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Thu, 12 Nov 2020 13:14:27 +0000 (UTC) Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 0639EAD31; Thu, 12 Nov 2020 13:14:27 +0000 (UTC) X-Outflank-Mailman: Message body and most headers restored to incoming version X-BeenThere: xen-devel@lists.xenproject.org List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Precedence: list Sender: "Xen-devel" X-Inumbo-ID: 4a20110c-d835-4432-bc95-9ad6e4a819ca X-Virus-Scanned: by amavisd-new at test-mx.suse.de DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1605186867; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=fMXlwXyF+4tXesHMIFZzu/eTSNLM+Yoxq+N7JqzPdL0=; b=JDE5qnZR4u+Zq1WJB6ZqJyBKZJFybw6R6w8kazehxa0oN32V0eBsZPGb/WEeyFqkeVMZuM Bm63Y9xjhWJpJ/YsMXTckP/rKNzlySF4lrbHvUE1jGM/FBvcgJZOHdMhlaoueHAJA7GQ11 kjb3KXmNwwdUxAb92B06K8zAeJjrIT4= From: Juergen Gross To: xen-devel@lists.xenproject.org Cc: Juergen Gross , Jan Beulich , Andrew Cooper , =?UTF-8?q?Roger=20Pau=20Monn=C3=A9?= , Wei Liu Subject: [PATCH v5 2/3] xen/oprofile: use NMI continuation for sending virq to guest Date: Thu, 12 Nov 2020 14:14:23 +0100 Message-Id: <20201112131424.9930-3-jgross@suse.com> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20201112131424.9930-1-jgross@suse.com> References: <20201112131424.9930-1-jgross@suse.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-ZohoMail-DKIM: pass (identity @suse.com) Content-Type: text/plain; charset="utf-8" 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 Reviewed-by: Jan Beulich --- V5: - use Linux coding style (Jan Beulich) - assume races could happen (Jan Beulich) V4: - rework to less generic approach Signed-off-by: Juergen Gross --- 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_in= t.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]; =20 static char *cpu_type; =20 +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 =3D vcpu_vpmu(current); @@ -83,14 +85,27 @@ void passive_domain_destroy(struct vcpu *v) model->free_msr(v); } =20 +bool nmi_oprofile_send_virq(void) +{ + struct vcpu *v =3D 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; =20 ovf =3D model->check_ctrs(cpu, &cpu_msrs[cpu], regs); xen_mode =3D 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) =3D current; + trigger_nmi_continuation(); + } =20 if ( ovf =3D=3D 2 ) current->arch.nmi_pending =3D 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 #include #include +#include #include #include #include @@ -1805,6 +1806,9 @@ bool nmi_check_continuation(void) { bool ret =3D false; =20 + if ( nmi_oprofile_send_virq() ) + ret =3D true; + return ret; } =20 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 *m= sr_content); int passive_domain_do_wrmsr(unsigned int msr, uint64_t msr_content); void passive_domain_destroy(struct vcpu *v); =20 +bool nmi_oprofile_send_virq(void); + #else =20 static inline int passive_domain_do_rdmsr(unsigned int msr, @@ -85,6 +87,11 @@ static inline int passive_domain_do_wrmsr(unsigned int m= sr, =20 static inline void passive_domain_destroy(struct vcpu *v) {} =20 +static inline bool nmi_oprofile_send_virq(void) +{ + return false; +} + #endif /* CONFIG_XENOPROF */ =20 #endif /* __ASM_X86_XENOPROF_H__ */ --=20 2.26.2