> -----Original Message-----
> From: Marc Zyngier <maz@xxxxxxxxxx>
> Sent: Wednesday, August 19, 2020 6:00 PM
> To: Jianyong Wu <Jianyong.Wu@xxxxxxx>
> Cc: Paolo Bonzini <pbonzini@xxxxxxxxxx>; Peng Hao
> <richard.peng@xxxxxxxx>; kernel-team@xxxxxxxxxxx;
> kvm@xxxxxxxxxxxxxxx; Will Deacon <will@xxxxxxxxxx>; Catalin Marinas
> <Catalin.Marinas@xxxxxxx>; Alexander Graf <graf@xxxxxxxxxx>;
> kvmarm@xxxxxxxxxxxxxxxxxxxxx; linux-arm-kernel@xxxxxxxxxxxxxxxxxxx
> Subject: Re: [PATCH 47/56] KVM: arm64: timers: Move timer registers to the
> sys_regs file
>
> On 2020-08-19 10:24, Jianyong Wu wrote:
> > Hi Marc,
> >
> > -----Original Message-----
> > From: kvmarm-bounces@xxxxxxxxxxxxxxxxxxxxx
> > <kvmarm-bounces@xxxxxxxxxxxxxxxxxxxxx> On Behalf Of Marc Zyngier
> > Sent: Thursday, August 6, 2020 1:57 AM
> > To: Paolo Bonzini <pbonzini@xxxxxxxxxx>
> > Cc: Peng Hao <richard.peng@xxxxxxxx>; kernel-team@xxxxxxxxxxx;
> > kvm@xxxxxxxxxxxxxxx; Will Deacon <will@xxxxxxxxxx>; Catalin Marinas
> > <Catalin.Marinas@xxxxxxx>; Alexander Graf <graf@xxxxxxxxxx>;
> > kvmarm@xxxxxxxxxxxxxxxxxxxxx; linux-arm-kernel@xxxxxxxxxxxxxxxxxxx
> > Subject: [PATCH 47/56] KVM: arm64: timers: Move timer registers to the
> > sys_regs file
> >
> > Move the timer gsisters to the sysreg file. This will further help
> > when they are directly changed by a nesting hypervisor in the VNCR
> > page.
> >
> > This requires moving the initialisation of the timer struct so that
> > some of the helpers (such as arch_timer_ctx_index) can work correctly
> > at an early stage.
> >
> > Signed-off-by: Marc Zyngier <maz@xxxxxxxxxx>
> > ---
> > arch/arm64/include/asm/kvm_host.h | 6 ++
> > arch/arm64/kvm/arch_timer.c | 155 +++++++++++++++++++++++-------
> > arch/arm64/kvm/trace_arm.h | 8 +-
> > include/kvm/arm_arch_timer.h | 11 +--
> > 4 files changed, 136 insertions(+), 44 deletions(-)
> >
> > +static u64 timer_get_offset(struct arch_timer_context *ctxt) {
> > + struct kvm_vcpu *vcpu = ctxt->vcpu;
> > +
> > + switch(arch_timer_ctx_index(ctxt)) {
> > + case TIMER_VTIMER:
> > + return __vcpu_sys_reg(vcpu, CNTVOFF_EL2);
> > + default:
> > + return 0;
> > + }
> > +}
> > +
> > Can I export this helper? As in my ptp_kvm implementation I need get
> > VCNT offset value separately not just give me a result of VCNT.
>
> Sorry, you need to give me a bit more context. What do you need the offset
> for exactly?
Yeah,
In my ptp_kvm implementation, I need acquire wall time and counter cycle in the same time in host. After get host counter cycle, I need subtract it by VCNT offset to obtain VCNT. See https://lkml.org/lkml/2020/6/19/441 https://lkml.org/lkml/2020/6/19/441
But now I can't get the VCNT offset easily like before using " vcpu_vtimer(vcpu)->cntvoff" and I can't use the helper like "kvm_arm_timer_read" as I need acquire the counter cycle in the same time with the host wall time.
Thanks
Jianyong
>
> M.
> --
> Jazz is not dead. It just smells funny...
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