51 lines
1.6 KiB
Diff
51 lines
1.6 KiB
Diff
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# HG changeset patch
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# User Keir Fraser <keir@xen.org>
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# Date 1285340011 -3600
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# Node ID eb247ea9db8c8b541a7f8c9cdc51c064c4c9e41c
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# Parent 105c938eacbbc250447a676bb2088f804033b82b
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x86: check CPUID level before enabling xsave
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References: bnc#640773
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While not as relevant after c/s 21894, is still seems safer to check
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the CPUID level here, just like Linux does. The is particularly
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relevant for the 4.0 tree (which doesn't have said c/s), but also
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possibly for nested environments where writing MSR_IA32_MISC_ENABLE
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may not actually take effect (Xen itself ignores such writes).
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Signed-off-by: Jan Beulich <jbeulich@novell.com>
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--- a/xen/arch/x86/i387.c
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+++ b/xen/arch/x86/i387.c
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@@ -132,6 +132,8 @@ void restore_fpu(struct vcpu *v)
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}
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}
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+#define XSTATE_CPUID 0xd
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+
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/*
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* Maximum size (in byte) of the XSAVE/XRSTOR save area required by all
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* the supported and enabled features on the processor, including the
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@@ -148,7 +150,12 @@ void xsave_init(void)
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int cpu = smp_processor_id();
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u32 min_size;
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- cpuid_count(0xd, 0, &eax, &ebx, &ecx, &edx);
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+ if ( boot_cpu_data.cpuid_level < XSTATE_CPUID ) {
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+ printk(XENLOG_ERR "XSTATE_CPUID missing\n");
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+ return;
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+ }
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+
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+ cpuid_count(XSTATE_CPUID, 0, &eax, &ebx, &ecx, &edx);
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printk("%s: cpu%d: cntxt_max_size: 0x%x and states: %08x:%08x\n",
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__func__, cpu, ecx, edx, eax);
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@@ -169,7 +176,7 @@ void xsave_init(void)
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*/
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set_in_cr4(X86_CR4_OSXSAVE);
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set_xcr0(eax & XCNTXT_MASK);
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- cpuid_count(0xd, 0, &eax, &ebx, &ecx, &edx);
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+ cpuid_count(XSTATE_CPUID, 0, &eax, &ebx, &ecx, &edx);
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clear_in_cr4(X86_CR4_OSXSAVE);
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if ( cpu == 0 )
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