The SPE driver allows userspace to use physical timestamps for records only if the process if perfmon_capable(). Do the same for a virtual machine with the SPE feature.
Signed-off-by: Alexandru Elisei <[email protected]> --- arch/arm64/include/asm/kvm_host.h | 2 ++ arch/arm64/include/asm/kvm_spe.h | 7 +++++++ arch/arm64/kvm/hyp/nvhe/spe-sr.c | 2 +- arch/arm64/kvm/hyp/vhe/spe-sr.c | 2 +- arch/arm64/kvm/spe.c | 14 ++++++++++++++ 5 files changed, 25 insertions(+), 2 deletions(-) diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h index 66f0b999cb5f..cc46f1406196 100644 --- a/arch/arm64/include/asm/kvm_host.h +++ b/arch/arm64/include/asm/kvm_host.h @@ -157,6 +157,8 @@ struct kvm_arch { /* Memory Tagging Extension enabled for the guest */ bool mte_enabled; + + struct kvm_spe spe; }; struct kvm_vcpu_fault_info { diff --git a/arch/arm64/include/asm/kvm_spe.h b/arch/arm64/include/asm/kvm_spe.h index 6b8d4cf2cd37..272f1eec64f2 100644 --- a/arch/arm64/include/asm/kvm_spe.h +++ b/arch/arm64/include/asm/kvm_spe.h @@ -21,6 +21,10 @@ struct kvm_vcpu_spe { int irq_num; /* Buffer management interrut number */ }; +struct kvm_spe { + bool perfmon_capable; /* Is the VM perfmon_capable()? */ +}; + void kvm_spe_init_supported_cpus(void); void kvm_spe_vm_init(struct kvm *kvm); int kvm_spe_vcpu_first_run_init(struct kvm_vcpu *vcpu); @@ -41,6 +45,9 @@ int kvm_spe_has_attr(struct kvm_vcpu *vcpu, struct kvm_device_attr *attr); struct kvm_vcpu_spe { }; +struct kvm_spe { +}; + static inline void kvm_spe_init_supported_cpus(void) {} static inline void kvm_spe_vm_init(struct kvm *kvm) {} static inline int kvm_spe_vcpu_first_run_init(struct kvm_vcpu *vcpu) { return -ENOEXEC; } diff --git a/arch/arm64/kvm/hyp/nvhe/spe-sr.c b/arch/arm64/kvm/hyp/nvhe/spe-sr.c index 46e47c9fd08f..4f6579daddb5 100644 --- a/arch/arm64/kvm/hyp/nvhe/spe-sr.c +++ b/arch/arm64/kvm/hyp/nvhe/spe-sr.c @@ -83,5 +83,5 @@ void __spe_restore_guest_state_nvhe(struct kvm_vcpu *vcpu, write_sysreg_s(ctxt_sys_reg(guest_ctxt, PMBSR_EL1), SYS_PMBSR_EL1); write_sysreg_s(ctxt_sys_reg(guest_ctxt, PMBLIMITR_EL1), SYS_PMBLIMITR_EL1); write_sysreg_s(ctxt_sys_reg(guest_ctxt, PMSCR_EL1), SYS_PMSCR_EL1); - write_sysreg_el2(0, SYS_PMSCR); + write_sysreg_el2(ctxt_sys_reg(guest_ctxt, PMSCR_EL2), SYS_PMSCR); } diff --git a/arch/arm64/kvm/hyp/vhe/spe-sr.c b/arch/arm64/kvm/hyp/vhe/spe-sr.c index 00eab9e2ec60..f557ac64a1cc 100644 --- a/arch/arm64/kvm/hyp/vhe/spe-sr.c +++ b/arch/arm64/kvm/hyp/vhe/spe-sr.c @@ -21,7 +21,7 @@ void __spe_save_host_state_vhe(struct kvm_vcpu *vcpu, /* Disable profiling while the SPE context is being switched. */ pmscr_el2 = read_sysreg_el2(SYS_PMSCR); - write_sysreg_el2(0, SYS_PMSCR); + write_sysreg_el2(__vcpu_sys_reg(vcpu, PMSCR_EL2), SYS_PMSCR); isb(); pmblimitr = read_sysreg_s(SYS_PMBLIMITR_EL1); diff --git a/arch/arm64/kvm/spe.c b/arch/arm64/kvm/spe.c index 711736c49f63..054bb16bbd79 100644 --- a/arch/arm64/kvm/spe.c +++ b/arch/arm64/kvm/spe.c @@ -3,6 +3,7 @@ * Copyright (C) 2021 - ARM Ltd */ +#include <linux/capability.h> #include <linux/cpumask.h> #include <linux/kvm_host.h> #include <linux/perf/arm_pmu.h> @@ -29,6 +30,16 @@ void kvm_spe_vm_init(struct kvm *kvm) { /* Set supported_cpus if it isn't already initialized. */ kvm_spe_init_supported_cpus(); + + /* + * Allow the guest to use the physical timer for timestamps only if the + * VMM is perfmon_capable(), similar to what the SPE driver allows. + * + * CAP_PERFMON can be changed during the lifetime of the VM, so record + * its value when the VM is created to avoid situations where only some + * VCPUs allow physical timer timestamps, while others don't. + */ + kvm->arch.spe.perfmon_capable = perfmon_capable(); } static int kvm_spe_check_supported_cpus(struct kvm_vcpu *vcpu) @@ -54,6 +65,9 @@ int kvm_spe_vcpu_first_run_init(struct kvm_vcpu *vcpu) if (!vcpu->arch.spe.initialized) return -EPERM; + if (vcpu->kvm->arch.spe.perfmon_capable) + __vcpu_sys_reg(vcpu, PMSCR_EL2) = BIT(SYS_PMSCR_EL1_PCT_SHIFT); + return 0; } -- 2.33.0 _______________________________________________ kvmarm mailing list [email protected] https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
