[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [PATCH v5 2/3] xen/oprofile: use NMI continuation for sending virq to guest
Instead of calling send_guest_vcpu_virq() from NMI context use the NMI continuation framework for that purpose. This avoids taking locks in NMI mode. Signed-off-by: Juergen Gross <jgross@xxxxxxxx> --- V5: - use Linux coding style (Jan Beulich) - assume races could happen (Jan Beulich) V4: - rework to less generic approach Signed-off-by: Juergen Gross <jgross@xxxxxxxx> --- xen/arch/x86/oprofile/nmi_int.c | 19 +++++++++++++++++-- xen/arch/x86/traps.c | 4 ++++ xen/include/asm-x86/xenoprof.h | 7 +++++++ 3 files changed, 28 insertions(+), 2 deletions(-) diff --git a/xen/arch/x86/oprofile/nmi_int.c b/xen/arch/x86/oprofile/nmi_int.c index 0f103d80a6..a13bd82915 100644 --- a/xen/arch/x86/oprofile/nmi_int.c +++ b/xen/arch/x86/oprofile/nmi_int.c @@ -38,6 +38,8 @@ static unsigned long saved_lvtpc[NR_CPUS]; static char *cpu_type; +static DEFINE_PER_CPU(struct vcpu *, nmi_cont_vcpu); + static int passive_domain_msr_op_checks(unsigned int msr, int *typep, int *indexp) { struct vpmu_struct *vpmu = vcpu_vpmu(current); @@ -83,14 +85,27 @@ void passive_domain_destroy(struct vcpu *v) model->free_msr(v); } +bool nmi_oprofile_send_virq(void) +{ + struct vcpu *v = xchg(&this_cpu(nmi_cont_vcpu), NULL); + + if (v) + send_guest_vcpu_virq(v, VIRQ_XENOPROF); + + return v; +} + static int nmi_callback(const struct cpu_user_regs *regs, int cpu) { int xen_mode, ovf; ovf = model->check_ctrs(cpu, &cpu_msrs[cpu], regs); xen_mode = ring_0(regs); - if ( ovf && is_active(current->domain) && !xen_mode ) - send_guest_vcpu_virq(current, VIRQ_XENOPROF); + if (ovf && is_active(current->domain) && !xen_mode && + !this_cpu(nmi_cont_vcpu)) { + this_cpu(nmi_cont_vcpu) = current; + trigger_nmi_continuation(); + } if ( ovf == 2 ) current->arch.nmi_pending = true; diff --git a/xen/arch/x86/traps.c b/xen/arch/x86/traps.c index 5cbaa49031..240fd1b089 100644 --- a/xen/arch/x86/traps.c +++ b/xen/arch/x86/traps.c @@ -65,6 +65,7 @@ #include <asm/debugger.h> #include <asm/msr.h> #include <asm/nmi.h> +#include <asm/xenoprof.h> #include <asm/shared.h> #include <asm/x86_emulate.h> #include <asm/traps.h> @@ -1805,6 +1806,9 @@ bool nmi_check_continuation(void) { bool ret = false; + if ( nmi_oprofile_send_virq() ) + ret = true; + return ret; } diff --git a/xen/include/asm-x86/xenoprof.h b/xen/include/asm-x86/xenoprof.h index 1026ba2e1f..cf6af8c5df 100644 --- a/xen/include/asm-x86/xenoprof.h +++ b/xen/include/asm-x86/xenoprof.h @@ -69,6 +69,8 @@ int passive_domain_do_rdmsr(unsigned int msr, uint64_t *msr_content); int passive_domain_do_wrmsr(unsigned int msr, uint64_t msr_content); void passive_domain_destroy(struct vcpu *v); +bool nmi_oprofile_send_virq(void); + #else static inline int passive_domain_do_rdmsr(unsigned int msr, @@ -85,6 +87,11 @@ static inline int passive_domain_do_wrmsr(unsigned int msr, static inline void passive_domain_destroy(struct vcpu *v) {} +static inline bool nmi_oprofile_send_virq(void) +{ + return false; +} + #endif /* CONFIG_XENOPROF */ #endif /* __ASM_X86_XENOPROF_H__ */ -- 2.26.2
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