[PATCH] KVM: arm64: Do not let a L1 hypervisor access the *32_EL2 sysregs

[Eric Auger]

Hi Marc,

On 10/14/23 00:33, Marc Zyngier wrote:
> DBGVCR32_EL2, DACR32_EL2, IFSR32_EL2 and FPEXC32_EL2 are required to
> UNDEF when AArch32 isn't implemented, which is definitely the case when
> running NV.
> 
> Given that this is the only case where these registers can trap,
> unconditionally inject an UNDEF exception.
> 
> Signed-off-by: Marc Zyngier <maz at kernel.org>
Reviewed-by: Eric Auger <eric.auger at redhat.com>

Eric

> ---
>  arch/arm64/kvm/sys_regs.c | 8 ++++----
>  1 file changed, 4 insertions(+), 4 deletions(-)
> 
> diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
> index 0afd6136e275..0071ccccaf00 100644
> --- a/arch/arm64/kvm/sys_regs.c
> +++ b/arch/arm64/kvm/sys_regs.c
> @@ -1961,7 +1961,7 @@ static const struct sys_reg_desc sys_reg_descs[] = {
>  	// DBGDTR[TR]X_EL0 share the same encoding
>  	{ SYS_DESC(SYS_DBGDTRTX_EL0), trap_raz_wi },
>  
> -	{ SYS_DESC(SYS_DBGVCR32_EL2), NULL, reset_val, DBGVCR32_EL2, 0 },
> +	{ SYS_DESC(SYS_DBGVCR32_EL2), trap_undef, reset_val, DBGVCR32_EL2, 0 },
>  
>  	{ SYS_DESC(SYS_MPIDR_EL1), NULL, reset_mpidr, MPIDR_EL1 },
>  
> @@ -2380,18 +2380,18 @@ static const struct sys_reg_desc sys_reg_descs[] = {
>  	EL2_REG(VTTBR_EL2, access_rw, reset_val, 0),
>  	EL2_REG(VTCR_EL2, access_rw, reset_val, 0),
>  
> -	{ SYS_DESC(SYS_DACR32_EL2), NULL, reset_unknown, DACR32_EL2 },
> +	{ SYS_DESC(SYS_DACR32_EL2), trap_undef, reset_unknown, DACR32_EL2 },
>  	EL2_REG(HDFGRTR_EL2, access_rw, reset_val, 0),
>  	EL2_REG(HDFGWTR_EL2, access_rw, reset_val, 0),
>  	EL2_REG(SPSR_EL2, access_rw, reset_val, 0),
>  	EL2_REG(ELR_EL2, access_rw, reset_val, 0),
>  	{ SYS_DESC(SYS_SP_EL1), access_sp_el1},
>  
> -	{ SYS_DESC(SYS_IFSR32_EL2), NULL, reset_unknown, IFSR32_EL2 },
> +	{ SYS_DESC(SYS_IFSR32_EL2), trap_undef, reset_unknown, IFSR32_EL2 },
>  	EL2_REG(AFSR0_EL2, access_rw, reset_val, 0),
>  	EL2_REG(AFSR1_EL2, access_rw, reset_val, 0),
>  	EL2_REG(ESR_EL2, access_rw, reset_val, 0),
> -	{ SYS_DESC(SYS_FPEXC32_EL2), NULL, reset_val, FPEXC32_EL2, 0x700 },
> +	{ SYS_DESC(SYS_FPEXC32_EL2), trap_undef, reset_val, FPEXC32_EL2, 0x700 },
>  
>  	EL2_REG(FAR_EL2, access_rw, reset_val, 0),
>  	EL2_REG(HPFAR_EL2, access_rw, reset_val, 0),