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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] [PATCH v8 2/2] x86/viridian: Add partition time reference counter MSR support
This patch optionally re-instates support for the partition time reference
counter that was previously introduced by commit
e36cd2cdc9674a7a4855d21fb7b3e6e17c4bb33b and reverted by commit
1cd4fab14ce25859efa4a2af13475e6650a5506c. The previous implementation was
non-optional and flawed.
This implementation uses the tsc of vcpu0, which is preserved across
save/restore as part of the architectural state, and then converts that
to a 100ns tick using the domain's tsc_khz.
Signed-off-by: Paul Durrant <paul.durrant@xxxxxxxxxx>
Cc: Keir Fraser <keir@xxxxxxx>
Cc: Jan Beulich <jbeulich@xxxxxxxx>
Cc: Ian Campbell <ian.campbell@xxxxxxxxxx>
Cc: Ian Jackson <ian.jackson@xxxxxxxxxxxxx>
Cc: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>
Cc: Christoph Egger <chegger@xxxxxxxxx>
---
docs/man/xl.cfg.pod.5 | 7 +++++++
tools/libxl/libxl_dom.c | 3 +++
tools/libxl/libxl_types.idl | 1 +
xen/arch/x86/hvm/viridian.c | 29 ++++++++++++++++++++++++-----
xen/arch/x86/time.c | 4 ++--
xen/include/asm-x86/perfc_defn.h | 1 +
xen/include/asm-x86/time.h | 4 ++++
xen/include/public/hvm/params.h | 9 ++++++++-
8 files changed, 50 insertions(+), 8 deletions(-)
diff --git a/docs/man/xl.cfg.pod.5 b/docs/man/xl.cfg.pod.5
index d91f101..ac3798a 100644
--- a/docs/man/xl.cfg.pod.5
+++ b/docs/man/xl.cfg.pod.5
@@ -1131,6 +1131,13 @@ This set incorporates the TSC and APIC frequency MSRs.
This enlightenment can improve performance of Windows 7 and Windows
Server 2008 R2 onwards.
+=item B<time_ref_count>
+
+This set incorporates Partition Time Reference Counter MSR.
+
+This enlightenment can improve performance of Windows 8 and Windows
+Server 2012 onwards.
+
=back
See the latest version of Microsoft's Hypervisor Top-Level Functional
diff --git a/tools/libxl/libxl_dom.c b/tools/libxl/libxl_dom.c
index e854984..579188a 100644
--- a/tools/libxl/libxl_dom.c
+++ b/tools/libxl/libxl_dom.c
@@ -241,6 +241,9 @@ static void hvm_set_viridian_features(libxl__gc *gc,
uint32_t domid,
case LIBXL_VIRIDIAN_ENLIGHTENMENT_FREQ:
feature_mask &= ~HVMPV_no_freq;
break;
+ case LIBXL_VIRIDIAN_ENLIGHTENMENT_TIME_REF_COUNT:
+ feature_mask |= HVMPV_time_ref_count;
+ break;
default:
LIBXL__LOG(CTX, LIBXL__LOG_WARNING,
"Unknown viridian enlightenment %d\n",
diff --git a/tools/libxl/libxl_types.idl b/tools/libxl/libxl_types.idl
index 3b0059c..a2a523e 100644
--- a/tools/libxl/libxl_types.idl
+++ b/tools/libxl/libxl_types.idl
@@ -183,6 +183,7 @@ libxl_viridian_enlightenment =
Enumeration("viridian_enlightenment", [
(0, "unknown"),
(1, "base"),
(2, "freq"),
+ (3, "time_ref_count"),
])
#
diff --git a/xen/arch/x86/hvm/viridian.c b/xen/arch/x86/hvm/viridian.c
index 28c4479..53138fd 100644
--- a/xen/arch/x86/hvm/viridian.c
+++ b/xen/arch/x86/hvm/viridian.c
@@ -36,11 +36,11 @@
#define HvNotifyLongSpinWait 8
/* Viridian CPUID 4000003, Viridian MSR availability. */
-#define CPUID3A_MSR_REF_COUNT (1 << 1)
-#define CPUID3A_MSR_APIC_ACCESS (1 << 4)
-#define CPUID3A_MSR_HYPERCALL (1 << 5)
-#define CPUID3A_MSR_VP_INDEX (1 << 6)
-#define CPUID3A_MSR_FREQ (1 << 11)
+#define CPUID3A_MSR_TIME_REF_COUNT (1 << 1)
+#define CPUID3A_MSR_APIC_ACCESS (1 << 4)
+#define CPUID3A_MSR_HYPERCALL (1 << 5)
+#define CPUID3A_MSR_VP_INDEX (1 << 6)
+#define CPUID3A_MSR_FREQ (1 << 11)
/* Viridian CPUID 4000004, Implementation Recommendations. */
#define CPUID4A_MSR_BASED_APIC (1 << 3)
@@ -93,6 +93,8 @@ int cpuid_viridian_leaves(unsigned int leaf, unsigned int
*eax,
CPUID3A_MSR_VP_INDEX);
if ( !(viridian_feature_mask(d) & HVMPV_no_freq) )
*eax |= CPUID3A_MSR_FREQ;
+ if ( viridian_feature_mask(d) & HVMPV_time_ref_count )
+ *eax |= CPUID3A_MSR_TIME_REF_COUNT;
break;
case 4:
/* Recommended hypercall usage. */
@@ -344,6 +346,23 @@ int rdmsr_viridian_regs(uint32_t idx, uint64_t *val)
*val = v->arch.hvm_vcpu.viridian.apic_assist.raw;
break;
+ case VIRIDIAN_MSR_TIME_REF_COUNT:
+ {
+ uint64_t tsc;
+ struct time_scale tsc_to_ns;
+
+ if ( !(viridian_feature_mask(d) & HVMPV_time_ref_count) )
+ return 0;
+
+ perfc_incr(mshv_rdmsr_time_ref_count);
+ tsc = hvm_get_guest_tsc(pt_global_vcpu_target(d));
+
+ /* convert tsc to count of 100ns periods */
+ set_time_scale(&tsc_to_ns, (uint64_t)d->arch.tsc_khz * 1000ul);
+ *val = scale_delta(tsc, &tsc_to_ns) / 100ul;
+ break;
+ }
+
default:
return 0;
}
diff --git a/xen/arch/x86/time.c b/xen/arch/x86/time.c
index bd89219..74c01e3 100644
--- a/xen/arch/x86/time.c
+++ b/xen/arch/x86/time.c
@@ -121,7 +121,7 @@ static inline u32 mul_frac(u32 multiplicand, u32 multiplier)
* Scale a 64-bit delta by scaling and multiplying by a 32-bit fraction,
* yielding a 64-bit result.
*/
-static inline u64 scale_delta(u64 delta, struct time_scale *scale)
+u64 scale_delta(u64 delta, struct time_scale *scale)
{
u64 product;
@@ -272,7 +272,7 @@ static u64 init_pit_and_calibrate_tsc(void)
return ((end - start) * (u64)CALIBRATE_FRAC);
}
-static void set_time_scale(struct time_scale *ts, u64 ticks_per_sec)
+void set_time_scale(struct time_scale *ts, u64 ticks_per_sec)
{
u64 tps64 = ticks_per_sec;
u32 tps32;
diff --git a/xen/include/asm-x86/perfc_defn.h b/xen/include/asm-x86/perfc_defn.h
index 7d802cc..170da00 100644
--- a/xen/include/asm-x86/perfc_defn.h
+++ b/xen/include/asm-x86/perfc_defn.h
@@ -120,6 +120,7 @@ PERFCOUNTER(mshv_rdmsr_hc_page, "MS Hv rdmsr
hypercall page")
PERFCOUNTER(mshv_rdmsr_vp_index, "MS Hv rdmsr vp index")
PERFCOUNTER(mshv_rdmsr_tsc_frequency, "MS Hv rdmsr TSC frequency")
PERFCOUNTER(mshv_rdmsr_apic_frequency, "MS Hv rdmsr APIC frequency")
+PERFCOUNTER(mshv_rdmsr_time_ref_count, "MS Hv rdmsr time ref count")
PERFCOUNTER(mshv_rdmsr_icr, "MS Hv rdmsr icr")
PERFCOUNTER(mshv_rdmsr_tpr, "MS Hv rdmsr tpr")
PERFCOUNTER(mshv_rdmsr_apic_assist, "MS Hv rdmsr APIC assist")
diff --git a/xen/include/asm-x86/time.h b/xen/include/asm-x86/time.h
index 420620e..c4d82f6 100644
--- a/xen/include/asm-x86/time.h
+++ b/xen/include/asm-x86/time.h
@@ -76,4 +76,8 @@ void cpuid_time_leaf(uint32_t sub_idx, uint32_t *eax,
uint32_t *ebx,
u64 stime2tsc(s_time_t stime);
+struct time_scale;
+void set_time_scale(struct time_scale *ts, u64 ticks_per_sec);
+u64 scale_delta(u64 delta, struct time_scale *scale);
+
#endif /* __X86_TIME_H__ */
diff --git a/xen/include/public/hvm/params.h b/xen/include/public/hvm/params.h
index 68d26fd..3c51072 100644
--- a/xen/include/public/hvm/params.h
+++ b/xen/include/public/hvm/params.h
@@ -88,7 +88,14 @@
#define _HVMPV_no_freq 1
#define HVMPV_no_freq (1 << _HVMPV_no_freq)
-#define HVMPV_feature_mask (HVMPV_base_freq|HVMPV_no_freq)
+/* Enable Partition Time Reference Counter (HV_X64_MSR_TIME_REF_COUNT) */
+#define _HVMPV_time_ref_count 2
+#define HVMPV_time_ref_count (1 << _HVMPV_time_ref_count)
+
+#define HVMPV_feature_mask \
+ (HVMPV_base_freq | \
+ HVMPV_no_freq | \
+ HVMPV_time_ref_count)
#endif
--
1.7.10.4
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