Re: [PATCH] KVM: arm: Enable emulation of the physical timer

From: Christoffer Dall
Date: Fri Feb 16 2018 - 03:13:36 EST


On Tue, Feb 13, 2018 at 11:41:16AM +0100, Jérémy Fanguède wrote:
> 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@xxxxxxxxxxxxxxxxxxxxxx>
> ---
>
> This patch is the equivalent of this one: [1], but for arm 32bits
> instead of ARMv8 aarch32.
>
> [1] https://patchwork.kernel.org/patch/10207019/
>

Thanks, both queued.

-Christoffer

> ---
> 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
>