On Tue, May 06, 2025 at 05:43:38PM +0100, Marc Zyngier wrote:
> Another benefit of mapping bits to features is that it becomes trivial
> to define which bits should be handled as RES0.
>
> Let's apply this principle to the guest's view of the FGT registers.
>
> Signed-off-by: Marc Zyngier <maz@xxxxxxxxxx>
> ---
> arch/arm64/include/asm/kvm_host.h | 1 +
> arch/arm64/kvm/config.c | 46 +++++++++++
> arch/arm64/kvm/nested.c | 129 +++---------------------------
> 3 files changed, 57 insertions(+), 119 deletions(-)
>
> diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
> index 59bfb049ce987..0eff513167868 100644
> --- a/arch/arm64/include/asm/kvm_host.h
> +++ b/arch/arm64/include/asm/kvm_host.h
> @@ -1611,6 +1611,7 @@ void kvm_set_vm_id_reg(struct kvm *kvm, u32 reg, u64 val);
> (kvm_has_feat((k), ID_AA64MMFR3_EL1, S1POE, IMP))
>
> void compute_fgu(struct kvm *kvm, enum fgt_group_id fgt);
> +void get_reg_fixed_bits(struct kvm *kvm, enum vcpu_sysreg reg, u64 *res0, u64*res1);
nit: u64* res1
> void check_feature_map(void);
>
> #endif /* __ARM64_KVM_HOST_H__ */
> diff --git a/arch/arm64/kvm/config.c b/arch/arm64/kvm/config.c
> index 242c82eefd5e4..388f207bf64f6 100644
> --- a/arch/arm64/kvm/config.c
> +++ b/arch/arm64/kvm/config.c
> @@ -616,3 +616,49 @@ void compute_fgu(struct kvm *kvm, enum fgt_group_id fgt)
>
> kvm->arch.fgu[fgt] = val;
> }
> +
> +void get_reg_fixed_bits(struct kvm *kvm, enum vcpu_sysreg reg, u64 *res0, u64 *res1)
> +{
> + switch (reg) {
> + case HFGRTR_EL2:
> + *res0 = compute_res0_bits(kvm, hfgrtr_feat_map,
> + ARRAY_SIZE(hfgrtr_feat_map), 0, 0);
> + *res0 |= hfgrtr_masks.res0;
> + *res1 = HFGRTR_EL2_RES1;
> + break;
> + case HFGWTR_EL2:
> + *res0 = compute_res0_bits(kvm, hfgwtr_feat_map,
> + ARRAY_SIZE(hfgwtr_feat_map), 0, 0);
> + *res0 |= hfgwtr_masks.res0;
> + *res1 = HFGWTR_EL2_RES1;
> + break;
> + case HFGITR_EL2:
> + *res0 = compute_res0_bits(kvm, hfgitr_feat_map,
> + ARRAY_SIZE(hfgitr_feat_map), 0, 0);
> + *res0 |= hfgitr_masks.res0;
> + *res1 = HFGITR_EL2_RES1;
> + break;
> + case HDFGRTR_EL2:
> + *res0 = compute_res0_bits(kvm, hdfgrtr_feat_map,
> + ARRAY_SIZE(hdfgrtr_feat_map), 0, 0);
> + *res0 |= hdfgrtr_masks.res0;
> + *res1 = HDFGRTR_EL2_RES1;
> + break;
> + case HDFGWTR_EL2:
> + *res0 = compute_res0_bits(kvm, hdfgwtr_feat_map,
> + ARRAY_SIZE(hdfgwtr_feat_map), 0, 0);
> + *res0 |= hdfgwtr_masks.res0;
> + *res1 = HDFGWTR_EL2_RES1;
> + break;
> + case HAFGRTR_EL2:
> + *res0 = compute_res0_bits(kvm, hafgrtr_feat_map,
> + ARRAY_SIZE(hafgrtr_feat_map), 0, 0);
> + *res0 |= hafgrtr_masks.res0;
> + *res1 = HAFGRTR_EL2_RES1;
> + break;
> + default:
> + WARN_ON_ONCE(1);
> + *res0 = *res1 = 0;
> + break;
> + }
> +}
> diff --git a/arch/arm64/kvm/nested.c b/arch/arm64/kvm/nested.c
> index 666df85230c9b..3d91a0233652b 100644
> --- a/arch/arm64/kvm/nested.c
> +++ b/arch/arm64/kvm/nested.c
> @@ -1100,132 +1100,23 @@ int kvm_init_nv_sysregs(struct kvm_vcpu *vcpu)
> set_sysreg_masks(kvm, HCRX_EL2, res0, res1);
>
> /* HFG[RW]TR_EL2 */
> - res0 = res1 = 0;
> - if (!(kvm_vcpu_has_feature(kvm, KVM_ARM_VCPU_PTRAUTH_ADDRESS) &&
> - kvm_vcpu_has_feature(kvm, KVM_ARM_VCPU_PTRAUTH_GENERIC)))
The change from checking kvm_vcpu_has_feature() to using feat_pauth() (from
"KVM: arm64: Switch to table-driven FGU configuration" patch 31) is fine
because the ID regs (ID_AA64ISAR1_EL, ID_AA64ISAR2_EL) are sanitised by
__kvm_read_sanitised_id_reg(), which checks vcpu_has_feature() via
vcpu_has_ptrauth().
> - res0 |= (HFGRTR_EL2_APDAKey | HFGRTR_EL2_APDBKey |
> - HFGRTR_EL2_APGAKey | HFGRTR_EL2_APIAKey |
> - HFGRTR_EL2_APIBKey);
> - if (!kvm_has_feat(kvm, ID_AA64MMFR1_EL1, LO, IMP))
> - res0 |= (HFGRTR_EL2_LORC_EL1 | HFGRTR_EL2_LOREA_EL1 |
> - HFGRTR_EL2_LORID_EL1 | HFGRTR_EL2_LORN_EL1 |
> - HFGRTR_EL2_LORSA_EL1);
> - if (!kvm_has_feat(kvm, ID_AA64PFR0_EL1, CSV2, CSV2_2) &&
> - !kvm_has_feat(kvm, ID_AA64PFR1_EL1, CSV2_frac, CSV2_1p2))
> - res0 |= (HFGRTR_EL2_SCXTNUM_EL1 | HFGRTR_EL2_SCXTNUM_EL0);
> - if (!kvm_has_feat(kvm, ID_AA64PFR0_EL1, GIC, IMP))
> - res0 |= HFGRTR_EL2_ICC_IGRPENn_EL1;
> - if (!kvm_has_feat(kvm, ID_AA64PFR0_EL1, RAS, IMP))
> - res0 |= (HFGRTR_EL2_ERRIDR_EL1 | HFGRTR_EL2_ERRSELR_EL1 |
> - HFGRTR_EL2_ERXFR_EL1 | HFGRTR_EL2_ERXCTLR_EL1 |
> - HFGRTR_EL2_ERXSTATUS_EL1 | HFGRTR_EL2_ERXMISCn_EL1 |
> - HFGRTR_EL2_ERXPFGF_EL1 | HFGRTR_EL2_ERXPFGCTL_EL1 |
> - HFGRTR_EL2_ERXPFGCDN_EL1 | HFGRTR_EL2_ERXADDR_EL1);
> - if (!kvm_has_feat(kvm, ID_AA64ISAR1_EL1, LS64, LS64_ACCDATA))
> - res0 |= HFGRTR_EL2_nACCDATA_EL1;
> - if (!kvm_has_feat(kvm, ID_AA64PFR1_EL1, GCS, IMP))
> - res0 |= (HFGRTR_EL2_nGCS_EL0 | HFGRTR_EL2_nGCS_EL1);
> - if (!kvm_has_feat(kvm, ID_AA64PFR1_EL1, SME, IMP))
> - res0 |= (HFGRTR_EL2_nSMPRI_EL1 | HFGRTR_EL2_nTPIDR2_EL0);
> - if (!kvm_has_feat(kvm, ID_AA64PFR1_EL1, THE, IMP))
> - res0 |= HFGRTR_EL2_nRCWMASK_EL1;
> - if (!kvm_has_s1pie(kvm))
> - res0 |= (HFGRTR_EL2_nPIRE0_EL1 | HFGRTR_EL2_nPIR_EL1);
> - if (!kvm_has_s1poe(kvm))
> - res0 |= (HFGRTR_EL2_nPOR_EL0 | HFGRTR_EL2_nPOR_EL1);
> - if (!kvm_has_feat(kvm, ID_AA64MMFR3_EL1, S2POE, IMP))
> - res0 |= HFGRTR_EL2_nS2POR_EL1;
> - if (!kvm_has_feat(kvm, ID_AA64MMFR3_EL1, AIE, IMP))
> - res0 |= (HFGRTR_EL2_nMAIR2_EL1 | HFGRTR_EL2_nAMAIR2_EL1);
> - set_sysreg_masks(kvm, HFGRTR_EL2, res0 | hfgrtr_masks.res0, res1);
> - set_sysreg_masks(kvm, HFGWTR_EL2, res0 | hfgwtr_masks.res0, res1);
> + get_reg_fixed_bits(kvm, HFGRTR_EL2, &res0, &res1);
> + set_sysreg_masks(kvm, HFGRTR_EL2, res0, res1);
> + get_reg_fixed_bits(kvm, HFGWTR_EL2, &res0, &res1);
> + set_sysreg_masks(kvm, HFGWTR_EL2, res0, res1);
>
> /* HDFG[RW]TR_EL2 */
> - res0 = res1 = 0;
> - if (!kvm_has_feat(kvm, ID_AA64DFR0_EL1, DoubleLock, IMP))
> - res0 |= HDFGRTR_EL2_OSDLR_EL1;
> - if (!kvm_has_feat(kvm, ID_AA64DFR0_EL1, PMUVer, IMP))
> - res0 |= (HDFGRTR_EL2_PMEVCNTRn_EL0 | HDFGRTR_EL2_PMEVTYPERn_EL0 |
> - HDFGRTR_EL2_PMCCFILTR_EL0 | HDFGRTR_EL2_PMCCNTR_EL0 |
> - HDFGRTR_EL2_PMCNTEN | HDFGRTR_EL2_PMINTEN |
> - HDFGRTR_EL2_PMOVS | HDFGRTR_EL2_PMSELR_EL0 |
> - HDFGRTR_EL2_PMMIR_EL1 | HDFGRTR_EL2_PMUSERENR_EL0 |
> - HDFGRTR_EL2_PMCEIDn_EL0);
> - if (!kvm_has_feat(kvm, ID_AA64DFR0_EL1, PMSVer, IMP))
> - res0 |= (HDFGRTR_EL2_PMBLIMITR_EL1 | HDFGRTR_EL2_PMBPTR_EL1 |
> - HDFGRTR_EL2_PMBSR_EL1 | HDFGRTR_EL2_PMSCR_EL1 |
> - HDFGRTR_EL2_PMSEVFR_EL1 | HDFGRTR_EL2_PMSFCR_EL1 |
> - HDFGRTR_EL2_PMSICR_EL1 | HDFGRTR_EL2_PMSIDR_EL1 |
> - HDFGRTR_EL2_PMSIRR_EL1 | HDFGRTR_EL2_PMSLATFR_EL1 |
> - HDFGRTR_EL2_PMBIDR_EL1);
> - if (!kvm_has_feat(kvm, ID_AA64DFR0_EL1, TraceVer, IMP))
> - res0 |= (HDFGRTR_EL2_TRC | HDFGRTR_EL2_TRCAUTHSTATUS |
> - HDFGRTR_EL2_TRCAUXCTLR | HDFGRTR_EL2_TRCCLAIM |
> - HDFGRTR_EL2_TRCCNTVRn | HDFGRTR_EL2_TRCID |
> - HDFGRTR_EL2_TRCIMSPECn | HDFGRTR_EL2_TRCOSLSR |
> - HDFGRTR_EL2_TRCPRGCTLR | HDFGRTR_EL2_TRCSEQSTR |
> - HDFGRTR_EL2_TRCSSCSRn | HDFGRTR_EL2_TRCSTATR |
> - HDFGRTR_EL2_TRCVICTLR);
> - if (!kvm_has_feat(kvm, ID_AA64DFR0_EL1, TraceBuffer, IMP))
> - res0 |= (HDFGRTR_EL2_TRBBASER_EL1 | HDFGRTR_EL2_TRBIDR_EL1 |
> - HDFGRTR_EL2_TRBLIMITR_EL1 | HDFGRTR_EL2_TRBMAR_EL1 |
> - HDFGRTR_EL2_TRBPTR_EL1 | HDFGRTR_EL2_TRBSR_EL1 |
> - HDFGRTR_EL2_TRBTRG_EL1);
> - if (!kvm_has_feat(kvm, ID_AA64DFR0_EL1, BRBE, IMP))
> - res0 |= (HDFGRTR_EL2_nBRBIDR | HDFGRTR_EL2_nBRBCTL |
> - HDFGRTR_EL2_nBRBDATA);
> - if (!kvm_has_feat(kvm, ID_AA64DFR0_EL1, PMSVer, V1P2))
> - res0 |= HDFGRTR_EL2_nPMSNEVFR_EL1;
> - set_sysreg_masks(kvm, HDFGRTR_EL2, res0 | hdfgrtr_masks.res0, res1);
> -
> - /* Reuse the bits from the read-side and add the write-specific stuff */
> - if (!kvm_has_feat(kvm, ID_AA64DFR0_EL1, PMUVer, IMP))
> - res0 |= (HDFGWTR_EL2_PMCR_EL0 | HDFGWTR_EL2_PMSWINC_EL0);
> - if (!kvm_has_feat(kvm, ID_AA64DFR0_EL1, TraceVer, IMP))
> - res0 |= HDFGWTR_EL2_TRCOSLAR;
> - if (!kvm_has_feat(kvm, ID_AA64DFR0_EL1, TraceFilt, IMP))
> - res0 |= HDFGWTR_EL2_TRFCR_EL1;
> - set_sysreg_masks(kvm, HFGWTR_EL2, res0 | hdfgwtr_masks.res0, res1);
> + get_reg_fixed_bits(kvm, HDFGRTR_EL2, &res0, &res1);
> + set_sysreg_masks(kvm, HDFGRTR_EL2, res0, res1);
> + get_reg_fixed_bits(kvm, HDFGWTR_EL2, &res0, &res1);
> + set_sysreg_masks(kvm, HDFGWTR_EL2, res0, res1);
>
> /* HFGITR_EL2 */
> - res0 = hfgitr_masks.res0;
> - res1 = HFGITR_EL2_RES1;
> - if (!kvm_has_feat(kvm, ID_AA64ISAR1_EL1, DPB, DPB2))
> - res0 |= HFGITR_EL2_DCCVADP;
> - if (!kvm_has_feat(kvm, ID_AA64MMFR1_EL1, PAN, PAN2))
> - res0 |= (HFGITR_EL2_ATS1E1RP | HFGITR_EL2_ATS1E1WP);
> - if (!kvm_has_feat(kvm, ID_AA64ISAR0_EL1, TLB, OS))
> - res0 |= (HFGITR_EL2_TLBIRVAALE1OS | HFGITR_EL2_TLBIRVALE1OS |
> - HFGITR_EL2_TLBIRVAAE1OS | HFGITR_EL2_TLBIRVAE1OS |
> - HFGITR_EL2_TLBIVAALE1OS | HFGITR_EL2_TLBIVALE1OS |
> - HFGITR_EL2_TLBIVAAE1OS | HFGITR_EL2_TLBIASIDE1OS |
> - HFGITR_EL2_TLBIVAE1OS | HFGITR_EL2_TLBIVMALLE1OS);
> - if (!kvm_has_feat(kvm, ID_AA64ISAR0_EL1, TLB, RANGE))
> - res0 |= (HFGITR_EL2_TLBIRVAALE1 | HFGITR_EL2_TLBIRVALE1 |
> - HFGITR_EL2_TLBIRVAAE1 | HFGITR_EL2_TLBIRVAE1 |
> - HFGITR_EL2_TLBIRVAALE1IS | HFGITR_EL2_TLBIRVALE1IS |
> - HFGITR_EL2_TLBIRVAAE1IS | HFGITR_EL2_TLBIRVAE1IS |
> - HFGITR_EL2_TLBIRVAALE1OS | HFGITR_EL2_TLBIRVALE1OS |
> - HFGITR_EL2_TLBIRVAAE1OS | HFGITR_EL2_TLBIRVAE1OS);
> - if (!kvm_has_feat(kvm, ID_AA64ISAR1_EL1, SPECRES, IMP))
> - res0 |= (HFGITR_EL2_CFPRCTX | HFGITR_EL2_DVPRCTX |
> - HFGITR_EL2_CPPRCTX);
> - if (!kvm_has_feat(kvm, ID_AA64DFR0_EL1, BRBE, IMP))
> - res0 |= (HFGITR_EL2_nBRBINJ | HFGITR_EL2_nBRBIALL);
> - if (!kvm_has_feat(kvm, ID_AA64PFR1_EL1, GCS, IMP))
> - res0 |= (HFGITR_EL2_nGCSPUSHM_EL1 | HFGITR_EL2_nGCSSTR_EL1 |
> - HFGITR_EL2_nGCSEPP);
> - if (!kvm_has_feat(kvm, ID_AA64ISAR1_EL1, SPECRES, COSP_RCTX))
> - res0 |= HFGITR_EL2_COSPRCTX;
> - if (!kvm_has_feat(kvm, ID_AA64ISAR2_EL1, ATS1A, IMP))
> - res0 |= HFGITR_EL2_ATS1E1A;
> + get_reg_fixed_bits(kvm, HFGITR_EL2, &res0, &res1);
> set_sysreg_masks(kvm, HFGITR_EL2, res0, res1);
>
> /* HAFGRTR_EL2 - not a lot to see here */
> - res0 = hafgrtr_masks.res0;
> - res1 = HAFGRTR_EL2_RES1;
> - if (!kvm_has_feat(kvm, ID_AA64PFR0_EL1, AMU, V1P1))
> - res0 |= ~(res0 | res1);
> + get_reg_fixed_bits(kvm, HAFGRTR_EL2, &res0, &res1);
> set_sysreg_masks(kvm, HAFGRTR_EL2, res0, res1);
>
> /* TCR2_EL2 */
Reviewed-by: Joey Gouly <joey.gouly@xxxxxxx>
