On Mon, May 14, 2012 at 9:04 AM, Marc Zyngier <marc.zyngier at arm.com> wrote:
> The ACTLR is implementation dependant, and better left untouched
> by the guest.
>
> Trap the access by ignoring writes, and let reads return the host
> view of the ACTLR, adjusted to reflect whether the guest is SMP
> or not.
>
> Signed-off-by: Marc Zyngier <marc.zyngier at arm.com>
> ---
> ?arch/arm/include/asm/kvm_arm.h | ? ?2 +-
> ?arch/arm/kvm/emulate.c ? ? ? ? | ? 24 ++++++++++++++++++++++++
> ?2 files changed, 25 insertions(+), 1 deletions(-)
>
> diff --git a/arch/arm/include/asm/kvm_arm.h b/arch/arm/include/asm/kvm_arm.h
> index 29f3a36..b9e4197 100644
> --- a/arch/arm/include/asm/kvm_arm.h
> +++ b/arch/arm/include/asm/kvm_arm.h
> @@ -49,7 +49,7 @@
> ?#define HCR_SWIO ? ? ? (1 << 1)
> ?#define HCR_VM ? ? ? ? 1
> ?#define HCR_GUEST_MASK (HCR_TSC | HCR_TWI | HCR_VM | HCR_BSU_IS | HCR_FB | \
> - ? ? ? ? ? ? ? ? ? ? ? HCR_AMO | HCR_IMO | HCR_FMO | HCR_SWIO)
> + ? ? ? ? ? ? ? ? ? ? ? HCR_TAC | HCR_AMO | HCR_IMO | HCR_FMO | HCR_SWIO)
> ?#define HCR_VIRT_EXCP_MASK (HCR_VA | HCR_VI | HCR_VF)
>
> ?/* Hyp System Control Register (HSCTLR) bits */
> diff --git a/arch/arm/kvm/emulate.c b/arch/arm/kvm/emulate.c
> index e356d1c..6eaa97d 100644
> --- a/arch/arm/kvm/emulate.c
> +++ b/arch/arm/kvm/emulate.c
> @@ -238,6 +238,23 @@ static bool read_l2ctlr(struct kvm_vcpu *vcpu,
> ? ? ? ?return true;
> ?}
>
> +static bool read_actlr(struct kvm_vcpu *vcpu,
> + ? ? ? ? ? ? ? ? ? ? ?const struct coproc_params *p,
> + ? ? ? ? ? ? ? ? ? ? ?unsigned long arg)
> +{
> + ? ? ? u32 actlr;
> +
> + ? ? ? asm volatile("mrc p15, 0, %0, c1, c0, 1\n" : "=r" (actlr));
> + ? ? ? /* Make the SMP bit consistent with the guest configuration */
> + ? ? ? if (atomic_read(&vcpu->kvm->online_vcpus) > 1)
> + ? ? ? ? ? ? ? actlr |= 1U << 6;
should we not check the MIDR here since it's implementation defined?
(refer to Russel's "Check the cpuid we're being asked to emulate"
patch)
> + ? ? ? else
> + ? ? ? ? ? ? ? actlr &= ~(1U << 6);
> + ? ? ? *vcpu_reg(vcpu, p->Rt1) = actlr;
> +
> + ? ? ? return true;
> +}
> +
> ?static bool access_cp15_reg(struct kvm_vcpu *vcpu,
> ? ? ? ? ? ? ? ? ? ? ? ? ? ?const struct coproc_params *p,
> ? ? ? ? ? ? ? ? ? ? ? ? ? ?unsigned long cp15_reg)
> @@ -278,6 +295,13 @@ struct coproc_emulate {
>
> ?static const struct coproc_emulate coproc_emulate[] = {
> ? ? ? ?/*
> + ? ? ? ?* ACTRL access:
> + ? ? ? ?*
> + ? ? ? ?* Ignore writes, and read returns the host settings.
> + ? ? ? ?*/
> + ? ? ? { CRn( 1), CRm( 0), Op1( 0), Op2( 1), is32, WRITE, ignore_write},
> + ? ? ? { CRn( 1), CRm( 0), Op1( 0), Op2( 1), is32, READ, ?read_actlr},
> + ? ? ? /*
> ? ? ? ? * L2CTLR access:
> ? ? ? ? *
> ? ? ? ? * Ignore writes completely.
> --
> 1.7.7.1
>
>
otherwise looks good to me.
Thanks,
Christoffer
