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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 <oupton@kernel.org>,
	Zenghui Yu <yuzenghui@huawei.com>, Fuad Tabba <tabba@google.com>,
	Will Deacon <will@kernel.org>,
	Catalin Marinas <catalin.marinas@arm.com>
Subject: [PATCH 14/20] KVM: arm64: Simplify handling of HCR_EL2.E2H RESx
Date: Mon, 26 Jan 2026 12:16:48 +0000	[thread overview]
Message-ID: <20260126121655.1641736-15-maz@kernel.org> (raw)
In-Reply-To: <20260126121655.1641736-1-maz@kernel.org>

Now that we can link the RESx behaviour with the value of HCR_EL2.E2H,
we can trivially express the tautological constraint that makes E2H
a reserved value at all times.

Fun, isn't it?

Signed-off-by: Marc Zyngier <maz@kernel.org>
---
 arch/arm64/kvm/config.c | 13 ++-----------
 1 file changed, 2 insertions(+), 11 deletions(-)

diff --git a/arch/arm64/kvm/config.c b/arch/arm64/kvm/config.c
index d5871758f1fcc..187d047a9cf4a 100644
--- a/arch/arm64/kvm/config.c
+++ b/arch/arm64/kvm/config.c
@@ -394,16 +394,6 @@ static bool feat_vmid16(struct kvm *kvm)
 	return kvm_has_feat_enum(kvm, ID_AA64MMFR1_EL1, VMIDBits, 16);
 }
 
-static bool compute_hcr_e2h(struct kvm *kvm, struct resx *bits)
-{
-	if (kvm_has_feat(kvm, FEAT_E2H0))
-		bits->res0 |= HCR_EL2_E2H;
-	else
-		bits->res1 |= HCR_EL2_E2H;
-
-	return true;
-}
-
 static const struct reg_bits_to_feat_map hfgrtr_feat_map[] = {
 	NEEDS_FEAT(HFGRTR_EL2_nAMAIR2_EL1	|
 		   HFGRTR_EL2_nMAIR2_EL1,
@@ -1023,7 +1013,8 @@ static const struct reg_bits_to_feat_map hcr_feat_map[] = {
 	NEEDS_FEAT(HCR_EL2_TWEDEL	|
 		   HCR_EL2_TWEDEn,
 		   FEAT_TWED),
-	NEEDS_FEAT_FIXED(HCR_EL2_E2H, compute_hcr_e2h),
+	NEEDS_FEAT_FLAG(HCR_EL2_E2H, RES0_WHEN_E2H0 | RES1_WHEN_E2H1,
+			enforce_resx),
 	FORCE_RES0(HCR_EL2_RES0),
 	FORCE_RES1(HCR_EL2_RES1),
 };
-- 
2.47.3



  parent reply	other threads:[~2026-01-26 12:18 UTC|newest]

Thread overview: 53+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-01-26 12:16 [PATCH 00/20] KVM: arm64: Generalise RESx handling Marc Zyngier
2026-01-26 12:16 ` [PATCH 01/20] arm64: Convert SCTLR_EL2 to sysreg infrastructure Marc Zyngier
2026-01-26 17:53   ` Fuad Tabba
2026-01-26 12:16 ` [PATCH 02/20] KVM: arm64: Remove duplicate configuration for SCTLR_EL1.{EE,E0E} Marc Zyngier
2026-01-26 18:04   ` Fuad Tabba
2026-01-26 12:16 ` [PATCH 03/20] KVM: arm64: Introduce standalone FGU computing primitive Marc Zyngier
2026-01-26 18:35   ` Fuad Tabba
2026-01-26 12:16 ` [PATCH 04/20] KVM: arm64: Introduce data structure tracking both RES0 and RES1 bits Marc Zyngier
2026-01-26 18:54   ` Fuad Tabba
2026-01-26 12:16 ` [PATCH 05/20] KVM: arm64: Extend unified RESx handling to runtime sanitisation Marc Zyngier
2026-01-26 19:15   ` Fuad Tabba
2026-01-27 10:52     ` Marc Zyngier
2026-01-26 12:16 ` [PATCH 06/20] KVM: arm64: Inherit RESx bits from FGT register descriptors Marc Zyngier
2026-01-27 15:21   ` Joey Gouly
2026-01-27 17:58   ` Fuad Tabba
2026-01-26 12:16 ` [PATCH 07/20] KVM: arm64: Allow RES1 bits to be inferred from configuration Marc Zyngier
2026-01-27 15:26   ` Joey Gouly
2026-01-27 17:58   ` Fuad Tabba
2026-01-26 12:16 ` [PATCH 08/20] KVM: arm64: Correctly handle SCTLR_EL1 RES1 bits for unsupported features Marc Zyngier
2026-01-27 18:06   ` Fuad Tabba
2026-01-26 12:16 ` [PATCH 09/20] KVM: arm64: Convert HCR_EL2.RW to AS_RES1 Marc Zyngier
2026-01-27 18:09   ` Fuad Tabba
2026-01-26 12:16 ` [PATCH 10/20] KVM: arm64: Simplify FIXED_VALUE handling Marc Zyngier
2026-01-27 18:20   ` Fuad Tabba
2026-01-26 12:16 ` [PATCH 11/20] KVM: arm64: Add REQUIRES_E2H1 constraint as configuration flags Marc Zyngier
2026-01-27 18:28   ` Fuad Tabba
2026-01-26 12:16 ` [PATCH 12/20] KVM: arm64: Add RESx_WHEN_E2Hx constraints " Marc Zyngier
2026-01-28 17:43   ` Fuad Tabba
2026-01-29 10:14     ` Marc Zyngier
2026-01-29 10:30       ` Fuad Tabba
2026-01-26 12:16 ` [PATCH 13/20] KVM: arm64: Move RESx into individual register descriptors Marc Zyngier
2026-01-29 16:29   ` Fuad Tabba
2026-01-29 17:19     ` Marc Zyngier
2026-01-29 17:39       ` Fuad Tabba
2026-01-29 18:07       ` Marc Zyngier
2026-01-29 18:13         ` Fuad Tabba
2026-01-30  9:06           ` Marc Zyngier
2026-01-26 12:16 ` Marc Zyngier [this message]
2026-01-29 16:41   ` [PATCH 14/20] KVM: arm64: Simplify handling of HCR_EL2.E2H RESx Fuad Tabba
2026-01-26 12:16 ` [PATCH 15/20] KVM: arm64: Get rid of FIXED_VALUE altogether Marc Zyngier
2026-01-29 16:54   ` Fuad Tabba
2026-01-26 12:16 ` [PATCH 16/20] KVM: arm64: Simplify handling of full register invalid constraint Marc Zyngier
2026-01-29 17:34   ` Fuad Tabba
2026-01-26 12:16 ` [PATCH 17/20] KVM: arm64: Remove all traces of FEAT_TME Marc Zyngier
2026-01-29 17:43   ` Fuad Tabba
2026-01-26 12:16 ` [PATCH 18/20] KVM: arm64: Remove all traces of HCR_EL2.MIOCNCE Marc Zyngier
2026-01-29 17:51   ` Fuad Tabba
2026-01-26 12:16 ` [PATCH 19/20] KVM: arm64: Add sanitisation to SCTLR_EL2 Marc Zyngier
2026-01-29 18:11   ` Fuad Tabba
2026-01-26 12:16 ` [PATCH 20/20] KVM: arm64: Add debugfs file dumping computed RESx values Marc Zyngier
2026-02-02  8:59   ` Fuad Tabba
2026-02-02  9:14     ` Marc Zyngier
2026-02-02  9:57       ` Fuad Tabba

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