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Re: [Xen-devel] [PATCH v5 1/6] x86/hvm: Collect information of TSC scaling ratio

On 02/23/2016 09:10 AM, Jan Beulich wrote:
On 23.02.16 at 15:00, <boris.ostrovsky@xxxxxxxxxx> wrote:
On 02/22/2016 09:04 PM, Haozhong Zhang wrote:

+ if ( cpu_has_tsc_ratio )
+        svm_function_table.tsc_scaling.ratio_frac_bits = 32;

+#define hvm_tsc_scaling_supported \
+    (!!hvm_funcs.tsc_scaling.ratio_frac_bits)
What is the difference (in usage) between cpu_has_tsc_ratio and
hvm_tsc_scaling_supported? Isn't the first imply the second (and if yes
then what's the reason for having the latter)?
Iiuc cpu_has_tsc_ratio is AMD/SVM specific, while
hvm_tsc_scaling_supported is meant to be vendor independent.

Ah, OK. Can we then

#define hvm_tsc_scaling_supported (cpu_has_vmx_tsc_scaling || cpu_has_tsc_ratio)


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