KVM: arm64: nv: Handle TLB invalidation targeting L2 stage-1

While dealing with TLB invalidation targeting the guest hypervisor's
own stage-1 was easy, doing the same thing for its own guests is
a bit more involved.

Since such an invalidation is scoped by VMID, it needs to apply to
all s2_mmu contexts that have been tagged by that VMID, irrespective
of the value of VTTBR_EL2.BADDR.

So for each s2_mmu context matching that VMID, we invalidate the
corresponding TLBs, each context having its own "physical" 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/20240614144552.2773592-8-maz@kernel.orgSigned-off-by: Oliver Upton <oliver.upton@linux.dev>

arch/arm64/include/asm/kvm_nested.h

@@ -65,6 +65,13 @@ extern void kvm_init_nested(struct kvm *kvm);
 extern int kvm_vcpu_init_nested(struct kvm_vcpu *vcpu);
 extern void kvm_init_nested_s2_mmu(struct kvm_s2_mmu *mmu);
 extern struct kvm_s2_mmu *lookup_s2_mmu(struct kvm_vcpu *vcpu);
+
+union tlbi_info;
+
+extern void kvm_s2_mmu_iterate_by_vmid(struct kvm *kvm, u16 vmid,
+				       const union tlbi_info *info,
+				       void (*)(struct kvm_s2_mmu *,
+						const union tlbi_info *));
 extern void kvm_vcpu_load_hw_mmu(struct kvm_vcpu *vcpu);
 extern void kvm_vcpu_put_hw_mmu(struct kvm_vcpu *vcpu);
 

arch/arm64/kvm/nested.c

@@ -364,6 +364,41 @@ int kvm_walk_nested_s2(struct kvm_vcpu *vcpu, phys_addr_t gipa,
 	return ret;
 }
 
+/*
+ * We can have multiple *different* MMU contexts with the same VMID:
+ *
+ * - S2 being enabled or not, hence differing by the HCR_EL2.VM bit
+ *
+ * - Multiple vcpus using private S2s (huh huh...), hence differing by the
+ *   VBBTR_EL2.BADDR address
+ *
+ * - A combination of the above...
+ *
+ * We can always identify which MMU context to pick at run-time.  However,
+ * TLB invalidation involving a VMID must take action on all the TLBs using
+ * this particular VMID. This translates into applying the same invalidation
+ * operation to all the contexts that are using this VMID. Moar phun!
+ */
+void kvm_s2_mmu_iterate_by_vmid(struct kvm *kvm, u16 vmid,
+				const union tlbi_info *info,
+				void (*tlbi_callback)(struct kvm_s2_mmu *,
+						      const union tlbi_info *))
+{
+	write_lock(&kvm->mmu_lock);
+
+	for (int i = 0; i < kvm->arch.nested_mmus_size; i++) {
+		struct kvm_s2_mmu *mmu = &kvm->arch.nested_mmus[i];
+
+		if (!kvm_s2_mmu_valid(mmu))
+			continue;
+
+		if (vmid == get_vmid(mmu->tlb_vttbr))
+			tlbi_callback(mmu, info);
+	}
+
+	write_unlock(&kvm->mmu_lock);
+}
+
 struct kvm_s2_mmu *lookup_s2_mmu(struct kvm_vcpu *vcpu)
 {
 	struct kvm *kvm = vcpu->kvm;

arch/arm64/kvm/sys_regs.c

@@ -2741,6 +2741,73 @@ static const struct sys_reg_desc sys_reg_descs[] = {
 	EL2_REG(SP_EL2, NULL, reset_unknown, 0),
 };
 
+/* Only defined here as this is an internal "abstraction" */
+union tlbi_info {
+	struct {
+		u64	start;
+		u64	size;
+	} range;
+
+	struct {
+		u64	addr;
+	} ipa;
+
+	struct {
+		u64	addr;
+		u32	encoding;
+	} va;
+};
+
+static void s2_mmu_tlbi_s1e1(struct kvm_s2_mmu *mmu,
+			     const union tlbi_info *info)
+{
+	WARN_ON(__kvm_tlbi_s1e2(mmu, info->va.addr, info->va.encoding));
+}
+
+static bool handle_tlbi_el1(struct kvm_vcpu *vcpu, struct sys_reg_params *p,
+			    const struct sys_reg_desc *r)
+{
+	u32 sys_encoding = sys_insn(p->Op0, p->Op1, p->CRn, p->CRm, p->Op2);
+	u64 vttbr = vcpu_read_sys_reg(vcpu, VTTBR_EL2);
+
+	/*
+	 * If we're here, this is because we've trapped on a EL1 TLBI
+	 * instruction that affects the EL1 translation regime while
+	 * we're running in a context that doesn't allow us to let the
+	 * HW do its thing (aka vEL2):
+	 *
+	 * - HCR_EL2.E2H == 0 : a non-VHE guest
+	 * - HCR_EL2.{E2H,TGE} == { 1, 0 } : a VHE guest in guest mode
+	 *
+	 * We don't expect these helpers to ever be called when running
+	 * in a vEL1 context.
+	 */
+
+	WARN_ON(!vcpu_is_el2(vcpu));
+
+	if (!kvm_supported_tlbi_s1e1_op(vcpu, sys_encoding)) {
+		kvm_inject_undefined(vcpu);
+		return false;
+	}
+
+	kvm_s2_mmu_iterate_by_vmid(vcpu->kvm, get_vmid(vttbr),
+				   &(union tlbi_info) {
+					   .va = {
+						   .addr = p->regval,
+						   .encoding = sys_encoding,
+					   },
+				   },
+				   s2_mmu_tlbi_s1e1);
+
+	return true;
+}
+
+#define SYS_INSN(insn, access_fn)					\
+	{								\
+		SYS_DESC(OP_##insn),					\
+		.access = (access_fn),					\
+	}
+
 static struct sys_reg_desc sys_insn_descs[] = {
 	{ SYS_DESC(SYS_DC_ISW), access_dcsw },
 	{ SYS_DESC(SYS_DC_IGSW), access_dcgsw },
@@ -2751,6 +2818,19 @@ static struct sys_reg_desc sys_insn_descs[] = {
 	{ SYS_DESC(SYS_DC_CISW), access_dcsw },
 	{ SYS_DESC(SYS_DC_CIGSW), access_dcgsw },
 	{ SYS_DESC(SYS_DC_CIGDSW), access_dcgsw },
+
+	SYS_INSN(TLBI_VMALLE1IS, handle_tlbi_el1),
+	SYS_INSN(TLBI_VAE1IS, handle_tlbi_el1),
+	SYS_INSN(TLBI_ASIDE1IS, handle_tlbi_el1),
+	SYS_INSN(TLBI_VAAE1IS, handle_tlbi_el1),
+	SYS_INSN(TLBI_VALE1IS, handle_tlbi_el1),
+	SYS_INSN(TLBI_VAALE1IS, handle_tlbi_el1),
+	SYS_INSN(TLBI_VMALLE1, handle_tlbi_el1),
+	SYS_INSN(TLBI_VAE1, handle_tlbi_el1),
+	SYS_INSN(TLBI_ASIDE1, handle_tlbi_el1),
+	SYS_INSN(TLBI_VAAE1, handle_tlbi_el1),
+	SYS_INSN(TLBI_VALE1, handle_tlbi_el1),
+	SYS_INSN(TLBI_VAALE1, handle_tlbi_el1),
 };
 
 static const struct sys_reg_desc *first_idreg;