[v3,2/3] xen/oprofile: use set_nmi_continuation() for sending virq to guest

Commit Message

Jürgen Groß Oct. 16, 2020, 8:53 a.m. UTC

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 <[e-mail]>
---
 xen/arch/x86/oprofile/nmi_int.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

Patch

diff --git a/xen/arch/x86/oprofile/nmi_int.c b/xen/arch/x86/oprofile/nmi_int.c
index 0f103d80a6..825f0aeef0 100644
--- a/xen/arch/x86/oprofile/nmi_int.c
+++ b/xen/arch/x86/oprofile/nmi_int.c
@@ -83,6 +83,13 @@  void passive_domain_destroy(struct vcpu *v)
 		model->free_msr(v);
 }
 
+static void nmi_oprofile_send_virq(void *arg)
+{
+	struct vcpu *v = arg;
+
+	send_guest_vcpu_virq(v, VIRQ_XENOPROF);
+}
+
 static int nmi_callback(const struct cpu_user_regs *regs, int cpu)
 {
 	int xen_mode, ovf;
@@ -90,7 +97,7 @@  static int nmi_callback(const struct cpu_user_regs *regs, int cpu)
 	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);
+		set_nmi_continuation(nmi_oprofile_send_virq, current);
 
 	if ( ovf == 2 )
 		current->arch.nmi_pending = true;