* Re: kvm: RDTSCP on AMD
@ 2018-12-10 18:13 Borislav Petkov
2018-12-10 18:37 ` Eduardo Habkost
0 siblings, 1 reply; 22+ messages in thread
From: Borislav Petkov @ 2018-12-10 18:13 UTC (permalink / raw)
To: Paolo Bonzini
Cc: Eduardo Habkost, Jörg Rödel, Andre Przywara, kvm ML,
lkml, Tom Lendacky
Reviving an old thread here.
On Wed, Jul 06, 2016 at 11:27:16PM +0200, Paolo Bonzini wrote:
> On 06/07/2016 19:34, Eduardo Habkost wrote:
> >> > Nothing is needed in the kernel actually. You can skip the intercept
> >> > by running the guest with MSR_TSC_AUX set to the guest's expected value.
> >> > Which KVM does, except that it's botched so I need to apply the
> >> > patch in https://lkml.org/lkml/2016/4/13/802.
> > Do you mean -cpu Opteron_G*,+rdtscp will be buggy on Linux v4.5?
> > (v4.5 reports rdtscp as supported in GET_SUPPORTED_CPUID)
> >
> > Can we do something to make QEMU detect the buggy kernel before
> > allowing rdtscp to be enabled, or should we just tell people to
> > upgrade their kernel?
>
> We usually just tell people to use the latest stable kernel.
>
> Adding new CPU models is not a big deal, in fact it's almost easier than
> getting compat properties right. :)
Ok, can we finally revert
33b5e8c03ae7 ("target-i386: Disable rdtscp on Opteron_G* CPU models")
in the qemu tree?
Three years should be enough by now for
46896c73c1a4 ("KVM: svm: add support for RDTSCP")
to have percolated downstream.
Btw, its commit message talks about Linux not using RDTSCP but that will
change soon. :-)
Oh, and the EPYC qemu CPU model has CPUID_EXT2_RDTSCP and works just
fine when patching in RDTSCP:
[ 0.543197] apply_alternatives: feat: 3*32+18, old: (read_tsc+0x0/0x10 (ffffffff8101d1c0) len: 5), repl: (ffffffff824e6d33, len: 5), pad: 3
[ 0.544448] ffffffff8101d1c0: old_insn: 0f 31 90 90 90
[ 0.545023] ffffffff824e6d33: rpl_insn: 0f ae e8 0f 31
[ 0.545598] ffffffff8101d1c0: final_insn: 0f ae e8 0f 31
[ 0.546193] apply_alternatives: feat: 1*32+27, old: (read_tsc+0x0/0x10 (ffffffff8101d1c0) len: 5), repl: (ffffffff824e6d38, len: 3), pad: 3
[ 0.547195] ffffffff8101d1c0: old_insn: 0f ae e8 0f 31
[ 0.547775] ffffffff824e6d38: rpl_insn: 0f 01 f9
[ 0.548307] ffffffff8101d1c0: final_insn: 0f 01 f9 66 90
That final_insn which gets patched to by the alternatives is
ffffffff8101d1c0: 0f 01 f9 rdtscp
ffffffff8101d1c3: 66 90 xchg %ax,%ax
Thx.
--
Regards/Gruss,
Boris.
Good mailing practices for 400: avoid top-posting and trim the reply.
^ permalink raw reply [flat|nested] 22+ messages in thread* Re: kvm: RDTSCP on AMD 2018-12-10 18:13 kvm: RDTSCP on AMD Borislav Petkov @ 2018-12-10 18:37 ` Eduardo Habkost 2018-12-10 18:41 ` Borislav Petkov 0 siblings, 1 reply; 22+ messages in thread From: Eduardo Habkost @ 2018-12-10 18:37 UTC (permalink / raw) To: Borislav Petkov Cc: Paolo Bonzini, Jörg Rödel, Andre Przywara, kvm ML, lkml, Tom Lendacky On Mon, Dec 10, 2018 at 07:13:28PM +0100, Borislav Petkov wrote: > Reviving an old thread here. > > On Wed, Jul 06, 2016 at 11:27:16PM +0200, Paolo Bonzini wrote: > > On 06/07/2016 19:34, Eduardo Habkost wrote: > > >> > Nothing is needed in the kernel actually. You can skip the intercept > > >> > by running the guest with MSR_TSC_AUX set to the guest's expected value. > > >> > Which KVM does, except that it's botched so I need to apply the > > >> > patch in https://lkml.org/lkml/2016/4/13/802. > > > Do you mean -cpu Opteron_G*,+rdtscp will be buggy on Linux v4.5? > > > (v4.5 reports rdtscp as supported in GET_SUPPORTED_CPUID) > > > > > > Can we do something to make QEMU detect the buggy kernel before > > > allowing rdtscp to be enabled, or should we just tell people to > > > upgrade their kernel? > > > > We usually just tell people to use the latest stable kernel. > > > > Adding new CPU models is not a big deal, in fact it's almost easier than > > getting compat properties right. :) > > Ok, can we finally revert > > 33b5e8c03ae7 ("target-i386: Disable rdtscp on Opteron_G* CPU models") > > in the qemu tree? > > Three years should be enough by now for > > 46896c73c1a4 ("KVM: svm: add support for RDTSCP") > > to have percolated downstream. That's Linux v4.5, released in March 2016. It isn't as simply as reverting commit 33b5e8c03ae7, but we can surely re-add RDTSCP on pc-*-4.0 and newer. I thought we added documentation mentioning the minimum kernel version required by QEMU, but I can't find it. In either case, it seems reasonable to require Linux 4.5 or newer on newer machine-types. -- Eduardo ^ permalink raw reply [flat|nested] 22+ messages in thread
* Re: kvm: RDTSCP on AMD 2018-12-10 18:37 ` Eduardo Habkost @ 2018-12-10 18:41 ` Borislav Petkov 2018-12-10 19:06 ` Eduardo Habkost 2018-12-10 19:47 ` kvm: RDTSCP on AMD Eduardo Habkost 0 siblings, 2 replies; 22+ messages in thread From: Borislav Petkov @ 2018-12-10 18:41 UTC (permalink / raw) To: Eduardo Habkost Cc: Paolo Bonzini, Jörg Rödel, Andre Przywara, kvm ML, lkml, Tom Lendacky On Mon, Dec 10, 2018 at 04:37:30PM -0200, Eduardo Habkost wrote: > It isn't as simply as reverting commit 33b5e8c03ae7, but we can > surely re-add RDTSCP on pc-*-4.0 and newer. Sure. If you could only point me to an example how to add that to pc-*-4.0 and newer, I'll gladly cook up a patch and test it. > I thought we added documentation mentioning the minimum kernel > version required by QEMU, but I can't find it. In either case, > it seems reasonable to require Linux 4.5 or newer on newer > machine-types. When you say "require" does that mean, one puts it in a text file somewhere in the qemu sources or do we enforce it somehow? Thx. -- Regards/Gruss, Boris. Good mailing practices for 400: avoid top-posting and trim the reply. ^ permalink raw reply [flat|nested] 22+ messages in thread
* Re: kvm: RDTSCP on AMD 2018-12-10 18:41 ` Borislav Petkov @ 2018-12-10 19:06 ` Eduardo Habkost 2018-12-10 19:42 ` Borislav Petkov 2018-12-10 19:47 ` kvm: RDTSCP on AMD Eduardo Habkost 1 sibling, 1 reply; 22+ messages in thread From: Eduardo Habkost @ 2018-12-10 19:06 UTC (permalink / raw) To: Borislav Petkov Cc: Paolo Bonzini, Jörg Rödel, Andre Przywara, kvm ML, lkml, Tom Lendacky On Mon, Dec 10, 2018 at 07:41:53PM +0100, Borislav Petkov wrote: > On Mon, Dec 10, 2018 at 04:37:30PM -0200, Eduardo Habkost wrote: > > It isn't as simply as reverting commit 33b5e8c03ae7, but we can > > surely re-add RDTSCP on pc-*-4.0 and newer. > > Sure. If you could only point me to an example how to add that to > pc-*-4.0 and newer, I'll gladly cook up a patch and test it. > > > I thought we added documentation mentioning the minimum kernel > > version required by QEMU, but I can't find it. In either case, > > it seems reasonable to require Linux 4.5 or newer on newer > > machine-types. > > When you say "require" does that mean, one puts it in a text file > somewhere in the qemu sources or do we enforce it somehow? I mean documenting it. We already have code that will print warnings if a feature isn't available. See my previous attempt to document the minimum kernel version at <https://www.mail-archive.com/qemu-devel@nongnu.org/msg486559.html>. -- Eduardo ^ permalink raw reply [flat|nested] 22+ messages in thread
* Re: kvm: RDTSCP on AMD 2018-12-10 19:06 ` Eduardo Habkost @ 2018-12-10 19:42 ` Borislav Petkov 2018-12-10 20:08 ` Eduardo Habkost 0 siblings, 1 reply; 22+ messages in thread From: Borislav Petkov @ 2018-12-10 19:42 UTC (permalink / raw) To: Eduardo Habkost Cc: Paolo Bonzini, Jörg Rödel, Andre Przywara, kvm ML, lkml, Tom Lendacky On Mon, Dec 10, 2018 at 05:06:00PM -0200, Eduardo Habkost wrote: > I mean documenting it. We already have code that will print > warnings if a feature isn't available. > > See my previous attempt to document the minimum kernel version > at <https://www.mail-archive.com/qemu-devel@nongnu.org/msg486559.html>. Something like this? I still have no clue how to add RDTSCP on pc-*-4.0 and newer. Thx. --- diff --git a/qemu-doc.texi b/qemu-doc.texi index f7ad1dfe4b69..913b2ef68d54 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 +2814,13 @@ 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. @include qemu-tech.texi diff --git a/target/i386/cpu.c b/target/i386/cpu.c index f81d35e1f914..34bb5b74136d 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 */ .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, .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, .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, .features[FEAT_8000_0001_ECX] = CPUID_EXT3_TBM | CPUID_EXT3_FMA4 | CPUID_EXT3_XOP | CPUID_EXT3_3DNOWPREFETCH | CPUID_EXT3_MISALIGNSSE | -- Regards/Gruss, Boris. Good mailing practices for 400: avoid top-posting and trim the reply. ^ permalink raw reply related [flat|nested] 22+ messages in thread
* Re: kvm: RDTSCP on AMD 2018-12-10 19:42 ` Borislav Petkov @ 2018-12-10 20:08 ` Eduardo Habkost 2018-12-10 20:39 ` Borislav Petkov 2018-12-11 10:38 ` Daniel P. Berrangé 0 siblings, 2 replies; 22+ messages in thread From: Eduardo Habkost @ 2018-12-10 20:08 UTC (permalink / raw) To: Borislav Petkov Cc: Paolo Bonzini, Jörg Rödel, Andre Przywara, kvm ML, lkml, Tom Lendacky, Daniel P. Berrange, Eric Blake On Mon, Dec 10, 2018 at 08:42:58PM +0100, Borislav Petkov wrote: > On Mon, Dec 10, 2018 at 05:06:00PM -0200, Eduardo Habkost wrote: > > I mean documenting it. We already have code that will print > > warnings if a feature isn't available. > > > > See my previous attempt to document the minimum kernel version > > at <https://www.mail-archive.com/qemu-devel@nongnu.org/msg486559.html>. > > Something like this? > > I still have no clue how to add RDTSCP on pc-*-4.0 and newer. qemu.git master have no PC_COMPAT_3_1 and pc-*-4.0 machine-types yet. I've sent another reply with additional pointers. > > Thx. > > --- > diff --git a/qemu-doc.texi b/qemu-doc.texi > index f7ad1dfe4b69..913b2ef68d54 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 +2814,13 @@ 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. > Sounds good, but it would be nice to document what exactly makes Linux 4.5+ necessary. e.g.: | On x86_64 hosts, it is recommended to run Linux 4.5 or newer on | the host when using the KVM accelerator. | | The Opteron_G2, OpteronG3, Opteron_G4, and Opteron_G5 CPU | models require KVM support for RDTSCP, which was added on | Linux 4.5. I'm CCing some people who may help review English grammar and style. -- Eduardo ^ permalink raw reply [flat|nested] 22+ messages in thread
* Re: kvm: RDTSCP on AMD 2018-12-10 20:08 ` Eduardo Habkost @ 2018-12-10 20:39 ` Borislav Petkov 2018-12-11 10:38 ` Daniel P. Berrangé 1 sibling, 0 replies; 22+ messages in thread From: Borislav Petkov @ 2018-12-10 20:39 UTC (permalink / raw) To: Eduardo Habkost Cc: Paolo Bonzini, Jörg Rödel, Andre Przywara, kvm ML, lkml, Tom Lendacky, Daniel P. Berrange, Eric Blake On Mon, Dec 10, 2018 at 06:08:43PM -0200, Eduardo Habkost wrote: > | The Opteron_G2, OpteronG3, Opteron_G4, and Opteron_G5 CPU > | models require KVM support for RDTSCP, which was added on > | Linux 4.5. I've added that to the current diff: "The OpteronG[345] CPU models require KVM support for RDTSCP, which was added with Linux 4.5." In the meantime, I tried executing RDTSCP on a K8 laptop and it gave SIGILL so I'd say the AMD docs have a typo and family 0xf - at least the A-E revisions of which model 6 is a part of - doesn't have RDTSCP. But let's see... Thx. -- Regards/Gruss, Boris. Good mailing practices for 400: avoid top-posting and trim the reply. ^ permalink raw reply [flat|nested] 22+ messages in thread
* Re: kvm: RDTSCP on AMD 2018-12-10 20:08 ` Eduardo Habkost 2018-12-10 20:39 ` Borislav Petkov @ 2018-12-11 10:38 ` Daniel P. Berrangé 2018-12-11 11:55 ` Eduardo Habkost 1 sibling, 1 reply; 22+ messages in thread From: Daniel P. Berrangé @ 2018-12-11 10:38 UTC (permalink / raw) To: Eduardo Habkost Cc: Borislav Petkov, Paolo Bonzini, Jörg Rödel, Andre Przywara, kvm ML, lkml, Tom Lendacky, Eric Blake On Mon, Dec 10, 2018 at 06:08:43PM -0200, Eduardo Habkost wrote: > On Mon, Dec 10, 2018 at 08:42:58PM +0100, Borislav Petkov wrote: > > On Mon, Dec 10, 2018 at 05:06:00PM -0200, Eduardo Habkost wrote: > > > I mean documenting it. We already have code that will print > > > warnings if a feature isn't available. > > > > > > See my previous attempt to document the minimum kernel version > > > at <https://www.mail-archive.com/qemu-devel@nongnu.org/msg486559.html>. > > > > Something like this? > > > > I still have no clue how to add RDTSCP on pc-*-4.0 and newer. > > qemu.git master have no PC_COMPAT_3_1 and pc-*-4.0 machine-types > yet. I've sent another reply with additional pointers. > > > > > Thx. > > > > --- > > diff --git a/qemu-doc.texi b/qemu-doc.texi > > index f7ad1dfe4b69..913b2ef68d54 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 +2814,13 @@ 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. > > > > Sounds good, but it would be nice to document what exactly makes > Linux 4.5+ necessary. e.g.: > > | On x86_64 hosts, it is recommended to run Linux 4.5 or newer on > | the host when using the KVM accelerator. > | > | The Opteron_G2, OpteronG3, Opteron_G4, and Opteron_G5 CPU > | models require KVM support for RDTSCP, which was added on > | Linux 4.5. > > I'm CCing some people who may help review English grammar and > style. Note that QEMU has a declared supported platform list which is used to set the minimum software versions required. https://qemu.weilnetz.de/doc/qemu-doc.html#Linux-OS Based on that policy, the Linux distros we aim to support have the following kernel versions: - Debian Jessie: 4.5 - Debian Stretch: 4.5 - RHEL-7: 3.10 - Ubuntu LTS (Xenial): 4.5 - OpenSUSE Leap 15: 4.12.14 So we can't require Linux 4.5 as a minimum version at this time. Regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :| ^ permalink raw reply [flat|nested] 22+ messages in thread
* Re: kvm: RDTSCP on AMD 2018-12-11 10:38 ` Daniel P. Berrangé @ 2018-12-11 11:55 ` Eduardo Habkost 2018-12-11 14:35 ` Daniel P. Berrangé 2018-12-11 15:23 ` Paolo Bonzini 0 siblings, 2 replies; 22+ messages in thread From: Eduardo Habkost @ 2018-12-11 11:55 UTC (permalink / raw) To: Daniel P. Berrangé Cc: Borislav Petkov, Paolo Bonzini, Jörg Rödel, Andre Przywara, kvm ML, lkml, Tom Lendacky, Eric Blake On Tue, Dec 11, 2018 at 10:38:39AM +0000, Daniel P. Berrangé wrote: > On Mon, Dec 10, 2018 at 06:08:43PM -0200, Eduardo Habkost wrote: > > On Mon, Dec 10, 2018 at 08:42:58PM +0100, Borislav Petkov wrote: > > > On Mon, Dec 10, 2018 at 05:06:00PM -0200, Eduardo Habkost wrote: > > > > I mean documenting it. We already have code that will print > > > > warnings if a feature isn't available. > > > > > > > > See my previous attempt to document the minimum kernel version > > > > at <https://www.mail-archive.com/qemu-devel@nongnu.org/msg486559.html>. > > > > > > Something like this? > > > > > > I still have no clue how to add RDTSCP on pc-*-4.0 and newer. > > > > qemu.git master have no PC_COMPAT_3_1 and pc-*-4.0 machine-types > > yet. I've sent another reply with additional pointers. > > > > > > > > Thx. > > > > > > --- > > > diff --git a/qemu-doc.texi b/qemu-doc.texi > > > index f7ad1dfe4b69..913b2ef68d54 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 +2814,13 @@ 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. > > > > > > > Sounds good, but it would be nice to document what exactly makes > > Linux 4.5+ necessary. e.g.: > > > > | On x86_64 hosts, it is recommended to run Linux 4.5 or newer on > > | the host when using the KVM accelerator. > > | > > | The Opteron_G2, OpteronG3, Opteron_G4, and Opteron_G5 CPU > > | models require KVM support for RDTSCP, which was added on > > | Linux 4.5. > > > > I'm CCing some people who may help review English grammar and > > style. > > Note that QEMU has a declared supported platform list which is used to > set the minimum software versions required. > > https://qemu.weilnetz.de/doc/qemu-doc.html#Linux-OS > > Based on that policy, the Linux distros we aim to support have the > following kernel versions: > > - Debian Jessie: 4.5 > - Debian Stretch: 4.5 > - RHEL-7: 3.10 > - Ubuntu LTS (Xenial): 4.5 > - OpenSUSE Leap 15: 4.12.14 > > So we can't require Linux 4.5 as a minimum version at this time. I'd like us to take a step back and consider what exactly "support" means here. QEMU will still work on older kernels if we add RDTSCP to the CPU models, but at the same time I would like to document that our strict runnability guarantees may not be kept if running Linux < 4.5. -- Eduardo ^ permalink raw reply [flat|nested] 22+ messages in thread
* Re: kvm: RDTSCP on AMD 2018-12-11 11:55 ` Eduardo Habkost @ 2018-12-11 14:35 ` Daniel P. Berrangé 2018-12-11 15:23 ` Paolo Bonzini 1 sibling, 0 replies; 22+ messages in thread From: Daniel P. Berrangé @ 2018-12-11 14:35 UTC (permalink / raw) To: Eduardo Habkost Cc: Borislav Petkov, Paolo Bonzini, Jörg Rödel, Andre Przywara, kvm ML, lkml, Tom Lendacky, Eric Blake On Tue, Dec 11, 2018 at 09:55:46AM -0200, Eduardo Habkost wrote: > On Tue, Dec 11, 2018 at 10:38:39AM +0000, Daniel P. Berrangé wrote: > > On Mon, Dec 10, 2018 at 06:08:43PM -0200, Eduardo Habkost wrote: > > > On Mon, Dec 10, 2018 at 08:42:58PM +0100, Borislav Petkov wrote: > > > > On Mon, Dec 10, 2018 at 05:06:00PM -0200, Eduardo Habkost wrote: > > > > > I mean documenting it. We already have code that will print > > > > > warnings if a feature isn't available. > > > > > > > > > > See my previous attempt to document the minimum kernel version > > > > > at <https://www.mail-archive.com/qemu-devel@nongnu.org/msg486559.html>. > > > > > > > > Something like this? > > > > > > > > I still have no clue how to add RDTSCP on pc-*-4.0 and newer. > > > > > > qemu.git master have no PC_COMPAT_3_1 and pc-*-4.0 machine-types > > > yet. I've sent another reply with additional pointers. > > > > > > > > > > > Thx. > > > > > > > > --- > > > > diff --git a/qemu-doc.texi b/qemu-doc.texi > > > > index f7ad1dfe4b69..913b2ef68d54 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 +2814,13 @@ 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. > > > > > > > > > > Sounds good, but it would be nice to document what exactly makes > > > Linux 4.5+ necessary. e.g.: > > > > > > | On x86_64 hosts, it is recommended to run Linux 4.5 or newer on > > > | the host when using the KVM accelerator. > > > | > > > | The Opteron_G2, OpteronG3, Opteron_G4, and Opteron_G5 CPU > > > | models require KVM support for RDTSCP, which was added on > > > | Linux 4.5. > > > > > > I'm CCing some people who may help review English grammar and > > > style. > > > > Note that QEMU has a declared supported platform list which is used to > > set the minimum software versions required. > > > > https://qemu.weilnetz.de/doc/qemu-doc.html#Linux-OS > > > > Based on that policy, the Linux distros we aim to support have the > > following kernel versions: > > > > - Debian Jessie: 4.5 > > - Debian Stretch: 4.5 > > - RHEL-7: 3.10 > > - Ubuntu LTS (Xenial): 4.5 > > - OpenSUSE Leap 15: 4.12.14 > > > > So we can't require Linux 4.5 as a minimum version at this time. > > I'd like us to take a step back and consider what exactly > "support" means here. QEMU will still work on older kernels if > we add RDTSCP to the CPU models, but at the same time I would > like to document that our strict runnability guarantees may not > be kept if running Linux < 4.5. I've just noticed that this thread is not in fact on qemu-devel. So rather than debating the meaning of support here, lets discuss it once the patch adding rdtscp to OpteronG* CPU model is posted to qemu-devel. Regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :| ^ permalink raw reply [flat|nested] 22+ messages in thread
* Re: kvm: RDTSCP on AMD 2018-12-11 11:55 ` Eduardo Habkost 2018-12-11 14:35 ` Daniel P. Berrangé @ 2018-12-11 15:23 ` Paolo Bonzini 2018-12-11 15:30 ` Daniel P. Berrangé 1 sibling, 1 reply; 22+ messages in thread From: Paolo Bonzini @ 2018-12-11 15:23 UTC (permalink / raw) To: Eduardo Habkost, Daniel P. Berrangé Cc: Borislav Petkov, Jörg Rödel, Andre Przywara, kvm ML, lkml, Tom Lendacky, Eric Blake On 11/12/18 12:55, Eduardo Habkost wrote: >> - Debian Jessie: 4.5 >> - Debian Stretch: 4.5 >> - RHEL-7: 3.10 >> - Ubuntu LTS (Xenial): 4.5 >> - OpenSUSE Leap 15: 4.12.14 >> >> So we can't require Linux 4.5 as a minimum version at this time. > I'd like us to take a step back and consider what exactly > "support" means here. QEMU will still work on older kernels if > we add RDTSCP to the CPU models, but at the same time I would > like to document that our strict runnability guarantees may not > be kept if running Linux < 4.5. Anyway RHEL does have RDTSC support for AMD, and a bunch of other stuff. The frankenkernel's KVM is somewhere between 4.5 and 4.10, with a dash of 4.20 of course. :) Paolo ^ permalink raw reply [flat|nested] 22+ messages in thread
* Re: kvm: RDTSCP on AMD 2018-12-11 15:23 ` Paolo Bonzini @ 2018-12-11 15:30 ` Daniel P. Berrangé 2018-12-11 16:14 ` [Qemu-devel] " Borislav Petkov 0 siblings, 1 reply; 22+ messages in thread From: Daniel P. Berrangé @ 2018-12-11 15:30 UTC (permalink / raw) To: Paolo Bonzini Cc: Eduardo Habkost, Borislav Petkov, Jörg Rödel, Andre Przywara, kvm ML, lkml, Tom Lendacky, Eric Blake On Tue, Dec 11, 2018 at 04:23:51PM +0100, Paolo Bonzini wrote: > On 11/12/18 12:55, Eduardo Habkost wrote: > >> - Debian Jessie: 4.5 > >> - Debian Stretch: 4.5 > >> - RHEL-7: 3.10 > >> - Ubuntu LTS (Xenial): 4.5 > >> - OpenSUSE Leap 15: 4.12.14 > >> > >> So we can't require Linux 4.5 as a minimum version at this time. > > I'd like us to take a step back and consider what exactly > > "support" means here. QEMU will still work on older kernels if > > we add RDTSCP to the CPU models, but at the same time I would > > like to document that our strict runnability guarantees may not > > be kept if running Linux < 4.5. > > Anyway RHEL does have RDTSC support for AMD, and a bunch of other stuff. > The frankenkernel's KVM is somewhere between 4.5 and 4.10, with a dash > of 4.20 of course. :) 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 Regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :| ^ permalink raw reply [flat|nested] 22+ messages in thread
* [PATCH] target-i386: Reenable RDTSCP support on Opteron_G[345] CPU models 2018-12-11 15:30 ` Daniel P. Berrangé @ 2018-12-11 16:14 ` Borislav Petkov 0 siblings, 0 replies; 22+ messages in thread From: Borislav Petkov @ 2018-12-11 16:14 UTC (permalink / raw) To: Daniel P. Berrangé, Eduardo Habkost Cc: Paolo Bonzini, Jörg Rödel, Andre Przywara, kvm ML, lkml, Tom Lendacky, Eric Blake, qemu-devel + 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@suse.de> 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@suse.de> --- 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",\ + }, #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",\ },{\ .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 */ .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, .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, .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, .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. ^ permalink raw reply related [flat|nested] 22+ messages in thread
* [Qemu-devel] [PATCH] target-i386: Reenable RDTSCP support on Opteron_G[345] CPU models @ 2018-12-11 16:14 ` Borislav Petkov 0 siblings, 0 replies; 22+ messages in thread From: Borislav Petkov @ 2018-12-11 16:14 UTC (permalink / raw) To: Daniel P. Berrangé, Eduardo Habkost Cc: Paolo Bonzini, Jörg Rödel, Andre Przywara, kvm ML, lkml, Tom Lendacky, Eric Blake, qemu-devel + 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@suse.de> 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@suse.de> --- 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",\ + }, #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",\ },{\ .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 */ .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, .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, .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, .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. ^ permalink raw reply related [flat|nested] 22+ messages in thread
* Re: [PATCH] target-i386: Reenable RDTSCP support on Opteron_G[345] CPU models 2018-12-11 16:14 ` [Qemu-devel] " Borislav Petkov @ 2018-12-12 19:52 ` Eduardo Habkost -1 siblings, 0 replies; 22+ messages in thread From: Eduardo Habkost @ 2018-12-12 19:52 UTC (permalink / raw) To: Borislav Petkov Cc: Daniel P. Berrangé, Paolo Bonzini, Jörg Rödel, Andre Przywara, kvm ML, lkml, Tom Lendacky, Eric Blake, qemu-devel 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@suse.de> > 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@suse.de> > --- > 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 ^ permalink raw reply [flat|nested] 22+ messages in thread
* Re: [Qemu-devel] [PATCH] target-i386: Reenable RDTSCP support on Opteron_G[345] CPU models @ 2018-12-12 19:52 ` Eduardo Habkost 0 siblings, 0 replies; 22+ messages in thread From: Eduardo Habkost @ 2018-12-12 19:52 UTC (permalink / raw) To: Borislav Petkov Cc: Daniel P. Berrangé, Paolo Bonzini, Jörg Rödel, Andre Przywara, kvm ML, lkml, Tom Lendacky, Eric Blake, qemu-devel 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@suse.de> > 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@suse.de> > --- > 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 ^ permalink raw reply [flat|nested] 22+ messages in thread
* [PATCH -v2] target-i386: Reenable RDTSCP support on Opteron_G[345] CPU models CPU models 2018-12-12 19:52 ` [Qemu-devel] " Eduardo Habkost @ 2018-12-12 20:08 ` Borislav Petkov -1 siblings, 0 replies; 22+ messages in thread From: Borislav Petkov @ 2018-12-12 20:08 UTC (permalink / raw) To: Eduardo Habkost Cc: Daniel P. Berrangé, Paolo Bonzini, Jörg Rödel, Andre Przywara, kvm ML, lkml, Tom Lendacky, Eric Blake, qemu-devel On Wed, Dec 12, 2018 at 05:52:35PM -0200, Eduardo Habkost wrote: > 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. Ok, hunk reverted. v2 below. Thx. --- From: Borislav Petkov <bp@suse.de> 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@suse.de> --- v2: Keep Opteron_G2 in PC_COMPAT_2_4 unchanged. include/hw/i386/pc.h | 13 +++++++++++++ qemu-doc.texi | 13 +++++++++++++ target/i386/cpu.c | 11 ++++------- 3 files changed, 30 insertions(+), 7 deletions(-) diff --git a/include/hw/i386/pc.h b/include/hw/i386/pc.h index 9d29c4b1df2a..236d962d2547 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",\ + }, #define PC_COMPAT_3_0 \ HW_COMPAT_3_0 \ 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 */ .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, .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, .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, .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. ^ permalink raw reply related [flat|nested] 22+ messages in thread
* [Qemu-devel] [PATCH -v2] target-i386: Reenable RDTSCP support on Opteron_G[345] CPU models CPU models @ 2018-12-12 20:08 ` Borislav Petkov 0 siblings, 0 replies; 22+ messages in thread From: Borislav Petkov @ 2018-12-12 20:08 UTC (permalink / raw) To: Eduardo Habkost Cc: Daniel P. Berrangé, Paolo Bonzini, Jörg Rödel, Andre Przywara, kvm ML, lkml, Tom Lendacky, Eric Blake, qemu-devel On Wed, Dec 12, 2018 at 05:52:35PM -0200, Eduardo Habkost wrote: > 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. Ok, hunk reverted. v2 below. Thx. --- From: Borislav Petkov <bp@suse.de> 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@suse.de> --- v2: Keep Opteron_G2 in PC_COMPAT_2_4 unchanged. include/hw/i386/pc.h | 13 +++++++++++++ qemu-doc.texi | 13 +++++++++++++ target/i386/cpu.c | 11 ++++------- 3 files changed, 30 insertions(+), 7 deletions(-) diff --git a/include/hw/i386/pc.h b/include/hw/i386/pc.h index 9d29c4b1df2a..236d962d2547 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",\ + }, #define PC_COMPAT_3_0 \ HW_COMPAT_3_0 \ 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 */ .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, .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, .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, .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. ^ permalink raw reply related [flat|nested] 22+ messages in thread
* Re: [PATCH -v2] target-i386: Reenable RDTSCP support on Opteron_G[345] CPU models CPU models 2018-12-12 20:08 ` [Qemu-devel] " Borislav Petkov @ 2018-12-20 12:10 ` Eduardo Habkost -1 siblings, 0 replies; 22+ messages in thread From: Eduardo Habkost @ 2018-12-20 12:10 UTC (permalink / raw) To: Borislav Petkov Cc: Daniel P. Berrangé, Paolo Bonzini, Jörg Rödel, Andre Przywara, kvm ML, lkml, Tom Lendacky, Eric Blake, qemu-devel On Wed, Dec 12, 2018 at 09:08:03PM +0100, Borislav Petkov wrote: > On Wed, Dec 12, 2018 at 05:52:35PM -0200, Eduardo Habkost wrote: > > 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. > > Ok, hunk reverted. v2 below. > > Thx. > > --- > From: Borislav Petkov <bp@suse.de> > > 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@suse.de> Queued, thanks. -- Eduardo ^ permalink raw reply [flat|nested] 22+ messages in thread
* Re: [Qemu-devel] [PATCH -v2] target-i386: Reenable RDTSCP support on Opteron_G[345] CPU models CPU models @ 2018-12-20 12:10 ` Eduardo Habkost 0 siblings, 0 replies; 22+ messages in thread From: Eduardo Habkost @ 2018-12-20 12:10 UTC (permalink / raw) To: Borislav Petkov Cc: Daniel P. Berrangé, Paolo Bonzini, Jörg Rödel, Andre Przywara, kvm ML, lkml, Tom Lendacky, Eric Blake, qemu-devel On Wed, Dec 12, 2018 at 09:08:03PM +0100, Borislav Petkov wrote: > On Wed, Dec 12, 2018 at 05:52:35PM -0200, Eduardo Habkost wrote: > > 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. > > Ok, hunk reverted. v2 below. > > Thx. > > --- > From: Borislav Petkov <bp@suse.de> > > 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@suse.de> Queued, thanks. -- Eduardo ^ permalink raw reply [flat|nested] 22+ messages in thread
* Re: kvm: RDTSCP on AMD 2018-12-10 18:41 ` Borislav Petkov 2018-12-10 19:06 ` Eduardo Habkost @ 2018-12-10 19:47 ` Eduardo Habkost 2018-12-10 20:16 ` Borislav Petkov 1 sibling, 1 reply; 22+ messages in thread From: Eduardo Habkost @ 2018-12-10 19:47 UTC (permalink / raw) To: Borislav Petkov Cc: Paolo Bonzini, Jörg Rödel, Andre Przywara, kvm ML, lkml, Tom Lendacky On Mon, Dec 10, 2018 at 07:41:53PM +0100, Borislav Petkov wrote: > On Mon, Dec 10, 2018 at 04:37:30PM -0200, Eduardo Habkost wrote: > > It isn't as simply as reverting commit 33b5e8c03ae7, but we can > > surely re-add RDTSCP on pc-*-4.0 and newer. > > Sure. If you could only point me to an example how to add that to > pc-*-4.0 and newer, I'll gladly cook up a patch and test it. Sorry, I forgot to reply to this part. See commit 33b5e8c03ae7 for reference. The differences will be: * Instead of removing RDTSCP from builtin_x86_defs, you'll be adding it. * Instead of adding rdtscp=on entries to PC_COMPAT_2_4, you'll be adding rdtscp=off entries to PC_COMPAT_3_1. PC_COMPAT_3_1 is added by the patch that creates the 4.0 machine-types. You can find it on my machine-next branch at: http://github.com/ehabkost/qemu -- Eduardo ^ permalink raw reply [flat|nested] 22+ messages in thread
* Re: kvm: RDTSCP on AMD 2018-12-10 19:47 ` kvm: RDTSCP on AMD Eduardo Habkost @ 2018-12-10 20:16 ` Borislav Petkov 0 siblings, 0 replies; 22+ messages in thread From: Borislav Petkov @ 2018-12-10 20:16 UTC (permalink / raw) To: Eduardo Habkost Cc: Paolo Bonzini, Jörg Rödel, Andre Przywara, kvm ML, lkml, Tom Lendacky On Mon, Dec 10, 2018 at 05:47:25PM -0200, Eduardo Habkost wrote: > On Mon, Dec 10, 2018 at 07:41:53PM +0100, Borislav Petkov wrote: > > On Mon, Dec 10, 2018 at 04:37:30PM -0200, Eduardo Habkost wrote: > > > It isn't as simply as reverting commit 33b5e8c03ae7, but we can > > > surely re-add RDTSCP on pc-*-4.0 and newer. > > > > Sure. If you could only point me to an example how to add that to > > pc-*-4.0 and newer, I'll gladly cook up a patch and test it. > > Sorry, I forgot to reply to this part. > > See commit 33b5e8c03ae7 for reference. The differences will be: > * Instead of removing RDTSCP from builtin_x86_defs, you'll be adding it. > * Instead of adding rdtscp=on entries to PC_COMPAT_2_4, you'll > be adding rdtscp=off entries to PC_COMPAT_3_1. > > PC_COMPAT_3_1 is added by the patch that creates the 4.0 > machine-types. You can find it on my machine-next branch at: > > http://github.com/ehabkost/qemu Thanks for the patient explanation, diff below ontop of your branch. It is notable to point out that Opteron_G2 - it being family 0xf, model 6 - should not deal with RDTSCP as it doesn't have it. Although looking at the docs, they say it does but I *have* a K8 laptop which I just checked and it *doesn't* have RDTSCP in CPUID. So lemme clarify that aspect first with folks. :) --- 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",\ + }, #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",\ },{\ .driver = "Opteron_G3" "-" TYPE_X86_CPU,\ .property = "rdtscp",\ diff --git a/qemu-doc.texi b/qemu-doc.texi index f7ad1dfe4b69..913b2ef68d54 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 +2814,13 @@ 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. @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 */ .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, .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, .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, .features[FEAT_8000_0001_ECX] = CPUID_EXT3_TBM | CPUID_EXT3_FMA4 | CPUID_EXT3_XOP | CPUID_EXT3_3DNOWPREFETCH | CPUID_EXT3_MISALIGNSSE | -- Regards/Gruss, Boris. Good mailing practices for 400: avoid top-posting and trim the reply. ^ permalink raw reply related [flat|nested] 22+ messages in thread
end of thread, other threads:[~2018-12-20 12:10 UTC | newest] Thread overview: 22+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2018-12-10 18:13 kvm: RDTSCP on AMD Borislav Petkov 2018-12-10 18:37 ` Eduardo Habkost 2018-12-10 18:41 ` Borislav Petkov 2018-12-10 19:06 ` Eduardo Habkost 2018-12-10 19:42 ` Borislav Petkov 2018-12-10 20:08 ` Eduardo Habkost 2018-12-10 20:39 ` Borislav Petkov 2018-12-11 10:38 ` Daniel P. Berrangé 2018-12-11 11:55 ` Eduardo Habkost 2018-12-11 14:35 ` Daniel P. Berrangé 2018-12-11 15:23 ` Paolo Bonzini 2018-12-11 15:30 ` Daniel P. Berrangé 2018-12-11 16:14 ` [PATCH] target-i386: Reenable RDTSCP support on Opteron_G[345] CPU models Borislav Petkov 2018-12-11 16:14 ` [Qemu-devel] " Borislav Petkov 2018-12-12 19:52 ` Eduardo Habkost 2018-12-12 19:52 ` [Qemu-devel] " Eduardo Habkost 2018-12-12 20:08 ` [PATCH -v2] target-i386: Reenable RDTSCP support on Opteron_G[345] CPU models " Borislav Petkov 2018-12-12 20:08 ` [Qemu-devel] " Borislav Petkov 2018-12-20 12:10 ` Eduardo Habkost 2018-12-20 12:10 ` [Qemu-devel] " Eduardo Habkost 2018-12-10 19:47 ` kvm: RDTSCP on AMD Eduardo Habkost 2018-12-10 20:16 ` Borislav Petkov
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