@@ -358,22 +358,35 @@ static int kvm_gmem_error_folio(struct address_space *mapping, struct folio *fol
}
#ifdef CONFIG_HAVE_KVM_ARCH_GMEM_INVALIDATE
-static void kvm_gmem_free_folio(struct folio *folio)
+static bool kvm_gmem_release_folio(struct folio *folio, gfp_t gfp)
{
struct page *page = folio_page(folio, 0);
kvm_pfn_t pfn = page_to_pfn(page);
int order = folio_order(folio);
kvm_arch_gmem_invalidate(pfn, pfn + (1ul << order));
+
+ return true;
+}
+
+static void kvm_gmem_invalidate_folio(struct folio *folio, size_t offset,
+ size_t len)
+{
+ WARN_ON_ONCE(offset != 0);
+ WARN_ON_ONCE(len != folio_size(folio));
+
+ if (offset == 0 && len == folio_size(folio))
+ filemap_release_folio(folio, 0);
}
#endif
static const struct address_space_operations kvm_gmem_aops = {
.dirty_folio = noop_dirty_folio,
- .migrate_folio = kvm_gmem_migrate_folio,
+ .migrate_folio = kvm_gmem_migrate_folio,
.error_remove_folio = kvm_gmem_error_folio,
#ifdef CONFIG_HAVE_KVM_ARCH_GMEM_INVALIDATE
- .free_folio = kvm_gmem_free_folio,
+ .release_folio = kvm_gmem_release_folio,
+ .invalidate_folio = kvm_gmem_invalidate_folio,
#endif
};
When guest_memfd becomes a library, a callback will need to be made to the owner (KVM SEV) to transition pages back to hypervisor-owned/shared state. This is currently being done as part of .free_folio() address space op, but this callback shouldn't assume that the mapping still exists. guest_memfd library will need the mapping to still exist to look up its operations table. .release_folio() and .invalidate_folio() address space ops can serve the same purpose here. The key difference between release_folio() and free_folio() is whether the mapping is still valid at time of the callback. This approach was discussed in the link in the footer, but not taken because free_folio() was easier to implement. Link: https://lore.kernel.org/kvm/20231016115028.996656-1-michael.roth@amd.com/ Signed-off-by: Elliot Berman <quic_eberman@quicinc.com> --- virt/kvm/guest_memfd.c | 19 ++++++++++++++++--- 1 file changed, 16 insertions(+), 3 deletions(-)