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From: Marc Zyngier <maz@kernel.org>
To: kvmarm@lists.linux.dev, linux-arm-kernel@lists.infradead.org,
	kvm@vger.kernel.org
Cc: Joey Gouly <joey.gouly@arm.com>,
	Suzuki K Poulose <suzuki.poulose@arm.com>,
	Oliver Upton <oliver.upton@linux.dev>,
	Zenghui Yu <yuzenghui@huawei.com>,
	Eric Auger <eric.auger@redhat.com>
Subject: [PATCH 2/4] KVM: arm64: Clarify the check for reset callback in check_sysreg_table()
Date: Fri, 18 Jul 2025 12:11:52 +0100	[thread overview]
Message-ID: <20250718111154.104029-3-maz@kernel.org> (raw)
In-Reply-To: <20250718111154.104029-1-maz@kernel.org>

check_sysreg_table() has a wonky 'is_32" parameter, which is really
an indication that we should enforce the presence of a reset helper.

Clean this up by naming the variable accordingly and inverting the
condition. Contrary to popular belief, system instructions don't
have a reset value (duh!), and therefore do not need to be checked
for reset (they escaped the check through luck...).

Signed-off-by: Marc Zyngier <maz@kernel.org>
---
 arch/arm64/kvm/sys_regs.c | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index af743494538a2..f8b10966d0c3e 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -4335,12 +4335,12 @@ static const struct sys_reg_desc cp15_64_regs[] = {
 };
 
 static bool check_sysreg_table(const struct sys_reg_desc *table, unsigned int n,
-			       bool is_32)
+			       bool reset_check)
 {
 	unsigned int i;
 
 	for (i = 0; i < n; i++) {
-		if (!is_32 && table[i].reg && !table[i].reset) {
+		if (reset_check && table[i].reg && !table[i].reset) {
 			kvm_err("sys_reg table %pS entry %d (%s) lacks reset\n",
 				&table[i], i, table[i].name);
 			return false;
@@ -5334,11 +5334,11 @@ int __init kvm_sys_reg_table_init(void)
 	int ret = 0;
 
 	/* Make sure tables are unique and in order. */
-	valid &= check_sysreg_table(sys_reg_descs, ARRAY_SIZE(sys_reg_descs), false);
-	valid &= check_sysreg_table(cp14_regs, ARRAY_SIZE(cp14_regs), true);
-	valid &= check_sysreg_table(cp14_64_regs, ARRAY_SIZE(cp14_64_regs), true);
-	valid &= check_sysreg_table(cp15_regs, ARRAY_SIZE(cp15_regs), true);
-	valid &= check_sysreg_table(cp15_64_regs, ARRAY_SIZE(cp15_64_regs), true);
+	valid &= check_sysreg_table(sys_reg_descs, ARRAY_SIZE(sys_reg_descs), true);
+	valid &= check_sysreg_table(cp14_regs, ARRAY_SIZE(cp14_regs), false);
+	valid &= check_sysreg_table(cp14_64_regs, ARRAY_SIZE(cp14_64_regs), false);
+	valid &= check_sysreg_table(cp15_regs, ARRAY_SIZE(cp15_regs), false);
+	valid &= check_sysreg_table(cp15_64_regs, ARRAY_SIZE(cp15_64_regs), false);
 	valid &= check_sysreg_table(sys_insn_descs, ARRAY_SIZE(sys_insn_descs), false);
 
 	if (!valid)
-- 
2.39.2


  parent reply	other threads:[~2025-07-18 11:12 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-07-18 11:11 [PATCH 0/4] KVM: arm64: Userspace GICv3 sysreg access fixes and testing Marc Zyngier
2025-07-18 11:11 ` [PATCH 1/4] KVM: arm64: vgic-v3: Fix ordering of ICH_HCR_EL2 Marc Zyngier
2025-07-23 15:38   ` Sebastian Ott
2025-07-18 11:11 ` Marc Zyngier [this message]
2025-07-23 15:38   ` [PATCH 2/4] KVM: arm64: Clarify the check for reset callback in check_sysreg_table() Sebastian Ott
2025-07-18 11:11 ` [PATCH 3/4] KVM: arm64: Enforce the sorting of the GICv3 system register table Marc Zyngier
2025-07-23 15:40   ` Sebastian Ott
2025-07-18 11:11 ` [PATCH 4/4] KVM: arm64: selftest: vgic-v3: Add basic GICv3 sysreg userspace access test Marc Zyngier
2025-07-23  5:00   ` Itaru Kitayama
2025-07-23  8:15     ` Marc Zyngier
2025-07-23  8:46       ` Itaru Kitayama
2025-07-23 15:56   ` Sebastian Ott
2025-07-28 17:15 ` [PATCH 0/4] KVM: arm64: Userspace GICv3 sysreg access fixes and testing Oliver Upton

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