From 483c6ad426dbab72d912fe4793d7d558671aa727 Mon Sep 17 00:00:00 2001 From: Borislav Petkov Date: Thu, 20 Dec 2018 10:07:32 -0200 Subject: [PATCH] target-i386: Reenable RDTSCP support on Opteron_G[345] CPU models CPU models The missing functionality was added ~3 years ago with the Linux commit 46896c73c1a4 ("KVM: svm: add support for RDTSCP") so reenable RDTSCP support on those CPU models. Opteron_G2 - being family 15, model 6, doesn't have RDTSCP support (the real hardware doesn't have it. K8 got RDTSCP support with the NPT models, i.e., models >= 0x40). Document the host's minimum required kernel version, while at it. Signed-off-by: Borislav Petkov Message-ID: <20181212200803.GG6653@zn.tnic> [ehabkost: moved compat properties code to pc.c] Signed-off-by: Eduardo Habkost --- hw/i386/pc.c | 3 +++ qemu-doc.texi | 13 +++++++++++++ target/i386/cpu.c | 11 ++++------- 3 files changed, 20 insertions(+), 7 deletions(-) diff --git a/hw/i386/pc.c b/hw/i386/pc.c index fc65049e1d..5cac33fcb9 100644 --- a/hw/i386/pc.c +++ b/hw/i386/pc.c @@ -112,6 +112,9 @@ struct hpet_fw_config hpet_cfg = {.count = UINT8_MAX}; GlobalProperty pc_compat_3_1[] = { { "intel-iommu", "dma-drain", "off" }, + { "Opteron_G3" "-" TYPE_X86_CPU, "rdtscp", "off" }, + { "Opteron_G4" "-" TYPE_X86_CPU, "rdtscp", "off" }, + { "Opteron_G5" "-" TYPE_X86_CPU, "rdtscp", "off" }, }; const size_t pc_compat_3_1_len = G_N_ELEMENTS(pc_compat_3_1); diff --git a/qemu-doc.texi b/qemu-doc.texi index f7ad1dfe4b..16b955cbf9 100644 --- a/qemu-doc.texi +++ b/qemu-doc.texi @@ -37,6 +37,7 @@ * QEMU System emulator for non PC targets:: * QEMU Guest Agent:: * QEMU User space emulator:: +* System requirements:: * Implementation notes:: * Deprecated features:: * Supported build platforms:: @@ -2813,6 +2814,18 @@ Act as if the host page size was 'pagesize' bytes Run the emulation in single step mode. @end table +@node System requirements +@chapter System requirements + +@section KVM kernel module + +On x86_64 hosts, the default set of CPU features enabled by the KVM accelerator +require the host to be running Linux v4.5 or newer. + +The OpteronG[345] CPU models require KVM support for RDTSCP, which was +added with Linux 4.5 which is supported by the major distros. And even +if RHEL7 has kernel 3.10, KVM there has the required functionality there +to make it close to a 4.5 or newer kernel. @include qemu-tech.texi diff --git a/target/i386/cpu.c b/target/i386/cpu.c index bd005f5374..4cfc0daf97 100644 --- a/target/i386/cpu.c +++ b/target/i386/cpu.c @@ -2736,7 +2736,6 @@ static X86CPUDefinition builtin_x86_defs[] = { CPUID_DE | CPUID_FP87, .features[FEAT_1_ECX] = CPUID_EXT_CX16 | CPUID_EXT_SSE3, - /* Missing: CPUID_EXT2_RDTSCP */ .features[FEAT_8000_0001_EDX] = CPUID_EXT2_LM | CPUID_EXT2_NX | CPUID_EXT2_SYSCALL, .features[FEAT_8000_0001_ECX] = @@ -2760,9 +2759,9 @@ static X86CPUDefinition builtin_x86_defs[] = { .features[FEAT_1_ECX] = CPUID_EXT_POPCNT | CPUID_EXT_CX16 | CPUID_EXT_MONITOR | CPUID_EXT_SSE3, - /* Missing: CPUID_EXT2_RDTSCP */ .features[FEAT_8000_0001_EDX] = - CPUID_EXT2_LM | CPUID_EXT2_NX | CPUID_EXT2_SYSCALL, + CPUID_EXT2_LM | CPUID_EXT2_NX | CPUID_EXT2_SYSCALL | + CPUID_EXT2_RDTSCP, .features[FEAT_8000_0001_ECX] = CPUID_EXT3_MISALIGNSSE | CPUID_EXT3_SSE4A | CPUID_EXT3_ABM | CPUID_EXT3_SVM | CPUID_EXT3_LAHF_LM, @@ -2787,10 +2786,9 @@ static X86CPUDefinition builtin_x86_defs[] = { CPUID_EXT_POPCNT | CPUID_EXT_SSE42 | CPUID_EXT_SSE41 | CPUID_EXT_CX16 | CPUID_EXT_SSSE3 | CPUID_EXT_PCLMULQDQ | CPUID_EXT_SSE3, - /* Missing: CPUID_EXT2_RDTSCP */ .features[FEAT_8000_0001_EDX] = CPUID_EXT2_LM | CPUID_EXT2_PDPE1GB | CPUID_EXT2_NX | - CPUID_EXT2_SYSCALL, + CPUID_EXT2_SYSCALL | CPUID_EXT2_RDTSCP, .features[FEAT_8000_0001_ECX] = CPUID_EXT3_FMA4 | CPUID_EXT3_XOP | CPUID_EXT3_3DNOWPREFETCH | CPUID_EXT3_MISALIGNSSE | @@ -2818,10 +2816,9 @@ static X86CPUDefinition builtin_x86_defs[] = { CPUID_EXT_AES | CPUID_EXT_POPCNT | CPUID_EXT_SSE42 | CPUID_EXT_SSE41 | CPUID_EXT_CX16 | CPUID_EXT_FMA | CPUID_EXT_SSSE3 | CPUID_EXT_PCLMULQDQ | CPUID_EXT_SSE3, - /* Missing: CPUID_EXT2_RDTSCP */ .features[FEAT_8000_0001_EDX] = CPUID_EXT2_LM | CPUID_EXT2_PDPE1GB | CPUID_EXT2_NX | - CPUID_EXT2_SYSCALL, + CPUID_EXT2_SYSCALL | CPUID_EXT2_RDTSCP, .features[FEAT_8000_0001_ECX] = CPUID_EXT3_TBM | CPUID_EXT3_FMA4 | CPUID_EXT3_XOP | CPUID_EXT3_3DNOWPREFETCH | CPUID_EXT3_MISALIGNSSE | -- 2.39.2