Re: [PATCH v5 1/7] KVM: guest_memfd: Plumb the number of pages and max order into .invalidate()

[Sean Christopherson <seanjc@google.com>]

On Thu, Jul 16, 2026, Xiaoyao Li wrote:
> On 7/15/2026 7:10 AM, Sean Christopherson wrote:
> > Plumb the number of pages to "invalidate", i.e. reclaim, along with the max
> > order with which the pages can be mapped.  This will allow x86 to combine
> > its vendor-specific implementations for conversion and reclaim, a.k.a.
> > preparation and invalidation, into a single hook.
> > 
> > No functional change intended.
> > 
> > Signed-off-by: Sean Christopherson <seanjc@google.com>
> > ---
> >   arch/x86/kvm/x86.c       | 4 ++--
> >   include/linux/kvm_host.h | 2 +-
> >   virt/kvm/guest_memfd.c   | 7 ++-----
> >   3 files changed, 5 insertions(+), 8 deletions(-)
> > 
> > diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> > index 1f5dc685f049..a2cbf6fae118 100644
> > --- a/arch/x86/kvm/x86.c
> > +++ b/arch/x86/kvm/x86.c
> > @@ -10627,9 +10627,9 @@ int kvm_arch_gmem_prepare(struct kvm *kvm, gfn_t gfn, kvm_pfn_t pfn, int max_ord
> >   #endif
> >   #ifdef CONFIG_HAVE_KVM_ARCH_GMEM_INVALIDATE
> > -void kvm_arch_gmem_invalidate(kvm_pfn_t start, kvm_pfn_t end)
> > +void kvm_arch_gmem_invalidate(kvm_pfn_t pfn, kvm_pfn_t nr_pages, int max_order)
> 
> why use 'kvm_pfn_t' as the type for nr_pages instead of 'unsigned long'?
> 
> (I guess just because you kept the original type for @end)

Because the number of pages, i.e. number of PFNs, need to be in the same "domain"
as the staring PFN (and KVM's MMU needs to treat PFNs as u64s).