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authorJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>2010-09-18 22:25:30 -0700
committerKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>2011-04-06 08:31:00 -0400
commit61f4237d5b005767a76f4f3694e68e6f78f392d9 (patch)
tree479a885c9c5000a07db28e1b862931edd6fc537e
parentd88885d0923ae27b01dfcec644f94829b1e46bea (diff)
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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>
-rw-r--r--arch/x86/xen/enlighten.c18
1 files changed, 1 insertions, 17 deletions
diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c
index 49dbd78..66272a2 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)