[Intel-gfx] [PATCH 5/6] KVM: mmu: remove over-aggressive warnings

David Stevens
2021-06-24T03:59:52Z

From: David Stevens <stevensd@chromium.org>

Remove two warnings that require ref counts for pages to be non-zero, as
mapped pfns from follow_pfn may not have an initialized ref count.

Signed-off-by: David Stevens <stevensd@chromium.org>
---
arch/x86/kvm/mmu/mmu.c | 7 -------
virt/kvm/kvm_main.c | 2 +-
2 files changed, 1 insertion(+), 8 deletions(-)

diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index 8fa4a4a411ba..19249ad4b5b8 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -546,13 +546,6 @@ static int mmu_spte_clear_track_bits(u64 *sptep)

pfn = spte_to_pfn(old_spte);

- /*
- * KVM does not hold the refcount of the page used by
- * kvm mmu, before reclaiming the page, we should
- * unmap it from mmu first.
- */
- WARN_ON(!kvm_is_reserved_pfn(pfn) && !page_count(pfn_to_page(pfn)));
-
if (is_accessed_spte(old_spte))
kvm_set_pfn_accessed(pfn);

diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 898e90be4d0e..671361f30476 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -168,7 +168,7 @@ bool kvm_is_zone_device_pfn(kvm_pfn_t pfn)
* the device has been pinned, e.g. by get_user_pages(). WARN if the
* page_count() is zero to help detect bad usage of this helper.
*/
- if (!pfn_valid(pfn) || WARN_ON_ONCE(!page_count(pfn_to_page(pfn))))
+ if (!pfn_valid(pfn) || !page_count(pfn_to_page(pfn)))
return false;

return is_zone_device_page(pfn_to_page(pfn));
--
2.32.0.93.g670b81a890-goog