[PATCH v2 10/26] KVM: arm64: Correctly handle ACCDATA_EL1 traps

[Miguel Luis]

Hi Marc,

> On 28 Jul 2023, at 08:29, Marc Zyngier <maz at kernel.org> wrote:
> 
> As we blindly reset some HFGxTR_EL2 bits to 0, we also randomly trap
> unsuspecting sysregs that have their trap bits with a negative
> polarity.
> 
> ACCDATA_EL1 is one such register that can be accessed by the guest,
> causing a splat on the host as we don't have a proper handler for
> it.
> 
> Adding such handler addresses the issue, though there are a number
> of other registers missing as the current architecture documentation
> doesn't describe them yet.
> 
> Reviewed-by: Eric Auger <eric.auger at redhat.com>
> Signed-off-by: Marc Zyngier <maz at kernel.org>
> ---
> arch/arm64/include/asm/sysreg.h | 2 ++
> arch/arm64/kvm/sys_regs.c       | 2 ++
> 2 files changed, 4 insertions(+)
> 
> diff --git a/arch/arm64/include/asm/sysreg.h b/arch/arm64/include/asm/sysreg.h
> index 6d3d16fac227..d528a79417a0 100644
> --- a/arch/arm64/include/asm/sysreg.h
> +++ b/arch/arm64/include/asm/sysreg.h
> @@ -389,6 +389,8 @@
> #define SYS_ICC_IGRPEN0_EL1 sys_reg(3, 0, 12, 12, 6)
> #define SYS_ICC_IGRPEN1_EL1 sys_reg(3, 0, 12, 12, 7)
> 
> +#define SYS_ACCDATA_EL1 sys_reg(3, 0, 13, 0, 5)
> +
> #define SYS_CNTKCTL_EL1 sys_reg(3, 0, 14, 1, 0)
> 
> #define SYS_AIDR_EL1 sys_reg(3, 1, 0, 0, 7)
> diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
> index 2ca2973abe66..38f221f9fc98 100644
> --- a/arch/arm64/kvm/sys_regs.c
> +++ b/arch/arm64/kvm/sys_regs.c
> @@ -2151,6 +2151,8 @@ static const struct sys_reg_desc sys_reg_descs[] = {
> { SYS_DESC(SYS_CONTEXTIDR_EL1), access_vm_reg, reset_val, CONTEXTIDR_EL1, 0 },
> { SYS_DESC(SYS_TPIDR_EL1), NULL, reset_unknown, TPIDR_EL1 },
> 
> + { SYS_DESC(SYS_ACCDATA_EL1), undef_access },
> +

Per DDI0487J.a, adding ACCDATA_EL1 completes the list of sysregs
that would trap with a negative polarity bit on HFGxTR_EL2.

Reviewed-by: Miguel Luis <miguel.luis at oracle.com>

Thanks

Miguel


> { SYS_DESC(SYS_SCXTNUM_EL1), undef_access },
> 
> { SYS_DESC(SYS_CNTKCTL_EL1), NULL, reset_val, CNTKCTL_EL1, 0},
> -- 
> 2.34.1
>