| Message ID | 20240122201852.262057-3-maz@kernel.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | KVM/arm64: VM configuration enforcement | expand |
On Mon, Jan 22, 2024 at 08:18:29PM +0000, 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. > > Follow-up work will make heavy use of these. > > Signed-off-by: Marc Zyngier <maz@kernel.org> I very much like the way these helpers appear to work. However, I noticed there are still a few places where we are doing explicit feature checks against register values instead of using the macros, did you want to address these? Using kvm_has_feat() consistently in KVM will hopefully drive the point home that this is the way we want to see things done going forward. 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 30253bd19917..955eb06f821d 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; } @@ -2737,8 +2736,7 @@ 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) {}
On Fri, 26 Jan 2024 19:05:47 +0000, Oliver Upton <oliver.upton@linux.dev> wrote: > > On Mon, Jan 22, 2024 at 08:18:29PM +0000, 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. > > > > Follow-up work will make heavy use of these. > > > > Signed-off-by: Marc Zyngier <maz@kernel.org> > > I very much like the way these helpers appear to work. However, I > noticed there are still a few places where we are doing explicit feature > checks against register values instead of using the macros, did you want > to address these? Eventually, yes. It is just that there is a lot to do and I wanted to focus on the VM runtime configuration. > > Using kvm_has_feat() consistently in KVM will hopefully drive the point > home that this is the way we want to see things done going forward. Absolutely. I'll add these to the series. Thanks! M.
diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h index 21c57b812569..c0cf9c5f5e8d 100644 --- a/arch/arm64/include/asm/kvm_host.h +++ b/arch/arm64/include/asm/kvm_host.h @@ -1233,4 +1233,57 @@ 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)(id##_##fld##_##val)) + +#define __expand_field_sign_signed(id, fld, val) \ + ({ \ + s64 __val = id##_##fld##_##val; \ + __val <<= 64 - id##_##fld##_WIDTH; \ + __val >>= 64 - id##_##fld##_SHIFT - id##_##fld##_WIDTH; \ + \ + __val; \ + }) + +#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); \ + __val &= id##_##fld##_MASK; \ + __val >>= id##_##fld##_SHIFT; \ + \ + __val; \ + }) + +#define get_idreg_field_signed(kvm, id, fld) \ + ({ \ + s64 __val = IDREG(kvm, SYS_##id); \ + __val <<= 64 - id##_##fld##_SHIFT - id##_##fld##_WIDTH; \ + __val >>= id##_##fld##_SHIFT; \ + \ + __val; \ + }) + +#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, limit) \ + (get_idreg_field_unsigned((kvm), id, fld) == id##_##fld##_##limit) + +#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__ */
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. Follow-up work will make heavy use of these. Signed-off-by: Marc Zyngier <maz@kernel.org> --- arch/arm64/include/asm/kvm_host.h | 53 +++++++++++++++++++++++++++++++ 1 file changed, 53 insertions(+)