Hi Marc,
On Tue, Aug 15, 2023 at 11:47 AM Marc Zyngier <maz@xxxxxxxxxx> wrote:
>
> HFGITR_EL2 allows the trap of SVC instructions to EL2. Allow these
> traps to be forwarded. Take this opportunity to deny any 32bit activity
> when NV is enabled.
>
> Reviewed-by: Eric Auger <eric.auger@xxxxxxxxxx>
> Signed-off-by: Marc Zyngier <maz@xxxxxxxxxx>
> ---
> arch/arm64/kvm/arm.c | 4 ++++
> arch/arm64/kvm/handle_exit.c | 12 ++++++++++++
> 2 files changed, 16 insertions(+)
>
> diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
> index 72dc53a75d1c..8b51570a76f8 100644
> --- a/arch/arm64/kvm/arm.c
> +++ b/arch/arm64/kvm/arm.c
> @@ -36,6 +36,7 @@
> #include <asm/kvm_arm.h>
> #include <asm/kvm_asm.h>
> #include <asm/kvm_mmu.h>
> +#include <asm/kvm_nested.h>
> #include <asm/kvm_pkvm.h>
> #include <asm/kvm_emulate.h>
> #include <asm/sections.h>
> @@ -818,6 +819,9 @@ static bool vcpu_mode_is_bad_32bit(struct kvm_vcpu *vcpu)
> if (likely(!vcpu_mode_is_32bit(vcpu)))
> return false;
>
> + if (vcpu_has_nv(vcpu))
> + return true;
> +
> return !kvm_supports_32bit_el0();
> }
>
> diff --git a/arch/arm64/kvm/handle_exit.c b/arch/arm64/kvm/handle_exit.c
> index 6dcd6604b6bc..3b86d534b995 100644
> --- a/arch/arm64/kvm/handle_exit.c
> +++ b/arch/arm64/kvm/handle_exit.c
> @@ -226,6 +226,17 @@ static int kvm_handle_eret(struct kvm_vcpu *vcpu)
> return 1;
> }
>
> +static int handle_svc(struct kvm_vcpu *vcpu)
> +{
> + /*
> + * So far, SVC traps only for NV via HFGITR_EL2. A SVC from a
> + * 32bit guest would be caught by vpcu_mode_is_bad_32bit(), so
> + * we should only have to deal with a 64 bit exception.
> + */
> + kvm_inject_nested_sync(vcpu, kvm_vcpu_get_esr(vcpu));
> + return 1;
> +}
> +
> static exit_handle_fn arm_exit_handlers[] = {
> [0 ... ESR_ELx_EC_MAX] = kvm_handle_unknown_ec,
> [ESR_ELx_EC_WFx] = kvm_handle_wfx,
> @@ -239,6 +250,7 @@ static exit_handle_fn arm_exit_handlers[] = {
> [ESR_ELx_EC_SMC32] = handle_smc,
> [ESR_ELx_EC_HVC64] = handle_hvc,
> [ESR_ELx_EC_SMC64] = handle_smc,
> + [ESR_ELx_EC_SVC64] = handle_svc,
> [ESR_ELx_EC_SYS64] = kvm_handle_sys_reg,
> [ESR_ELx_EC_SVE] = handle_sve,
> [ESR_ELx_EC_ERET] = kvm_handle_eret,
> --
> 2.34.1
>
Reviewed-by: Jing Zhang <jingzhangos@xxxxxxxxxx>
Jing
