From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:60128) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1gWkgL-0001gx-QT for qemu-devel@nongnu.org; Tue, 11 Dec 2018 11:14:51 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1gWkgK-000892-M1 for qemu-devel@nongnu.org; Tue, 11 Dec 2018 11:14:49 -0500 Received: from mail.skyhub.de ([2a01:4f8:190:11c2::b:1457]:48714) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1gWkgK-00081J-Am for qemu-devel@nongnu.org; Tue, 11 Dec 2018 11:14:48 -0500 Date: Tue, 11 Dec 2018 17:14:40 +0100 From: Borislav Petkov Message-ID: <20181211161440.GG27375@zn.tnic> References: <20181210181328.GA762@zn.tnic> <20181210183730.GJ4669@habkost.net> <20181210184153.GB5482@zn.tnic> <20181210190600.GK4669@habkost.net> <20181210194258.GD5482@zn.tnic> <20181210200843.GN4669@habkost.net> <20181211103839.GC921@redhat.com> <20181211115546.GQ4669@habkost.net> <20181211153017.GN921@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20181211153017.GN921@redhat.com> Content-Transfer-Encoding: quoted-printable Subject: [Qemu-devel] [PATCH] target-i386: Reenable RDTSCP support on Opteron_G[345] CPU models List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= , Eduardo Habkost Cc: Paolo Bonzini , =?utf-8?B?SsO2cmcgUsO2ZGVs?= , Andre Przywara , kvm ML , lkml , Tom Lendacky , Eric Blake , qemu-devel@nongnu.org + qemu-devel. On Tue, Dec 11, 2018 at 03:30:17PM +0000, Daniel P. Berrang=C3=A9 wrote: > Great, then, this is a non-issue - we just need to mention that fact > in the commit that sets the min version for the kernel Ok, here's a first draft ontop of Eduardo's machine-next branch from http://github.com/ehabkost/qemu Also, thanks for the help Eduardo! :-) --- From: Borislav Petkov Date: Tue, 11 Dec 2018 17:01:00 +0100 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 >=3D 0x40). Document the host's minimum required kernel version, while at it. Signed-off-by: Borislav Petkov --- include/hw/i386/pc.h | 17 +++++++++++++---- qemu-doc.texi | 13 +++++++++++++ target/i386/cpu.c | 11 ++++------- 3 files changed, 30 insertions(+), 11 deletions(-) diff --git a/include/hw/i386/pc.h b/include/hw/i386/pc.h index 9d29c4b1df2a..ebc28e816b04 100644 --- a/include/hw/i386/pc.h +++ b/include/hw/i386/pc.h @@ -296,6 +296,19 @@ bool e820_get_entry(int, uint32_t, uint64_t *, uint6= 4_t *); =20 #define PC_COMPAT_3_1 \ HW_COMPAT_3_1 \ + {\ + .driver =3D "Opteron_G3" "-" TYPE_X86_CPU,\ + .property =3D "rdtscp",\ + .value =3D "off",\ + },{\ + .driver =3D "Opteron_G4" "-" TYPE_X86_CPU,\ + .property =3D "rdtscp",\ + .value =3D "off",\ + },{\ + .driver =3D "Opteron_G5" "-" TYPE_X86_CPU,\ + .property =3D "rdtscp",\ + .value =3D "off",\ + }, =20 #define PC_COMPAT_3_0 \ HW_COMPAT_3_0 \ @@ -527,10 +540,6 @@ bool e820_get_entry(int, uint32_t, uint64_t *, uint6= 4_t *); .driver =3D "qemu32" "-" TYPE_X86_CPU,\ .property =3D "popcnt",\ .value =3D "on",\ - },{\ - .driver =3D "Opteron_G2" "-" TYPE_X86_CPU,\ - .property =3D "rdtscp",\ - .value =3D "on",\ },{\ .driver =3D "Opteron_G3" "-" TYPE_X86_CPU,\ .property =3D "rdtscp",\ diff --git a/qemu-doc.texi b/qemu-doc.texi index f7ad1dfe4b69..16b955cbf985 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 =20 +@node System requirements +@chapter System requirements + +@section KVM kernel module + +On x86_64 hosts, the default set of CPU features enabled by the KVM acce= lerator +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. =20 @include qemu-tech.texi =20 diff --git a/target/i386/cpu.c b/target/i386/cpu.c index f81d35e1f914..a7def11b27cd 100644 --- a/target/i386/cpu.c +++ b/target/i386/cpu.c @@ -2706,7 +2706,6 @@ static X86CPUDefinition builtin_x86_defs[] =3D { CPUID_DE | CPUID_FP87, .features[FEAT_1_ECX] =3D CPUID_EXT_CX16 | CPUID_EXT_SSE3, - /* Missing: CPUID_EXT2_RDTSCP */ .features[FEAT_8000_0001_EDX] =3D CPUID_EXT2_LM | CPUID_EXT2_NX | CPUID_EXT2_SYSCALL, .features[FEAT_8000_0001_ECX] =3D @@ -2730,9 +2729,9 @@ static X86CPUDefinition builtin_x86_defs[] =3D { .features[FEAT_1_ECX] =3D CPUID_EXT_POPCNT | CPUID_EXT_CX16 | CPUID_EXT_MONITOR | CPUID_EXT_SSE3, - /* Missing: CPUID_EXT2_RDTSCP */ .features[FEAT_8000_0001_EDX] =3D - 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] =3D CPUID_EXT3_MISALIGNSSE | CPUID_EXT3_SSE4A | CPUID_EXT3_ABM | CPUID_EXT3_SVM | CPUID_EXT3_LAHF_LM, @@ -2757,10 +2756,9 @@ static X86CPUDefinition builtin_x86_defs[] =3D { 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] =3D CPUID_EXT2_LM | CPUID_EXT2_PDPE1GB | CPUID_EXT2_NX | - CPUID_EXT2_SYSCALL, + CPUID_EXT2_SYSCALL | CPUID_EXT2_RDTSCP, .features[FEAT_8000_0001_ECX] =3D CPUID_EXT3_FMA4 | CPUID_EXT3_XOP | CPUID_EXT3_3DNOWPREFETCH | CPUID_EXT3_MISALIGNSSE | @@ -2788,10 +2786,9 @@ static X86CPUDefinition builtin_x86_defs[] =3D { 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] =3D CPUID_EXT2_LM | CPUID_EXT2_PDPE1GB | CPUID_EXT2_NX | - CPUID_EXT2_SYSCALL, + CPUID_EXT2_SYSCALL | CPUID_EXT2_RDTSCP, .features[FEAT_8000_0001_ECX] =3D CPUID_EXT3_TBM | CPUID_EXT3_FMA4 | CPUID_EXT3_XOP | CPUID_EXT3_3DNOWPREFETCH | CPUID_EXT3_MISALIGNSSE | --=20 2.19.1 --=20 Regards/Gruss, Boris. Good mailing practices for 400: avoid top-posting and trim the reply.