[PATCH v4 23/28] KVM: arm64: nv: Add SVC trap forwarding

[Jing Zhang]

Hi Marc,

On Tue, Aug 15, 2023 at 11:47 AM Marc Zyngier <maz at kernel.org> 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 at redhat.com>
> Signed-off-by: Marc Zyngier <maz at kernel.org>
> ---
>  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 at google.com>

Jing