linux-kernel - [RFC 5/8] KVM: arm64: Add the EL1 physical timer access handler

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Date:   Mon, 26 Dec 2016 12:12:03 -0500
From:   Jintack Lim <jintack@...columbia.edu>
To:     kvmarm@...ts.cs.columbia.edu, christoffer.dall@...aro.org,
        marc.zyngier@....com
Cc:     pbonzini@...hat.com, rkrcmar@...hat.com, linux@...linux.org.uk,
        catalin.marinas@....com, will.deacon@....com,
        andre.przywara@....com, linux-arm-kernel@...ts.infradead.org,
        kvm@...r.kernel.org, linux-kernel@...r.kernel.org,
        Jintack Lim <jintack@...columbia.edu>
Subject: [RFC 5/8] KVM: arm64: Add the EL1 physical timer access handler

KVM traps on the EL1 phys timer accesses from VMs, but it doesn't handle
those traps. This results in terminating VMs. Instead, set a handler for
the EL1 phys timer access, and inject an undefined exception as an
intermediate step.

Signed-off-by: Jintack Lim <jintack@...columbia.edu>
---
 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 87e7e66..fd9e747 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -820,6 +820,30 @@ static bool access_pmuserenr(struct kvm_vcpu *vcpu, struct sys_reg_params *p,
 	  CRm((0b1100 | (((n) >> 3) & 0x3))), Op2(((n) & 0x7)),		\
 	  access_pmu_evtyper, reset_unknown, (PMEVTYPER0_EL0 + n), }
 
+static bool access_cntp_tval(struct kvm_vcpu *vcpu,
+		struct sys_reg_params *p,
+		const struct sys_reg_desc *r)
+{
+	kvm_inject_undefined(vcpu);
+	return true;
+}
+
+static bool access_cntp_ctl(struct kvm_vcpu *vcpu,
+		struct sys_reg_params *p,
+		const struct sys_reg_desc *r)
+{
+	kvm_inject_undefined(vcpu);
+	return true;
+}
+
+static bool access_cntp_cval(struct kvm_vcpu *vcpu,
+		struct sys_reg_params *p,
+		const struct sys_reg_desc *r)
+{
+	kvm_inject_undefined(vcpu);
+	return true;
+}
+
 /*
  * Architected system registers.
  * Important: Must be sorted ascending by Op0, Op1, CRn, CRm, Op2
@@ -1029,6 +1053,16 @@ static bool access_pmuserenr(struct kvm_vcpu *vcpu, struct sys_reg_params *p,
 	{ Op0(0b11), Op1(0b011), CRn(0b1101), CRm(0b0000), Op2(0b011),
 	  NULL, reset_unknown, TPIDRRO_EL0 },
 
+	/* CNTP_TVAL_EL0 */
+	{ Op0(0b11), Op1(0b011), CRn(0b1110), CRm(0b0010), Op2(0b000),
+	  access_cntp_tval },
+	/* CNTP_CTL_EL0 */
+	{ Op0(0b11), Op1(0b011), CRn(0b1110), CRm(0b0010), Op2(0b001),
+	  access_cntp_ctl },
+	/* CNTP_CVAL_EL0 */
+	{ Op0(0b11), Op1(0b011), CRn(0b1110), CRm(0b0010), Op2(0b010),
+	  access_cntp_cval },
+
 	/* PMEVCNTRn_EL0 */
 	PMU_PMEVCNTR_EL0(0),
 	PMU_PMEVCNTR_EL0(1),
-- 
1.9.1