linux-kernel - [PATCH] KVM: guest_memfd: Don't set FGP

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Message-ID: <20260129172646.2361462-1-ackerleytng@google.com>
Date: Thu, 29 Jan 2026 09:26:46 -0800
From: Ackerley Tng <ackerleytng@...gle.com>
To: pbonzini@...hat.com, seanjc@...gle.com, kvm@...r.kernel.org, 
	linux-kernel@...r.kernel.org
Cc: david@...nel.org, vannapurve@...nel.org, 
	Ackerley Tng <ackerleytng@...gle.com>, Vlastimil Babka <vbabka@...e.cz>
Subject: [PATCH] KVM: guest_memfd: Don't set FGP_ACCESSED when getting folios

guest_memfd folios don't care about accessed flags since the memory is
unevictable and there is no storage to write back to, hence, cleanup the
allocation path by not setting FGP_ACCESSED.

Signed-off-by: Ackerley Tng <ackerleytng@...gle.com>
[sean: split to separate patch]
Signed-off-by: Sean Christopherson <seanjc@...gle.com>
Acked-by: Vlastimil Babka <vbabka@...e.cz>
---
 virt/kvm/guest_memfd.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/virt/kvm/guest_memfd.c b/virt/kvm/guest_memfd.c
index fdaea3422c30..b3117f3359af 100644
--- a/virt/kvm/guest_memfd.c
+++ b/virt/kvm/guest_memfd.c
@@ -140,14 +140,13 @@ static struct folio *kvm_gmem_get_folio(struct inode *inode, pgoff_t index)
 	 * Fast-path: See if folio is already present in mapping to avoid
 	 * policy_lookup.
 	 */
-	folio = __filemap_get_folio(inode->i_mapping, index,
-				    FGP_LOCK | FGP_ACCESSED, 0);
+	folio = filemap_lock_folio(inode->i_mapping, index);
 	if (!IS_ERR(folio))
 		return folio;
 
 	policy = mpol_shared_policy_lookup(&GMEM_I(inode)->policy, index);
 	folio = __filemap_get_folio_mpol(inode->i_mapping, index,
-					 FGP_LOCK | FGP_ACCESSED | FGP_CREAT,
+					 FGP_LOCK | FGP_CREAT,
 					 mapping_gfp_mask(inode->i_mapping), policy);
 	mpol_cond_put(policy);
 
-- 
2.53.0.rc1.225.gd81095ad13-goog