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SubjectRe: [PATCH 01/10] KVM: selftests: Take vcpu pointer instead of id in vm_vcpu_rm()
On Mon, Apr 13, 2020 at 02:26:59PM -0700, Sean Christopherson wrote:
> On Mon, Apr 13, 2020 at 03:26:55PM -0300, Wainer dos Santos Moschetta wrote:
> >
> > On 4/10/20 8:16 PM, Sean Christopherson wrote:
> > >The sole caller of vm_vcpu_rm() already has the vcpu pointer, take it
> > >directly instead of doing an extra lookup.
> >
> >
> > Most of (if not all) vcpu related functions in kvm_util.c receives an id, so
> > this change creates an inconsistency.
>
> Ya, but taking the id is done out of "necessity", as everything is public
> and for whatever reason the design of the selftest framework is to not
> expose 'struct vcpu' outside of the utils. vm_vcpu_rm() is internal only,
> IMO pulling the id out of the vcpu just to lookup the same vcpu is a waste
> of time.

Agreed

>
> FWIW, I think the whole vcpuid thing is a bad interface, almost all the
> tests end up defining an arbitrary number for the sole VCPU_ID, i.e. the
> vcpuid interface just adds a pointless layer of obfuscation. I haven't
> looked through all the tests, but returning the vcpu and making the struct
> opaque, same as kvm_vm, seems like it would yield more readable code with
> less overhead.

Agreed

>
> While I'm on a soapbox, hiding 'struct vcpu' and 'struct kvm_vm' also seems
> rather silly, but at least that doesn't directly lead to funky code.

Agreed. While the concept has been slowly growing on me, I think accessor
functions for each of the structs members are growing even faster...

Thanks,
drew

>
> > Disregarding the above comment, the changes look good to me. So:
> >
> > Reviewed-by: Wainer dos Santos Moschetta <wainersm@redhat.com>
> >
> >
> > >
> > >Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
> > >---
> > > tools/testing/selftests/kvm/lib/kvm_util.c | 7 +++----
> > > 1 file changed, 3 insertions(+), 4 deletions(-)
> > >
> > >diff --git a/tools/testing/selftests/kvm/lib/kvm_util.c b/tools/testing/selftests/kvm/lib/kvm_util.c
> > >index 8a3523d4434f..9a783c20dd26 100644
> > >--- a/tools/testing/selftests/kvm/lib/kvm_util.c
> > >+++ b/tools/testing/selftests/kvm/lib/kvm_util.c
> > >@@ -393,7 +393,7 @@ struct vcpu *vcpu_find(struct kvm_vm *vm, uint32_t vcpuid)
> > > *
> > > * Input Args:
> > > * vm - Virtual Machine
> > >- * vcpuid - VCPU ID
> > >+ * vcpu - VCPU to remove
> > > *
> > > * Output Args: None
> > > *
> > >@@ -401,9 +401,8 @@ struct vcpu *vcpu_find(struct kvm_vm *vm, uint32_t vcpuid)
> > > *
> > > * Within the VM specified by vm, removes the VCPU given by vcpuid.
> > > */
> > >-static void vm_vcpu_rm(struct kvm_vm *vm, uint32_t vcpuid)
> > >+static void vm_vcpu_rm(struct kvm_vm *vm, struct vcpu *vcpu)
> > > {
> > >- struct vcpu *vcpu = vcpu_find(vm, vcpuid);
> > > int ret;
> > > ret = munmap(vcpu->state, sizeof(*vcpu->state));
> > >@@ -427,7 +426,7 @@ void kvm_vm_release(struct kvm_vm *vmp)
> > > int ret;
> > > while (vmp->vcpu_head)
> > >- vm_vcpu_rm(vmp, vmp->vcpu_head->id);
> > >+ vm_vcpu_rm(vmp, vmp->vcpu_head);
> > > ret = close(vmp->fd);
> > > TEST_ASSERT(ret == 0, "Close of vm fd failed,\n"
> >
>

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