linux-kernel - [RFC PATCH v2 28/31] KVM: arm64: Emulate TLBI IPAS2E1* instructions

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Date:   Mon,  2 Oct 2017 22:11:10 -0500
From:   Jintack Lim <jintack.lim@...aro.org>
To:     christoffer.dall@...aro.org, marc.zyngier@....com,
        kvmarm@...ts.cs.columbia.edu
Cc:     jintack@...columbia.edu, pbonzini@...hat.com, rkrcmar@...hat.com,
        catalin.marinas@....com, will.deacon@....com,
        linux@...linux.org.uk, mark.rutland@....com,
        linux-arm-kernel@...ts.infradead.org, kvm@...r.kernel.org,
        linux-kernel@...r.kernel.org, Jintack Lim <jintack.lim@...aro.org>
Subject: [RFC PATCH v2 28/31] KVM: arm64: Emulate TLBI IPAS2E1* instructions

Based on the same principle as TLBI ALLE1(IS) and TLBI VMALLS12E1(IS)
emulation, we clear the mappings in the shadow stage-2 page tables and
invalidate TLB entries. We do it only for one mapping for the current
VMID from the guest hypervisor's view.

Signed-off-by: Jintack Lim <jintack.lim@...aro.org>
---
 arch/arm64/kvm/sys_regs.c | 38 ++++++++++++++++++++++++++++++++++----
 1 file changed, 34 insertions(+), 4 deletions(-)

diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index 5fd47ad..eb91f00 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -1849,6 +1849,36 @@ static bool handle_vmalls12e1is(struct kvm_vcpu *vcpu, struct sys_reg_params *p,
 	return true;
 }
 
+static bool handle_ipas2e1is(struct kvm_vcpu *vcpu, struct sys_reg_params *p,
+			     const struct sys_reg_desc *r)
+{
+	u64 vttbr;
+	struct kvm_s2_mmu *mmu;
+	bool ret;
+
+	spin_lock(&vcpu->kvm->mmu_lock);
+	/*
+	 * Clear a mapping in the shadow page tables and invalidate the stage
+	 * 2 TLB entries via kvm_tlb_flush_vmid_ipa() for the current
+	 * VMID and the given ipa.
+	 */
+	ret = kvm_nested_s2_clear_curr_vmid(vcpu, p->regval, PAGE_SIZE);
+	spin_unlock(&vcpu->kvm->mmu_lock);
+
+	if (!ret) {
+		/*
+		 * Invalidate TLB entries explicitly for the case that the
+		 * current VMID is for the host OS in the VM; we don't manage
+		 * shadow stage 2 page tables for it.
+		 */
+		mmu = &vcpu->kvm->arch.mmu;
+		vttbr = kvm_get_vttbr(&mmu->vmid, mmu);
+		kvm_call_hyp(__kvm_tlb_flush_vmid_ipa, vttbr, p->regval);
+	}
+
+	return true;
+}
+
 /*
  * AT instruction emulation
  *
@@ -1930,15 +1960,15 @@ static bool handle_vmalls12e1is(struct kvm_vcpu *vcpu, struct sys_reg_params *p,
 	SYS_INSN_TO_DESC(AT_S12E1W, handle_s12w, NULL),
 	SYS_INSN_TO_DESC(AT_S12E0R, handle_s12r, NULL),
 	SYS_INSN_TO_DESC(AT_S12E0W, handle_s12w, NULL),
-	SYS_INSN_TO_DESC(TLBI_IPAS2E1IS, NULL, NULL),
-	SYS_INSN_TO_DESC(TLBI_IPAS2LE1IS, NULL, NULL),
+	SYS_INSN_TO_DESC(TLBI_IPAS2E1IS, handle_ipas2e1is, NULL),
+	SYS_INSN_TO_DESC(TLBI_IPAS2LE1IS, handle_ipas2e1is, NULL),
 	SYS_INSN_TO_DESC(TLBI_ALLE2IS, handle_alle2is, NULL),
 	SYS_INSN_TO_DESC(TLBI_VAE2IS, handle_vae2, NULL),
 	SYS_INSN_TO_DESC(TLBI_ALLE1IS, handle_alle1is, NULL),
 	SYS_INSN_TO_DESC(TLBI_VALE2IS, handle_vae2, NULL),
 	SYS_INSN_TO_DESC(TLBI_VMALLS12E1IS, handle_vmalls12e1is, NULL),
-	SYS_INSN_TO_DESC(TLBI_IPAS2E1, NULL, NULL),
-	SYS_INSN_TO_DESC(TLBI_IPAS2LE1, NULL, NULL),
+	SYS_INSN_TO_DESC(TLBI_IPAS2E1, handle_ipas2e1is, NULL),
+	SYS_INSN_TO_DESC(TLBI_IPAS2LE1, handle_ipas2e1is, NULL),
 	SYS_INSN_TO_DESC(TLBI_ALLE2, handle_alle2, NULL),
 	SYS_INSN_TO_DESC(TLBI_VAE2, handle_vae2, NULL),
 	SYS_INSN_TO_DESC(TLBI_ALLE1, handle_alle1is, NULL),
-- 
1.9.1