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Message-ID: <CA+EHjTxAzGrgxtSbhb8f5cs4mj_mD31gOGhwUEZFN21xGfoKyg@mail.gmail.com>
Date: Thu, 8 Jan 2026 14:09:54 +0000
From: Fuad Tabba <tabba@...gle.com>
To: Mark Brown <broonie@...nel.org>
Cc: Marc Zyngier <maz@...nel.org>, Joey Gouly <joey.gouly@....com>,
Catalin Marinas <catalin.marinas@....com>, Suzuki K Poulose <suzuki.poulose@....com>,
Will Deacon <will@...nel.org>, Paolo Bonzini <pbonzini@...hat.com>, Jonathan Corbet <corbet@....net>,
Shuah Khan <shuah@...nel.org>, Oliver Upton <oupton@...nel.org>, Dave Martin <Dave.Martin@....com>,
Mark Rutland <mark.rutland@....com>, Ben Horgan <ben.horgan@....com>,
linux-arm-kernel@...ts.infradead.org, kvmarm@...ts.linux.dev,
linux-kernel@...r.kernel.org, kvm@...r.kernel.org, linux-doc@...r.kernel.org,
linux-kselftest@...r.kernel.org, Peter Maydell <peter.maydell@...aro.org>,
Eric Auger <eric.auger@...hat.com>
Subject: Re: [PATCH v9 09/30] KVM: arm64: Rename SVE finalization constants to
be more general
On Tue, 23 Dec 2025 at 01:22, Mark Brown <broonie@...nel.org> wrote:
>
> Due to the overlap between SVE and SME vector length configuration
> created by streaming mode SVE we will finalize both at once. Rename the
> existing finalization to use _VEC (vector) for the naming to avoid
> confusion.
>
> Since this includes the userspace API we create an alias
> KVM_ARM_VCPU_VEC for the existing KVM_ARM_VCPU_SVE capability, existing
> code which does not enable SME will be unaffected and any SME only code
> will not need to use SVE constants.
>
> No functional change.
>
> Signed-off-by: Mark Brown <broonie@...nel.org>
Reviewed-by: Fuad Tabba <tabba@...gle.com>
Cheers,
/fuad
> ---
> arch/arm64/include/asm/kvm_host.h | 8 +++++---
> arch/arm64/include/uapi/asm/kvm.h | 6 ++++++
> arch/arm64/kvm/guest.c | 10 +++++-----
> arch/arm64/kvm/hyp/nvhe/pkvm.c | 2 +-
> arch/arm64/kvm/reset.c | 20 ++++++++++----------
> 5 files changed, 27 insertions(+), 19 deletions(-)
>
> diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
> index e6d25db10a6b..0f3d26467bf0 100644
> --- a/arch/arm64/include/asm/kvm_host.h
> +++ b/arch/arm64/include/asm/kvm_host.h
> @@ -988,8 +988,8 @@ struct kvm_vcpu_arch {
>
> /* KVM_ARM_VCPU_INIT completed */
> #define VCPU_INITIALIZED __vcpu_single_flag(cflags, BIT(0))
> -/* SVE config completed */
> -#define VCPU_SVE_FINALIZED __vcpu_single_flag(cflags, BIT(1))
> +/* Vector config completed */
> +#define VCPU_VEC_FINALIZED __vcpu_single_flag(cflags, BIT(1))
> /* pKVM VCPU setup completed */
> #define VCPU_PKVM_FINALIZED __vcpu_single_flag(cflags, BIT(2))
>
> @@ -1062,6 +1062,8 @@ struct kvm_vcpu_arch {
> #define vcpu_has_sve(vcpu) kvm_has_sve((vcpu)->kvm)
> #endif
>
> +#define vcpu_has_vec(vcpu) vcpu_has_sve(vcpu)
> +
> #ifdef CONFIG_ARM64_PTR_AUTH
> #define vcpu_has_ptrauth(vcpu) \
> ((cpus_have_final_cap(ARM64_HAS_ADDRESS_AUTH) || \
> @@ -1458,7 +1460,7 @@ struct kvm *kvm_arch_alloc_vm(void);
> int kvm_arm_vcpu_finalize(struct kvm_vcpu *vcpu, int feature);
> bool kvm_arm_vcpu_is_finalized(struct kvm_vcpu *vcpu);
>
> -#define kvm_arm_vcpu_sve_finalized(vcpu) vcpu_get_flag(vcpu, VCPU_SVE_FINALIZED)
> +#define kvm_arm_vcpu_vec_finalized(vcpu) vcpu_get_flag(vcpu, VCPU_VEC_FINALIZED)
>
> #define kvm_has_mte(kvm) \
> (system_supports_mte() && \
> diff --git a/arch/arm64/include/uapi/asm/kvm.h b/arch/arm64/include/uapi/asm/kvm.h
> index a792a599b9d6..c67564f02981 100644
> --- a/arch/arm64/include/uapi/asm/kvm.h
> +++ b/arch/arm64/include/uapi/asm/kvm.h
> @@ -107,6 +107,12 @@ struct kvm_regs {
> #define KVM_ARM_VCPU_HAS_EL2 7 /* Support nested virtualization */
> #define KVM_ARM_VCPU_HAS_EL2_E2H0 8 /* Limit NV support to E2H RES0 */
>
> +/*
> + * An alias for _SVE since we finalize VL configuration for both SVE and SME
> + * simultaneously.
> + */
> +#define KVM_ARM_VCPU_VEC KVM_ARM_VCPU_SVE
> +
> struct kvm_vcpu_init {
> __u32 target;
> __u32 features[7];
> diff --git a/arch/arm64/kvm/guest.c b/arch/arm64/kvm/guest.c
> index 1c87699fd886..d15aa2da1891 100644
> --- a/arch/arm64/kvm/guest.c
> +++ b/arch/arm64/kvm/guest.c
> @@ -342,7 +342,7 @@ static int set_sve_vls(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
> if (!vcpu_has_sve(vcpu))
> return -ENOENT;
>
> - if (kvm_arm_vcpu_sve_finalized(vcpu))
> + if (kvm_arm_vcpu_vec_finalized(vcpu))
> return -EPERM; /* too late! */
>
> if (WARN_ON(vcpu->arch.sve_state))
> @@ -497,7 +497,7 @@ static int get_sve_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
> if (ret)
> return ret;
>
> - if (!kvm_arm_vcpu_sve_finalized(vcpu))
> + if (!kvm_arm_vcpu_vec_finalized(vcpu))
> return -EPERM;
>
> if (copy_to_user(uptr, vcpu->arch.sve_state + region.koffset,
> @@ -523,7 +523,7 @@ static int set_sve_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
> if (ret)
> return ret;
>
> - if (!kvm_arm_vcpu_sve_finalized(vcpu))
> + if (!kvm_arm_vcpu_vec_finalized(vcpu))
> return -EPERM;
>
> if (copy_from_user(vcpu->arch.sve_state + region.koffset, uptr,
> @@ -599,7 +599,7 @@ static unsigned long num_sve_regs(const struct kvm_vcpu *vcpu)
> return 0;
>
> /* Policed by KVM_GET_REG_LIST: */
> - WARN_ON(!kvm_arm_vcpu_sve_finalized(vcpu));
> + WARN_ON(!kvm_arm_vcpu_vec_finalized(vcpu));
>
> return slices * (SVE_NUM_PREGS + SVE_NUM_ZREGS + 1 /* FFR */)
> + 1; /* KVM_REG_ARM64_SVE_VLS */
> @@ -617,7 +617,7 @@ static int copy_sve_reg_indices(const struct kvm_vcpu *vcpu,
> return 0;
>
> /* Policed by KVM_GET_REG_LIST: */
> - WARN_ON(!kvm_arm_vcpu_sve_finalized(vcpu));
> + WARN_ON(!kvm_arm_vcpu_vec_finalized(vcpu));
>
> /*
> * Enumerate this first, so that userspace can save/restore in
> diff --git a/arch/arm64/kvm/hyp/nvhe/pkvm.c b/arch/arm64/kvm/hyp/nvhe/pkvm.c
> index 8911338961c5..b402dcb7691e 100644
> --- a/arch/arm64/kvm/hyp/nvhe/pkvm.c
> +++ b/arch/arm64/kvm/hyp/nvhe/pkvm.c
> @@ -445,7 +445,7 @@ static int pkvm_vcpu_init_sve(struct pkvm_hyp_vcpu *hyp_vcpu, struct kvm_vcpu *h
> int ret = 0;
>
> if (!vcpu_has_feature(vcpu, KVM_ARM_VCPU_SVE)) {
> - vcpu_clear_flag(vcpu, VCPU_SVE_FINALIZED);
> + vcpu_clear_flag(vcpu, VCPU_VEC_FINALIZED);
> return 0;
> }
>
> diff --git a/arch/arm64/kvm/reset.c b/arch/arm64/kvm/reset.c
> index 959532422d3a..f7c63e145d54 100644
> --- a/arch/arm64/kvm/reset.c
> +++ b/arch/arm64/kvm/reset.c
> @@ -92,7 +92,7 @@ static void kvm_vcpu_enable_sve(struct kvm_vcpu *vcpu)
> * Finalize vcpu's maximum SVE vector length, allocating
> * vcpu->arch.sve_state as necessary.
> */
> -static int kvm_vcpu_finalize_sve(struct kvm_vcpu *vcpu)
> +static int kvm_vcpu_finalize_vec(struct kvm_vcpu *vcpu)
> {
> void *buf;
> unsigned int vl;
> @@ -122,21 +122,21 @@ static int kvm_vcpu_finalize_sve(struct kvm_vcpu *vcpu)
> }
>
> vcpu->arch.sve_state = buf;
> - vcpu_set_flag(vcpu, VCPU_SVE_FINALIZED);
> + vcpu_set_flag(vcpu, VCPU_VEC_FINALIZED);
> return 0;
> }
>
> int kvm_arm_vcpu_finalize(struct kvm_vcpu *vcpu, int feature)
> {
> switch (feature) {
> - case KVM_ARM_VCPU_SVE:
> - if (!vcpu_has_sve(vcpu))
> + case KVM_ARM_VCPU_VEC:
> + if (!vcpu_has_vec(vcpu))
> return -EINVAL;
>
> - if (kvm_arm_vcpu_sve_finalized(vcpu))
> + if (kvm_arm_vcpu_vec_finalized(vcpu))
> return -EPERM;
>
> - return kvm_vcpu_finalize_sve(vcpu);
> + return kvm_vcpu_finalize_vec(vcpu);
> }
>
> return -EINVAL;
> @@ -144,7 +144,7 @@ int kvm_arm_vcpu_finalize(struct kvm_vcpu *vcpu, int feature)
>
> bool kvm_arm_vcpu_is_finalized(struct kvm_vcpu *vcpu)
> {
> - if (vcpu_has_sve(vcpu) && !kvm_arm_vcpu_sve_finalized(vcpu))
> + if (vcpu_has_vec(vcpu) && !kvm_arm_vcpu_vec_finalized(vcpu))
> return false;
>
> return true;
> @@ -163,7 +163,7 @@ void kvm_arm_vcpu_destroy(struct kvm_vcpu *vcpu)
> kfree(vcpu->arch.ccsidr);
> }
>
> -static void kvm_vcpu_reset_sve(struct kvm_vcpu *vcpu)
> +static void kvm_vcpu_reset_vec(struct kvm_vcpu *vcpu)
> {
> if (vcpu_has_sve(vcpu))
> memset(vcpu->arch.sve_state, 0, vcpu_sve_state_size(vcpu));
> @@ -203,11 +203,11 @@ void kvm_reset_vcpu(struct kvm_vcpu *vcpu)
> if (loaded)
> kvm_arch_vcpu_put(vcpu);
>
> - if (!kvm_arm_vcpu_sve_finalized(vcpu)) {
> + if (!kvm_arm_vcpu_vec_finalized(vcpu)) {
> if (vcpu_has_feature(vcpu, KVM_ARM_VCPU_SVE))
> kvm_vcpu_enable_sve(vcpu);
> } else {
> - kvm_vcpu_reset_sve(vcpu);
> + kvm_vcpu_reset_vec(vcpu);
> }
>
> if (vcpu_el1_is_32bit(vcpu))
>
> --
> 2.47.3
>
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