search for: reenlighten

...wrote: >> >> Andy Lutomirski <luto at kernel.org> writes: >> >>> Hi Vitaly, Paolo, Radim, etc., >>> >> The notification you're talking about exists, it is called >> Reenligntenment, see 0092e4346f49 "x86/kvm: Support Hyper-V >> reenlightenment"). When TSC page changes (and this only happens when L1 >> is migrated to a different host with a different TSC frequency and TSC >> scaling is not supported by the CPU) we receive an interrupt in L1 (at >> this moment all TSC accesses are emulated which guarantees the &g...

...wrote: >> >> Andy Lutomirski <luto at kernel.org> writes: >> >>> Hi Vitaly, Paolo, Radim, etc., >>> >> The notification you're talking about exists, it is called >> Reenligntenment, see 0092e4346f49 "x86/kvm: Support Hyper-V >> reenlightenment"). When TSC page changes (and this only happens when L1 >> is migrated to a different host with a different TSC frequency and TSC >> scaling is not supported by the CPU) we receive an interrupt in L1 (at >> this moment all TSC accesses are emulated which guarantees the &g...

...; Andy Lutomirski <luto at kernel.org> writes: >>> >>>> Hi Vitaly, Paolo, Radim, etc., >>>> >>> The notification you're talking about exists, it is called >>> Reenligntenment, see 0092e4346f49 "x86/kvm: Support Hyper-V >>> reenlightenment"). When TSC page changes (and this only happens when L1 >>> is migrated to a different host with a different TSC frequency and TSC >>> scaling is not supported by the CPU) we receive an interrupt in L1 (at >>> this moment all TSC accesses are emulated which guara...

...scale and KVM was tought to treat this clocksource as a good one (see b0c39dc68e3b "x86/kvm: Pass stable clocksource to guests when running nested on Hyper-V"). The notification you're talking about exists, it is called Reenligntenment, see 0092e4346f49 "x86/kvm: Support Hyper-V reenlightenment"). When TSC page changes (and this only happens when L1 is migrated to a different host with a different TSC frequency and TSC scaling is not supported by the CPU) we receive an interrupt in L1 (at this moment all TSC accesses are emulated which guarantees the correctness of the readings),...

...scale and KVM was tought to treat this clocksource as a good one (see b0c39dc68e3b "x86/kvm: Pass stable clocksource to guests when running nested on Hyper-V"). The notification you're talking about exists, it is called Reenligntenment, see 0092e4346f49 "x86/kvm: Support Hyper-V reenlightenment"). When TSC page changes (and this only happens when L1 is migrated to a different host with a different TSC frequency and TSC scaling is not supported by the CPU) we receive an interrupt in L1 (at this moment all TSC accesses are emulated which guarantees the correctness of the readings),...

On Wed, 3 Oct 2018, Andy Lutomirski wrote: > > On Oct 3, 2018, at 5:01 AM, Vitaly Kuznetsov <vkuznets at redhat.com> wrote: > > Not all Hyper-V hosts support reenlightenment notifications (and, if I'm > > not mistaken, you need to enable nesting for the VM to get the feature - > > and most VMs don't have this) so I think we'll have to keep Hyper-V > > vclock for the time being. > > > But this does suggest that the correct way...

...could pass *hyperv's* clock, but > > > L1 isn't notified when the data structure changes, so how the heck is > > > it supposed to update the kvmclock structure? > > > > I don't parse your question. > > Let me ask it more intelligently: when the "reenlightenment" IRQ > happens, what tells KVM to do its own update for its guests? Update of what, and why it needs to update anything from IRQ? The update i can think of is from host kernel clocksource, which there is a notifier for.

...could pass *hyperv's* clock, but > > > L1 isn't notified when the data structure changes, so how the heck is > > > it supposed to update the kvmclock structure? > > > > I don't parse your question. > > Let me ask it more intelligently: when the "reenlightenment" IRQ > happens, what tells KVM to do its own update for its guests? Update of what, and why it needs to update anything from IRQ? The update i can think of is from host kernel clocksource, which there is a notifier for.

On Tue, Oct 02, 2018 at 10:15:49PM -0700, Andy Lutomirski wrote: > Hi Vitaly, Paolo, Radim, etc., > > On Fri, Sep 14, 2018 at 5:52 AM Thomas Gleixner <tglx at linutronix.de> wrote: > > > > Matt attempted to add CLOCK_TAI support to the VDSO clock_gettime() > > implementation, which extended the clockid switch case and added yet > > another slightly different

On Tue, Oct 02, 2018 at 10:15:49PM -0700, Andy Lutomirski wrote: > Hi Vitaly, Paolo, Radim, etc., > > On Fri, Sep 14, 2018 at 5:52 AM Thomas Gleixner <tglx at linutronix.de> wrote: > > > > Matt attempted to add CLOCK_TAI support to the VDSO clock_gettime() > > implementation, which extended the clockid switch case and added yet > > another slightly different

...guest when L0 is hyperv. KVM could pass *hyperv's* clock, but > > L1 isn't notified when the data structure changes, so how the heck is > > it supposed to update the kvmclock structure? > > I don't parse your question. Let me ask it more intelligently: when the "reenlightenment" IRQ happens, what tells KVM to do its own update for its guests?

...ck, but > > > > L1 isn't notified when the data structure changes, so how the heck is > > > > it supposed to update the kvmclock structure? > > > > > > I don't parse your question. > > > > Let me ask it more intelligently: when the "reenlightenment" IRQ > > happens, what tells KVM to do its own update for its guests? > > Update of what, and why it needs to update anything from IRQ? > > The update i can think of is from host kernel clocksource, > which there is a notifier for. > > Unless I've missed som...

...eat > this clocksource as a good one (see b0c39dc68e3b "x86/kvm: Pass stable > clocksource to guests when running nested on Hyper-V"). > > The notification you're talking about exists, it is called > Reenligntenment, see 0092e4346f49 "x86/kvm: Support Hyper-V > reenlightenment"). When TSC page changes (and this only happens when L1 > is migrated to a different host with a different TSC frequency and TSC > scaling is not supported by the CPU) we receive an interrupt in L1 (at > this moment all TSC accesses are emulated which guarantees the > correctne...

...eat > this clocksource as a good one (see b0c39dc68e3b "x86/kvm: Pass stable > clocksource to guests when running nested on Hyper-V"). > > The notification you're talking about exists, it is called > Reenligntenment, see 0092e4346f49 "x86/kvm: Support Hyper-V > reenlightenment"). When TSC page changes (and this only happens when L1 > is migrated to a different host with a different TSC frequency and TSC > scaling is not supported by the CPU) we receive an interrupt in L1 (at > this moment all TSC accesses are emulated which guarantees the > correctne...

https://bugs.freedesktop.org/show_bug.cgi?id=112070 Bug ID: 112070 Summary: H/W Acceleration sufficiently buggy on Debian to hard lock machine GeForce 7600 GO Product: xorg Version: unspecified Hardware: x86-64 (AMD64) OS: other Status: NEW Severity: critical Priority: not

Matt attempted to add CLOCK_TAI support to the VDSO clock_gettime() implementation, which extended the clockid switch case and added yet another slightly different copy of the same code. Especially the extended switch case is problematic as the compiler tends to generate a jump table which then requires to use retpolines. If jump tables are disabled it adds yet another conditional to the existing

Matt attempted to add CLOCK_TAI support to the VDSO clock_gettime() implementation, which extended the clockid switch case and added yet another slightly different copy of the same code. Especially the extended switch case is problematic as the compiler tends to generate a jump table which then requires to use retpolines. If jump tables are disabled it adds yet another conditional to the existing