We may want a partitioned PMU but not have FEAT_FGT to untrap the specific registers that would normally be. Add a handler for those registers in the fast path so we can still get a performance boost from partitioning.
Signed-off-by: Colton Lewis coltonlewis@google.com --- arch/arm64/include/asm/arm_pmuv3.h | 37 ++++- arch/arm64/include/asm/kvm_pmu.h | 10 ++ arch/arm64/kvm/hyp/include/hyp/switch.h | 174 ++++++++++++++++++++++++ arch/arm64/kvm/pmu.c | 16 +++ arch/arm64/kvm/sys_regs.c | 16 --- 5 files changed, 236 insertions(+), 17 deletions(-)
diff --git a/arch/arm64/include/asm/arm_pmuv3.h b/arch/arm64/include/asm/arm_pmuv3.h index 3bddde5f4ebb..12004fd04018 100644 --- a/arch/arm64/include/asm/arm_pmuv3.h +++ b/arch/arm64/include/asm/arm_pmuv3.h @@ -41,6 +41,16 @@ static inline unsigned long read_pmevtypern(int n) return 0; }
+static inline void write_pmxevcntr(u64 val) +{ + write_sysreg(val, pmxevcntr_el0); +} + +static inline u64 read_pmxevcntr(void) +{ + return read_sysreg(pmxevcntr_el0); +} + static inline unsigned long read_pmmir(void) { return read_cpuid(PMMIR_EL1); @@ -107,21 +117,41 @@ static inline void write_pmcntenset(u64 val) write_sysreg(val, pmcntenset_el0); }
+static inline u64 read_pmcntenset(void) +{ + return read_sysreg(pmcntenset_el0); +} + static inline void write_pmcntenclr(u64 val) { write_sysreg(val, pmcntenclr_el0); }
+static inline u64 read_pmcntenclr(void) +{ + return read_sysreg(pmcntenclr_el0); +} + static inline void write_pmintenset(u64 val) { write_sysreg(val, pmintenset_el1); }
+static inline u64 read_pmintenset(void) +{ + return read_sysreg(pmintenset_el1); +} + static inline void write_pmintenclr(u64 val) { write_sysreg(val, pmintenclr_el1); }
+static inline u64 read_pmintenclr(void) +{ + return read_sysreg(pmintenclr_el1); +} + static inline void write_pmccfiltr(u64 val) { write_sysreg(val, pmccfiltr_el0); @@ -162,11 +192,16 @@ static inline u64 read_pmovsclr(void) return read_sysreg(pmovsclr_el0); }
-static inline void write_pmuserenr(u32 val) +static inline void write_pmuserenr(u64 val) { write_sysreg(val, pmuserenr_el0); }
+static inline u64 read_pmuserenr(void) +{ + return read_sysreg(pmuserenr_el0); +} + static inline void write_pmuacr(u64 val) { write_sysreg_s(val, SYS_PMUACR_EL1); diff --git a/arch/arm64/include/asm/kvm_pmu.h b/arch/arm64/include/asm/kvm_pmu.h index 73b7161e3f4e..62c8032a548f 100644 --- a/arch/arm64/include/asm/kvm_pmu.h +++ b/arch/arm64/include/asm/kvm_pmu.h @@ -81,6 +81,8 @@ struct kvm_pmu_events *kvm_get_pmu_events(void); void kvm_set_pmu_events(u64 set, struct perf_event_attr *attr); void kvm_clr_pmu_events(u64 clr); bool kvm_set_pmuserenr(u64 val); +bool check_pmu_access_disabled(struct kvm_vcpu *vcpu, u64 flags); +bool pmu_access_el0_disabled(struct kvm_vcpu *vcpu); void kvm_vcpu_pmu_restore_guest(struct kvm_vcpu *vcpu); void kvm_vcpu_pmu_restore_host(struct kvm_vcpu *vcpu); void kvm_vcpu_pmu_resync_el0(void); @@ -214,6 +216,14 @@ static inline bool kvm_set_pmuserenr(u64 val) { return false; } +static inline bool check_pmu_access_disabled(struct kvm_vcpu *vcpu, u64 flags) +{ + return false; +} +static inline bool pmu_access_el0_disabled(struct kvm_vcpu *vcpu) +{ + return false; +} static inline void kvm_vcpu_pmu_restore_guest(struct kvm_vcpu *vcpu) {} static inline void kvm_vcpu_pmu_restore_host(struct kvm_vcpu *vcpu) {} static inline void kvm_vcpu_reload_pmu(struct kvm_vcpu *vcpu) {} diff --git a/arch/arm64/kvm/hyp/include/hyp/switch.h b/arch/arm64/kvm/hyp/include/hyp/switch.h index 47d2db8446df..4920b7da9ce8 100644 --- a/arch/arm64/kvm/hyp/include/hyp/switch.h +++ b/arch/arm64/kvm/hyp/include/hyp/switch.h @@ -25,12 +25,14 @@ #include <asm/kvm_emulate.h> #include <asm/kvm_hyp.h> #include <asm/kvm_mmu.h> +#include <asm/kvm_pmu.h> #include <asm/kvm_nested.h> #include <asm/fpsimd.h> #include <asm/debug-monitors.h> #include <asm/processor.h> #include <asm/traps.h>
+#include <../../sys_regs.h> #include "arm_psci.h"
struct kvm_exception_table_entry { @@ -782,6 +784,175 @@ static bool handle_ampere1_tcr(struct kvm_vcpu *vcpu) return true; }
+/** + * handle_pmu_reg() - Handle fast access to most PMU regs + * @vcpu: Ponter to kvm_vcpu struct + * @p: System register parameters (read/write, Op0, Op1, CRm, CRn, Op2) + * @reg: VCPU register identifier + * @rt: Target general register + * @val: Value to write + * @readfn: Sysreg read function + * @writefn: Sysreg write function + * + * Handle fast access to most PMU regs. Writethrough to the physical + * register. This function is a wrapper for the simplest case, but + * sadly there aren't many of those. + * + * Always return true. The boolean makes usage more consistent with + * similar functions. + * + * Return: True + */ +static bool handle_pmu_reg(struct kvm_vcpu *vcpu, struct sys_reg_params *p, + enum vcpu_sysreg reg, u8 rt, u64 val, + u64 (*readfn)(void), void (*writefn)(u64)) +{ + if (p->is_write) { + __vcpu_assign_sys_reg(vcpu, reg, val); + writefn(val); + } else { + vcpu_set_reg(vcpu, rt, readfn()); + } + + return true; +} + +/** + * kvm_hyp_handle_pmu_regs() - Fast handler for PMU registers + * @vcpu: Pointer to vcpu struct + * + * This handler immediately writes through certain PMU registers when + * we have a partitioned PMU (that is, MDCR_EL2.HPMN is set to reserve + * a range of counters for the guest) but the machine does not have + * FEAT_FGT to selectively untrap the registers we want. + * + * Return: True if the exception was successfully handled, false otherwise + */ +static bool kvm_hyp_handle_pmu_regs(struct kvm_vcpu *vcpu) +{ + struct sys_reg_params p; + u64 esr; + u32 sysreg; + u8 rt; + u64 val; + u8 idx; + bool ret; + + if (!kvm_vcpu_pmu_is_partitioned(vcpu) + || pmu_access_el0_disabled(vcpu)) + return false; + + esr = kvm_vcpu_get_esr(vcpu); + p = esr_sys64_to_params(esr); + sysreg = esr_sys64_to_sysreg(esr); + rt = kvm_vcpu_sys_get_rt(vcpu); + val = vcpu_get_reg(vcpu, rt); + + switch (sysreg) { + case SYS_PMCR_EL0: + val &= ARMV8_PMU_PMCR_MASK; + + if (p.is_write) { + write_pmcr(val); + __vcpu_assign_sys_reg(vcpu, PMCR_EL0, read_pmcr()); + } else { + val = u64_replace_bits( + read_pmcr(), + vcpu->kvm->arch.nr_pmu_counters, + ARMV8_PMU_PMCR_N); + vcpu_set_reg(vcpu, rt, val); + } + + ret = true; + break; + case SYS_PMUSERENR_EL0: + val &= ARMV8_PMU_USERENR_MASK; + ret = handle_pmu_reg(vcpu, &p, PMUSERENR_EL0, rt, val, + &read_pmuserenr, &write_pmuserenr); + break; + case SYS_PMSELR_EL0: + val &= PMSELR_EL0_SEL_MASK; + ret = handle_pmu_reg(vcpu, &p, PMSELR_EL0, rt, val, + &read_pmselr, &write_pmselr); + break; + case SYS_PMINTENCLR_EL1: + val &= kvm_pmu_accessible_counter_mask(vcpu); + if (p.is_write) { + __vcpu_rmw_sys_reg(vcpu, PMINTENSET_EL1, &=, ~val); + write_pmintenclr(val); + } else { + vcpu_set_reg(vcpu, rt, read_pmintenclr()); + } + ret = true; + break; + case SYS_PMINTENSET_EL1: + val &= kvm_pmu_accessible_counter_mask(vcpu); + if (p.is_write) { + __vcpu_rmw_sys_reg(vcpu, PMINTENSET_EL1, |=, val); + write_pmintenset(val); + } else { + vcpu_set_reg(vcpu, rt, read_pmintenset()); + } + ret = true; + break; + case SYS_PMCNTENCLR_EL0: + val &= kvm_pmu_accessible_counter_mask(vcpu); + if (p.is_write) { + __vcpu_rmw_sys_reg(vcpu, PMCNTENSET_EL0, &=, ~val); + write_pmcntenclr(val); + } else { + vcpu_set_reg(vcpu, rt, read_pmcntenclr()); + } + ret = true; + break; + case SYS_PMCNTENSET_EL0: + val &= kvm_pmu_accessible_counter_mask(vcpu); + if (p.is_write) { + __vcpu_rmw_sys_reg(vcpu, PMCNTENSET_EL0, |=, val); + write_pmcntenset(val); + } else { + vcpu_set_reg(vcpu, rt, read_pmcntenset()); + } + ret = true; + break; + case SYS_PMCCNTR_EL0: + ret = handle_pmu_reg(vcpu, &p, PMCCNTR_EL0, rt, val, + &read_pmccntr, &write_pmccntr); + break; + case SYS_PMXEVCNTR_EL0: + idx = FIELD_GET(PMSELR_EL0_SEL, read_pmselr()); + + if (idx >= vcpu->kvm->arch.nr_pmu_counters) + return false; + + ret = handle_pmu_reg(vcpu, &p, PMEVCNTR0_EL0 + idx, rt, val, + &read_pmxevcntr, &write_pmxevcntr); + break; + case SYS_PMEVCNTRn_EL0(0) ... SYS_PMEVCNTRn_EL0(30): + idx = ((p.CRm & 3) << 3) | (p.Op2 & 7); + + if (idx >= vcpu->kvm->arch.nr_pmu_counters) + return false; + + if (p.is_write) { + write_pmevcntrn(idx, val); + __vcpu_assign_sys_reg(vcpu, PMEVCNTR0_EL0 + idx, val); + } else { + vcpu_set_reg(vcpu, rt, read_pmevcntrn(idx)); + } + + ret = true; + break; + default: + ret = false; + } + + if (ret) + __kvm_skip_instr(vcpu); + + return ret; +} + static inline bool kvm_hyp_handle_sysreg(struct kvm_vcpu *vcpu, u64 *exit_code) { if (cpus_have_final_cap(ARM64_WORKAROUND_CAVIUM_TX2_219_TVM) && @@ -799,6 +970,9 @@ static inline bool kvm_hyp_handle_sysreg(struct kvm_vcpu *vcpu, u64 *exit_code) if (kvm_handle_cntxct(vcpu)) return true;
+ if (kvm_hyp_handle_pmu_regs(vcpu)) + return true; + return false; }
diff --git a/arch/arm64/kvm/pmu.c b/arch/arm64/kvm/pmu.c index 67216451b8ce..338e7eebf0d1 100644 --- a/arch/arm64/kvm/pmu.c +++ b/arch/arm64/kvm/pmu.c @@ -891,3 +891,19 @@ u64 kvm_vcpu_read_pmcr(struct kvm_vcpu *vcpu)
return u64_replace_bits(pmcr, n, ARMV8_PMU_PMCR_N); } + +bool check_pmu_access_disabled(struct kvm_vcpu *vcpu, u64 flags) +{ + u64 reg = __vcpu_sys_reg(vcpu, PMUSERENR_EL0); + bool enabled = (reg & flags) || vcpu_mode_priv(vcpu); + + if (!enabled) + kvm_inject_undefined(vcpu); + + return !enabled; +} + +bool pmu_access_el0_disabled(struct kvm_vcpu *vcpu) +{ + return check_pmu_access_disabled(vcpu, ARMV8_PMU_USERENR_EN); +} diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c index cfbce4537b4c..b80cf6194fa3 100644 --- a/arch/arm64/kvm/sys_regs.c +++ b/arch/arm64/kvm/sys_regs.c @@ -842,22 +842,6 @@ static u64 reset_pmcr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r) return __vcpu_sys_reg(vcpu, r->reg); }
-static bool check_pmu_access_disabled(struct kvm_vcpu *vcpu, u64 flags) -{ - u64 reg = __vcpu_sys_reg(vcpu, PMUSERENR_EL0); - bool enabled = (reg & flags) || vcpu_mode_priv(vcpu); - - if (!enabled) - kvm_inject_undefined(vcpu); - - return !enabled; -} - -static bool pmu_access_el0_disabled(struct kvm_vcpu *vcpu) -{ - return check_pmu_access_disabled(vcpu, ARMV8_PMU_USERENR_EN); -} - static bool pmu_write_swinc_el0_disabled(struct kvm_vcpu *vcpu) { return check_pmu_access_disabled(vcpu, ARMV8_PMU_USERENR_SW | ARMV8_PMU_USERENR_EN);