[PATCH v3 06/13] x86/hvm: Collect information of TSC scaling ratio

[Haozhong Zhang <haozhong.zhang@intel.com>]

Both VMX TSC scaling and SVM TSC ratio use the 64-bit TSC scaling ratio,
but the number of fractional bits of the ratio is different between VMX
and SVM. This patch adds the architecture code to collect the number of
fractional bits and other related information into fields of struct
hvm_function_table so that they can be used in the common code.

Signed-off-by: Haozhong Zhang <haozhong.zhang@intel.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
---
Changes in v3:
 (addressing Kevin Tian's comments)
 * Fix a typo: maxmimum -> maximum

 xen/arch/x86/hvm/svm/svm.c    |  7 +++++++
 xen/include/asm-x86/hvm/hvm.h | 12 ++++++++++++
 2 files changed, 19 insertions(+)

diff --git a/xen/arch/x86/hvm/svm/svm.c b/xen/arch/x86/hvm/svm/svm.c
index 8891c78..95795ce 100644
--- a/xen/arch/x86/hvm/svm/svm.c
+++ b/xen/arch/x86/hvm/svm/svm.c
@@ -1451,6 +1451,9 @@ const struct hvm_function_table * __init start_svm(void)
     if ( !cpu_has_svm_nrips )
         clear_bit(SVM_FEATURE_DECODEASSISTS, &svm_feature_flags);
 
+    if ( cpu_has_tsc_ratio )
+        svm_function_table.tsc_scaling_supported = 1;
+
 #define P(p,s) if ( p ) { printk(" - %s\n", s); printed = 1; }
     P(cpu_has_svm_npt, "Nested Page Tables (NPT)");
     P(cpu_has_svm_lbrv, "Last Branch Record (LBR) Virtualisation");
@@ -2272,6 +2275,10 @@ static struct hvm_function_table __initdata svm_function_table = {
     .nhvm_hap_walk_L1_p2m = nsvm_hap_walk_L1_p2m,
 
     .scale_tsc            = svm_scale_tsc,
+
+    .default_tsc_scaling_ratio   = DEFAULT_TSC_RATIO,
+    .max_tsc_scaling_ratio       = ~TSC_RATIO_RSVD_BITS,
+    .tsc_scaling_ratio_frac_bits = 32,
 };
 
 void svm_vmexit_handler(struct cpu_user_regs *regs)
diff --git a/xen/include/asm-x86/hvm/hvm.h b/xen/include/asm-x86/hvm/hvm.h
index ba6259e..12f9f24 100644
--- a/xen/include/asm-x86/hvm/hvm.h
+++ b/xen/include/asm-x86/hvm/hvm.h
@@ -100,6 +100,18 @@ struct hvm_function_table {
     unsigned int hap_capabilities;
 
     /*
+     * Parameters of hardware-assisted TSC scaling.
+     */
+    /* is TSC scaling supported? */
+    bool_t   tsc_scaling_supported;
+    /* number of bits of the fractional part of TSC scaling ratio */
+    uint8_t  tsc_scaling_ratio_frac_bits;
+    /* default TSC scaling ratio (no scaling) */
+    uint64_t default_tsc_scaling_ratio;
+    /* maximum-allowed TSC scaling ratio */
+    uint64_t max_tsc_scaling_ratio;
+
+    /*
      * Initialise/destroy HVM domain/vcpu resources
      */
     int  (*domain_initialise)(struct domain *d);
-- 
2.4.8