On Tue, Jul 18, 2017 at 11:59:03AM -0500, Jintack Lim wrote:
> Forward ELR_EL1, SPSR_EL1 and VBAR_EL1 traps to the virtual EL2 if the
> virtual HCR_EL2.NV bit is set.
>
> This is for recursive nested virtualization.
>
> Signed-off-by: Jintack Lim <jintack@xxxxxxxxxxxxxxx>
> ---
> arch/arm64/include/asm/kvm_arm.h | 1 +
> arch/arm64/kvm/sys_regs.c | 18 ++++++++++++++++++
> 2 files changed, 19 insertions(+)
>
> diff --git a/arch/arm64/include/asm/kvm_arm.h b/arch/arm64/include/asm/kvm_arm.h
> index aeaac4e..a1274b7 100644
> --- a/arch/arm64/include/asm/kvm_arm.h
> +++ b/arch/arm64/include/asm/kvm_arm.h
> @@ -23,6 +23,7 @@
> #include <asm/types.h>
>
> /* Hyp Configuration Register (HCR) bits */
> +#define HCR_NV1 (UL(1) << 43)
> #define HCR_NV (UL(1) << 42)
> #define HCR_E2H (UL(1) << 34)
> #define HCR_ID (UL(1) << 33)
> diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
> index 3e4ec5e..6f67666 100644
> --- a/arch/arm64/kvm/sys_regs.c
> +++ b/arch/arm64/kvm/sys_regs.c
> @@ -1031,6 +1031,15 @@ static bool trap_el2_regs(struct kvm_vcpu *vcpu,
> return true;
> }
>
> +/* This function is to support the recursive nested virtualization */
> +static bool forward_nv1_traps(struct kvm_vcpu *vcpu, struct sys_reg_params *p)
> +{
> + if (!vcpu_mode_el2(vcpu) && (vcpu_sys_reg(vcpu, HCR_EL2) & HCR_NV1))
> + return true;
> +
> + return false;
> +}
> +
> static bool access_elr(struct kvm_vcpu *vcpu,
> struct sys_reg_params *p,
> const struct sys_reg_desc *r)
> @@ -1038,6 +1047,9 @@ static bool access_elr(struct kvm_vcpu *vcpu,
> if (el12_reg(p) && forward_nv_traps(vcpu))
> return kvm_inject_nested_sync(vcpu, kvm_vcpu_get_hsr(vcpu));
>
> + if (!el12_reg(p) && forward_nv1_traps(vcpu, p))
> + return kvm_inject_nested_sync(vcpu, kvm_vcpu_get_hsr(vcpu));
> +
> access_rw(p, &vcpu->arch.ctxt.gp_regs.elr_el1);
> return true;
> }
> @@ -1049,6 +1061,9 @@ static bool access_spsr(struct kvm_vcpu *vcpu,
> if (el12_reg(p) && forward_nv_traps(vcpu))
> return kvm_inject_nested_sync(vcpu, kvm_vcpu_get_hsr(vcpu));
>
> + if (!el12_reg(p) && forward_nv1_traps(vcpu, p))
> + return kvm_inject_nested_sync(vcpu, kvm_vcpu_get_hsr(vcpu));
> +
> access_rw(p, &vcpu->arch.ctxt.gp_regs.spsr[KVM_SPSR_EL1]);
> return true;
> }
> @@ -1060,6 +1075,9 @@ static bool access_vbar(struct kvm_vcpu *vcpu,
> if (el12_reg(p) && forward_nv_traps(vcpu))
> return kvm_inject_nested_sync(vcpu, kvm_vcpu_get_hsr(vcpu));
>
> + if (!el12_reg(p) && forward_nv1_traps(vcpu, p))
> + return kvm_inject_nested_sync(vcpu, kvm_vcpu_get_hsr(vcpu));
> +
> access_rw(p, &vcpu_sys_reg(vcpu, r->reg));
> return true;
> }
> --
> 1.9.1
>
Will we ever trap on any of these if !el12_reg() && !forward_nv_traps()
?
If not, do we need the !el12_reg() checks here?
Thanks,
-Christoffer
