[PATCH v3 02/26] KVM: arm64: Add feature checking helpers
Suzuki K Poulose
suzuki.poulose at arm.com
Mon Feb 5 09:38:23 PST 2024
On 05/02/2024 10:34, Marc Zyngier wrote:
> In order to make it easier to check whether a particular feature
> is exposed to a guest, add a new set of helpers, with kvm_has_feat()
> being the most useful.
>
> Let's start making use of them in the PMU code (courtesy of Oliver).
> Follow-up changes will introduce additional use patterns.
>
> Co-developed--by: Oliver Upton <oliver.upton at linux.dev>
> Signed-off-by: Oliver Upton <oliver.upton at linux.dev>
> Signed-off-by: Marc Zyngier <maz at kernel.org>
Reviewed-by: Suzuki K Poulose <suzuki.poulose at arm.com>
> ---
> arch/arm64/include/asm/kvm_host.h | 44 +++++++++++++++++++++++++++++++
> arch/arm64/kvm/pmu-emul.c | 11 ++++----
> arch/arm64/kvm/sys_regs.c | 6 ++---
> include/kvm/arm_pmu.h | 11 --------
> 4 files changed, 52 insertions(+), 20 deletions(-)
>
> diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
> index 21c57b812569..527da3d2cedb 100644
> --- a/arch/arm64/include/asm/kvm_host.h
> +++ b/arch/arm64/include/asm/kvm_host.h
> @@ -1233,4 +1233,48 @@ static inline void kvm_hyp_reserve(void) { }
> void kvm_arm_vcpu_power_off(struct kvm_vcpu *vcpu);
> bool kvm_arm_vcpu_stopped(struct kvm_vcpu *vcpu);
>
> +#define __expand_field_sign_unsigned(id, fld, val) \
> + ((u64)SYS_FIELD_VALUE(id, fld, val))
> +
> +#define __expand_field_sign_signed(id, fld, val) \
> + ({ \
> + u64 __val = SYS_FIELD_VALUE(id, fld, val); \
> + sign_extend64(__val, id##_##fld##_WIDTH - 1); \
> + })
> +
> +#define expand_field_sign(id, fld, val) \
> + (id##_##fld##_SIGNED ? \
> + __expand_field_sign_signed(id, fld, val) : \
> + __expand_field_sign_unsigned(id, fld, val))
> +
> +#define get_idreg_field_unsigned(kvm, id, fld) \
> + ({ \
> + u64 __val = IDREG((kvm), SYS_##id); \
> + FIELD_GET(id##_##fld##_MASK, __val); \
> + })
> +
> +#define get_idreg_field_signed(kvm, id, fld) \
> + ({ \
> + u64 __val = get_idreg_field_unsigned(kvm, id, fld); \
> + sign_extend64(__val, id##_##fld##_WIDTH - 1); \
> + })
> +
> +#define get_idreg_field_enum(kvm, id, fld) \
> + get_idreg_field_unsigned(kvm, id, fld)
> +
> +#define get_idreg_field(kvm, id, fld) \
> + (id##_##fld##_SIGNED ? \
> + get_idreg_field_signed(kvm, id, fld) : \
> + get_idreg_field_unsigned(kvm, id, fld))
> +
> +#define kvm_has_feat(kvm, id, fld, limit) \
> + (get_idreg_field((kvm), id, fld) >= expand_field_sign(id, fld, limit))
> +
> +#define kvm_has_feat_enum(kvm, id, fld, val) \
> + (get_idreg_field_unsigned((kvm), id, fld) == __expand_field_sign_unsigned(id, fld, val))
> +
> +#define kvm_has_feat_range(kvm, id, fld, min, max) \
> + (get_idreg_field((kvm), id, fld) >= expand_field_sign(id, fld, min) && \
> + get_idreg_field((kvm), id, fld) <= expand_field_sign(id, fld, max))
> +
> #endif /* __ARM64_KVM_HOST_H__ */
> diff --git a/arch/arm64/kvm/pmu-emul.c b/arch/arm64/kvm/pmu-emul.c
> index 3d9467ff73bc..925522470b2b 100644
> --- a/arch/arm64/kvm/pmu-emul.c
> +++ b/arch/arm64/kvm/pmu-emul.c
> @@ -64,12 +64,11 @@ u64 kvm_pmu_evtyper_mask(struct kvm *kvm)
> {
> u64 mask = ARMV8_PMU_EXCLUDE_EL1 | ARMV8_PMU_EXCLUDE_EL0 |
> kvm_pmu_event_mask(kvm);
> - u64 pfr0 = IDREG(kvm, SYS_ID_AA64PFR0_EL1);
>
> - if (SYS_FIELD_GET(ID_AA64PFR0_EL1, EL2, pfr0))
> + if (kvm_has_feat(kvm, ID_AA64PFR0_EL1, EL2, IMP))
> mask |= ARMV8_PMU_INCLUDE_EL2;
>
> - if (SYS_FIELD_GET(ID_AA64PFR0_EL1, EL3, pfr0))
> + if (kvm_has_feat(kvm, ID_AA64PFR0_EL1, EL3, IMP))
> mask |= ARMV8_PMU_EXCLUDE_NS_EL0 |
> ARMV8_PMU_EXCLUDE_NS_EL1 |
> ARMV8_PMU_EXCLUDE_EL3;
> @@ -83,8 +82,10 @@ u64 kvm_pmu_evtyper_mask(struct kvm *kvm)
> */
> static bool kvm_pmc_is_64bit(struct kvm_pmc *pmc)
> {
> + struct kvm_vcpu *vcpu = kvm_pmc_to_vcpu(pmc);
> +
> return (pmc->idx == ARMV8_PMU_CYCLE_IDX ||
> - kvm_pmu_is_3p5(kvm_pmc_to_vcpu(pmc)));
> + kvm_has_feat(vcpu->kvm, ID_AA64DFR0_EL1, PMUVer, V3P5));
> }
>
> static bool kvm_pmc_has_64bit_overflow(struct kvm_pmc *pmc)
> @@ -556,7 +557,7 @@ void kvm_pmu_handle_pmcr(struct kvm_vcpu *vcpu, u64 val)
> return;
>
> /* Fixup PMCR_EL0 to reconcile the PMU version and the LP bit */
> - if (!kvm_pmu_is_3p5(vcpu))
> + if (!kvm_has_feat(vcpu->kvm, ID_AA64DFR0_EL1, PMUVer, V3P5))
> val &= ~ARMV8_PMU_PMCR_LP;
>
> /* The reset bits don't indicate any state, and shouldn't be saved. */
> diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
> index 041b11825578..3c31f8cb9eef 100644
> --- a/arch/arm64/kvm/sys_regs.c
> +++ b/arch/arm64/kvm/sys_regs.c
> @@ -505,10 +505,9 @@ static bool trap_loregion(struct kvm_vcpu *vcpu,
> struct sys_reg_params *p,
> const struct sys_reg_desc *r)
> {
> - u64 val = IDREG(vcpu->kvm, SYS_ID_AA64MMFR1_EL1);
> u32 sr = reg_to_encoding(r);
>
> - if (!(val & (0xfUL << ID_AA64MMFR1_EL1_LO_SHIFT))) {
> + if (!kvm_has_feat(vcpu->kvm, ID_AA64MMFR1_EL1, LO, IMP)) {
> kvm_inject_undefined(vcpu);
> return false;
> }
> @@ -2748,8 +2747,7 @@ static bool trap_dbgdidr(struct kvm_vcpu *vcpu,
> return ignore_write(vcpu, p);
> } else {
> u64 dfr = IDREG(vcpu->kvm, SYS_ID_AA64DFR0_EL1);
> - u64 pfr = IDREG(vcpu->kvm, SYS_ID_AA64PFR0_EL1);
> - u32 el3 = !!SYS_FIELD_GET(ID_AA64PFR0_EL1, EL3, pfr);
> + u32 el3 = kvm_has_feat(vcpu->kvm, ID_AA64PFR0_EL1, EL3, IMP);
>
> p->regval = ((SYS_FIELD_GET(ID_AA64DFR0_EL1, WRPs, dfr) << 28) |
> (SYS_FIELD_GET(ID_AA64DFR0_EL1, BRPs, dfr) << 24) |
> diff --git a/include/kvm/arm_pmu.h b/include/kvm/arm_pmu.h
> index 4b9d8fb393a8..eb4c369a79eb 100644
> --- a/include/kvm/arm_pmu.h
> +++ b/include/kvm/arm_pmu.h
> @@ -90,16 +90,6 @@ void kvm_vcpu_pmu_resync_el0(void);
> vcpu->arch.pmu.events = *kvm_get_pmu_events(); \
> } while (0)
>
> -/*
> - * Evaluates as true when emulating PMUv3p5, and false otherwise.
> - */
> -#define kvm_pmu_is_3p5(vcpu) ({ \
> - u64 val = IDREG(vcpu->kvm, SYS_ID_AA64DFR0_EL1); \
> - u8 pmuver = SYS_FIELD_GET(ID_AA64DFR0_EL1, PMUVer, val); \
> - \
> - pmuver >= ID_AA64DFR0_EL1_PMUVer_V3P5; \
> -})
> -
> u8 kvm_arm_pmu_get_pmuver_limit(void);
> u64 kvm_pmu_evtyper_mask(struct kvm *kvm);
> int kvm_arm_set_default_pmu(struct kvm *kvm);
> @@ -168,7 +158,6 @@ static inline u64 kvm_pmu_get_pmceid(struct kvm_vcpu *vcpu, bool pmceid1)
> }
>
> #define kvm_vcpu_has_pmu(vcpu) ({ false; })
> -#define kvm_pmu_is_3p5(vcpu) ({ false; })
> static inline void kvm_pmu_update_vcpu_events(struct kvm_vcpu *vcpu) {}
> static inline void kvm_vcpu_pmu_restore_guest(struct kvm_vcpu *vcpu) {}
> static inline void kvm_vcpu_pmu_restore_host(struct kvm_vcpu *vcpu) {}
More information about the linux-arm-kernel
mailing list