On Wed, 4 Jun 2025 at 13:25, David Hildenbrand <david@xxxxxxxxxx> wrote: > > On 27.05.25 20:02, Fuad Tabba wrote: > > Track whether a guest_memfd-backed memslot supports shared memory within > > the memslot itself, using the flags field. The top half of memslot flags > > is reserved for internal use in KVM. Add a flag there to track shared > > memory support. > > > > This saves the caller from having to check the guest_memfd-backed file > > for this support, a potentially more expensive operation due to the need > > to get/put the file. > > > > Suggested-by: David Hildenbrand <david@xxxxxxxxxx> > > Signed-off-by: Fuad Tabba <tabba@xxxxxxxxxx> > > --- > > include/linux/kvm_host.h | 11 ++++++++++- > > virt/kvm/guest_memfd.c | 8 ++++++-- > > 2 files changed, 16 insertions(+), 3 deletions(-) > > > > diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h > > index ba83547e62b0..edb3795a64b9 100644 > > --- a/include/linux/kvm_host.h > > +++ b/include/linux/kvm_host.h > > @@ -54,7 +54,8 @@ > > * used in kvm, other bits are visible for userspace which are defined in > > * include/uapi/linux/kvm.h. > > */ > > -#define KVM_MEMSLOT_INVALID (1UL << 16) > > +#define KVM_MEMSLOT_INVALID (1UL << 16) > > +#define KVM_MEMSLOT_SUPPORTS_SHARED (1UL << 17) > > Should there be a "GMEM" in there? I'll change it to KVM_MEMSLOT_SUPPORTS_GMEM_SHARED. I thought of adding _MEM as well, but it starts getting too long :) Thanks, /fuad > -- > Cheers, > > David / dhildenb >
