49 lines
1.7 KiB
Diff
49 lines
1.7 KiB
Diff
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# HG changeset patch
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# User Andreas Herrmann <andreas.herrmann3@amd.com>
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# Date 1338452142 -7200
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# Node ID d7ae665b03afb88a813c6f197612215697eaf8f6
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# Parent a120d24f90fb5e94244331e530aacf5b0ea86f25
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x86/amd: re-enable CPU topology extensions in case BIOS has disabled it
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BIOS will switch off the corresponding feature flag on family
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15h models 10h-1fh non-desktop CPUs.
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The topology extension CPUID leafs are required to detect which
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cores belong to the same compute unit. (thread siblings mask is
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set accordingly and also correct information about L1i and L2
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cache sharing depends on this).
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W/o this patch we wouldn't see which cores belong to the same
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compute unit and also cache sharing information for L1i and L2
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would be incorrect on such systems.
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Signed-off-by: Andreas Herrmann <andreas.herrmann3@amd.com>
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Signed-off-by: Jan Beulich <jbeulich@suse.com>
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Acked-by: Keir Fraser <keir@xen.org>
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Committed-by: Jan Beulich <jbeulich@suse.com>
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--- a/xen/arch/x86/cpu/amd.c
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+++ b/xen/arch/x86/cpu/amd.c
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@@ -612,6 +612,21 @@ static void __devinit init_amd(struct cp
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}
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}
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+ /* re-enable TopologyExtensions if switched off by BIOS */
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+ if ((c->x86 == 0x15) &&
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+ (c->x86_model >= 0x10) && (c->x86_model <= 0x1f) &&
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+ !cpu_has(c, X86_FEATURE_TOPOEXT) &&
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+ !rdmsr_safe(MSR_K8_EXT_FEATURE_MASK, value)) {
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+ value |= 1ULL << 54;
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+ wrmsr_safe(MSR_K8_EXT_FEATURE_MASK, value);
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+ rdmsrl(MSR_K8_EXT_FEATURE_MASK, value);
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+ if (value & (1ULL << 54)) {
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+ set_bit(X86_FEATURE_TOPOEXT, c->x86_capability);
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+ printk(KERN_INFO "CPU: Re-enabling disabled "
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+ "Topology Extensions Support\n");
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+ }
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+ }
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+
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amd_get_topology(c);
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/* Pointless to use MWAIT on Family10 as it does not deep sleep. */
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