[PATCH 08/11] KVM: arm64: Advertise FGT2 registers to userspace

Marc Zyngier maz at kernel.org
Mon Jul 14 05:26:31 PDT 2025


While a guest is able to use the FEAT_FGT2 registers, we're missing
them being exposed to userspace. Add them to the (very long) list.

Signed-off-by: Marc Zyngier <maz at kernel.org>
---
 arch/arm64/kvm/sys_regs.c | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index b441049368c7e..554c7145ec1cd 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -2592,6 +2592,16 @@ static unsigned int tcr2_el2_visibility(const struct kvm_vcpu *vcpu,
 	return __el2_visibility(vcpu, rd, tcr2_visibility);
 }
 
+static unsigned int fgt2_visibility(const struct kvm_vcpu *vcpu,
+				    const struct sys_reg_desc *rd)
+{
+	if (el2_visibility(vcpu, rd) == 0 &&
+	    kvm_has_feat(vcpu->kvm, ID_AA64MMFR0_EL1, FGT, FGT2))
+		return 0;
+
+	return REG_HIDDEN;
+}
+
 static unsigned int fgt_visibility(const struct kvm_vcpu *vcpu,
 				   const struct sys_reg_desc *rd)
 {
@@ -3341,9 +3351,14 @@ static const struct sys_reg_desc sys_reg_descs[] = {
 			 vncr_el2_visibility),
 
 	{ SYS_DESC(SYS_DACR32_EL2), undef_access, reset_unknown, DACR32_EL2 },
+	EL2_REG_VNCR_FILT(HDFGRTR2_EL2, fgt2_visibility),
+	EL2_REG_VNCR_FILT(HDFGWTR2_EL2, fgt2_visibility),
+	EL2_REG_VNCR_FILT(HFGRTR2_EL2, fgt2_visibility),
+	EL2_REG_VNCR_FILT(HFGWTR2_EL2, fgt2_visibility),
 	EL2_REG_VNCR_FILT(HDFGRTR_EL2, fgt_visibility),
 	EL2_REG_VNCR_FILT(HDFGWTR_EL2, fgt_visibility),
 	EL2_REG_VNCR_FILT(HAFGRTR_EL2, fgt_visibility),
+	EL2_REG_VNCR_FILT(HFGITR2_EL2, fgt2_visibility),
 	EL2_REG_REDIR(SPSR_EL2, reset_val, 0),
 	EL2_REG_REDIR(ELR_EL2, reset_val, 0),
 	{ SYS_DESC(SYS_SP_EL1), access_sp_el1},
-- 
2.39.2




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