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Commit 61f4237d authored by Jeremy Fitzhardinge's avatar Jeremy Fitzhardinge Committed by Konrad Rzeszutek Wilk
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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: default avatarJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: default avatarKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
parent d88885d0

arch/x86/xen/enlighten.c

+1 −17
Original line number Diff line number Diff line
@@ -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)