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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] [PATCH for 4.5] x86/viridian: Freeze time reference counter when domain is paused
In XenServer system test it has become apparent that versions of Windows
that make use of the time reference counter enlightenment cannot cope with
large jumps forward in the value read from the MSR. Specifically,
suspending a very large domain took approx. 45 minutes to complete and
when the domain was resumed it was discovered that the WMI (Windows
Management Instrumentation) service had hung.
This patch adds code to freeze the value of the time reference counter
on domain pause and 'thaw' it on domain unpause, but only if the domain is
not shutting down. The absolute value of the counter is then saved in the
viridian domain context record. This prevents the guest OS from experiencing
large jumps in the value of the MSR and has been shown to reliably fix
the problem with WMI.
Signed-off-by: Paul Durrant <paul.durrant@xxxxxxxxxx>
Cc: Keir Fraser <keir@xxxxxxx>
Cc: Jan Beulich <jbeulich@xxxxxxxx>
Cc: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
---
xen/arch/x86/hvm/viridian.c | 62 +++++++++++++++++++++++++-------
xen/common/domain.c | 41 +++++++++++++++------
xen/include/asm-x86/hvm/hvm.h | 9 ++++-
xen/include/asm-x86/hvm/viridian.h | 27 ++++++++++++++
xen/include/public/arch-x86/hvm/save.h | 1 +
5 files changed, 116 insertions(+), 24 deletions(-)
diff --git a/xen/arch/x86/hvm/viridian.c b/xen/arch/x86/hvm/viridian.c
index 6726168..7d55363 100644
--- a/xen/arch/x86/hvm/viridian.c
+++ b/xen/arch/x86/hvm/viridian.c
@@ -289,6 +289,39 @@ int wrmsr_viridian_regs(uint32_t idx, uint64_t val)
return 1;
}
+static int64_t raw_trc_val(struct domain *d)
+{
+ uint64_t tsc;
+ struct time_scale tsc_to_ns;
+
+ tsc = hvm_get_guest_tsc(pt_global_vcpu_target(d));
+
+ /* convert tsc to count of 100ns periods */
+ set_time_scale(&tsc_to_ns, d->arch.tsc_khz * 1000ul);
+ return scale_delta(tsc, &tsc_to_ns) / 100ul;
+}
+
+void viridian_time_ref_count_freeze(struct domain *d)
+{
+ struct viridian_time_ref_count *trc;
+
+ trc = &d->arch.hvm_domain.viridian.time_ref_count;
+
+ if ( test_and_clear_bit(_TRC_running, &trc->flags) )
+ trc->val = raw_trc_val(d) + trc->off;
+}
+
+void viridian_time_ref_count_thaw(struct domain *d)
+{
+ struct viridian_time_ref_count *trc;
+
+ trc = &d->arch.hvm_domain.viridian.time_ref_count;
+
+ if ( !d->is_shutting_down &&
+ !test_and_set_bit(_TRC_running, &trc->flags) )
+ trc->off = (int64_t)trc->val - raw_trc_val(d);
+}
+
int rdmsr_viridian_regs(uint32_t idx, uint64_t *val)
{
struct vcpu *v = current;
@@ -348,18 +381,19 @@ int rdmsr_viridian_regs(uint32_t idx, uint64_t *val)
case VIRIDIAN_MSR_TIME_REF_COUNT:
{
- uint64_t tsc;
- struct time_scale tsc_to_ns;
+ struct viridian_time_ref_count *trc;
+
+ trc = &d->arch.hvm_domain.viridian.time_ref_count;
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));
+ if ( !test_and_set_bit(_TRC_accessed, &trc->flags) )
+ printk(XENLOG_G_INFO "d%d: VIRIDIAN MSR_TIME_REF_COUNT:
accessed\n",
+ d->domain_id);
- /* convert tsc to count of 100ns periods */
- set_time_scale(&tsc_to_ns, d->arch.tsc_khz * 1000ul);
- *val = scale_delta(tsc, &tsc_to_ns) / 100ul;
+ perfc_incr(mshv_rdmsr_time_ref_count);
+ *val = raw_trc_val(d) + trc->off;
break;
}
@@ -450,9 +484,10 @@ static int viridian_save_domain_ctxt(struct domain *d,
hvm_domain_context_t *h)
if ( !is_viridian_domain(d) )
return 0;
- ctxt.hypercall_gpa = d->arch.hvm_domain.viridian.hypercall_gpa.raw;
- ctxt.guest_os_id = d->arch.hvm_domain.viridian.guest_os_id.raw;
-
+ ctxt.time_ref_count = d->arch.hvm_domain.viridian.time_ref_count.val;
+ ctxt.hypercall_gpa = d->arch.hvm_domain.viridian.hypercall_gpa.raw;
+ ctxt.guest_os_id = d->arch.hvm_domain.viridian.guest_os_id.raw;
+
return (hvm_save_entry(VIRIDIAN_DOMAIN, 0, h, &ctxt) != 0);
}
@@ -460,11 +495,12 @@ static int viridian_load_domain_ctxt(struct domain *d,
hvm_domain_context_t *h)
{
struct hvm_viridian_domain_context ctxt;
- if ( hvm_load_entry(VIRIDIAN_DOMAIN, h, &ctxt) != 0 )
+ if ( hvm_load_entry_zeroextend(VIRIDIAN_DOMAIN, h, &ctxt) != 0 )
return -EINVAL;
- d->arch.hvm_domain.viridian.hypercall_gpa.raw = ctxt.hypercall_gpa;
- d->arch.hvm_domain.viridian.guest_os_id.raw = ctxt.guest_os_id;
+ d->arch.hvm_domain.viridian.time_ref_count.val = ctxt.time_ref_count;
+ d->arch.hvm_domain.viridian.hypercall_gpa.raw = ctxt.hypercall_gpa;
+ d->arch.hvm_domain.viridian.guest_os_id.raw = ctxt.guest_os_id;
return 0;
}
diff --git a/xen/common/domain.c b/xen/common/domain.c
index 190998c..af5dc82 100644
--- a/xen/common/domain.c
+++ b/xen/common/domain.c
@@ -43,6 +43,10 @@
#include <xen/trace.h>
#include <xen/tmem.h>
+#ifdef CONFIG_X86
+#include <asm/hvm/viridian.h>
+#endif
+
/* Linux config option: propageted to domain0 */
/* xen_processor_pmbits: xen control Cx, Px, ... */
unsigned int xen_processor_pmbits = XEN_PROCESSOR_PM_PX;
@@ -706,6 +710,11 @@ void domain_shutdown(struct domain *d, u8 reason)
v->paused_for_shutdown = 1;
}
+#ifdef CONFIG_X86
+ if ( has_viridian_time_ref_count(d) )
+ viridian_time_ref_count_freeze(d);
+#endif
+
__domain_finalise_shutdown(d);
spin_unlock(&d->shutdown_lock);
@@ -925,32 +934,44 @@ int vcpu_unpause_by_systemcontroller(struct vcpu *v)
return 0;
}
-void domain_pause(struct domain *d)
+void do_domain_pause(struct domain *d, bool_t nosync)
{
struct vcpu *v;
- ASSERT(d != current->domain);
-
atomic_inc(&d->pause_count);
for_each_vcpu( d, v )
- vcpu_sleep_sync(v);
+ if ( nosync )
+ vcpu_sleep_nosync(v);
+ else
+ vcpu_sleep_sync(v);
+
+#ifdef CONFIG_X86
+ if ( has_viridian_time_ref_count(d) )
+ viridian_time_ref_count_freeze(d);
+#endif
}
-void domain_pause_nosync(struct domain *d)
+void domain_pause(struct domain *d)
{
- struct vcpu *v;
-
- atomic_inc(&d->pause_count);
+ ASSERT(d != current->domain);
+ do_domain_pause(d, 0);
+}
- for_each_vcpu( d, v )
- vcpu_sleep_nosync(v);
+void domain_pause_nosync(struct domain *d)
+{
+ do_domain_pause(d, 1);
}
void domain_unpause(struct domain *d)
{
struct vcpu *v;
+#ifdef CONFIG_X86
+ if ( has_viridian_time_ref_count(d) )
+ viridian_time_ref_count_thaw(d);
+#endif
+
if ( atomic_dec_and_test(&d->pause_count) )
for_each_vcpu( d, v )
vcpu_wake(v);
diff --git a/xen/include/asm-x86/hvm/hvm.h b/xen/include/asm-x86/hvm/hvm.h
index 0d94c48..2dda908 100644
--- a/xen/include/asm-x86/hvm/hvm.h
+++ b/xen/include/asm-x86/hvm/hvm.h
@@ -340,12 +340,19 @@ static inline unsigned long hvm_get_shadow_gs_base(struct
vcpu *v)
return hvm_funcs.get_shadow_gs_base(v);
}
+
+#define has_hvm_params(d) \
+ ((d)->arch.hvm_domain.params != NULL)
+
#define viridian_feature_mask(d) \
- ((d)->arch.hvm_domain.params[HVM_PARAM_VIRIDIAN])
+ (has_hvm_params(d) && (d)->arch.hvm_domain.params[HVM_PARAM_VIRIDIAN])
#define is_viridian_domain(d) \
(is_hvm_domain(d) && (viridian_feature_mask(d) & HVMPV_base_freq))
+#define has_viridian_time_ref_count(d) \
+ (is_viridian_domain(d) && (viridian_feature_mask(d) &
HVMPV_time_ref_count))
+
void hvm_hypervisor_cpuid_leaf(uint32_t sub_idx,
uint32_t *eax, uint32_t *ebx,
uint32_t *ecx, uint32_t *edx);
diff --git a/xen/include/asm-x86/hvm/viridian.h
b/xen/include/asm-x86/hvm/viridian.h
index 496da33..4cab2e8 100644
--- a/xen/include/asm-x86/hvm/viridian.h
+++ b/xen/include/asm-x86/hvm/viridian.h
@@ -48,10 +48,24 @@ union viridian_hypercall_gpa
} fields;
};
+struct viridian_time_ref_count
+{
+ unsigned long flags;
+
+#define _TRC_accessed 0
+#define TRC_accessed (1 << _TRC_accessed)
+#define _TRC_running 1
+#define TRC_running (1 << _TRC_running)
+
+ uint64_t val;
+ int64_t off;
+};
+
struct viridian_domain
{
union viridian_guest_os_id guest_os_id;
union viridian_hypercall_gpa hypercall_gpa;
+ struct viridian_time_ref_count time_ref_count;
};
int
@@ -75,4 +89,17 @@ rdmsr_viridian_regs(
int
viridian_hypercall(struct cpu_user_regs *regs);
+void viridian_time_ref_count_freeze(struct domain *d);
+void viridian_time_ref_count_thaw(struct domain *d);
+
#endif /* __ASM_X86_HVM_VIRIDIAN_H__ */
+
+/*
+ * Local variables:
+ * mode: C
+ * c-file-style: "BSD"
+ * c-basic-offset: 4
+ * tab-width: 4
+ * indent-tabs-mode: nil
+ * End:
+ */
diff --git a/xen/include/public/arch-x86/hvm/save.h
b/xen/include/public/arch-x86/hvm/save.h
index 16d85a3..88aab7e 100644
--- a/xen/include/public/arch-x86/hvm/save.h
+++ b/xen/include/public/arch-x86/hvm/save.h
@@ -568,6 +568,7 @@ struct hvm_hw_cpu_xsave {
struct hvm_viridian_domain_context {
uint64_t hypercall_gpa;
uint64_t guest_os_id;
+ uint64_t time_ref_count;
};
DECLARE_HVM_SAVE_TYPE(VIRIDIAN_DOMAIN, 15, struct hvm_viridian_domain_context);
--
1.7.10.4
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