From 72c62700b27922e3ea456f01684c8e5e29755544 Mon Sep 17 00:00:00 2001 From: Marc Zyngier Date: Mon, 14 Jul 2025 13:26:30 +0100 Subject: [PATCH] KVM: arm64: Condition FGT registers on feature availability We shouldn't expose the FEAT_FGT registers unconditionally. Make them dependent on FEAT_FGT being actually advertised to the guest. Signed-off-by: Marc Zyngier Link: https://lore.kernel.org/r/20250714122634.3334816-8-maz@kernel.org Signed-off-by: Oliver Upton --- arch/arm64/kvm/sys_regs.c | 20 +++++++++++++++----- 1 file changed, 15 insertions(+), 5 deletions(-) diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c index 6763910fdf1f3..b441049368c7e 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 fgt_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, IMP)) + return 0; + + return REG_HIDDEN; +} + static unsigned int s1pie_visibility(const struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd) { @@ -3310,8 +3320,8 @@ static const struct sys_reg_desc sys_reg_descs[] = { EL2_REG(MDCR_EL2, access_mdcr, reset_mdcr, 0), EL2_REG(CPTR_EL2, access_rw, reset_val, CPTR_NVHE_EL2_RES1), EL2_REG_VNCR(HSTR_EL2, reset_val, 0), - EL2_REG_VNCR(HFGRTR_EL2, reset_val, 0), - EL2_REG_VNCR(HFGWTR_EL2, reset_val, 0), + EL2_REG_VNCR_FILT(HFGRTR_EL2, fgt_visibility), + EL2_REG_VNCR_FILT(HFGWTR_EL2, fgt_visibility), EL2_REG_VNCR(HFGITR_EL2, reset_val, 0), EL2_REG_VNCR(HACR_EL2, reset_val, 0), @@ -3331,9 +3341,9 @@ 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(HDFGRTR_EL2, reset_val, 0), - EL2_REG_VNCR(HDFGWTR_EL2, reset_val, 0), - EL2_REG_VNCR(HAFGRTR_EL2, reset_val, 0), + 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_REDIR(SPSR_EL2, reset_val, 0), EL2_REG_REDIR(ELR_EL2, reset_val, 0), { SYS_DESC(SYS_SP_EL1), access_sp_el1}, -- 2.47.2