Re: [v2 3/6] KVM: arm64: Support pvlock preempted via shared structure

[Usama Arif]

On 07/11/2022 18:02, Punit Agrawal wrote:
> Usama Arif <usama.arif@xxxxxxxxxxxxx> writes:
>
> > Implement the service call for configuring a shared structure between a
> > VCPU and the hypervisor in which the hypervisor can tell whether the
> > VCPU is running or not.
> >
> > The preempted field is zero if the VCPU is not preempted.
> > Any other value means the VCPU has been preempted.
> >
> > Signed-off-by: Zengruan Ye <yezengruan@xxxxxxxxxx>
> > Signed-off-by: Usama Arif <usama.arif@xxxxxxxxxxxxx>
> > ---
> >   Documentation/virt/kvm/arm/hypercalls.rst |  3 ++
> >   arch/arm64/include/asm/kvm_host.h         | 18 ++++++++++
> >   arch/arm64/include/uapi/asm/kvm.h         |  1 +
> >   arch/arm64/kvm/Makefile                   |  2 +-
> >   arch/arm64/kvm/arm.c                      |  8 +++++
> >   arch/arm64/kvm/hypercalls.c               |  8 +++++
> >   arch/arm64/kvm/pvlock.c                   | 43 +++++++++++++++++++++++
> >   tools/arch/arm64/include/uapi/asm/kvm.h   |  1 +
> >   8 files changed, 83 insertions(+), 1 deletion(-)
> >   create mode 100644 arch/arm64/kvm/pvlock.c
> >
> > diff --git a/Documentation/virt/kvm/arm/hypercalls.rst b/Documentation/virt/kvm/arm/hypercalls.rst
> > index 3e23084644ba..872a16226ace 100644
> > --- a/Documentation/virt/kvm/arm/hypercalls.rst
> > +++ b/Documentation/virt/kvm/arm/hypercalls.rst
> > @@ -127,6 +127,9 @@ The pseudo-firmware bitmap register are as follows:
> >       Bit-1: KVM_REG_ARM_VENDOR_HYP_BIT_PTP:
> >         The bit represents the Precision Time Protocol KVM service.
> >   
> > +    Bit-2: KVM_REG_ARM_VENDOR_HYP_BIT_PV_LOCK:
> > +      The bit represents the Paravirtualized lock service.
> > +
> >   Errors:
> >   
> >       =======  =============================================================
> > diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
> > index 45e2136322ba..18303b30b7e9 100644
> > --- a/arch/arm64/include/asm/kvm_host.h
> > +++ b/arch/arm64/include/asm/kvm_host.h
> > @@ -417,6 +417,11 @@ struct kvm_vcpu_arch {
> >   		u64 last_steal;
> >   		gpa_t base;
> >   	} steal;
> > +
> > +	/* Guest PV lock state */
> > +	struct {
> > +		gpa_t base;
> > +	} pv;
>
> Using "pv" for the structure isn't quite describing the usage well. It'd
> be better to call it "pv_lock" or "pvlock" at the least.
Yes makes sense, will change in next patchset, Thanks.

> [...]