Re: [PATCH v3 26/28] KVM: selftests: Split out helper to allocate guest mem via memfd

Paolo Bonzini
2022-03-02T18:36:49Z

On 3/1/22 00:36, David Woodhouse wrote:
> On Sat, 2022-02-26 at 00:15 +0000, Sean Christopherson wrote:
>> Extract the code for allocating guest memory via memfd out of
>> vm_userspace_mem_region_add() and into a new helper, kvm_memfd_alloc().
>> A future selftest to populate a guest with the maximum amount of guest
>> memory will abuse KVM's memslots to alias guest memory regions to a
>> single memfd-backed host region, i.e. needs to back a guest with memfd
>> memory without a 1:1 association between a memslot and a memfd instance.
>>
>> No functional change intended.
>>
>> Signed-off-by: Sean Christopherson <seanjc@google.com>
>
> While we're at it, please can we make the whole thing go away and just
> return failure #ifndef MFD_CLOEXEC, instead of breaking the build on
> older userspace?

We can just use old school F_SETFD if that's helpful for you.

Paolo