[PATCH v3 21/26] KVM: arm64: Make TLBI OS/Range UNDEF if not advertised to the guest

[Marc Zyngier <maz@kernel.org>]

Outer Shareable and Range TLBI instructions shouldn't be made available
to the guest if they are not advertised. Use FGU to disable those,
and set HCR_EL2.TLBIOS in the case the host doesn't have FGT. Note
that in that later case, we cannot efficiently disable TLBI Range
instructions, as this would require to trap all TLBIs.

Signed-off-by: Marc Zyngier <maz@kernel.org>
Reviewed-by: Joey Gouly <joey.gouly@arm.com>
---
 arch/arm64/kvm/sys_regs.c | 34 ++++++++++++++++++++++++++++++++++
 1 file changed, 34 insertions(+)

diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index 39e7c7f74717..f07ee7c89822 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -3948,6 +3948,14 @@ void kvm_init_sysreg(struct kvm_vcpu *vcpu)
 
 	mutex_lock(&kvm->arch.config_lock);
 
+	/*
+	 * In the absence of FGT, we cannot independently trap TLBI
+	 * Range instructions. This isn't great, but trapping all
+	 * TLBIs would be far worse. Live with it...
+	 */
+	if (!kvm_has_feat(kvm, ID_AA64ISAR0_EL1, TLB, OS))
+		vcpu->arch.hcr_el2 |= HCR_TTLBOS;
+
 	if (test_bit(KVM_ARCH_FLAG_FGU_INITIALIZED, &kvm->arch.flags))
 		goto out;
 
@@ -3960,6 +3968,32 @@ void kvm_init_sysreg(struct kvm_vcpu *vcpu)
 				       HFGxTR_EL2_nSMPRI_EL1_MASK	|
 				       HFGxTR_EL2_nTPIDR2_EL0_MASK);
 
+	if (!kvm_has_feat(kvm, ID_AA64ISAR0_EL1, TLB, OS))
+		kvm->arch.fgu[HFGITR_GROUP] |= (HFGITR_EL2_TLBIRVAALE1OS|
+						HFGITR_EL2_TLBIRVALE1OS	|
+						HFGITR_EL2_TLBIRVAAE1OS	|
+						HFGITR_EL2_TLBIRVAE1OS	|
+						HFGITR_EL2_TLBIVAALE1OS	|
+						HFGITR_EL2_TLBIVALE1OS	|
+						HFGITR_EL2_TLBIVAAE1OS	|
+						HFGITR_EL2_TLBIASIDE1OS	|
+						HFGITR_EL2_TLBIVAE1OS	|
+						HFGITR_EL2_TLBIVMALLE1OS);
+
+	if (!kvm_has_feat(kvm, ID_AA64ISAR0_EL1, TLB, RANGE))
+		kvm->arch.fgu[HFGITR_GROUP] |= (HFGITR_EL2_TLBIRVAALE1	|
+						HFGITR_EL2_TLBIRVALE1	|
+						HFGITR_EL2_TLBIRVAAE1	|
+						HFGITR_EL2_TLBIRVAE1	|
+						HFGITR_EL2_TLBIRVAALE1IS|
+						HFGITR_EL2_TLBIRVALE1IS	|
+						HFGITR_EL2_TLBIRVAAE1IS	|
+						HFGITR_EL2_TLBIRVAE1IS	|
+						HFGITR_EL2_TLBIRVAALE1OS|
+						HFGITR_EL2_TLBIRVALE1OS	|
+						HFGITR_EL2_TLBIRVAAE1OS	|
+						HFGITR_EL2_TLBIRVAE1OS);
+
 	set_bit(KVM_ARCH_FLAG_FGU_INITIALIZED, &kvm->arch.flags);
 out:
 	mutex_unlock(&kvm->arch.config_lock);
-- 
2.39.2


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