDmaLib >>> >>> diff --git a/OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgLib.c >> b/OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgLib.c >>> index 1bf725d..d2560a3 100644 >>> --- a/OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgLib.c >>> +++ b/OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgLib.c >>> @@ -47,6 +47,111 @@ QemuFwCfgSelectItem ( >>> >>> >>> /** >>> + Transfer an array of bytes, or skip a number of bytes, using the SEV >> DMA bounce >>> + interface. The function is same as InternalQemuFwCfgDmaBytes with >> excpetion that >>> + it uses bounce buffer >>> + >>> + @param[in] Size Size in bytes to transfer or skip. >>> + >>> + @param[in,out] HostBuffer Buffer to read data into or write data >> from. Ignored, >>> + and may be NULL, if Size is zero, or >> Control is >>> + FW_CFG_DMA_CTL_SKIP. >>> + >>> + @param[in] Control One of the following: >>> + FW_CFG_DMA_CTL_WRITE - write to fw_cfg from >> Buffer. >>> + FW_CFG_DMA_CTL_READ - read from fw_cfg into >> Buffer. >>> + FW_CFG_DMA_CTL_SKIP - skip bytes in fw_cfg. >>> +**/ >>> +VOID >>> +InternalQemuFwCfgSevDmaBytes ( >>> + IN UINT32 Size, >>> + IN OUT VOID *HostBuffer OPTIONAL, >>> + IN UINT32 Control >>> + ) >>> +{ >>> + volatile FW_CFG_DMA_ACCESS *Access; >>> + UINT32 AccessHigh, AccessLow; >>> + UINT32 Status; >>> + UINT32 NumPages; >>> + VOID *DmaBuffer, *Buffer; >>> + >>> + // >>> + // Calculate number of pages we need to allocate for this operation >>> + // >>> + if (Control == FW_CFG_DMA_CTL_SKIP) { >>> + // >>> + // Control data does not need the actual buffer >>> + // >>> + NumPages = EFI_SIZE_TO_PAGES (sizeof (*Access)); >>> + } else { >>> + NumPages = EFI_SIZE_TO_PAGES (sizeof (*Access) + Size); >>> + } >>> + >>> + // >>> + // Allocate DMA bounce buffer >>> + // >>> + InternalQemuFwCfgSevDmaAllocateBuffer (NumPages, &DmaBuffer); >>> + >>> + Access = (FW_CFG_DMA_ACCESS *)DmaBuffer; >>> + Buffer = DmaBuffer + sizeof(*Access); >>> + >>> + Access->Control = SwapBytes32 (Control); >>> + Access->Length = SwapBytes32 (Size); >>> + Access->Address = SwapBytes64 ((UINTN)Buffer); >>> + >>> + // >>> + // Copy data from Host buffer into DMA buffer >>> + // >>> + if (HostBuffer && (Control == FW_CFG_DMA_CTL_WRITE)) { >>> + CopyMem (Buffer, HostBuffer, Size); >>> + } >>> + >>> + // >>> + // Delimit the transfer from (a) modifications to Access, (b) in case >> of a >>> + // write, from writes to Buffer by the caller. >>> + // >>> + MemoryFence (); >>> + >>> + // >>> + // Start the transfer. >>> + // >>> + AccessHigh = (UINT32)RShiftU64 ((UINTN)Access, 32); >>> + AccessLow = (UINT32)(UINTN)Access; >>> + IoWrite32 (FW_CFG_IO_DMA_ADDRESS, SwapBytes32 (AccessHigh)); >>> + IoWrite32 (FW_CFG_IO_DMA_ADDRESS + 4, SwapBytes32 (AccessLow)); >>> + >>> + // >>> + // Don't look at Access->Control before starting the transfer. >>> + // >>> + MemoryFence (); >>> + >>> + // >>> + // Wait for the transfer to complete. >>> + // >>> + do { >>> + Status = SwapBytes32 (Access->Control); >>> + ASSERT ((Status & FW_CFG_DMA_CTL_ERROR) == 0); >>> + } while (Status != 0); >>> + >>> + // >>> + // After a read, the caller will want to use Buffer. >>> + // >>> + MemoryFence (); >>> + >>> + // >>> + // Copy data from DMA buffer into Host Buffer >>> + // >>> + if (HostBuffer && (Control == FW_CFG_DMA_CTL_READ)) { >>> + CopyMem (HostBuffer, Buffer, Size); >>> + } >>> + >>> + // >>> + // Free the DMA bounce buffer >>> + // >>> + InternalQemuFwCfgSevDmaFreeBuffer (DmaBuffer, NumPages); >>> +} >>> + >>> +/** >>> Transfer an array of bytes, or skip a number of bytes, using the DMA >>> interface. >>> >>> @@ -79,6 +184,13 @@ InternalQemuFwCfgDmaBytes ( >>> return; >>> } >>> >>> + // >>> + // When SEV is enabled then use SEV version of DmaReadWrite >>> + // >>> + if (InternalQemuFwCfgSevIsEnabled ()) { >>> + return InternalQemuFwCfgSevDmaBytes (Size, Buffer, Control); >>> + } >>> + >>> Access.Control = SwapBytes32 (Control); >>> Access.Length = SwapBytes32 (Size); >>> Access.Address = SwapBytes64 ((UINTN)Buffer); >>> diff --git a/OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgLibInternal.h >> b/OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgLibInternal.h >>> index 6e87c62..8e2ff45 100644 >>> --- a/OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgLibInternal.h >>> +++ b/OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgLibInternal.h >>> @@ -2,6 +2,7 @@ >>> Internal interfaces specific to the QemuFwCfgLib instances in OvmfPkg. >>> >>> Copyright (C) 2016, Red Hat, Inc. >>> + Copyright (C) 2017, Advanced Micro Devices. >>> >>> This program and the accompanying materials are licensed and made >> available >>> under the terms and conditions of the BSD License which accompanies >> this >>> @@ -43,4 +44,41 @@ InternalQemuFwCfgDmaIsAvailable ( >>> VOID >>> ); >>> >>> +/** >>> + Returns a boolean indicating whether the SEV is enabled >>> + >>> + @retval TRUE SEV is enabled >>> + @retval FALSE SEV is not enabled >>> +**/ >>> +BOOLEAN >>> +InternalQemuFwCfgSevIsEnabled ( >>> + VOID >>> + ); >>> + >>> +/** >>> + Allocate a bounce buffer for SEV DMA. >>> + >>> + @param[in] NumPage Number of pages. >>> + @param[out] Buffer Allocated DMA Buffer pointer >>> + >>> +**/ >>> +VOID >>> +InternalQemuFwCfgSevDmaAllocateBuffer ( >>> + IN UINT32 NumPages, >>> + OUT VOID **Buffer >>> + ); >>> + >>> +/** >>> + Free the DMA buffer allocated using InternalQemuFwCfgSevDmaAllocat >> eBuffer >>> + >>> + @param[in] NumPage Number of pages. >>> + @param[in] Buffer DMA Buffer pointer >>> + >>> +**/ >>> +VOID >>> +InternalQemuFwCfgSevDmaFreeBuffer ( >>> + IN VOID *Buffer, >>> + IN UINT32 NumPages >>> + ); >>> + >>> #endif >>> diff --git a/OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgPei.c >> b/OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgPei.c >>> index ac05f4c..3dc9270 100644 >>> --- a/OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgPei.c >>> +++ b/OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgPei.c >>> @@ -4,6 +4,7 @@ >>> >>> Copyright (C) 2013, Red Hat, Inc. >>> Copyright (c) 2011 - 2013, Intel Corporation. All rights reserved.
>>> + Copyright (c) 2017, Advanced Micro Devices. All rights reserved.
>>> >>> This program and the accompanying materials are licensed and made >> available >>> under the terms and conditions of the BSD License which accompanies >> this >>> @@ -14,14 +15,55 @@ >>> WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED. >>> **/ >>> >>> +#include >>> #include >>> #include >>> +#include >>> +#include >>> >>> #include "QemuFwCfgLibInternal.h" >>> >>> STATIC BOOLEAN mQemuFwCfgSupported = FALSE; >>> STATIC BOOLEAN mQemuFwCfgDmaSupported; >>> >>> +/** >>> + Returns a boolean indicating whether the SEV is enabled >>> + >>> + @retval TRUE SEV is enabled >>> + @retval FALSE SEV is not enabled >>> +**/ >>> +BOOLEAN >>> +InternalQemuFwCfgSevIsEnabled ( >>> + VOID >>> + ) >>> +{ >>> + UINT32 RegEax; >>> + MSR_SEV_STATUS_REGISTER Msr; >>> + CPUID_MEMORY_ENCRYPTION_INFO_EAX Eax; >>> + >>> + // >>> + // Check if memory encryption leaf exist >>> + // >>> + AsmCpuid (CPUID_EXTENDED_FUNCTION, &RegEax, NULL, NULL, NULL); >>> + if (RegEax >= CPUID_MEMORY_ENCRYPTION_INFO) { >>> + // >>> + // CPUID Fn8000_001F[EAX] Bit 1 (Sev supported) >>> + // >>> + AsmCpuid (CPUID_MEMORY_ENCRYPTION_INFO, &Eax.Uint32, NULL, NULL, >> NULL); >>> + >>> + if (Eax.Bits.SevBit) { >>> + // >>> + // Check MSR_0xC0010131 Bit 0 (Sev Enabled) >>> + // >>> + Msr.Uint32 = AsmReadMsr32 (MSR_SEV_STATUS); >>> + if (Msr.Bits.SevBit) { >>> + return TRUE; >>> + } >>> + } >>> + } >>> + >>> + return FALSE; >>> +} >>> >>> /** >>> Returns a boolean indicating if the firmware configuration interface >>> @@ -79,6 +121,17 @@ QemuFwCfgInitialize ( >>> mQemuFwCfgDmaSupported = TRUE; >>> DEBUG ((DEBUG_INFO, "QemuFwCfg interface (DMA) is supported.\n")); >>> } >>> + >>> + // >>> + // When SEV is enabled then we do not support DMA interface. >>> + // This is because we need to use bounce buffer to support DMA >> operation in SEV guest. >>> + // Allocating memory for bounce buffer can get painful in Pei phase >>> + // >>> + if (mQemuFwCfgDmaSupported && InternalQemuFwCfgSevIsEnabled ()) { >>> + mQemuFwCfgDmaSupported = FALSE; >>> + DEBUG ((DEBUG_INFO, "QemuFwCfg disabling DMA interface and >> defaulting to IO Port.\n")); >>> + } >>> + >>> return RETURN_SUCCESS; >>> } >>> >>> @@ -114,3 +167,43 @@ InternalQemuFwCfgDmaIsAvailable ( >>> { >>> return mQemuFwCfgDmaSupported; >>> } >>> + >>> +/** >>> + Allocate a bounce buffer for SEV DMA. >>> + >>> + @param[in] NumPage Number of pages. >>> + @param[out] Buffer Allocated DMA Buffer pointer >>> + >>> +**/ >>> +VOID >>> +InternalQemuFwCfgSevDmaAllocateBuffer ( >>> + IN UINT32 NumPages, >>> + OUT VOID **Buffer >>> + ) >>> +{ >>> + // >>> + // We should never reach here >>> + // >>> + ASSERT (FALSE); >>> + CpuDeadLoop (); >>> +} >>> + >>> +/** >>> + Free the DMA buffer allocated using InternalQemuFwCfgSevDmaAllocat >> eBuffer >>> + >>> + @param[in] NumPage Number of pages. >>> + @param[in] Buffer DMA Buffer pointer >>> + >>> +**/ >>> +VOID >>> +InternalQemuFwCfgSevDmaFreeBuffer ( >>> + IN VOID *Buffer, >>> + IN UINT32 NumPages >>> + ) >>> +{ >>> + // >>> + // We should never reach here >>> + // >>> + ASSERT (FALSE); >>> + CpuDeadLoop (); >>> +} >>> diff --git a/OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgPeiLib.inf >> b/OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgPeiLib.inf >>> index 4f966a8..83cc0de 100644 >>> --- a/OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgPeiLib.inf >>> +++ b/OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgPeiLib.inf >>> @@ -39,7 +39,9 @@ >>> >>> [Packages] >>> MdePkg/MdePkg.dec >>> + MdeModulePkg/MdeModulePkg.dec >>> OvmfPkg/OvmfPkg.dec >>> + UefiCpuPkg/UefiCpuPkg.dec >>> >>> [LibraryClasses] >>> BaseLib >>> diff --git a/OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgSec.c >> b/OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgSec.c >>> index 465ccbe..70b0a47 100644 >>> --- a/OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgSec.c >>> +++ b/OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgSec.c >>> @@ -16,8 +16,11 @@ >>> WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED. >>> **/ >>> >>> +#include >>> #include >>> #include >>> +#include >>> +#include >>> >>> #include "QemuFwCfgLibInternal.h" >>> >>> @@ -94,3 +97,82 @@ InternalQemuFwCfgDmaIsAvailable ( >>> { >>> return FALSE; >>> } >>> + >>> +/** >>> + Returns a boolean indicating whether the SEV is enabled >>> + >>> + @retval TRUE SEV is enabled >>> + @retval FALSE SEV is not enabled >>> +**/ >>> +BOOLEAN >>> +InternalQemuFwCfgSevIsEnabled ( >>> + VOID >>> + ) >>> +{ >>> + UINT32 RegEax; >>> + MSR_SEV_STATUS_REGISTER Msr; >>> + CPUID_MEMORY_ENCRYPTION_INFO_EAX Eax; >>> + >>> + // >>> + // Check if memory encryption leaf exist >>> + // >>> + AsmCpuid (CPUID_EXTENDED_FUNCTION, &RegEax, NULL, NULL, NULL); >>> + if (RegEax >= CPUID_MEMORY_ENCRYPTION_INFO) { >>> + // >>> + // CPUID Fn8000_001F[EAX] Bit 1 (Sev supported) >>> + // >>> + AsmCpuid (CPUID_MEMORY_ENCRYPTION_INFO, &Eax.Uint32, NULL, NULL, >> NULL); >>> + >>> + if (Eax.Bits.SevBit) { >>> + // >>> + // Check MSR_0xC0010131 Bit 0 (Sev Enabled) >>> + // >>> + Msr.Uint32 = AsmReadMsr32 (MSR_SEV_STATUS); >>> + if (Msr.Bits.SevBit) { >>> + return TRUE; >>> + } >>> + } >>> + } >>> + >>> + return FALSE; >>> +} >>> + >>> +/** >>> + Allocate a bounce buffer for SEV DMA. >>> + >>> + @param[in] NumPage Number of pages. >>> + @param[out] Buffer Allocated DMA Buffer pointer >>> + >>> +**/ >>> +VOID >>> +InternalQemuFwCfgSevDmaAllocateBuffer ( >>> + IN UINT32 NumPages, >>> + OUT VOID **Buffer >>> + ) >>> +{ >>> + // >>> + // We should never reach here >>> + // >>> + ASSERT (FALSE); >>> + CpuDeadLoop (); >>> +} >>> + >>> +/** >>> + Free the DMA buffer allocated using InternalQemuFwCfgSevDmaAllocat >> eBuffer >>> + >>> + @param[in] NumPage Number of pages. >>> + @param[in] Buffer DMA Buffer pointer >>> + >>> +**/ >>> +VOID >>> +InternalQemuFwCfgSevDmaFreeBuffer ( >>> + IN VOID *Buffer, >>> + IN UINT32 NumPages >>> + ) >>> +{ >>> + // >>> + // We should never reach here >>> + // >>> + ASSERT (FALSE); >>> + CpuDeadLoop (); >>> +} >>> >>> _______________________________________________ >>> edk2-devel mailing list >>> edk2-devel@lists.01.org >>> https://lists.01.org/mailman/listinfo/edk2-devel >>> >> >> > >