KVM: arm64: nv: Handle EL2 Stage-1 TLB invalidation

Due to the way FEAT_NV2 suppresses traps when accessing EL2
system registers, we can't track when the guest changes its
HCR_EL2.TGE setting. This means we always trap EL1 TLBIs,
even if they don't affect any L2 guest.

Given that invalidating the EL2 TLBs doesn't require any messing
with the shadow stage-2 page-tables, we can simply emulate the
instructions early and return directly to the guest.

This is conditioned on the instruction being an EL1 one and
the guest's HCR_EL2.{E2H,TGE} being {1,1} (indicating that
the instruction targets the EL2 S1 TLBs), or the instruction
being one of the EL2 ones (which are not ambiguous).

EL1 TLBIs issued with HCR_EL2.{E2H,TGE}={1,0} are not handled
here, and cause a full exit so that they can be handled in
the context of a VMID.

Co-developed-by: Jintack Lim <jintack.lim@linaro.org>
Co-developed-by: Christoffer Dall <christoffer.dall@arm.com>
Signed-off-by: Jintack Lim <jintack.lim@linaro.org>
Signed-off-by: Christoffer Dall <christoffer.dall@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20240614144552.2773592-7-maz@kernel.org
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>

1 files changed, 55 insertions, 0 deletions

diff --git a/arch/arm64/include/asm/kvm_nested.h b/arch/arm64/include/asm/kvm_nested.h
index 6f770405574f..76b88c640602 100644
--- a/arch/arm64/include/asm/kvm_nested.h
+++ b/arch/arm64/include/asm/kvm_nested.h
@@ -117,6 +117,61 @@ extern void kvm_nested_s2_wp(struct kvm *kvm);
 extern void kvm_nested_s2_unmap(struct kvm *kvm);
 extern void kvm_nested_s2_flush(struct kvm *kvm);
 
+static inline bool kvm_supported_tlbi_s1e1_op(struct kvm_vcpu *vpcu, u32 instr)
+{
+	struct kvm *kvm = vpcu->kvm;
+	u8 CRm = sys_reg_CRm(instr);
+
+	if (!(sys_reg_Op0(instr) == TLBI_Op0 &&
+	      sys_reg_Op1(instr) == TLBI_Op1_EL1))
+		return false;
+
+	if (!(sys_reg_CRn(instr) == TLBI_CRn_XS ||
+	      (sys_reg_CRn(instr) == TLBI_CRn_nXS &&
+	       kvm_has_feat(kvm, ID_AA64ISAR1_EL1, XS, IMP))))
+		return false;
+
+	if (CRm == TLBI_CRm_nROS &&
+	    !kvm_has_feat(kvm, ID_AA64ISAR0_EL1, TLB, OS))
+		return false;
+
+	if ((CRm == TLBI_CRm_RIS || CRm == TLBI_CRm_ROS ||
+	     CRm == TLBI_CRm_RNS) &&
+	    !kvm_has_feat(kvm, ID_AA64ISAR0_EL1, TLB, RANGE))
+		return false;
+
+	return true;
+}
+
+static inline bool kvm_supported_tlbi_s1e2_op(struct kvm_vcpu *vpcu, u32 instr)
+{
+	struct kvm *kvm = vpcu->kvm;
+	u8 CRm = sys_reg_CRm(instr);
+
+	if (!(sys_reg_Op0(instr) == TLBI_Op0 &&
+	      sys_reg_Op1(instr) == TLBI_Op1_EL2))
+		return false;
+
+	if (!(sys_reg_CRn(instr) == TLBI_CRn_XS ||
+	      (sys_reg_CRn(instr) == TLBI_CRn_nXS &&
+	       kvm_has_feat(kvm, ID_AA64ISAR1_EL1, XS, IMP))))
+		return false;
+
+	if (CRm == TLBI_CRm_IPAIS || CRm == TLBI_CRm_IPAONS)
+		return false;
+
+	if (CRm == TLBI_CRm_nROS &&
+	    !kvm_has_feat(kvm, ID_AA64ISAR0_EL1, TLB, OS))
+		return false;
+
+	if ((CRm == TLBI_CRm_RIS || CRm == TLBI_CRm_ROS ||
+	     CRm == TLBI_CRm_RNS) &&
+	    !kvm_has_feat(kvm, ID_AA64ISAR0_EL1, TLB, RANGE))
+		return false;
+
+	return true;
+}
+
 int kvm_init_nv_sysregs(struct kvm *kvm);
 
 #ifdef CONFIG_ARM64_PTR_AUTH