Hi David,

On Thu, 24 Jun 2021 04:57:45 +0100,
David Stevens [off-list ref] wrote:

From: David Stevens <redacted>

Return a struct kvm_pfn_page containing both a pfn and an optional
struct page from the gfn_to_pfn family of functions. This differentiates
the gup and follow_fault_pfn cases, which allows callers that only need
a pfn to avoid touching the page struct in the latter case. For callers
that need a struct page, introduce a helper function that unwraps a
struct kvm_pfn_page into a struct page. This helper makes the call to
kvm_get_pfn which had previously been in hva_to_pfn_remapped.

For now, wrap all calls to gfn_to_pfn functions in the new helper
function. Callers which don't need the page struct will be updated in
follow-up patches.

Signed-off-by: David Stevens <redacted>
---
 arch/arm64/kvm/mmu.c                   |   5 +-
 arch/mips/kvm/mmu.c                    |   3 +-
 arch/powerpc/kvm/book3s.c              |   3 +-
 arch/powerpc/kvm/book3s_64_mmu_hv.c    |   5 +-
 arch/powerpc/kvm/book3s_64_mmu_radix.c |   5 +-
 arch/powerpc/kvm/book3s_hv_uvmem.c     |   4 +-
 arch/powerpc/kvm/e500_mmu_host.c       |   2 +-
 arch/x86/kvm/mmu/mmu.c                 |  11 ++-
 arch/x86/kvm/mmu/mmu_audit.c           |   2 +-
 arch/x86/kvm/x86.c                     |   2 +-
 drivers/gpu/drm/i915/gvt/kvmgt.c       |   2 +-
 include/linux/kvm_host.h               |  27 ++++--
 include/linux/kvm_types.h              |   5 +
 virt/kvm/kvm_main.c                    | 121 +++++++++++++------------
 14 files changed, 109 insertions(+), 88 deletions(-)

[...]

+kvm_pfn_t kvm_pfn_page_unwrap(struct kvm_pfn_page pfnpg)
+{
+	if (pfnpg.page)
+		return pfnpg.pfn;
+
+	kvm_get_pfn(pfnpg.pfn);
+	return pfnpg.pfn;
+}
+EXPORT_SYMBOL_GPL(kvm_pfn_page_unwrap);

I'd really like to see a tiny bit of documentation explaining that
calls to kvm_pfn_page_unwrap() are not idempotent.

Otherwise, looks good to me.

Thanks,

	M.

-- 
Without deviation from the norm, progress is not possible.