linux-kernel - [RFC PATCH v2 24/31] KVM: arm64: Emulate TLBI ALLE2(IS) instruction

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Date:   Mon,  2 Oct 2017 22:11:06 -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 24/31] KVM: arm64: Emulate TLBI ALLE2(IS) instruction

Emulate TLBI ALLE2(IS) instruction executed in the virtual EL2. Since we
emulate the virtual EL2 in the EL1, we invalidate EL1&0 regime stage 1
TLB entries with setting vttbr_el2 having the VMID of the virtual EL2.

Note that we are able to emulate TLBI ALLE2IS precisely by only
invalidating stage 1 TLB entries via TLBI VMALL1IS instruction, but to
make it simeple, we reuse the existing function, __kvm_tlb_flush_vmid(),
which invalidates both of stage 1 and 2 TLB entries.

Signed-off-by: Jintack Lim <jintack.lim@...aro.org>
---
 arch/arm64/kvm/sys_regs.c | 35 +++++++++++++++++++++++++++++++++--
 1 file changed, 33 insertions(+), 2 deletions(-)

diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index 7950ee0..90329b7 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -1747,6 +1747,37 @@ static bool handle_s12w(struct kvm_vcpu *vcpu, struct sys_reg_params *p,
 	return handle_s12(vcpu, p, r, true);
 }
 
+static bool handle_alle2(struct kvm_vcpu *vcpu, struct sys_reg_params *p,
+			 const struct sys_reg_desc *r)
+{
+	struct kvm_s2_mmu *mmu = &vcpu->kvm->arch.mmu;
+	u64 vttbr = kvm_get_vttbr(&mmu->el2_vmid, mmu);
+
+	/*
+	 * To emulate invalidating all EL2 regime stage 1 TLB entries,
+	 * invalidate EL1&0 regime stage 1 TLB entries with the virtual EL2's
+	 * VMID.
+	 */
+	kvm_call_hyp(__kvm_tlb_flush_local_vmid, vttbr);
+	return true;
+}
+
+static bool handle_alle2is(struct kvm_vcpu *vcpu, struct sys_reg_params *p,
+			   const struct sys_reg_desc *r)
+{
+	struct kvm_s2_mmu *mmu = &vcpu->kvm->arch.mmu;
+	u64 vttbr = kvm_get_vttbr(&mmu->el2_vmid, mmu);
+
+	/*
+	 * To emulate invalidating all EL2 regime stage 1 TLB entries for all
+	 * PEs, executing TLBI VMALLE1IS is enough. But reuse the existing
+	 * interface for the simplicity; invalidating stage 2 entries doesn't
+	 * affect the correctness.
+	 */
+	kvm_call_hyp(__kvm_tlb_flush_vmid, vttbr);
+	return true;
+}
+
 /*
  * AT instruction emulation
  *
@@ -1830,14 +1861,14 @@ static bool handle_s12w(struct kvm_vcpu *vcpu, struct sys_reg_params *p,
 	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_ALLE2IS, NULL, NULL),
+	SYS_INSN_TO_DESC(TLBI_ALLE2IS, handle_alle2is, NULL),
 	SYS_INSN_TO_DESC(TLBI_VAE2IS, NULL, NULL),
 	SYS_INSN_TO_DESC(TLBI_ALLE1IS, NULL, NULL),
 	SYS_INSN_TO_DESC(TLBI_VALE2IS, NULL, NULL),
 	SYS_INSN_TO_DESC(TLBI_VMALLS12E1IS, NULL, NULL),
 	SYS_INSN_TO_DESC(TLBI_IPAS2E1, NULL, NULL),
 	SYS_INSN_TO_DESC(TLBI_IPAS2LE1, NULL, NULL),
-	SYS_INSN_TO_DESC(TLBI_ALLE2, NULL, NULL),
+	SYS_INSN_TO_DESC(TLBI_ALLE2, handle_alle2, NULL),
 	SYS_INSN_TO_DESC(TLBI_VAE2, NULL, NULL),
 	SYS_INSN_TO_DESC(TLBI_ALLE1, NULL, NULL),
 	SYS_INSN_TO_DESC(TLBI_VALE2, NULL, NULL),
-- 
1.9.1