[PATCH v2 19/26] KVM: arm64: nv: Add trap forwarding for HFGxTR_EL2

Eric Auger eric.auger at redhat.com
Mon Aug 7 06:14:07 PDT 2023


Hi Marc,

On 7/28/23 10:29, Marc Zyngier wrote:
> Fine Grained Traps are fun. Not.
>
> Implement the trap forwarding for traps describer by HFGxTR_EL2,
described
> reusing the Coarse Grained Traps infrastructure previously implemented.
>
> Each sysreg/instruction inserted in the xarray gets a FGT group
> (vaguely equivalent to a register number), a bit number in that register,
> and a polarity.
>
> It is then pretty easy to check the FGT state at handling time, just
> like we do for the coarse version (it is just faster).
>
> Signed-off-by: Marc Zyngier <maz at kernel.org>
> ---
>  arch/arm64/kvm/emulate-nested.c | 133 +++++++++++++++++++++++++++++++-
>  1 file changed, 132 insertions(+), 1 deletion(-)
>
> diff --git a/arch/arm64/kvm/emulate-nested.c b/arch/arm64/kvm/emulate-nested.c
> index 74b67895c791..5f4cf824eadc 100644
> --- a/arch/arm64/kvm/emulate-nested.c
> +++ b/arch/arm64/kvm/emulate-nested.c
> @@ -922,6 +922,88 @@ static const struct encoding_to_trap_config encoding_to_cgt[] __initconst = {
>  
>  static DEFINE_XARRAY(sr_forward_xa);
>  
> +enum fgt_group_id {
> +	__NO_FGT_GROUP__,
> +	HFGxTR_GROUP,
> +};
> +
> +#define SR_FGT(sr, g, b, p)					\
> +	{							\
> +		.encoding	= sr,				\
> +		.end		= sr,				\
> +		.tc		= {				\
> +			.fgt = g ## _GROUP,			\
> +			.bit = g ## _EL2_ ## b ## _SHIFT,	\
> +			.pol = p,				\
> +		},						\
> +	}
> +
> +static const struct encoding_to_trap_config encoding_to_fgt[] __initconst = {
> +	/* HFGTR_EL2, HFGWTR_EL2 */
HFGRTR_EL2
> +	SR_FGT(SYS_TPIDR2_EL0,		HFGxTR, nTPIDR2_EL0, 0),
> +	SR_FGT(SYS_SMPRI_EL1,		HFGxTR, nSMPRI_EL1, 0),
> +	SR_FGT(SYS_ACCDATA_EL1,		HFGxTR, nACCDATA_EL1, 0),
> +	SR_FGT(SYS_ERXADDR_EL1,		HFGxTR, ERXADDR_EL1, 1),
> +	SR_FGT(SYS_ERXPFGCDN_EL1,	HFGxTR, ERXPFGCDN_EL1, 1),
> +	SR_FGT(SYS_ERXPFGCTL_EL1,	HFGxTR, ERXPFGCTL_EL1, 1),
> +	SR_FGT(SYS_ERXPFGF_EL1,		HFGxTR, ERXPFGF_EL1, 1),
> +	SR_FGT(SYS_ERXMISC0_EL1,	HFGxTR, ERXMISCn_EL1, 1),
> +	SR_FGT(SYS_ERXMISC1_EL1,	HFGxTR, ERXMISCn_EL1, 1),
> +	SR_FGT(SYS_ERXMISC2_EL1,	HFGxTR, ERXMISCn_EL1, 1),
> +	SR_FGT(SYS_ERXMISC3_EL1,	HFGxTR, ERXMISCn_EL1, 1),
> +	SR_FGT(SYS_ERXSTATUS_EL1,	HFGxTR, ERXSTATUS_EL1, 1),
> +	SR_FGT(SYS_ERXCTLR_EL1,		HFGxTR, ERXCTLR_EL1, 1),
> +	SR_FGT(SYS_ERXFR_EL1,		HFGxTR, ERXFR_EL1, 1),
> +	SR_FGT(SYS_ERRSELR_EL1,		HFGxTR, ERRSELR_EL1, 1),
> +	SR_FGT(SYS_ERRIDR_EL1,		HFGxTR, ERRIDR_EL1, 1),
> +	SR_FGT(SYS_ICC_IGRPEN0_EL1,	HFGxTR, ICC_IGRPENn_EL1, 1),
> +	SR_FGT(SYS_ICC_IGRPEN1_EL1,	HFGxTR, ICC_IGRPENn_EL1, 1),
> +	SR_FGT(SYS_VBAR_EL1,		HFGxTR, VBAR_EL1, 1),
> +	SR_FGT(SYS_TTBR1_EL1,		HFGxTR, TTBR1_EL1, 1),
> +	SR_FGT(SYS_TTBR0_EL1,		HFGxTR, TTBR0_EL1, 1),
> +	SR_FGT(SYS_TPIDR_EL0,		HFGxTR, TPIDR_EL0, 1),
> +	SR_FGT(SYS_TPIDRRO_EL0,		HFGxTR, TPIDRRO_EL0, 1),
> +	SR_FGT(SYS_TPIDR_EL1,		HFGxTR, TPIDR_EL1, 1),
> +	SR_FGT(SYS_TCR_EL1,		HFGxTR, TCR_EL1, 1),
> +	SR_FGT(SYS_SCXTNUM_EL0,		HFGxTR, SCXTNUM_EL0, 1),
> +	SR_FGT(SYS_SCXTNUM_EL1, 	HFGxTR, SCXTNUM_EL1, 1),
> +	SR_FGT(SYS_SCTLR_EL1, 		HFGxTR, SCTLR_EL1, 1),
> +	SR_FGT(SYS_REVIDR_EL1, 		HFGxTR, REVIDR_EL1, 1),
> +	SR_FGT(SYS_PAR_EL1, 		HFGxTR, PAR_EL1, 1),
> +	SR_FGT(SYS_MPIDR_EL1, 		HFGxTR, MPIDR_EL1, 1),
> +	SR_FGT(SYS_MIDR_EL1, 		HFGxTR, MIDR_EL1, 1),
> +	SR_FGT(SYS_MAIR_EL1, 		HFGxTR, MAIR_EL1, 1),
> +	SR_FGT(SYS_LORSA_EL1, 		HFGxTR, LORSA_EL1, 1),
> +	SR_FGT(SYS_LORN_EL1, 		HFGxTR, LORN_EL1, 1),
> +	SR_FGT(SYS_LORID_EL1, 		HFGxTR, LORID_EL1, 1),
> +	SR_FGT(SYS_LOREA_EL1, 		HFGxTR, LOREA_EL1, 1),
> +	SR_FGT(SYS_LORC_EL1, 		HFGxTR, LORC_EL1, 1),
> +	SR_FGT(SYS_ISR_EL1, 		HFGxTR, ISR_EL1, 1),
> +	SR_FGT(SYS_FAR_EL1, 		HFGxTR, FAR_EL1, 1),
> +	SR_FGT(SYS_ESR_EL1, 		HFGxTR, ESR_EL1, 1),
> +	SR_FGT(SYS_DCZID_EL0, 		HFGxTR, DCZID_EL0, 1),
> +	SR_FGT(SYS_CTR_EL0, 		HFGxTR, CTR_EL0, 1),
> +	SR_FGT(SYS_CSSELR_EL1, 		HFGxTR, CSSELR_EL1, 1),
> +	SR_FGT(SYS_CPACR_EL1, 		HFGxTR, CPACR_EL1, 1),
> +	SR_FGT(SYS_CONTEXTIDR_EL1, 	HFGxTR, CONTEXTIDR_EL1, 1),
> +	SR_FGT(SYS_CLIDR_EL1, 		HFGxTR, CLIDR_EL1, 1),
> +	SR_FGT(SYS_CCSIDR_EL1, 		HFGxTR, CCSIDR_EL1, 1),
> +	SR_FGT(SYS_APIBKEYLO_EL1, 	HFGxTR, APIBKey, 1),
> +	SR_FGT(SYS_APIBKEYHI_EL1, 	HFGxTR, APIBKey, 1),
> +	SR_FGT(SYS_APIAKEYLO_EL1, 	HFGxTR, APIAKey, 1),
> +	SR_FGT(SYS_APIAKEYHI_EL1, 	HFGxTR, APIAKey, 1),
> +	SR_FGT(SYS_APGAKEYLO_EL1, 	HFGxTR, APGAKey, 1),
> +	SR_FGT(SYS_APGAKEYHI_EL1, 	HFGxTR, APGAKey, 1),
> +	SR_FGT(SYS_APDBKEYLO_EL1, 	HFGxTR, APDBKey, 1),
> +	SR_FGT(SYS_APDBKEYHI_EL1, 	HFGxTR, APDBKey, 1),
> +	SR_FGT(SYS_APDAKEYLO_EL1, 	HFGxTR, APDAKey, 1),
> +	SR_FGT(SYS_APDAKEYHI_EL1, 	HFGxTR, APDAKey, 1),
> +	SR_FGT(SYS_AMAIR_EL1, 		HFGxTR, AMAIR_EL1, 1),
> +	SR_FGT(SYS_AIDR_EL1, 		HFGxTR, AIDR_EL1, 1),
> +	SR_FGT(SYS_AFSR1_EL1, 		HFGxTR, AFSR1_EL1, 1),
> +	SR_FGT(SYS_AFSR0_EL1, 		HFGxTR, AFSR0_EL1, 1),
> +};
> +
>  static union trap_config get_trap_config(u32 sysreg)
>  {
>  	return (union trap_config) {
> @@ -943,6 +1025,27 @@ void __init populate_nv_trap_config(void)
>  	kvm_info("nv: %ld coarse grained trap handlers\n",
>  		 ARRAY_SIZE(encoding_to_cgt));
>  
> +	for (int i = 0; i < ARRAY_SIZE(encoding_to_fgt); i++) {
> +		const struct encoding_to_trap_config *fgt = &encoding_to_fgt[i];
> +		union trap_config tc;
> +
> +		tc = get_trap_config(fgt->encoding);
> +
> +		WARN(tc.fgt,
> +		     "Duplicate FGT for sys_reg(%d, %d, %d, %d, %d)\n",
> +		     sys_reg_Op0(fgt->encoding),
> +		     sys_reg_Op1(fgt->encoding),
> +		     sys_reg_CRn(fgt->encoding),
> +		     sys_reg_CRm(fgt->encoding),
> +		     sys_reg_Op2(fgt->encoding));
> +
> +		tc.val |= fgt->tc.val;
> +		xa_store(&sr_forward_xa, fgt->encoding,
> +			 xa_mk_value(tc.val), GFP_KERNEL);
> +	}
> +
> +	kvm_info("nv: %ld fine grained trap handlers\n",
> +		 ARRAY_SIZE(encoding_to_fgt));
>  }
>  
>  static enum trap_behaviour get_behaviour(struct kvm_vcpu *vcpu,
> @@ -992,13 +1095,26 @@ static enum trap_behaviour compute_trap_behaviour(struct kvm_vcpu *vcpu,
>  	return __do_compute_trap_behaviour(vcpu, tc.cgt, b);
>  }
>  
> +static bool check_fgt_bit(u64 val, const union trap_config tc)
> +{
> +	return ((val >> tc.bit) & 1) == tc.pol;
> +}
> +
> +#define sanitised_sys_reg(vcpu, reg)			\
> +	({						\
> +		u64 __val;				\
> +		__val = __vcpu_sys_reg(vcpu, reg);	\
> +		__val &= ~__ ## reg ## _RES0;		\
> +		(__val);				\
> +	})
> +
>  bool __check_nv_sr_forward(struct kvm_vcpu *vcpu)
>  {
>  	union trap_config tc;
>  	enum trap_behaviour b;
>  	bool is_read;
>  	u32 sysreg;
> -	u64 esr;
> +	u64 esr, val;
>  
>  	if (!vcpu_has_nv(vcpu) || is_hyp_ctxt(vcpu))
>  		return false;
> @@ -1009,6 +1125,21 @@ bool __check_nv_sr_forward(struct kvm_vcpu *vcpu)
>  
>  	tc = get_trap_config(sysreg);
>  
> +	switch ((enum fgt_group_id)tc.fgt) {
> +	case __NO_FGT_GROUP__:
> +		break;
> +
> +	case HFGxTR_GROUP:
> +		if (is_read)
> +			val = sanitised_sys_reg(vcpu, HFGRTR_EL2);
> +		else
> +			val = sanitised_sys_reg(vcpu, HFGWTR_EL2);
> +		break;
> +	}
> +
> +	if (tc.fgt != __NO_FGT_GROUP__ && check_fgt_bit(val, tc))
> +		goto inject;
> +
>  	b = compute_trap_behaviour(vcpu, tc);
>  
>  	if (((b & BEHAVE_FORWARD_READ) && is_read) ||
With Oliver's comments
Reviewed-by: Eric Auger <eric.auger at redhat.com>

Eric




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