linux-kernel - [PATCH v2 05/11] x86/xen: use capabilities instead of fake cpuid values for acc

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Date:   Thu, 13 Apr 2017 12:11:10 +0200
From:   Juergen Gross <jgross@...e.com>
To:     linux-kernel@...r.kernel.org, xen-devel@...ts.xenproject.org
Cc:     boris.ostrovsky@...cle.com, Juergen Gross <jgross@...e.com>
Subject: [PATCH v2 05/11] x86/xen: use capabilities instead of fake cpuid values for acc

When running as pv domain xen_cpuid() is being used instead of
native_cpuid(). In xen_cpuid() the acc feature (thermal monitoring)
is indicated as not being present by special casing the related
cpuid leaf.

Instead of delivering fake cpuid values clear the cpu capability bit
for acc instead.

Signed-off-by: Juergen Gross <jgross@...e.com>
---
 arch/x86/xen/enlighten_pv.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/arch/x86/xen/enlighten_pv.c b/arch/x86/xen/enlighten_pv.c
index 37e174d9009b..53fe97bd720f 100644
--- a/arch/x86/xen/enlighten_pv.c
+++ b/arch/x86/xen/enlighten_pv.c
@@ -294,9 +294,6 @@ static void __init xen_init_cpuid_mask(void)
 	unsigned int ax, bx, cx, dx;
 	unsigned int xsave_mask;
 
-	cpuid_leaf1_edx_mask =
-		~(1 << X86_FEATURE_ACC);   /* thermal monitoring */
-
 	if (!xen_initial_domain())
 		cpuid_leaf1_edx_mask &=
 			~((1 << X86_FEATURE_ACPI));  /* disable ACPI */
@@ -325,6 +322,7 @@ static void __init xen_init_capabilities(void)
 	setup_clear_cpu_cap(X86_FEATURE_DCA);
 	setup_clear_cpu_cap(X86_FEATURE_APERFMPERF);
 	setup_clear_cpu_cap(X86_FEATURE_MTRR);
+	setup_clear_cpu_cap(X86_FEATURE_ACC);
 }
 
 static void xen_set_debugreg(int reg, unsigned long val)
-- 
2.12.0