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KVM: arm64: Add feature checking helpers

Browse source 
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.

Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Co-developed--by: Oliver Upton <oliver.upton@linux.dev>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20240214131827.2856277-3-maz@kernel.org
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
This commit is contained in:
Marc Zyngier 2024-02-14 13:18:03 +00:00 committed by Oliver Upton
parent aeddd5b214
commit c62d7a23b9
4 changed files with 52 additions and 20 deletions
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44
arch/arm64/include/asm/kvm_host.h
View file

@ -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__ */

11
arch/arm64/kvm/pmu-emul.c
View file

@ -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. */

6
arch/arm64/kvm/sys_regs.c
View file

@ -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) |

11
include/kvm/arm_pmu.h
View file

@ -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) {}