diff mbox series

[RFC,v3,10/21] riscv: kvm: remove stack copy address of pXd in pXd_offset()

Message ID 20260902-dummy_ptxp3-v3-10-5d8f5b17c25c@arm.com
State New
Headers show
Series mm: change behavior of pXdp_get()/pXd_page() in compile-time folded pgtable | expand

Commit Message

Yeoreum Yun Sept. 2, 2026, 11:56 a.m. UTC 
The behaviour of pXdp_get() will change with generic compile-time folded
page tables. To prepare for that, rework get_hva_mapping_size() to avoid
use of a stack copy of a pXd and pass it as argument to pXd_offset() so that
the folded entries value is ignored.

Replace direct uses of stack-based pXd values with pXd_offset_lockless()
and there should be no functional change.

Reviewed-by: David Hildenbrand (Arm) <david@kernel.org>
Signed-off-by: Yeoreum Yun <yeoreum.yun@arm.com>
---
 arch/riscv/kvm/mmu.c | 20 ++++++++++++--------
 1 file changed, 12 insertions(+), 8 deletions(-)
diff mbox series

Patch

diff --git a/arch/riscv/kvm/mmu.c b/arch/riscv/kvm/mmu.c
index 6035b5ec9503..dd5a7b0bd084 100644
--- a/arch/riscv/kvm/mmu.c
+++ b/arch/riscv/kvm/mmu.c
@@ -450,10 +450,10 @@  static int get_hva_mapping_size(struct kvm *kvm,
 {
 	int size = PAGE_SIZE;
 	unsigned long flags;
-	pgd_t pgd;
-	p4d_t p4d;
-	pud_t pud;
-	pmd_t pmd;
+	pgd_t *pgdp, pgd;
+	p4d_t *p4dp, p4d;
+	pud_t *pudp, pud;
+	pmd_t *pmdp, pmd;
 
 	/*
 	 * Disable IRQs to prevent concurrent tear down of host page tables,
@@ -469,15 +469,18 @@  static int get_hva_mapping_size(struct kvm *kvm,
 	 * value) and then p*d_offset() walks into the target huge page instead
 	 * of the old page table (sees the new value).
 	 */
-	pgd = pgdp_get(pgd_offset(kvm->mm, hva));
+	pgdp = pgd_offset(kvm->mm, hva);
+	pgd = pgdp_get(pgdp);
 	if (pgd_none(pgd))
 		goto out;
 
-	p4d = p4dp_get(p4d_offset(&pgd, hva));
+	p4dp = p4d_offset_lockless(pgdp, pgd, hva);
+	p4d = p4dp_get(p4dp);
 	if (p4d_none(p4d) || !p4d_present(p4d))
 		goto out;
 
-	pud = pudp_get(pud_offset(&p4d, hva));
+	pudp = pud_offset_lockless(p4dp, p4d, hva);
+	pud = pudp_get(pudp);
 	if (pud_none(pud) || !pud_present(pud))
 		goto out;
 
@@ -486,7 +489,8 @@  static int get_hva_mapping_size(struct kvm *kvm,
 		goto out;
 	}
 
-	pmd = pmdp_get(pmd_offset(&pud, hva));
+	pmdp = pmd_offset_lockless(pudp, pud, hva);
+	pmd = pmdp_get(pmdp);
 	if (pmd_none(pmd) || !pmd_present(pmd))
 		goto out;