From 61f4237d5b005767a76f4f3694e68e6f78f392d9 Mon Sep 17 00:00:00 2001
From: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Date: Sat, 18 Sep 2010 22:25:30 -0700
Subject: [PATCH] xen: just completely disable XSAVE
Some (old) versions of Xen just kill the domain if it tries to set any
unknown bits in CR4, so we can't reliably probe for OSXSAVE in
CR4.
Since Xen doesn't support XSAVE for guests at the moment, and no such
support is being worked on, there's no downside in just unconditionally
masking XSAVE support.
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
---
arch/x86/xen/enlighten.c | 18 +-----------------
1 file changed, 1 insertion(+), 17 deletions(-)
diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c
index 49dbd78ec3cb..66272a237622 100644
--- a/arch/x86/xen/enlighten.c
+++ b/arch/x86/xen/enlighten.c
@@ -250,23 +250,7 @@ static __init void xen_init_cpuid_mask(void)
~((1 << X86_FEATURE_APIC) | /* disable local APIC */
(1 << X86_FEATURE_ACPI)); /* disable ACPI */
- ax = 1;
- cx = 0;
- xen_cpuid(&ax, &bx, &cx, &dx);
-
- /* cpuid claims we support xsave; try enabling it to see what happens */
- if (cx & (1 << (X86_FEATURE_XSAVE % 32))) {
- unsigned long cr4;
-
- set_in_cr4(X86_CR4_OSXSAVE);
-
- cr4 = read_cr4();
-
- if ((cr4 & X86_CR4_OSXSAVE) == 0)
- cpuid_leaf1_ecx_mask &= ~(1 << (X86_FEATURE_XSAVE % 32));
-
- clear_in_cr4(X86_CR4_OSXSAVE);
- }
+ cpuid_leaf1_ecx_mask &= ~(1 << (X86_FEATURE_XSAVE % 32)); /* disable XSAVE */
}
static void xen_set_debugreg(int reg, unsigned long val)