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From: Juergen Gross <jgross@suse.com>
To: linux-kernel@vger.kernel.org, xen-devel@lists.xenproject.org
Cc: Juergen Gross <jgross@suse.com>,
	jeremy@goop.org, jdelvare@suse.com, peterz@infradead.org,
	hpa@zytor.com, akataria@vmware.com, x86@kernel.org,
	rusty@rustcorp.com.au, virtualization@lists.linux-foundation.org,
	chrisw@sous-sol.org, mingo@redhat.com, david.vrabel@citrix.com,
	Douglas_Warzecha@dell.com, pali.rohar@gmail.com,
	boris.ostrovsky@oracle.com, tglx@linutronix.de,
	linux@roeck-us.net
Subject: [PATCH v5 4/6] xen: add xen_pin_vcpu() to support calling functions on a dedicated pcpu
Date: Wed,  6 Apr 2016 16:17:44 +0200	[thread overview]
Message-ID: <1459952266-3687-5-git-send-email-jgross__40764.8110799075$1459952357$gmane$org@suse.com> (raw)
In-Reply-To: <1459952266-3687-1-git-send-email-jgross@suse.com>

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: Juergen Gross <jgross@suse.com>
Acked-by: David Vrabel <david.vrabel@citrix.com>
---
V5: less wordy messages as requested by David Vrabel
---
 arch/x86/xen/enlighten.c | 40 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 40 insertions(+)

diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c
index 880862c..bfa2f21 100644
--- a/arch/x86/xen/enlighten.c
+++ b/arch/x86/xen/enlighten.c
@@ -1885,6 +1885,45 @@ 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,
@@ -1893,6 +1932,7 @@ 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);
 
-- 
2.6.6


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  parent reply	other threads:[~2016-04-06 14:17 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <1459952266-3687-1-git-send-email-jgross@suse.com>
2016-04-06 14:17 ` [PATCH v5 1/6] xen: sync xen header Juergen Gross
2016-04-06 14:17 ` [PATCH v5 2/6] virt, sched: add generic vcpu pinning support Juergen Gross
2016-04-06 14:17 ` [PATCH v5 3/6] smp: add function to execute a function synchronously on a cpu Juergen Gross
2016-04-06 14:17 ` Juergen Gross [this message]
2016-04-06 14:17 ` [PATCH v5 5/6] dcdbas: make use of smp_call_on_cpu() Juergen Gross
2016-04-06 14:17 ` [PATCH v5 6/6] hwmon: use smp_call_on_cpu() for dell-smm i8k Juergen Gross
     [not found] ` <1459952266-3687-4-git-send-email-jgross@suse.com>
2016-04-06 18:04   ` [PATCH v5 3/6] smp: add function to execute a function synchronously on a cpu Peter Zijlstra
2016-04-13  8:49 ` [PATCH v5 0/6] Support calling functions on dedicated physical cpu Juergen Gross
     [not found] ` <570E07FD.4030403@suse.com>
2016-05-17 11:21   ` Juergen Gross
     [not found] ` <1459952266-3687-7-git-send-email-jgross@suse.com>
2016-06-13 19:05   ` [PATCH v5 6/6] hwmon: use smp_call_on_cpu() for dell-smm i8k Pali Rohár
     [not found] ` <1459952266-3687-3-git-send-email-jgross@suse.com>
2016-06-15 11:18   ` [PATCH v5 2/6] virt, sched: add generic vcpu pinning support Juergen Gross
     [not found] ` <1459952266-3687-6-git-send-email-jgross@suse.com>
2016-06-15 11:19   ` [PATCH v5 5/6] dcdbas: make use of smp_call_on_cpu() Juergen Gross
2016-06-20  8:40 ` [PATCH v5 0/6] Support calling functions on dedicated physical cpu Juergen Gross
2016-06-27 10:34 ` Juergen Gross

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