On Mon, Feb 19, 2024 at 09:20:06AM +0000, Marc Zyngier wrote:
> Honor the trap forwarding bits for both ERET and SMC, using a new
> helper that checks for common conditions.
>
> Co-developed-by: Jintack Lim <jintack.lim@xxxxxxxxxx>
> Signed-off-by: Jintack Lim <jintack.lim@xxxxxxxxxx>
> Signed-off-by: Marc Zyngier <maz@xxxxxxxxxx>
> ---
Reviewed-by: Joey Gouly <joey.gouly@xxxxxxx>
> arch/arm64/include/asm/kvm_nested.h | 1 +
> arch/arm64/kvm/emulate-nested.c | 27 +++++++++++++++++++++++++++
> arch/arm64/kvm/handle_exit.c | 7 +++++++
> 3 files changed, 35 insertions(+)
>
> diff --git a/arch/arm64/include/asm/kvm_nested.h b/arch/arm64/include/asm/kvm_nested.h
> index c77d795556e1..dbc4e3a67356 100644
> --- a/arch/arm64/include/asm/kvm_nested.h
> +++ b/arch/arm64/include/asm/kvm_nested.h
> @@ -60,6 +60,7 @@ static inline u64 translate_ttbr0_el2_to_ttbr0_el1(u64 ttbr0)
> return ttbr0 & ~GENMASK_ULL(63, 48);
> }
>
> +extern bool forward_smc_trap(struct kvm_vcpu *vcpu);
>
> int kvm_init_nv_sysregs(struct kvm *kvm);
>
> diff --git a/arch/arm64/kvm/emulate-nested.c b/arch/arm64/kvm/emulate-nested.c
> index 4697ba41b3a9..2d80e81ae650 100644
> --- a/arch/arm64/kvm/emulate-nested.c
> +++ b/arch/arm64/kvm/emulate-nested.c
> @@ -2117,6 +2117,26 @@ bool triage_sysreg_trap(struct kvm_vcpu *vcpu, int *sr_index)
> return true;
> }
>
> +static bool forward_traps(struct kvm_vcpu *vcpu, u64 control_bit)
> +{
> + bool control_bit_set;
> +
> + if (!vcpu_has_nv(vcpu))
> + return false;
> +
> + control_bit_set = __vcpu_sys_reg(vcpu, HCR_EL2) & control_bit;
> + if (!is_hyp_ctxt(vcpu) && control_bit_set) {
> + kvm_inject_nested_sync(vcpu, kvm_vcpu_get_esr(vcpu));
> + return true;
> + }
> + return false;
> +}
> +
> +bool forward_smc_trap(struct kvm_vcpu *vcpu)
> +{
> + return forward_traps(vcpu, HCR_TSC);
> +}
> +
> static u64 kvm_check_illegal_exception_return(struct kvm_vcpu *vcpu, u64 spsr)
> {
> u64 mode = spsr & PSR_MODE_MASK;
> @@ -2155,6 +2175,13 @@ void kvm_emulate_nested_eret(struct kvm_vcpu *vcpu)
> u64 spsr, elr, mode;
> bool direct_eret;
>
> + /*
> + * Forward this trap to the virtual EL2 if the virtual
> + * HCR_EL2.NV bit is set and this is coming from !EL2.
> + */
> + if (forward_traps(vcpu, HCR_NV))
> + return;
> +
> /*
> * Going through the whole put/load motions is a waste of time
> * if this is a VHE guest hypervisor returning to its own
> diff --git a/arch/arm64/kvm/handle_exit.c b/arch/arm64/kvm/handle_exit.c
> index 0646c623d1da..1ccdfe40c691 100644
> --- a/arch/arm64/kvm/handle_exit.c
> +++ b/arch/arm64/kvm/handle_exit.c
> @@ -55,6 +55,13 @@ static int handle_hvc(struct kvm_vcpu *vcpu)
>
> static int handle_smc(struct kvm_vcpu *vcpu)
> {
> + /*
> + * Forward this trapped smc instruction to the virtual EL2 if
> + * the guest has asked for it.
> + */
> + if (forward_smc_trap(vcpu))
> + return 1;
> +
> /*
> * "If an SMC instruction executed at Non-secure EL1 is
> * trapped to EL2 because HCR_EL2.TSC is 1, the exception is a
Thanks,
Joey
