Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 99bc6753 authored by Juergen Gross's avatar Juergen Gross Committed by Ingo Molnar
Browse files

xen: Add xen_pin_vcpu() to support calling functions on a dedicated pCPU 



Some hardware models (e.g. Dell Studio 1555 laptops) require calls to
the firmware to be issued on CPU 0 only. As Dom0 might have to use
these calls, add xen_pin_vcpu() to achieve this functionality.

In case either the domain doesn't have the privilege to make the
related hypercall or the hypervisor isn't supporting it, issue a
warning once and disable further pinning attempts.

Signed-off-by: default avatarJuergen Gross <jgross@suse.com>
Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: default avatarDavid Vrabel <david.vrabel@citrix.com>
Cc: Douglas_Warzecha@dell.com
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: akataria@vmware.com
Cc: boris.ostrovsky@oracle.com
Cc: chrisw@sous-sol.org
Cc: hpa@zytor.com
Cc: jdelvare@suse.com
Cc: jeremy@goop.org
Cc: linux@roeck-us.net
Cc: pali.rohar@gmail.com
Cc: rusty@rustcorp.com.au
Cc: virtualization@lists.linux-foundation.org
Cc: xen-devel@lists.xenproject.org
Link: http://lkml.kernel.org/r/1472453327-19050-5-git-send-email-jgross@suse.com


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent df8ce9d7

arch/x86/xen/enlighten.c

+40 −0
Original line number Diff line number Diff line
@@ -1925,6 +1925,45 @@ static void xen_set_cpu_features(struct cpuinfo_x86 *c) 
	}

}



static void xen_pin_vcpu(int cpu)

{

	static bool disable_pinning;

	struct sched_pin_override pin_override;

	int ret;



	if (disable_pinning)

		return;



	pin_override.pcpu = cpu;

	ret = HYPERVISOR_sched_op(SCHEDOP_pin_override, &pin_override);



	/* Ignore errors when removing override. */

	if (cpu < 0)

		return;



	switch (ret) {

	case -ENOSYS:

		pr_warn("Unable to pin on physical cpu %d. In case of problems consider vcpu pinning.\n",

			cpu);

		disable_pinning = true;

		break;

	case -EPERM:

		WARN(1, "Trying to pin vcpu without having privilege to do so\n");

		disable_pinning = true;

		break;

	case -EINVAL:

	case -EBUSY:

		pr_warn("Physical cpu %d not available for pinning. Check Xen cpu configuration.\n",

			cpu);

		break;

	case 0:

		break;

	default:

		WARN(1, "rc %d while trying to pin vcpu\n", ret);

		disable_pinning = true;

	}

}



const struct hypervisor_x86 x86_hyper_xen = {

	.name			= "Xen",

	.detect			= xen_platform,
@@ -1933,6 +1972,7 @@ const struct hypervisor_x86 x86_hyper_xen = { 
#endif

	.x2apic_available	= xen_x2apic_para_available,

	.set_cpu_features       = xen_set_cpu_features,

	.pin_vcpu               = xen_pin_vcpu,

};

EXPORT_SYMBOL(x86_hyper_xen);