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Subject[PATCH] KVM: arm: Enable emulation of the physical timer
Date
Set the handlers to emulate read and write operations for CNTP_CTL,
CNTP_CVAL and CNTP_TVAL registers in such a way that VMs can use the
physical timer.

Signed-off-by: Jérémy Fanguède <j.fanguede@virtualopensystems.com>
---

This patch is the equivalent of this one: [1], but for arm 32bits
instead of ARMv8 aarch32.

[1] https://patchwork.kernel.org/patch/10207019/

---
arch/arm/kvm/coproc.c | 61 +++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 61 insertions(+)

diff --git a/arch/arm/kvm/coproc.c b/arch/arm/kvm/coproc.c
index 6d1d2e2..3a02e76 100644
--- a/arch/arm/kvm/coproc.c
+++ b/arch/arm/kvm/coproc.c
@@ -270,6 +270,60 @@ static bool access_gic_sre(struct kvm_vcpu *vcpu,
return true;
}

+static bool access_cntp_tval(struct kvm_vcpu *vcpu,
+ const struct coproc_params *p,
+ const struct coproc_reg *r)
+{
+ u64 now = kvm_phys_timer_read();
+ u64 val;
+
+ if (p->is_write) {
+ val = *vcpu_reg(vcpu, p->Rt1);
+ kvm_arm_timer_set_reg(vcpu, KVM_REG_ARM_PTIMER_CVAL, val + now);
+ } else {
+ val = kvm_arm_timer_get_reg(vcpu, KVM_REG_ARM_PTIMER_CVAL);
+ *vcpu_reg(vcpu, p->Rt1) = val - now;
+ }
+
+ return true;
+}
+
+static bool access_cntp_ctl(struct kvm_vcpu *vcpu,
+ const struct coproc_params *p,
+ const struct coproc_reg *r)
+{
+ u32 val;
+
+ if (p->is_write) {
+ val = *vcpu_reg(vcpu, p->Rt1);
+ kvm_arm_timer_set_reg(vcpu, KVM_REG_ARM_PTIMER_CTL, val);
+ } else {
+ val = kvm_arm_timer_get_reg(vcpu, KVM_REG_ARM_PTIMER_CTL);
+ *vcpu_reg(vcpu, p->Rt1) = val;
+ }
+
+ return true;
+}
+
+static bool access_cntp_cval(struct kvm_vcpu *vcpu,
+ const struct coproc_params *p,
+ const struct coproc_reg *r)
+{
+ u64 val;
+
+ if (p->is_write) {
+ val = (u64)*vcpu_reg(vcpu, p->Rt2) << 32;
+ val |= *vcpu_reg(vcpu, p->Rt1);
+ kvm_arm_timer_set_reg(vcpu, KVM_REG_ARM_PTIMER_CVAL, val);
+ } else {
+ val = kvm_arm_timer_get_reg(vcpu, KVM_REG_ARM_PTIMER_CVAL);
+ *vcpu_reg(vcpu, p->Rt1) = val;
+ *vcpu_reg(vcpu, p->Rt2) = val >> 32;
+ }
+
+ return true;
+}
+
/*
* We could trap ID_DFR0 and tell the guest we don't support performance
* monitoring. Unfortunately the patch to make the kernel check ID_DFR0 was
@@ -423,10 +477,17 @@ static const struct coproc_reg cp15_regs[] = {
{ CRn(13), CRm( 0), Op1( 0), Op2( 4), is32,
NULL, reset_unknown, c13_TID_PRIV },

+ /* CNTP */
+ { CRm64(14), Op1( 2), is64, access_cntp_cval},
+
/* CNTKCTL: swapped by interrupt.S. */
{ CRn(14), CRm( 1), Op1( 0), Op2( 0), is32,
NULL, reset_val, c14_CNTKCTL, 0x00000000 },

+ /* CNTP */
+ { CRn(14), CRm( 2), Op1( 0), Op2( 0), is32, access_cntp_tval },
+ { CRn(14), CRm( 2), Op1( 0), Op2( 1), is32, access_cntp_ctl },
+
/* The Configuration Base Address Register. */
{ CRn(15), CRm( 0), Op1( 4), Op2( 0), is32, access_cbar},
};
--
2.7.4
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