Re: [PATCH 02/11] KVM: selftests: Add vm_mem_region_get_src_fd library function

[Ben Gardon <bgardon@google.com>]

On Fri, Mar 18, 2022 at 1:30 PM Ricardo Koller <ricarkol@google.com> wrote:
>
> On Wed, Mar 16, 2022 at 12:08:23PM -0600, Ben Gardon wrote:
> > On Fri, Mar 11, 2022 at 12:02 AM Ricardo Koller <ricarkol@google.com> wrote:
> > >
> > > Add a library function to get the backing source FD of a memslot.
> > >
> > > Signed-off-by: Ricardo Koller <ricarkol@google.com>
> >
> > This appears to be dead code as of this commit, would recommend
> > merging it into the commit in which it's actually used.
>
> I was trying to separate lib changes (which are mostly arch independent)
> with the actual test. Would move the commit to be right before the one
> that uses be better? and maybe add a commit comment mentioning how it's
> going to be used.

Ah, that makes sense, I can see why you'd want to separate them.
Moving it right before the commit where it's used sounds fine to me.
Thanks!

>
>
> >
> > > ---
> > >  .../selftests/kvm/include/kvm_util_base.h     |  1 +
> > >  tools/testing/selftests/kvm/lib/kvm_util.c    | 23 +++++++++++++++++++
> > >  2 files changed, 24 insertions(+)
> > >
> > > diff --git a/tools/testing/selftests/kvm/include/kvm_util_base.h b/tools/testing/selftests/kvm/include/kvm_util_base.h
> > > index 4ed6aa049a91..d6acec0858c0 100644
> > > --- a/tools/testing/selftests/kvm/include/kvm_util_base.h
> > > +++ b/tools/testing/selftests/kvm/include/kvm_util_base.h
> > > @@ -163,6 +163,7 @@ int _kvm_ioctl(struct kvm_vm *vm, unsigned long ioctl, void *arg);
> > >  void vm_mem_region_set_flags(struct kvm_vm *vm, uint32_t slot, uint32_t flags);
> > >  void vm_mem_region_move(struct kvm_vm *vm, uint32_t slot, uint64_t new_gpa);
> > >  void vm_mem_region_delete(struct kvm_vm *vm, uint32_t slot);
> > > +int vm_mem_region_get_src_fd(struct kvm_vm *vm, uint32_t memslot);
> > >  void vm_vcpu_add(struct kvm_vm *vm, uint32_t vcpuid);
> > >  vm_vaddr_t vm_vaddr_alloc(struct kvm_vm *vm, size_t sz, vm_vaddr_t vaddr_min);
> > >  vm_vaddr_t vm_vaddr_alloc_pages(struct kvm_vm *vm, int nr_pages);
> > > diff --git a/tools/testing/selftests/kvm/lib/kvm_util.c b/tools/testing/selftests/kvm/lib/kvm_util.c
> > > index d8cf851ab119..64ef245b73de 100644
> > > --- a/tools/testing/selftests/kvm/lib/kvm_util.c
> > > +++ b/tools/testing/selftests/kvm/lib/kvm_util.c
> > > @@ -580,6 +580,29 @@ kvm_userspace_memory_region_find(struct kvm_vm *vm, uint64_t start,
> > >         return &region->region;
> > >  }
> > >
> > > +/*
> > > + * KVM Userspace Memory Get Backing Source FD
> > > + *
> > > + * Input Args:
> > > + *   vm - Virtual Machine
> > > + *   memslot - KVM memory slot ID
> > > + *
> > > + * Output Args: None
> > > + *
> > > + * Return:
> > > + *   Backing source file descriptor, -1 if the memslot is an anonymous region.
> > > + *
> > > + * Returns the backing source fd of a memslot, so tests can use it to punch
> > > + * holes, or to setup permissions.
> > > + */
> > > +int vm_mem_region_get_src_fd(struct kvm_vm *vm, uint32_t memslot)
> > > +{
> > > +       struct userspace_mem_region *region;
> > > +
> > > +       region = memslot2region(vm, memslot);
> > > +       return region->fd;
> > > +}
> > > +
> > >  /*
> > >   * VCPU Find
> > >   *
> > > --
> > > 2.35.1.723.g4982287a31-goog
> > >