From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 656262F5463 for ; Wed, 3 Dec 2025 11:44:19 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.140.110.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764762261; cv=none; b=avtnYcWrLRx8TqorczpwbKBUJyNqEszkroI1DOkXMRbSBHz7Ti9UU6eZubnuEBRg4Dr0h5br0o5KDuMVrlynUxaQSvwGPAWu6BiVw5VfFQrkVdZYoSnzRGWZrYsctekMRecpzSmj1S0foZcUkLcrfCDU0c1HTfNufL923Ss+jtQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764762261; c=relaxed/simple; bh=T0pEXoK2d1wRcnvdbKf7FHxSn38/R/3bevwS2Lc8TCU=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=k3O9cJr8ZrE/KK60r4RNRLqPkkRp1ihoMA2Tme4U4m6K9klgevS/uy4VJdNaEKpfO6G0TFeXfhWP3Hvd6rpXbawdrDmz7tVhBQpkeT1ozb05IT5ZDng0QXFTScewdFdEcNVsu8zOW20+iBUgNiGqxl88HpZVXGCFAMCoP74BQmY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=arm.com; arc=none smtp.client-ip=217.140.110.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 0AE8F339; Wed, 3 Dec 2025 03:44:11 -0800 (PST) Received: from raptor (usa-sjc-mx-foss1.foss.arm.com [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 1B91C3F59E; Wed, 3 Dec 2025 03:44:16 -0800 (PST) Date: Wed, 3 Dec 2025 11:44:14 +0000 From: Alexandru Elisei To: Marc Zyngier Cc: kvmarm@lists.linux.dev, linux-arm-kernel@lists.infradead.org, kvm@vger.kernel.org, Joey Gouly , Suzuki K Poulose , Oliver Upton , Zenghui Yu Subject: Re: [PATCH 4/4] KVM: arm64: Convert VTCR_EL2 to config-driven sanitisation Message-ID: References: <20251129144525.2609207-1-maz@kernel.org> <20251129144525.2609207-5-maz@kernel.org> Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20251129144525.2609207-5-maz@kernel.org> Hi Marc, On Sat, Nov 29, 2025 at 02:45:25PM +0000, Marc Zyngier wrote: > Describe all the VTCR_EL2 fields and their respective configurations, > making sure that we correctly ignore the bits that are not defined > for a given guest configuration. > > Signed-off-by: Marc Zyngier > --- > arch/arm64/kvm/config.c | 69 +++++++++++++++++++++++++++++++++++++++++ > arch/arm64/kvm/nested.c | 3 +- > 2 files changed, 70 insertions(+), 2 deletions(-) > > diff --git a/arch/arm64/kvm/config.c b/arch/arm64/kvm/config.c > index a02c28d6a61c9..c36e133c51912 100644 > --- a/arch/arm64/kvm/config.c > +++ b/arch/arm64/kvm/config.c > @@ -141,6 +141,7 @@ struct reg_feat_map_desc { > #define FEAT_AA64EL1 ID_AA64PFR0_EL1, EL1, IMP > #define FEAT_AA64EL2 ID_AA64PFR0_EL1, EL2, IMP > #define FEAT_AA64EL3 ID_AA64PFR0_EL1, EL3, IMP > +#define FEAT_SEL2 ID_AA64PFR0_EL1, SEL2, IMP > #define FEAT_AIE ID_AA64MMFR3_EL1, AIE, IMP > #define FEAT_S2POE ID_AA64MMFR3_EL1, S2POE, IMP > #define FEAT_S1POE ID_AA64MMFR3_EL1, S1POE, IMP > @@ -202,6 +203,8 @@ struct reg_feat_map_desc { > #define FEAT_ASID2 ID_AA64MMFR4_EL1, ASID2, IMP > #define FEAT_MEC ID_AA64MMFR3_EL1, MEC, IMP > #define FEAT_HAFT ID_AA64MMFR1_EL1, HAFDBS, HAFT > +#define FEAT_HDBSS ID_AA64MMFR1_EL1, HAFDBS, HDBSS > +#define FEAT_HPDS2 ID_AA64MMFR1_EL1, HPDS, HPDS2 > #define FEAT_BTI ID_AA64PFR1_EL1, BT, IMP > #define FEAT_ExS ID_AA64MMFR0_EL1, EXS, IMP > #define FEAT_IESB ID_AA64MMFR2_EL1, IESB, IMP > @@ -219,6 +222,7 @@ struct reg_feat_map_desc { > #define FEAT_FGT2 ID_AA64MMFR0_EL1, FGT, FGT2 > #define FEAT_MTPMU ID_AA64DFR0_EL1, MTPMU, IMP > #define FEAT_HCX ID_AA64MMFR1_EL1, HCX, IMP > +#define FEAT_S2PIE ID_AA64MMFR3_EL1, S2PIE, IMP > > static bool not_feat_aa64el3(struct kvm *kvm) > { > @@ -362,6 +366,28 @@ static bool feat_pmuv3p9(struct kvm *kvm) > return check_pmu_revision(kvm, V3P9); > } > > +#define has_feat_s2tgran(k, s) \ > + ((kvm_has_feat_enum(kvm, ID_AA64MMFR0_EL1, TGRAN##s##_2, TGRAN##s) && \ > + !kvm_has_feat_enum(kvm, ID_AA64MMFR0_EL1, TGRAN##s, NI)) || \ Wouldn't that read better as kvm_has_feat(kvm, ID_AA64MMFR0_EL1, TGRAN##s, IMP)? I think that would also be correct. > + kvm_has_feat(kvm, ID_AA64MMFR0_EL1, TGRAN##s##_2, IMP)) A bit unexpected to treat the same field first as an enum, then as an integer, but it saves one line. > + > +static bool feat_lpa2(struct kvm *kvm) > +{ > + return ((kvm_has_feat(kvm, ID_AA64MMFR0_EL1, TGRAN4, 52_BIT) || > + !kvm_has_feat(kvm, ID_AA64MMFR0_EL1, TGRAN4, IMP)) && > + (kvm_has_feat(kvm, ID_AA64MMFR0_EL1, TGRAN16, 52_BIT) || > + !kvm_has_feat(kvm, ID_AA64MMFR0_EL1, TGRAN16, IMP)) && > + (kvm_has_feat(kvm, ID_AA64MMFR0_EL1, TGRAN4_2, 52_BIT) || > + !has_feat_s2tgran(kvm, 4)) && > + (kvm_has_feat(kvm, ID_AA64MMFR0_EL1, TGRAN16_2, 52_BIT) || > + !has_feat_s2tgran(kvm, 16))); > +} That was a doozy, but looks correct to me if the intention was to have the check as relaxed as possible - i.e, a VM can advertise 52 bit support for one granule, but not the other (same for stage 1 and stage 2). As far as I can tell, everything looks good to me: Reviewed-by: Alexandru Elisei Thanks, Alex > + > +static bool feat_vmid16(struct kvm *kvm) > +{ > + return kvm_has_feat_enum(kvm, ID_AA64MMFR1_EL1, VMIDBits, 16); > +} > + > static bool compute_hcr_rw(struct kvm *kvm, u64 *bits) > { > /* This is purely academic: AArch32 and NV are mutually exclusive */ > @@ -1168,6 +1194,44 @@ static const struct reg_bits_to_feat_map mdcr_el2_feat_map[] = { > static const DECLARE_FEAT_MAP(mdcr_el2_desc, MDCR_EL2, > mdcr_el2_feat_map, FEAT_AA64EL2); > > +static const struct reg_bits_to_feat_map vtcr_el2_feat_map[] = { > + NEEDS_FEAT(VTCR_EL2_HDBSS, FEAT_HDBSS), > + NEEDS_FEAT(VTCR_EL2_HAFT, FEAT_HAFT), > + NEEDS_FEAT(VTCR_EL2_TL0 | > + VTCR_EL2_TL1 | > + VTCR_EL2_AssuredOnly | > + VTCR_EL2_GCSH, > + FEAT_THE), > + NEEDS_FEAT(VTCR_EL2_D128, FEAT_D128), > + NEEDS_FEAT(VTCR_EL2_S2POE, FEAT_S2POE), > + NEEDS_FEAT(VTCR_EL2_S2PIE, FEAT_S2PIE), > + NEEDS_FEAT(VTCR_EL2_SL2 | > + VTCR_EL2_DS, > + feat_lpa2), > + NEEDS_FEAT(VTCR_EL2_NSA | > + VTCR_EL2_NSW, > + FEAT_SEL2), > + NEEDS_FEAT(VTCR_EL2_HWU62 | > + VTCR_EL2_HWU61 | > + VTCR_EL2_HWU60 | > + VTCR_EL2_HWU59, > + FEAT_HPDS2), > + NEEDS_FEAT(VTCR_EL2_HD, ID_AA64MMFR1_EL1, HAFDBS, DBM), > + NEEDS_FEAT(VTCR_EL2_HA, ID_AA64MMFR1_EL1, HAFDBS, AF), > + NEEDS_FEAT(VTCR_EL2_VS, feat_vmid16), > + NEEDS_FEAT(VTCR_EL2_PS | > + VTCR_EL2_TG0 | > + VTCR_EL2_SH0 | > + VTCR_EL2_ORGN0 | > + VTCR_EL2_IRGN0 | > + VTCR_EL2_SL0 | > + VTCR_EL2_T0SZ, > + FEAT_AA64EL1), > +}; > + > +static const DECLARE_FEAT_MAP(vtcr_el2_desc, VTCR_EL2, > + vtcr_el2_feat_map, FEAT_AA64EL2); > + > static void __init check_feat_map(const struct reg_bits_to_feat_map *map, > int map_size, u64 res0, const char *str) > { > @@ -1211,6 +1275,7 @@ void __init check_feature_map(void) > check_reg_desc(&tcr2_el2_desc); > check_reg_desc(&sctlr_el1_desc); > check_reg_desc(&mdcr_el2_desc); > + check_reg_desc(&vtcr_el2_desc); > } > > static bool idreg_feat_match(struct kvm *kvm, const struct reg_bits_to_feat_map *map) > @@ -1425,6 +1490,10 @@ void get_reg_fixed_bits(struct kvm *kvm, enum vcpu_sysreg reg, u64 *res0, u64 *r > *res0 = compute_reg_res0_bits(kvm, &mdcr_el2_desc, 0, 0); > *res1 = MDCR_EL2_RES1; > break; > + case VTCR_EL2: > + *res0 = compute_reg_res0_bits(kvm, &vtcr_el2_desc, 0, 0); > + *res1 = VTCR_EL2_RES1; > + break; > default: > WARN_ON_ONCE(1); > *res0 = *res1 = 0; > diff --git a/arch/arm64/kvm/nested.c b/arch/arm64/kvm/nested.c > index e1ef8930c97b3..606cebcaa7c09 100644 > --- a/arch/arm64/kvm/nested.c > +++ b/arch/arm64/kvm/nested.c > @@ -1719,8 +1719,7 @@ int kvm_init_nv_sysregs(struct kvm_vcpu *vcpu) > set_sysreg_masks(kvm, VTTBR_EL2, res0, res1); > > /* VTCR_EL2 */ > - res0 = GENMASK(63, 32) | GENMASK(30, 20); > - res1 = BIT(31); > + get_reg_fixed_bits(kvm, VTCR_EL2, &res0, &res1); > set_sysreg_masks(kvm, VTCR_EL2, res0, res1); > > /* VMPIDR_EL2 */ > -- > 2.47.3 >