linux-kernel - [PATCH 4.4 046/107] xen: set cpu capabilities from xen_start

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Date:   Mon, 23 Jul 2018 14:41:40 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Juergen Gross <jgross@...e.com>,
        Boris Ostrovsky <boris.ostrovsky@...cle.com>,
        "Srivatsa S. Bhat" <srivatsa@...il.mit.edu>,
        "Matt Helsley (VMware)" <matt.helsley@...il.com>,
        Alexey Makhalov <amakhalov@...are.com>,
        Bo Gan <ganb@...are.com>
Subject: [PATCH 4.4 046/107] xen: set cpu capabilities from xen_start_kernel()

4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Juergen Gross <jgross@...e.com>

Upstream commit: 0808e80cb760de2733c0527d2090ed2205a1eef8 ("xen: set
cpu capabilities from xen_start_kernel()")

There is no need to set the same capabilities for each cpu
individually. This can easily be done for all cpus when starting the
kernel.

Signed-off-by: Juergen Gross <jgross@...e.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@...cle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Signed-off-by: Srivatsa S. Bhat <srivatsa@...il.mit.edu>
Reviewed-by: Matt Helsley (VMware) <matt.helsley@...il.com>
Reviewed-by: Alexey Makhalov <amakhalov@...are.com>
Reviewed-by: Bo Gan <ganb@...are.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---

 arch/x86/xen/enlighten.c |   18 +++++++++---------
 1 file changed, 9 insertions(+), 9 deletions(-)

--- a/arch/x86/xen/enlighten.c
+++ b/arch/x86/xen/enlighten.c
@@ -460,6 +460,14 @@ static void __init xen_init_cpuid_mask(v
 		cpuid_leaf1_ecx_set_mask = (1 << (X86_FEATURE_MWAIT % 32));
 }
 
+static void __init xen_init_capabilities(void)
+{
+	if (xen_pv_domain()) {
+		setup_clear_cpu_cap(X86_BUG_SYSRET_SS_ATTRS);
+		setup_force_cpu_cap(X86_FEATURE_XENPV);
+	}
+}
+
 static void xen_set_debugreg(int reg, unsigned long val)
 {
 	HYPERVISOR_set_debugreg(reg, val);
@@ -1587,6 +1595,7 @@ asmlinkage __visible void __init xen_sta
 
 	xen_init_irq_ops();
 	xen_init_cpuid_mask();
+	xen_init_capabilities();
 
 #ifdef CONFIG_X86_LOCAL_APIC
 	/*
@@ -1883,14 +1892,6 @@ bool xen_hvm_need_lapic(void)
 }
 EXPORT_SYMBOL_GPL(xen_hvm_need_lapic);
 
-static void xen_set_cpu_features(struct cpuinfo_x86 *c)
-{
-	if (xen_pv_domain()) {
-		clear_cpu_bug(c, X86_BUG_SYSRET_SS_ATTRS);
-		set_cpu_cap(c, X86_FEATURE_XENPV);
-	}
-}
-
 const struct hypervisor_x86 x86_hyper_xen = {
 	.name			= "Xen",
 	.detect			= xen_platform,
@@ -1898,7 +1899,6 @@ const struct hypervisor_x86 x86_hyper_xe
 	.init_platform		= xen_hvm_guest_init,
 #endif
 	.x2apic_available	= xen_x2apic_para_available,
-	.set_cpu_features       = xen_set_cpu_features,
 };
 EXPORT_SYMBOL(x86_hyper_xen);