diff options
author | Oliver Upton <oliver.upton@linux.dev> | 2023-10-30 23:24:07 +0300 |
---|---|---|
committer | Oliver Upton <oliver.upton@linux.dev> | 2023-10-30 23:24:19 +0300 |
commit | 123f42f0ad6815014f54d0cc6eb9039c46ee2907 (patch) | |
tree | de36850d1b225790272b9690650f18d6384830a5 /arch/arm64/kvm/sys_regs.c | |
parent | 53ce49ea75602b51a1feb3844d535ced42b2d8c2 (diff) | |
parent | 62708be351fe7b06be6f6fd30e95c94095bf21d3 (diff) | |
download | linux-123f42f0ad6815014f54d0cc6eb9039c46ee2907.tar.xz |
Merge branch kvm-arm64/pmu_pmcr_n into kvmarm/next
* kvm-arm64/pmu_pmcr_n:
: User-defined PMC limit, courtesy Raghavendra Rao Ananta
:
: Certain VMMs may want to reserve some PMCs for host use while running a
: KVM guest. This was a bit difficult before, as KVM advertised all
: supported counters to the guest. Userspace can now limit the number of
: advertised PMCs by writing to PMCR_EL0.N, as KVM's sysreg and PMU
: emulation enforce the specified limit for handling guest accesses.
KVM: selftests: aarch64: vPMU test for validating user accesses
KVM: selftests: aarch64: vPMU register test for unimplemented counters
KVM: selftests: aarch64: vPMU register test for implemented counters
KVM: selftests: aarch64: Introduce vpmu_counter_access test
tools: Import arm_pmuv3.h
KVM: arm64: PMU: Allow userspace to limit PMCR_EL0.N for the guest
KVM: arm64: Sanitize PM{C,I}NTEN{SET,CLR}, PMOVS{SET,CLR} before first run
KVM: arm64: Add {get,set}_user for PM{C,I}NTEN{SET,CLR}, PMOVS{SET,CLR}
KVM: arm64: PMU: Set PMCR_EL0.N for vCPU based on the associated PMU
KVM: arm64: PMU: Add a helper to read a vCPU's PMCR_EL0
KVM: arm64: Select default PMU in KVM_ARM_VCPU_INIT handler
KVM: arm64: PMU: Introduce helpers to set the guest's PMU
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
Diffstat (limited to 'arch/arm64/kvm/sys_regs.c')
-rw-r--r-- | arch/arm64/kvm/sys_regs.c | 127 |
1 files changed, 102 insertions, 25 deletions
diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c index d541ce9f48b9..1a21c526e5e2 100644 --- a/arch/arm64/kvm/sys_regs.c +++ b/arch/arm64/kvm/sys_regs.c @@ -719,14 +719,9 @@ static unsigned int pmu_visibility(const struct kvm_vcpu *vcpu, static u64 reset_pmu_reg(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r) { - u64 n, mask = BIT(ARMV8_PMU_CYCLE_IDX); + u64 mask = BIT(ARMV8_PMU_CYCLE_IDX); + u8 n = vcpu->kvm->arch.pmcr_n; - /* No PMU available, any PMU reg may UNDEF... */ - if (!kvm_arm_support_pmu_v3()) - return 0; - - n = read_sysreg(pmcr_el0) >> ARMV8_PMU_PMCR_N_SHIFT; - n &= ARMV8_PMU_PMCR_N_MASK; if (n) mask |= GENMASK(n - 1, 0); @@ -766,17 +761,15 @@ static u64 reset_pmselr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r) static u64 reset_pmcr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r) { - u64 pmcr; - - /* No PMU available, PMCR_EL0 may UNDEF... */ - if (!kvm_arm_support_pmu_v3()) - return 0; + u64 pmcr = 0; - /* Only preserve PMCR_EL0.N, and reset the rest to 0 */ - pmcr = read_sysreg(pmcr_el0) & (ARMV8_PMU_PMCR_N_MASK << ARMV8_PMU_PMCR_N_SHIFT); if (!kvm_supports_32bit_el0()) pmcr |= ARMV8_PMU_PMCR_LC; + /* + * The value of PMCR.N field is included when the + * vCPU register is read via kvm_vcpu_read_pmcr(). + */ __vcpu_sys_reg(vcpu, r->reg) = pmcr; return __vcpu_sys_reg(vcpu, r->reg); @@ -826,7 +819,7 @@ static bool access_pmcr(struct kvm_vcpu *vcpu, struct sys_reg_params *p, * Only update writeable bits of PMCR (continuing into * kvm_pmu_handle_pmcr() as well) */ - val = __vcpu_sys_reg(vcpu, PMCR_EL0); + val = kvm_vcpu_read_pmcr(vcpu); val &= ~ARMV8_PMU_PMCR_MASK; val |= p->regval & ARMV8_PMU_PMCR_MASK; if (!kvm_supports_32bit_el0()) @@ -834,7 +827,7 @@ static bool access_pmcr(struct kvm_vcpu *vcpu, struct sys_reg_params *p, kvm_pmu_handle_pmcr(vcpu, val); } else { /* PMCR.P & PMCR.C are RAZ */ - val = __vcpu_sys_reg(vcpu, PMCR_EL0) + val = kvm_vcpu_read_pmcr(vcpu) & ~(ARMV8_PMU_PMCR_P | ARMV8_PMU_PMCR_C); p->regval = val; } @@ -883,7 +876,7 @@ static bool pmu_counter_idx_valid(struct kvm_vcpu *vcpu, u64 idx) { u64 pmcr, val; - pmcr = __vcpu_sys_reg(vcpu, PMCR_EL0); + pmcr = kvm_vcpu_read_pmcr(vcpu); val = (pmcr >> ARMV8_PMU_PMCR_N_SHIFT) & ARMV8_PMU_PMCR_N_MASK; if (idx >= val && idx != ARMV8_PMU_CYCLE_IDX) { kvm_inject_undefined(vcpu); @@ -998,6 +991,39 @@ static bool access_pmu_evtyper(struct kvm_vcpu *vcpu, struct sys_reg_params *p, return true; } +static int set_pmreg(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r, u64 val) +{ + bool set; + + val &= kvm_pmu_valid_counter_mask(vcpu); + + switch (r->reg) { + case PMOVSSET_EL0: + /* CRm[1] being set indicates a SET register, and CLR otherwise */ + set = r->CRm & 2; + break; + default: + /* Op2[0] being set indicates a SET register, and CLR otherwise */ + set = r->Op2 & 1; + break; + } + + if (set) + __vcpu_sys_reg(vcpu, r->reg) |= val; + else + __vcpu_sys_reg(vcpu, r->reg) &= ~val; + + return 0; +} + +static int get_pmreg(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r, u64 *val) +{ + u64 mask = kvm_pmu_valid_counter_mask(vcpu); + + *val = __vcpu_sys_reg(vcpu, r->reg) & mask; + return 0; +} + static bool access_pmcnten(struct kvm_vcpu *vcpu, struct sys_reg_params *p, const struct sys_reg_desc *r) { @@ -1107,6 +1133,51 @@ static bool access_pmuserenr(struct kvm_vcpu *vcpu, struct sys_reg_params *p, return true; } +static int get_pmcr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r, + u64 *val) +{ + *val = kvm_vcpu_read_pmcr(vcpu); + return 0; +} + +static int set_pmcr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r, + u64 val) +{ + u8 new_n = (val >> ARMV8_PMU_PMCR_N_SHIFT) & ARMV8_PMU_PMCR_N_MASK; + struct kvm *kvm = vcpu->kvm; + + mutex_lock(&kvm->arch.config_lock); + + /* + * The vCPU can't have more counters than the PMU hardware + * implements. Ignore this error to maintain compatibility + * with the existing KVM behavior. + */ + if (!kvm_vm_has_ran_once(kvm) && + new_n <= kvm_arm_pmu_get_max_counters(kvm)) + kvm->arch.pmcr_n = new_n; + + mutex_unlock(&kvm->arch.config_lock); + + /* + * Ignore writes to RES0 bits, read only bits that are cleared on + * vCPU reset, and writable bits that KVM doesn't support yet. + * (i.e. only PMCR.N and bits [7:0] are mutable from userspace) + * The LP bit is RES0 when FEAT_PMUv3p5 is not supported on the vCPU. + * But, we leave the bit as it is here, as the vCPU's PMUver might + * be changed later (NOTE: the bit will be cleared on first vCPU run + * if necessary). + */ + val &= ARMV8_PMU_PMCR_MASK; + + /* The LC bit is RES1 when AArch32 is not supported */ + if (!kvm_supports_32bit_el0()) + val |= ARMV8_PMU_PMCR_LC; + + __vcpu_sys_reg(vcpu, r->reg) = val; + return 0; +} + /* Silly macro to expand the DBG{BCR,BVR,WVR,WCR}n_EL1 registers in one go */ #define DBG_BCR_BVR_WCR_WVR_EL1(n) \ { SYS_DESC(SYS_DBGBVRn_EL1(n)), \ @@ -2188,9 +2259,11 @@ static const struct sys_reg_desc sys_reg_descs[] = { /* PMBIDR_EL1 is not trapped */ { PMU_SYS_REG(PMINTENSET_EL1), - .access = access_pminten, .reg = PMINTENSET_EL1 }, + .access = access_pminten, .reg = PMINTENSET_EL1, + .get_user = get_pmreg, .set_user = set_pmreg }, { PMU_SYS_REG(PMINTENCLR_EL1), - .access = access_pminten, .reg = PMINTENSET_EL1 }, + .access = access_pminten, .reg = PMINTENSET_EL1, + .get_user = get_pmreg, .set_user = set_pmreg }, { SYS_DESC(SYS_PMMIR_EL1), trap_raz_wi }, { SYS_DESC(SYS_MAIR_EL1), access_vm_reg, reset_unknown, MAIR_EL1 }, @@ -2238,14 +2311,17 @@ static const struct sys_reg_desc sys_reg_descs[] = { { SYS_DESC(SYS_CTR_EL0), access_ctr }, { SYS_DESC(SYS_SVCR), undef_access }, - { PMU_SYS_REG(PMCR_EL0), .access = access_pmcr, - .reset = reset_pmcr, .reg = PMCR_EL0 }, + { PMU_SYS_REG(PMCR_EL0), .access = access_pmcr, .reset = reset_pmcr, + .reg = PMCR_EL0, .get_user = get_pmcr, .set_user = set_pmcr }, { PMU_SYS_REG(PMCNTENSET_EL0), - .access = access_pmcnten, .reg = PMCNTENSET_EL0 }, + .access = access_pmcnten, .reg = PMCNTENSET_EL0, + .get_user = get_pmreg, .set_user = set_pmreg }, { PMU_SYS_REG(PMCNTENCLR_EL0), - .access = access_pmcnten, .reg = PMCNTENSET_EL0 }, + .access = access_pmcnten, .reg = PMCNTENSET_EL0, + .get_user = get_pmreg, .set_user = set_pmreg }, { PMU_SYS_REG(PMOVSCLR_EL0), - .access = access_pmovs, .reg = PMOVSSET_EL0 }, + .access = access_pmovs, .reg = PMOVSSET_EL0, + .get_user = get_pmreg, .set_user = set_pmreg }, /* * PM_SWINC_EL0 is exposed to userspace as RAZ/WI, as it was * previously (and pointlessly) advertised in the past... @@ -2273,7 +2349,8 @@ static const struct sys_reg_desc sys_reg_descs[] = { { PMU_SYS_REG(PMUSERENR_EL0), .access = access_pmuserenr, .reset = reset_val, .reg = PMUSERENR_EL0, .val = 0 }, { PMU_SYS_REG(PMOVSSET_EL0), - .access = access_pmovs, .reg = PMOVSSET_EL0 }, + .access = access_pmovs, .reg = PMOVSSET_EL0, + .get_user = get_pmreg, .set_user = set_pmreg }, { SYS_DESC(SYS_TPIDR_EL0), NULL, reset_unknown, TPIDR_EL0 }, { SYS_DESC(SYS_TPIDRRO_EL0), NULL, reset_unknown, TPIDRRO_EL0 }, |