x86/hvm: collect information of TSC scaling ratio

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: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>

diff --git a/xen/arch/x86/hvm/hvm.c b/xen/arch/x86/hvm/hvm.c
index fb2d81b1eed0f9ca6f3bd08a1c9c2dc6f9964e79..556071cff1fb44552ee5813e9c95db69a8458507 100644 (file)
--- a/xen/arch/x86/hvm/hvm.c
+++ b/xen/arch/x86/hvm/hvm.c
@@ -60,7 +60,6 @@
 #include <asm/hvm/nestedhvm.h>
 #include <asm/hvm/event.h>
 #include <asm/hvm/vmx/vmx.h>
-#include <asm/hvm/svm/svm.h> /* for cpu_has_tsc_ratio */
 #include <asm/altp2m.h>
 #include <asm/mtrr.h>
 #include <asm/apic.h>
@@ -312,8 +311,8 @@ void hvm_set_guest_tsc_fixed(struct vcpu *v, u64 guest_tsc, u64 at_tsc)
     else
     {
         tsc = at_tsc ?: rdtsc();
-        if ( cpu_has_tsc_ratio )
-            tsc = hvm_funcs.scale_tsc(v, tsc);
+        if ( hvm_tsc_scaling_supported )
+            tsc = hvm_funcs.tsc_scaling.scale_tsc(v, tsc);
     }
 
     delta_tsc = guest_tsc - tsc;
@@ -344,8 +343,8 @@ u64 hvm_get_guest_tsc_fixed(struct vcpu *v, uint64_t at_tsc)
     else
     {
         tsc = at_tsc ?: rdtsc();
-        if ( cpu_has_tsc_ratio )
-            tsc = hvm_funcs.scale_tsc(v, tsc);
+        if ( hvm_tsc_scaling_supported )
+            tsc = hvm_funcs.tsc_scaling.scale_tsc(v, tsc);
     }
 
     return tsc + v->arch.hvm_vcpu.cache_tsc_offset;

diff --git a/xen/arch/x86/hvm/svm/svm.c b/xen/arch/x86/hvm/svm/svm.c
index e62dfa1cf17410c1f5150c6768245c441ac97c7e..b22d4a1b3a22949c620b0a48765ccc7baa31b41a 100644 (file)
--- a/xen/arch/x86/hvm/svm/svm.c
+++ b/xen/arch/x86/hvm/svm/svm.c
@@ -1465,6 +1465,9 @@ 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.ratio_frac_bits = 32;
+
 #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");
@@ -2286,7 +2289,10 @@ static struct hvm_function_table __initdata svm_function_table = {
     .nhvm_intr_blocked = nsvm_intr_blocked,
     .nhvm_hap_walk_L1_p2m = nsvm_hap_walk_L1_p2m,
 
-    .scale_tsc            = svm_scale_tsc,
+    .tsc_scaling = {
+        .max_ratio = ~TSC_RATIO_RSVD_BITS,
+        .scale_tsc = svm_scale_tsc,
+    },
 };
 
 void svm_vmexit_handler(struct cpu_user_regs *regs)

diff --git a/xen/arch/x86/time.c b/xen/arch/x86/time.c
index 5819b9ffdb711545488f1dae9143fcf95a983000..2248dfa63f5b17a84e96289f75fbee989b79bf29 100644 (file)
--- a/xen/arch/x86/time.c
+++ b/xen/arch/x86/time.c
@@ -37,7 +37,6 @@
 #include <asm/hpet.h>
 #include <io_ports.h>
 #include <asm/setup.h> /* for early_time_init */
-#include <asm/hvm/svm/svm.h> /* for cpu_has_tsc_ratio */
 #include <public/arch-x86/cpuid.h>
 
 /* opt_clocksource: Force clocksource to one of: pit, hpet, acpi. */
@@ -815,9 +814,10 @@ static void __update_vcpu_system_time(struct vcpu *v, int force)
     }
     else
     {
-        if ( has_hvm_container_domain(d) && cpu_has_tsc_ratio )
+        if ( has_hvm_container_domain(d) && hvm_tsc_scaling_supported )
         {
-            tsc_stamp            = hvm_funcs.scale_tsc(v, t->local_tsc_stamp);
+            tsc_stamp            =
+                hvm_funcs.tsc_scaling.scale_tsc(v, t->local_tsc_stamp);
             _u.tsc_to_system_mul = d->arch.vtsc_to_ns.mul_frac;
             _u.tsc_shift         = d->arch.vtsc_to_ns.shift;
         }
@@ -1758,7 +1758,7 @@ void tsc_get_info(struct domain *d, uint32_t *tsc_mode,
                   uint32_t *incarnation)
 {
     bool_t enable_tsc_scaling = has_hvm_container_domain(d) &&
-                                cpu_has_tsc_ratio && !d->arch.vtsc;
+                                hvm_tsc_scaling_supported && !d->arch.vtsc;
 
     *incarnation = d->arch.incarnation;
     *tsc_mode = d->arch.tsc_mode;
@@ -1865,7 +1865,7 @@ void tsc_set_info(struct domain *d,
          */
         if ( tsc_mode == TSC_MODE_DEFAULT && host_tsc_is_safe() &&
              (has_hvm_container_domain(d) ?
-              d->arch.tsc_khz == cpu_khz || cpu_has_tsc_ratio :
+              d->arch.tsc_khz == cpu_khz || hvm_tsc_scaling_supported :
               incarnation == 0) )
         {
     case TSC_MODE_NEVER_EMULATE:
@@ -1879,7 +1879,7 @@ void tsc_set_info(struct domain *d,
         d->arch.vtsc = !boot_cpu_has(X86_FEATURE_RDTSCP) ||
                        !host_tsc_is_safe();
         enable_tsc_scaling = has_hvm_container_domain(d) &&
-                             cpu_has_tsc_ratio && !d->arch.vtsc;
+                             hvm_tsc_scaling_supported && !d->arch.vtsc;
         d->arch.tsc_khz = (enable_tsc_scaling && gtsc_khz) ? gtsc_khz : cpu_khz;
         set_time_scale(&d->arch.vtsc_to_ns, d->arch.tsc_khz * 1000 );
         d->arch.ns_to_vtsc = scale_reciprocal(d->arch.vtsc_to_ns);

diff --git a/xen/include/asm-x86/hvm/hvm.h b/xen/include/asm-x86/hvm/hvm.h
index 149fe1c7a7b9eaa5cc0b6fba3439e1f0be09b1aa..82d0f9d0c750a066584ef143203f00ad4f0620ed 100644 (file)
--- a/xen/include/asm-x86/hvm/hvm.h
+++ b/xen/include/asm-x86/hvm/hvm.h
@@ -222,7 +222,18 @@ struct hvm_function_table {
     bool_t (*altp2m_vcpu_emulate_ve)(struct vcpu *v);
     int (*altp2m_vcpu_emulate_vmfunc)(struct cpu_user_regs *regs);
 
-    uint64_t (*scale_tsc)(const struct vcpu *v, uint64_t tsc);
+    /*
+     * Parameters and callbacks for hardware-assisted TSC scaling,
+     * which are valid only when the hardware feature is available.
+     */
+    struct {
+        /* number of bits of the fractional part of TSC scaling ratio */
+        uint8_t  ratio_frac_bits;
+        /* maximum-allowed TSC scaling ratio */
+        uint64_t max_ratio;
+
+        uint64_t (*scale_tsc)(const struct vcpu *v, uint64_t tsc);
+    } tsc_scaling;
 };
 
 extern struct hvm_function_table hvm_funcs;
@@ -258,6 +269,9 @@ void hvm_set_guest_tsc_fixed(struct vcpu *v, u64 guest_tsc, u64 at_tsc);
 u64 hvm_get_guest_tsc_fixed(struct vcpu *v, u64 at_tsc);
 #define hvm_get_guest_tsc(v) hvm_get_guest_tsc_fixed(v, 0)
 
+#define hvm_tsc_scaling_supported \
+    (!!hvm_funcs.tsc_scaling.ratio_frac_bits)
+
 int hvm_set_mode(struct vcpu *v, int mode);
 void hvm_init_guest_time(struct domain *d);
 void hvm_set_guest_time(struct vcpu *v, u64 guest_time);