linux-kernel - [PATCH v2] KVM: arm64: ptdump: Don't test PTE

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Message-ID: <20250809135356.1003520-1-r09922117@csie.ntu.edu.tw>
Date: Sat,  9 Aug 2025 21:53:56 +0800
From: Wei-Lin Chang <r09922117@...e.ntu.edu.tw>
To: linux-arm-kernel@...ts.infradead.org,
	kvmarm@...ts.linux.dev,
	linux-kernel@...r.kernel.org
Cc: Marc Zyngier <maz@...nel.org>,
	Oliver Upton <oliver.upton@...ux.dev>,
	Joey Gouly <joey.gouly@....com>,
	Sebastian Ene <sebastianene@...gle.com>,
	Suzuki K Poulose <suzuki.poulose@....com>,
	Zenghui Yu <yuzenghui@...wei.com>,
	Catalin Marinas <catalin.marinas@....com>,
	Wei-Lin Chang <r09922117@...e.ntu.edu.tw>,
	Will Deacon <will@...nel.org>,
	Anshuman Khandual <anshuman.khandual@....com>,
	Mark Rutland <mark.rutland@....com>
Subject: [PATCH v2] KVM: arm64: ptdump: Don't test PTE_VALID alongside other attributes

The attribute masks and test values in the ptdump code are meant for
individual attributes, however for stage-2 ptdump we included PTE_VALID
while testing for R, W, X, and AF. This led to some confusion and the
flipped output for the executable attribute.

Remove PTE_VALID from all attribute masks and values so that each test
matches only the relevant bits.

Additionally, the executable attribute printing is updated to align with
stage-1 ptdump, printing "NX" for non-executable regions and "x " for
executable ones.

Suggested-by: Anshuman Khandual <anshuman.khandual@....com>
Suggested-by: Mark Rutland <mark.rutland@....com>
Suggested-by: Sebastian Ene <sebastianene@...gle.com>
Signed-off-by: Wei-Lin Chang <r09922117@...e.ntu.edu.tw>
---
Tested on QEMU.

Changes in v2, thanks to those listed in the Suggested-by tags:
  - remove PTE_VALID from .mask and .val
  - make executable attribute output format identical to stage-1 ptdump
  - Link to v1: https://lore.kernel.org/kvmarm/20250802104021.3076621-1-r09922117@csie.ntu.edu.tw/
---
 arch/arm64/kvm/ptdump.c | 20 ++++++++++----------
 1 file changed, 10 insertions(+), 10 deletions(-)

diff --git a/arch/arm64/kvm/ptdump.c b/arch/arm64/kvm/ptdump.c
index 098416d7e5c25..dc5acfb00af91 100644
--- a/arch/arm64/kvm/ptdump.c
+++ b/arch/arm64/kvm/ptdump.c
@@ -32,23 +32,23 @@ static const struct ptdump_prot_bits stage2_pte_bits[] = {
 		.set	= " ",
 		.clear	= "F",
 	}, {
-		.mask	= KVM_PTE_LEAF_ATTR_LO_S2_S2AP_R | PTE_VALID,
-		.val	= KVM_PTE_LEAF_ATTR_LO_S2_S2AP_R | PTE_VALID,
+		.mask	= KVM_PTE_LEAF_ATTR_LO_S2_S2AP_R,
+		.val	= KVM_PTE_LEAF_ATTR_LO_S2_S2AP_R,
 		.set	= "R",
 		.clear	= " ",
 	}, {
-		.mask	= KVM_PTE_LEAF_ATTR_LO_S2_S2AP_W | PTE_VALID,
-		.val	= KVM_PTE_LEAF_ATTR_LO_S2_S2AP_W | PTE_VALID,
+		.mask	= KVM_PTE_LEAF_ATTR_LO_S2_S2AP_W,
+		.val	= KVM_PTE_LEAF_ATTR_LO_S2_S2AP_W,
 		.set	= "W",
 		.clear	= " ",
 	}, {
-		.mask	= KVM_PTE_LEAF_ATTR_HI_S2_XN | PTE_VALID,
-		.val	= PTE_VALID,
-		.set	= " ",
-		.clear	= "X",
+		.mask	= KVM_PTE_LEAF_ATTR_HI_S2_XN,
+		.val	= KVM_PTE_LEAF_ATTR_HI_S2_XN,
+		.set	= "NX",
+		.clear	= "x ",
 	}, {
-		.mask	= KVM_PTE_LEAF_ATTR_LO_S2_AF | PTE_VALID,
-		.val	= KVM_PTE_LEAF_ATTR_LO_S2_AF | PTE_VALID,
+		.mask	= KVM_PTE_LEAF_ATTR_LO_S2_AF,
+		.val	= KVM_PTE_LEAF_ATTR_LO_S2_AF,
 		.set	= "AF",
 		.clear	= "  ",
 	}, {
-- 
2.50.1