From: Yeoreum Yun <yeoreum.yun@arm.com>
To: Russell King <linux@armlinux.org.uk>,
Huacai Chen <chenhuacai@kernel.org>,
WANG Xuerui <kernel@xen0n.name>,
Thomas Bogendoerfer <tsbogend@alpha.franken.de>,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will@kernel.org>, Arnd Bergmann <arnd@arndb.de>,
Andrew Morton <akpm@linux-foundation.org>,
Kairui Song <kasong@tencent.com>, Qi Zheng <qi.zheng@linux.dev>,
Shakeel Butt <shakeel.butt@linux.dev>,
Barry Song <baohua@kernel.org>,
Axel Rasmussen <axelrasmussen@google.com>,
Yuanchu Xie <yuanchu@google.com>, Wei Xu <weixugc@google.com>,
Johannes Weiner <hannes@cmpxchg.org>,
David Hildenbrand <david@kernel.org>,
Michal Hocko <mhocko@kernel.org>,
Lorenzo Stoakes <ljs@kernel.org>,
Tianrui Zhao <zhaotianrui@loongson.cn>,
Bibo Mao <maobibo@loongson.cn>, Anup Patel <anup@brainfault.org>,
Atish Patra <atish.patra@linux.dev>,
Paul Walmsley <pjw@kernel.org>,
Palmer Dabbelt <palmer@dabbelt.com>,
Albert Ou <aou@eecs.berkeley.edu>,
Alexandre Ghiti <alex@ghiti.fr>,
Dave Hansen <dave.hansen@linux.intel.com>,
Andy Lutomirski <luto@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Thomas Gleixner <tglx@kernel.org>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
x86@kernel.org, "H. Peter Anvin" <hpa@zytor.com>,
"Liam R. Howlett" <liam@infradead.org>,
Vlastimil Babka <vbabka@kernel.org>,
Mike Rapoport <rppt@kernel.org>,
Suren Baghdasaryan <surenb@google.com>,
Michal Hocko <mhocko@suse.com>, Jonas Bonn <jonas@southpole.se>,
Stefan Kristiansson <stefan.kristiansson@saunalahti.fi>,
Stafford Horne <shorne@gmail.com>
Cc: linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, loongarch@lists.linux.dev,
linux-mips@vger.kernel.org, linux-arch@vger.kernel.org,
linux-mm@kvack.org, kvm@vger.kernel.org,
kvm-riscv@lists.infradead.org, linux-riscv@lists.infradead.org,
linux-openrisc@vger.kernel.org,
Yeoreum Yun <yeoreum.yun@arm.com>
Subject: [PATCH RFC v3 09/21] loongarch: kvm: remove stack copy address of pXd in pXd_offset()
Date: Wed, 02 Sep 2026 12:56:11 +0100 [thread overview]
Message-ID: <20260902-dummy_ptxp3-v3-9-5d8f5b17c25c@arm.com> (raw)
In-Reply-To: <20260902-dummy_ptxp3-v3-0-5d8f5b17c25c@arm.com>
The behaviour of pXdp_get() will change with generic compile-time folded
page tables. To prepare for that, rework host_pfn_mapping_level() 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/loongarch/kvm/mmu.c | 20 ++++++++++++--------
1 file changed, 12 insertions(+), 8 deletions(-)
diff --git a/arch/loongarch/kvm/mmu.c b/arch/loongarch/kvm/mmu.c
index e104897aa532..837b40bb694f 100644
--- a/arch/loongarch/kvm/mmu.c
+++ b/arch/loongarch/kvm/mmu.c
@@ -669,10 +669,10 @@ static int host_pfn_mapping_level(struct kvm *kvm, gfn_t gfn,
int level = 0;
unsigned long hva;
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;
/*
* Note, using the already-retrieved memslot and __gfn_to_hva_memslot()
@@ -698,19 +698,23 @@ static int host_pfn_mapping_level(struct kvm *kvm, gfn_t gfn,
* 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;
- 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;
--
2.43.0
next prev parent reply other threads:[~2026-09-02 11:57 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-02 11:56 [PATCH RFC v3 00/21] mm: change behavior of pXdp_get()/pXd_page() in compile-time folded pgtable Yeoreum Yun
2026-09-02 11:56 ` [PATCH RFC v3 01/21] ARM: mm: make nommu pgd_t a scalar Yeoreum Yun
2026-09-02 11:56 ` [PATCH RFC v3 02/21] ARM: mm: make 2-level " Yeoreum Yun
2026-09-02 11:56 ` [PATCH RFC v3 03/21] ARM: mm: remove custom pgdp_get() Yeoreum Yun
2026-09-02 11:56 ` [PATCH RFC v3 04/21] LoongArch: mm: define pud_leaf() only when PUD exists Yeoreum Yun
2026-09-02 11:56 ` [PATCH RFC v3 05/21] MIPS: " Yeoreum Yun
2026-09-02 11:56 ` [PATCH RFC v3 06/21] mm/pgtable: define (pgd|p4d|pud)_leaf() for folded page tables Yeoreum Yun
2026-09-02 12:15 ` sashiko-bot
2026-09-02 11:56 ` [PATCH RFC v3 07/21] mm/pgtable: define (pgd|p4d|pud)_offset_lockless() " Yeoreum Yun
2026-09-02 11:56 ` [PATCH RFC v3 08/21] mm: vmscan: remove stack copy address of pud/pmd pass in walk_pud/pmd_range() Yeoreum Yun
2026-09-02 11:56 ` Yeoreum Yun [this message]
2026-09-02 12:19 ` [PATCH RFC v3 09/21] loongarch: kvm: remove stack copy address of pXd in pXd_offset() sashiko-bot
2026-09-02 12:38 ` Yeoreum Yun
2026-09-02 11:56 ` [PATCH RFC v3 10/21] riscv: " Yeoreum Yun
2026-09-02 11:56 ` [PATCH RFC v3 11/21] riscv: mm: use proper set_pXd() for generic compile-time folded patable in vmalloc_fault() Yeoreum Yun
2026-09-02 11:56 ` [PATCH RFC v3 12/21] mm/pgtable: redefine PGTABLE_LEVEL enum with ascend order from PGD Yeoreum Yun
2026-09-02 11:56 ` [PATCH RFC v3 13/21] x86: mm: use pgtable_level enum in effective_prot_pXd() Yeoreum Yun
2026-09-02 20:48 ` Dave Hansen
2026-09-02 11:56 ` [PATCH RFC v3 14/21] x86: mm: carve out the generic compile-time folded pgtable case in effective_prot() Yeoreum Yun
2026-09-02 20:46 ` Dave Hansen
2026-09-02 11:56 ` [PATCH RFC v3 15/21] x86: mm: skip collapse_pud_page() when CONFIG_X86_DIRECT_GBPAGES disabled Yeoreum Yun
2026-09-02 12:17 ` sashiko-bot
2026-09-02 12:29 ` Yeoreum Yun
2026-09-02 15:38 ` Dave Hansen
2026-09-02 16:48 ` Yeoreum Yun
2026-09-02 11:56 ` [PATCH RFC v3 16/21] openrisc/pgtable: drop __pmd_offset() Yeoreum Yun
2026-09-02 11:56 ` [PATCH RFC v3 17/21] mm/pgtable: optimize pmdp_get() and friends for folded pagetable levels Yeoreum Yun
2026-09-02 11:56 ` [PATCH RFC v3 18/21] mm/pgtable: catch abuse of folded dummy pgd_t/p4d_t/pud_t Yeoreum Yun
2026-09-02 11:56 ` [PATCH RFC v3 19/21] mm/pgtable: disallow calling (pgd|p4d|pud)_page, pgd_page_vaddr() and (p4d|pud)_pgtable with dummy Yeoreum Yun
2026-09-02 11:56 ` [PATCH RFC v3 20/21] mm/pgtable: disallow calling folded set_pgd/set_p4d/set_pud " Yeoreum Yun
2026-09-02 11:56 ` [PATCH RFC v3 21/21] Documentation: mm: clarify behaviour of compile-time folded page tables Yeoreum Yun
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