From 9388cc72866fc379d94cf3dc029292f4246bfe39 Mon Sep 17 00:00:00 2001 From: Gerd Hoffmann Date: Tue, 30 Jan 2024 14:04:38 +0100 Subject: [PATCH] OvmfPkg/Sec: Setup MTRR early in the boot process. RH-Author: Gerd Hoffmann RH-MergeRequest: 55: OvmfPkg/Sec: Setup MTRR early in the boot process. RH-Jira: RHEL-21704 RH-Acked-by: Laszlo Ersek RH-Commit: [1/4] c4061788d34f409944898b48642d610c259161f3 (kraxel.rh/centos-src-edk2) Specifically before running lzma uncompress of the main firmware volume. This is needed to make sure caching is enabled, otherwise the uncompress can be extremely slow. Adapt the ASSERTs and MTRR setup in PlatformInitLib to the changes. Background: Depending on virtual machine configuration kvm may uses EPT memory types to apply guest MTRR settings. In case MTRRs are disabled kvm will use the uncachable memory type for all mappings. The vmx_get_mt_mask() function in the linux kernel handles this and can be found here: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/tree/arch/x86/kvm/vmx/vmx.c?h=v6.7.1#n7580 In most VM configurations kvm uses MTRR_TYPE_WRBACK unconditionally. In case the VM has a mdev device assigned that is not the case though. Before commit e8aa4c6546ad ("UefiCpuPkg/ResetVector: Cache Disable should not be set by default in CR0") kvm also ended up using MTRR_TYPE_WRBACK due to KVM_X86_QUIRK_CD_NW_CLEARED. After that commit kvm evaluates guest mtrr settings, which why setting up MTRRs early is important now. Reviewed-by: Laszlo Ersek Signed-off-by: Gerd Hoffmann Message-ID: <20240130130441.772484-2-kraxel@redhat.com> [ kraxel: Downstream-only for now. Timely upstream merge is unlikely due to chinese holidays and rhel-9.4 deadlines are close. QE regression testing passed. So go with upstream posted series v3 ] patch_name: edk2-OvmfPkg-Sec-Setup-MTRR-early-in-the-boot-process.patch present_in_specfile: true location_in_specfile: 49 --- OvmfPkg/IntelTdx/Sec/SecMain.c | 32 +++++++++++++++++++++ OvmfPkg/Library/PlatformInitLib/MemDetect.c | 10 +++---- OvmfPkg/Sec/SecMain.c | 32 +++++++++++++++++++++ 3 files changed, 69 insertions(+), 5 deletions(-) diff --git a/OvmfPkg/IntelTdx/Sec/SecMain.c b/OvmfPkg/IntelTdx/Sec/SecMain.c index 42a587adfa..0daddac0a0 100644 --- a/OvmfPkg/IntelTdx/Sec/SecMain.c +++ b/OvmfPkg/IntelTdx/Sec/SecMain.c @@ -27,6 +27,8 @@ #include #include #include +#include +#include #define SEC_IDT_ENTRY_COUNT 34 @@ -48,6 +50,31 @@ IA32_IDT_GATE_DESCRIPTOR mIdtEntryTemplate = { } }; +// +// Enable MTRR early, set default type to write back. +// Needed to make sure caching is enabled, +// without this lzma decompress can be very slow. +// +STATIC +VOID +SecMtrrSetup ( + VOID + ) +{ + CPUID_VERSION_INFO_EDX Edx; + MSR_IA32_MTRR_DEF_TYPE_REGISTER DefType; + + AsmCpuid (CPUID_VERSION_INFO, NULL, NULL, NULL, &Edx.Uint32); + if (!Edx.Bits.MTRR) { + return; + } + + DefType.Uint64 = AsmReadMsr64 (MSR_IA32_MTRR_DEF_TYPE); + DefType.Bits.Type = 6; /* write back */ + DefType.Bits.E = 1; /* enable */ + AsmWriteMsr64 (MSR_IA32_MTRR_DEF_TYPE, DefType.Uint64); +} + VOID EFIAPI SecCoreStartupWithStack ( @@ -204,6 +231,11 @@ SecCoreStartupWithStack ( InitializeApicTimer (0, MAX_UINT32, TRUE, 5); DisableApicTimerInterrupt (); + // + // Initialize MTRR + // + SecMtrrSetup (); + PeilessStartup (&SecCoreData); ASSERT (FALSE); diff --git a/OvmfPkg/Library/PlatformInitLib/MemDetect.c b/OvmfPkg/Library/PlatformInitLib/MemDetect.c index f042517bb6..313f5e1f7f 100644 --- a/OvmfPkg/Library/PlatformInitLib/MemDetect.c +++ b/OvmfPkg/Library/PlatformInitLib/MemDetect.c @@ -1082,18 +1082,18 @@ PlatformQemuInitializeRam ( MtrrGetAllMtrrs (&MtrrSettings); // - // MTRRs disabled, fixed MTRRs disabled, default type is uncached + // See SecMtrrSetup(), default type should be write back // - ASSERT ((MtrrSettings.MtrrDefType & BIT11) == 0); + ASSERT ((MtrrSettings.MtrrDefType & BIT11) != 0); ASSERT ((MtrrSettings.MtrrDefType & BIT10) == 0); - ASSERT ((MtrrSettings.MtrrDefType & 0xFF) == 0); + ASSERT ((MtrrSettings.MtrrDefType & 0xFF) == MTRR_CACHE_WRITE_BACK); // // flip default type to writeback // - SetMem (&MtrrSettings.Fixed, sizeof MtrrSettings.Fixed, 0x06); + SetMem (&MtrrSettings.Fixed, sizeof MtrrSettings.Fixed, MTRR_CACHE_WRITE_BACK); ZeroMem (&MtrrSettings.Variables, sizeof MtrrSettings.Variables); - MtrrSettings.MtrrDefType |= BIT11 | BIT10 | 6; + MtrrSettings.MtrrDefType |= BIT10; MtrrSetAllMtrrs (&MtrrSettings); // diff --git a/OvmfPkg/Sec/SecMain.c b/OvmfPkg/Sec/SecMain.c index 31da5d0ace..3b7dc7205d 100644 --- a/OvmfPkg/Sec/SecMain.c +++ b/OvmfPkg/Sec/SecMain.c @@ -30,6 +30,8 @@ #include #include #include +#include +#include #include "AmdSev.h" #define SEC_IDT_ENTRY_COUNT 34 @@ -744,6 +746,31 @@ FindAndReportEntryPoints ( return; } +// +// Enable MTRR early, set default type to write back. +// Needed to make sure caching is enabled, +// without this lzma decompress can be very slow. +// +STATIC +VOID +SecMtrrSetup ( + VOID + ) +{ + CPUID_VERSION_INFO_EDX Edx; + MSR_IA32_MTRR_DEF_TYPE_REGISTER DefType; + + AsmCpuid (CPUID_VERSION_INFO, NULL, NULL, NULL, &Edx.Uint32); + if (!Edx.Bits.MTRR) { + return; + } + + DefType.Uint64 = AsmReadMsr64 (MSR_IA32_MTRR_DEF_TYPE); + DefType.Bits.Type = 6; /* write back */ + DefType.Bits.E = 1; /* enable */ + AsmWriteMsr64 (MSR_IA32_MTRR_DEF_TYPE, DefType.Uint64); +} + VOID EFIAPI SecCoreStartupWithStack ( @@ -942,6 +969,11 @@ SecCoreStartupWithStack ( InitializeApicTimer (0, MAX_UINT32, TRUE, 5); DisableApicTimerInterrupt (); + // + // Initialize MTRR + // + SecMtrrSetup (); + // // Initialize Debug Agent to support source level debug in SEC/PEI phases before memory ready. //