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 <alexandru.elisei@xxxxxxx>
---
arch/arm64/include/asm/kvm_host.h | 2 ++
arch/arm64/include/asm/kvm_spe.h | 9 +++++++++
arch/arm64/kvm/arm.c | 1 +
arch/arm64/kvm/hyp/nvhe/spe-sr.c | 2 +-
arch/arm64/kvm/hyp/vhe/spe-sr.c | 2 +-
arch/arm64/kvm/spe.c | 17 +++++++++++++++++
6 files changed, 31 insertions(+), 2 deletions(-)
diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index 3eef642d7bba..102e1c087798 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -158,6 +158,8 @@ 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 ce92d5f1db19..7b87cf1eed37 100644
--- a/arch/arm64/include/asm/kvm_spe.h
+++ b/arch/arm64/include/asm/kvm_spe.h
@@ -21,6 +21,11 @@ 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_vm(struct kvm *kvm);
int kvm_spe_vcpu_enable_spe(struct kvm_vcpu *vcpu);
int kvm_spe_vcpu_first_run_init(struct kvm_vcpu *vcpu);
@@ -40,6 +45,10 @@ 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_vm(struct kvm *kvm) {}
static inline int kvm_spe_vcpu_enable_spe(struct kvm_vcpu *vcpu)
{
return 0;
diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
index a4f17f7bf943..5e166ffc6067 100644
--- a/arch/arm64/kvm/arm.c
+++ b/arch/arm64/kvm/arm.c
@@ -177,6 +177,7 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type)
goto out_free_stage2_pgd;
kvm_vgic_early_init(kvm);
+ kvm_spe_init_vm(kvm);
/* The maximum number of VCPUs is limited by the host's GIC model */
kvm->arch.max_vcpus = kvm_arm_default_max_vcpus();
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 9c0567dadff1..f5e9dc249e9a 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_spe_pmu.h>
@@ -28,6 +29,19 @@ void kvm_host_spe_init(struct arm_spe_pmu *spe_pmu)
mutex_unlock(&supported_cpus_lock);
}
+void kvm_spe_init_vm(struct kvm *kvm)
+{
+ /*
+ * 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();
+}
+
int kvm_spe_vcpu_enable_spe(struct kvm_vcpu *vcpu)
{
if (!kvm_supports_spe())
@@ -53,6 +67,9 @@ int kvm_spe_vcpu_first_run_init(struct kvm_vcpu *vcpu)
if (!vcpu->arch.spe.initialized)
return -EINVAL;
+ if (vcpu->kvm->arch.spe.perfmon_capable)
+ __vcpu_sys_reg(vcpu, PMSCR_EL2) = BIT(SYS_PMSCR_EL1_PCT_SHIFT);
+
return 0;
}
--
2.33.1
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