On Tue, Dec 11, 2018 at 05:14:40PM +0100, Borislav Petkov wrote: > + qemu-devel. > > On Tue, Dec 11, 2018 at 03:30:17PM +0000, Daniel P. Berrangé 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 <bp@xxxxxxx> > 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 >= 0x40). > > Document the host's minimum required kernel version, while at it. > > Signed-off-by: Borislav Petkov <bp@xxxxxxx> > --- > 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 *, uint64_t *); > > #define PC_COMPAT_3_1 \ > HW_COMPAT_3_1 \ > + {\ > + .driver = "Opteron_G3" "-" TYPE_X86_CPU,\ > + .property = "rdtscp",\ > + .value = "off",\ > + },{\ > + .driver = "Opteron_G4" "-" TYPE_X86_CPU,\ > + .property = "rdtscp",\ > + .value = "off",\ > + },{\ > + .driver = "Opteron_G5" "-" TYPE_X86_CPU,\ > + .property = "rdtscp",\ > + .value = "off",\ > + }, This looks correct. > > #define PC_COMPAT_3_0 \ > HW_COMPAT_3_0 \ > @@ -527,10 +540,6 @@ bool e820_get_entry(int, uint32_t, uint64_t *, uint64_t *); > .driver = "qemu32" "-" TYPE_X86_CPU,\ > .property = "popcnt",\ > .value = "on",\ > - },{\ > - .driver = "Opteron_G2" "-" TYPE_X86_CPU,\ > - .property = "rdtscp",\ > - .value = "on",\ Why did you remove this entry from PC_COMPAT_2_4? We must keep compatibility with old behavior of Opteron_G2 on pc-2.4, even if the old behavior was incorrect. > },{\ > .driver = "Opteron_G3" "-" TYPE_X86_CPU,\ > .property = "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 > > +@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 f81d35e1f914..a7def11b27cd 100644 > --- a/target/i386/cpu.c > +++ b/target/i386/cpu.c > @@ -2706,7 +2706,6 @@ static X86CPUDefinition builtin_x86_defs[] = { > CPUID_DE | CPUID_FP87, > .features[FEAT_1_ECX] = > CPUID_EXT_CX16 | CPUID_EXT_SSE3, > - /* Missing: CPUID_EXT2_RDTSCP */ This is Opteron_G2, and feature is not being added. Looks correct. > .features[FEAT_8000_0001_EDX] = > CPUID_EXT2_LM | CPUID_EXT2_NX | CPUID_EXT2_SYSCALL, > .features[FEAT_8000_0001_ECX] = > @@ -2730,9 +2729,9 @@ 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, This is Opteron_G3. Looks correct. > .features[FEAT_8000_0001_ECX] = > 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[] = { > 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, This is Opteron_G4. Looks correct. > .features[FEAT_8000_0001_ECX] = > CPUID_EXT3_FMA4 | CPUID_EXT3_XOP | > CPUID_EXT3_3DNOWPREFETCH | CPUID_EXT3_MISALIGNSSE | > @@ -2788,10 +2786,9 @@ 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, This is Opteron_G5. Looks correct. > .features[FEAT_8000_0001_ECX] = > CPUID_EXT3_TBM | CPUID_EXT3_FMA4 | CPUID_EXT3_XOP | > CPUID_EXT3_3DNOWPREFETCH | CPUID_EXT3_MISALIGNSSE | > -- > 2.19.1 > > -- > Regards/Gruss, > Boris. > > Good mailing practices for 400: avoid top-posting and trim the reply. -- Eduardo
