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From:   Raghavendra Rao Ananta <rananta@google.com>
Date:   Tue, 14 Sep 2021 09:51:51 -0700
Message-ID: <CAJHc60w_p5d0=0_BthStcutUywNJaJjamMdJrhD6HbFt_BVFHw@mail.gmail.com>
Subject: Re: [PATCH v6 09/14] KVM: arm64: selftests: Add guest support to get
 the vcpuid
To:     Andrew Jones <drjones@redhat.com>
Cc:     Paolo Bonzini <pbonzini@redhat.com>, Marc Zyngier <maz@kernel.org>,
        James Morse <james.morse@arm.com>,
        Alexandru Elisei <alexandru.elisei@arm.com>,
        Suzuki K Poulose <suzuki.poulose@arm.com>,
        Catalin Marinas <catalin.marinas@arm.com>,
        Will Deacon <will@kernel.org>, Peter Shier <pshier@google.com>,
        Ricardo Koller <ricarkol@google.com>,
        Oliver Upton <oupton@google.com>,
        Reiji Watanabe <reijiw@google.com>,
        Jing Zhang <jingzhangos@google.com>,
        linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu,
        linux-kernel@vger.kernel.org, kvm@vger.kernel.org
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On Tue, Sep 14, 2021 at 12:03 AM Andrew Jones <drjones@redhat.com> wrote:
>
> On Mon, Sep 13, 2021 at 11:09:50PM +0000, Raghavendra Rao Ananta wrote:
> > At times, such as when in the interrupt handler, the guest wants
> > to get the vcpuid that it's running on to pull the per-cpu private
> > data. As a result, introduce guest_get_vcpuid() that returns the
> > vcpuid of the calling vcpu. The interface is architecture
> > independent, but defined only for arm64 as of now.
> >
> > Suggested-by: Reiji Watanabe <reijiw@google.com>
> > Signed-off-by: Raghavendra Rao Ananta <rananta@google.com>
> > Reviewed-by: Ricardo Koller <ricarkol@google.com>
> > ---
> >  tools/testing/selftests/kvm/include/kvm_util.h      | 2 ++
> >  tools/testing/selftests/kvm/lib/aarch64/processor.c | 6 ++++++
> >  2 files changed, 8 insertions(+)
> >
> > diff --git a/tools/testing/selftests/kvm/include/kvm_util.h b/tools/testing/selftests/kvm/include/kvm_util.h
> > index 010b59b13917..5770751a5735 100644
> > --- a/tools/testing/selftests/kvm/include/kvm_util.h
> > +++ b/tools/testing/selftests/kvm/include/kvm_util.h
> > @@ -400,4 +400,6 @@ uint64_t get_ucall(struct kvm_vm *vm, uint32_t vcpu_id, struct ucall *uc);
> >  int vm_get_stats_fd(struct kvm_vm *vm);
> >  int vcpu_get_stats_fd(struct kvm_vm *vm, uint32_t vcpuid);
> >
> > +int guest_get_vcpuid(void);
> > +
> >  #endif /* SELFTEST_KVM_UTIL_H */
> > diff --git a/tools/testing/selftests/kvm/lib/aarch64/processor.c b/tools/testing/selftests/kvm/lib/aarch64/processor.c
> > index db64ee206064..f1255f44dad0 100644
> > --- a/tools/testing/selftests/kvm/lib/aarch64/processor.c
> > +++ b/tools/testing/selftests/kvm/lib/aarch64/processor.c
> > @@ -277,6 +277,7 @@ void aarch64_vcpu_setup(struct kvm_vm *vm, int vcpuid, struct kvm_vcpu_init *ini
>
> x86's vcpu_setup strangely uses 'int' for vcpuid even though everywhere
> else we use uint32_t. Unfortunately that strangeness got inherited by
> aarch64 (my fault). We should change it to uint32_t here (as a separate
> patch) and...
>
I can send one out as a part of this series.

Regards,
Raghavendra
> >       set_reg(vm, vcpuid, KVM_ARM64_SYS_REG(SYS_TCR_EL1), tcr_el1);
> >       set_reg(vm, vcpuid, KVM_ARM64_SYS_REG(SYS_MAIR_EL1), DEFAULT_MAIR_EL1);
> >       set_reg(vm, vcpuid, KVM_ARM64_SYS_REG(SYS_TTBR0_EL1), vm->pgd);
> > +     set_reg(vm, vcpuid, KVM_ARM64_SYS_REG(SYS_TPIDR_EL1), vcpuid);
> >  }
> >
> >  void vcpu_dump(FILE *stream, struct kvm_vm *vm, uint32_t vcpuid, uint8_t indent)
> > @@ -426,3 +427,8 @@ void vm_install_exception_handler(struct kvm_vm *vm, int vector,
> >       assert(vector < VECTOR_NUM);
> >       handlers->exception_handlers[vector][0] = handler;
> >  }
> > +
> > +int guest_get_vcpuid(void)
> > +{
> > +     return read_sysreg(tpidr_el1);
> > +}
>
> ...return uint32_t here.
>
> Thanks,
> drew
>