[PATCH v2 2/5] KVM: arm64: Add ACCDATA_EL1 to the sysreg array

[Fuad Tabba <fuad.tabba@linux.dev>]

From: Marc Zyngier <maz@kernel.org>

Make ACCDATA_EL1 a first-class citizen, and add it to the sysreg
array. Visibility is conditioned on the feature being enabled.

Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20240815125959.2097734-4-maz@kernel.org
[Fuad: rebased]
Cc: stable@vger.kernel.org
Signed-off-by: Fuad Tabba <fuad.tabba@linux.dev>
---
 arch/arm64/include/asm/kvm_host.h |  3 +++
 arch/arm64/kvm/sys_regs.c         | 12 +++++++++++-
 2 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index 27fe0cd5b2d7a..5b1cd1f502b7d 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -498,6 +498,9 @@ enum vcpu_sysreg {
 	GCR_EL1,	/* Tag Control Register */
 	TFSRE0_EL1,	/* Tag Fault Status Register (EL0) */
 
+	/* Random stuff */
+	ACCDATA_EL1,	/* Accelerator Data */
+
 	POR_EL0,	/* Permission Overlay Register 0 (EL0) */
 
 	/* FP/SIMD/SVE */
diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index 44aae52c473d7..40f8be41da3a4 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -2914,6 +2914,15 @@ static unsigned int sve_el2_visibility(const struct kvm_vcpu *vcpu,
 	return __el2_visibility(vcpu, rd, sve_visibility);
 }
 
+static unsigned int accdata_visibility(const struct kvm_vcpu *vcpu,
+				       const struct sys_reg_desc *rd)
+{
+	if (kvm_has_feat(vcpu->kvm, ID_AA64ISAR1_EL1, LS64, LS64_ACCDATA))
+		return 0;
+
+	return REG_HIDDEN;
+}
+
 static unsigned int vncr_el2_visibility(const struct kvm_vcpu *vcpu,
 					const struct sys_reg_desc *rd)
 {
@@ -3601,7 +3610,8 @@ static const struct sys_reg_desc sys_reg_descs[] = {
 	{ SYS_DESC(SYS_CONTEXTIDR_EL1), access_vm_reg, reset_val, CONTEXTIDR_EL1, 0 },
 	{ SYS_DESC(SYS_TPIDR_EL1), NULL, reset_unknown, TPIDR_EL1 },
 
-	{ SYS_DESC(SYS_ACCDATA_EL1), undef_access },
+	{ SYS_DESC(SYS_ACCDATA_EL1), undef_access, reset_val, ACCDATA_EL1, 0,
+	  .visibility = accdata_visibility},
 
 	{ SYS_DESC(SYS_SCXTNUM_EL1), undef_access },
 
-- 
2.47.3