* [PATCH v2 0/3] xen: add full support for CONFIG_PARAVIRT_TIME_ACCOUNTING
@ 2016-07-06 5:00 Juergen Gross
2016-07-06 5:00 ` [PATCH v2 1/3] xen: update xen headers Juergen Gross
` (3 more replies)
0 siblings, 4 replies; 6+ messages in thread
From: Juergen Gross @ 2016-07-06 5:00 UTC (permalink / raw)
To: xen-devel, linux-kernel
Cc: sstabellini, boris.ostrovsky, david.vrabel, Juergen Gross
With most recent Xen hypervisor (4.8) it is now possible to add full
support of CONFIG_PARAVIRT_TIME_ACCOUNTING.
To be applied on top of commit ed2f61fdd2356c2a1d1239aa1507ce4e2e059306
"xen: add steal_clock support on x86" of kernel/git/xen/tip.git
Runtime tested on x86_64, compile tested on arm64.
Changes in V2:
- patch 3: removed static variable as requested by Stefano Stabellini
Juergen Gross (3):
xen: update xen headers
arm/xen: add support for vm_assist hypercall
xen: support runqueue steal time on xen
arch/arm/include/asm/xen/hypercall.h | 1 +
arch/arm/xen/enlighten.c | 1 +
arch/arm/xen/hypercall.S | 1 +
arch/arm64/xen/hypercall.S | 1 +
drivers/xen/time.c | 40 +++++++++++++++++++++---------------
include/xen/interface/vcpu.h | 24 ++++++++++++++--------
include/xen/interface/xen.h | 17 ++++++++++++++-
7 files changed, 58 insertions(+), 27 deletions(-)
--
2.6.6
^ permalink raw reply [flat|nested] 6+ messages in thread
* [PATCH v2 1/3] xen: update xen headers
2016-07-06 5:00 [PATCH v2 0/3] xen: add full support for CONFIG_PARAVIRT_TIME_ACCOUNTING Juergen Gross
@ 2016-07-06 5:00 ` Juergen Gross
2016-07-06 5:00 ` [PATCH v2 2/3] arm/xen: add support for vm_assist hypercall Juergen Gross
` (2 subsequent siblings)
3 siblings, 0 replies; 6+ messages in thread
From: Juergen Gross @ 2016-07-06 5:00 UTC (permalink / raw)
To: xen-devel, linux-kernel
Cc: sstabellini, boris.ostrovsky, david.vrabel, Juergen Gross
Update some Xen headers to be able to use new functionality.
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
---
include/xen/interface/vcpu.h | 24 +++++++++++++++---------
include/xen/interface/xen.h | 17 ++++++++++++++++-
2 files changed, 31 insertions(+), 10 deletions(-)
diff --git a/include/xen/interface/vcpu.h b/include/xen/interface/vcpu.h
index b05288c..98188c8 100644
--- a/include/xen/interface/vcpu.h
+++ b/include/xen/interface/vcpu.h
@@ -75,15 +75,21 @@
*/
#define VCPUOP_get_runstate_info 4
struct vcpu_runstate_info {
- /* VCPU's current state (RUNSTATE_*). */
- int state;
- /* When was current state entered (system time, ns)? */
- uint64_t state_entry_time;
- /*
- * Time spent in each RUNSTATE_* (ns). The sum of these times is
- * guaranteed not to drift from system time.
- */
- uint64_t time[4];
+ /* VCPU's current state (RUNSTATE_*). */
+ int state;
+ /* When was current state entered (system time, ns)? */
+ uint64_t state_entry_time;
+ /*
+ * Update indicator set in state_entry_time:
+ * When activated via VMASST_TYPE_runstate_update_flag, set during
+ * updates in guest memory mapped copy of vcpu_runstate_info.
+ */
+#define XEN_RUNSTATE_UPDATE (1ULL << 63)
+ /*
+ * Time spent in each RUNSTATE_* (ns). The sum of these times is
+ * guaranteed not to drift from system time.
+ */
+ uint64_t time[4];
};
DEFINE_GUEST_HANDLE_STRUCT(vcpu_runstate_info);
diff --git a/include/xen/interface/xen.h b/include/xen/interface/xen.h
index d133112..1b0d189 100644
--- a/include/xen/interface/xen.h
+++ b/include/xen/interface/xen.h
@@ -413,7 +413,22 @@ DEFINE_GUEST_HANDLE_STRUCT(mmuext_op);
/* x86/PAE guests: support PDPTs above 4GB. */
#define VMASST_TYPE_pae_extended_cr3 3
-#define MAX_VMASST_TYPE 3
+/*
+ * x86 guests: Sane behaviour for virtual iopl
+ * - virtual iopl updated from do_iret() hypercalls.
+ * - virtual iopl reported in bounce frames.
+ * - guest kernels assumed to be level 0 for the purpose of iopl checks.
+ */
+#define VMASST_TYPE_architectural_iopl 4
+
+/*
+ * All guests: activate update indicator in vcpu_runstate_info
+ * Enable setting the XEN_RUNSTATE_UPDATE flag in guest memory mapped
+ * vcpu_runstate_info during updates of the runstate information.
+ */
+#define VMASST_TYPE_runstate_update_flag 5
+
+#define MAX_VMASST_TYPE 5
#ifndef __ASSEMBLY__
--
2.6.6
^ permalink raw reply related [flat|nested] 6+ messages in thread
* [PATCH v2 2/3] arm/xen: add support for vm_assist hypercall
2016-07-06 5:00 [PATCH v2 0/3] xen: add full support for CONFIG_PARAVIRT_TIME_ACCOUNTING Juergen Gross
2016-07-06 5:00 ` [PATCH v2 1/3] xen: update xen headers Juergen Gross
@ 2016-07-06 5:00 ` Juergen Gross
2016-07-06 5:00 ` [PATCH v2 3/3] xen: support runqueue steal time on xen Juergen Gross
2016-07-06 12:06 ` [Xen-devel] [PATCH v2 0/3] xen: add full support for CONFIG_PARAVIRT_TIME_ACCOUNTING David Vrabel
3 siblings, 0 replies; 6+ messages in thread
From: Juergen Gross @ 2016-07-06 5:00 UTC (permalink / raw)
To: xen-devel, linux-kernel
Cc: sstabellini, boris.ostrovsky, david.vrabel, Juergen Gross
Add support for the Xen HYPERVISOR_vm_assist hypercall.
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Reviewed-by: Julien Grall <julien.grall@arm.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
---
arch/arm/include/asm/xen/hypercall.h | 1 +
arch/arm/xen/enlighten.c | 1 +
arch/arm/xen/hypercall.S | 1 +
arch/arm64/xen/hypercall.S | 1 +
4 files changed, 4 insertions(+)
diff --git a/arch/arm/include/asm/xen/hypercall.h b/arch/arm/include/asm/xen/hypercall.h
index b6b962d..9d874db 100644
--- a/arch/arm/include/asm/xen/hypercall.h
+++ b/arch/arm/include/asm/xen/hypercall.h
@@ -52,6 +52,7 @@ int HYPERVISOR_memory_op(unsigned int cmd, void *arg);
int HYPERVISOR_physdev_op(int cmd, void *arg);
int HYPERVISOR_vcpu_op(int cmd, int vcpuid, void *extra_args);
int HYPERVISOR_tmem_op(void *arg);
+int HYPERVISOR_vm_assist(unsigned int cmd, unsigned int type);
int HYPERVISOR_platform_op_raw(void *arg);
static inline int HYPERVISOR_platform_op(struct xen_platform_op *op)
{
diff --git a/arch/arm/xen/enlighten.c b/arch/arm/xen/enlighten.c
index 71db30c..0f3aa12 100644
--- a/arch/arm/xen/enlighten.c
+++ b/arch/arm/xen/enlighten.c
@@ -389,4 +389,5 @@ EXPORT_SYMBOL_GPL(HYPERVISOR_vcpu_op);
EXPORT_SYMBOL_GPL(HYPERVISOR_tmem_op);
EXPORT_SYMBOL_GPL(HYPERVISOR_platform_op);
EXPORT_SYMBOL_GPL(HYPERVISOR_multicall);
+EXPORT_SYMBOL_GPL(HYPERVISOR_vm_assist);
EXPORT_SYMBOL_GPL(privcmd_call);
diff --git a/arch/arm/xen/hypercall.S b/arch/arm/xen/hypercall.S
index 9a36f4f..a648dfc 100644
--- a/arch/arm/xen/hypercall.S
+++ b/arch/arm/xen/hypercall.S
@@ -91,6 +91,7 @@ HYPERCALL3(vcpu_op);
HYPERCALL1(tmem_op);
HYPERCALL1(platform_op_raw);
HYPERCALL2(multicall);
+HYPERCALL2(vm_assist);
ENTRY(privcmd_call)
stmdb sp!, {r4}
diff --git a/arch/arm64/xen/hypercall.S b/arch/arm64/xen/hypercall.S
index 70df80e..329c802 100644
--- a/arch/arm64/xen/hypercall.S
+++ b/arch/arm64/xen/hypercall.S
@@ -82,6 +82,7 @@ HYPERCALL3(vcpu_op);
HYPERCALL1(tmem_op);
HYPERCALL1(platform_op_raw);
HYPERCALL2(multicall);
+HYPERCALL2(vm_assist);
ENTRY(privcmd_call)
mov x16, x0
--
2.6.6
^ permalink raw reply related [flat|nested] 6+ messages in thread
* [PATCH v2 3/3] xen: support runqueue steal time on xen
2016-07-06 5:00 [PATCH v2 0/3] xen: add full support for CONFIG_PARAVIRT_TIME_ACCOUNTING Juergen Gross
2016-07-06 5:00 ` [PATCH v2 1/3] xen: update xen headers Juergen Gross
2016-07-06 5:00 ` [PATCH v2 2/3] arm/xen: add support for vm_assist hypercall Juergen Gross
@ 2016-07-06 5:00 ` Juergen Gross
2016-07-06 10:03 ` Stefano Stabellini
2016-07-06 12:06 ` [Xen-devel] [PATCH v2 0/3] xen: add full support for CONFIG_PARAVIRT_TIME_ACCOUNTING David Vrabel
3 siblings, 1 reply; 6+ messages in thread
From: Juergen Gross @ 2016-07-06 5:00 UTC (permalink / raw)
To: xen-devel, linux-kernel
Cc: sstabellini, boris.ostrovsky, david.vrabel, Juergen Gross
Up to now reading the stolen time of a remote cpu was not possible in a
performant way under Xen. This made support of runqueue steal time via
paravirt_steal_rq_enabled impossible.
With the addition of an appropriate hypervisor interface this is now
possible, so add the support.
Signed-off-by: Juergen Gross <jgross@suse.com>
---
V2: removed static variable as requested by Stefano Stabellini
---
drivers/xen/time.c | 40 +++++++++++++++++++++++-----------------
1 file changed, 23 insertions(+), 17 deletions(-)
diff --git a/drivers/xen/time.c b/drivers/xen/time.c
index 2257b66..a7fe35b 100644
--- a/drivers/xen/time.c
+++ b/drivers/xen/time.c
@@ -47,27 +47,31 @@ static u64 get64(const u64 *p)
return ret;
}
-/*
- * Runstate accounting
- */
-void xen_get_runstate_snapshot(struct vcpu_runstate_info *res)
+static void xen_get_runstate_snapshot_cpu(struct vcpu_runstate_info *res,
+ unsigned int cpu)
{
u64 state_time;
struct vcpu_runstate_info *state;
BUG_ON(preemptible());
- state = this_cpu_ptr(&xen_runstate);
+ state = per_cpu_ptr(&xen_runstate, cpu);
- /*
- * The runstate info is always updated by the hypervisor on
- * the current CPU, so there's no need to use anything
- * stronger than a compiler barrier when fetching it.
- */
do {
state_time = get64(&state->state_entry_time);
+ rmb(); /* Hypervisor might update data. */
*res = READ_ONCE(*state);
- } while (get64(&state->state_entry_time) != state_time);
+ rmb(); /* Hypervisor might update data. */
+ } while (get64(&state->state_entry_time) != state_time ||
+ (state_time & XEN_RUNSTATE_UPDATE));
+}
+
+/*
+ * Runstate accounting
+ */
+void xen_get_runstate_snapshot(struct vcpu_runstate_info *res)
+{
+ xen_get_runstate_snapshot_cpu(res, smp_processor_id());
}
/* return true when a vcpu could run but has no real cpu to run on */
@@ -80,8 +84,7 @@ static u64 xen_steal_clock(int cpu)
{
struct vcpu_runstate_info state;
- BUG_ON(cpu != smp_processor_id());
- xen_get_runstate_snapshot(&state);
+ xen_get_runstate_snapshot_cpu(&state, cpu);
return state.time[RUNSTATE_runnable] + state.time[RUNSTATE_offline];
}
@@ -98,11 +101,14 @@ void xen_setup_runstate_info(int cpu)
void __init xen_time_setup_guest(void)
{
+ bool xen_runstate_remote;
+
+ xen_runstate_remote = !HYPERVISOR_vm_assist(VMASST_CMD_enable,
+ VMASST_TYPE_runstate_update_flag);
+
pv_time_ops.steal_clock = xen_steal_clock;
static_key_slow_inc(¶virt_steal_enabled);
- /*
- * We can't set paravirt_steal_rq_enabled as this would require the
- * capability to read another cpu's runstate info.
- */
+ if (xen_runstate_remote)
+ static_key_slow_inc(¶virt_steal_rq_enabled);
}
--
2.6.6
^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: [PATCH v2 3/3] xen: support runqueue steal time on xen
2016-07-06 5:00 ` [PATCH v2 3/3] xen: support runqueue steal time on xen Juergen Gross
@ 2016-07-06 10:03 ` Stefano Stabellini
0 siblings, 0 replies; 6+ messages in thread
From: Stefano Stabellini @ 2016-07-06 10:03 UTC (permalink / raw)
To: Juergen Gross
Cc: xen-devel, linux-kernel, sstabellini, boris.ostrovsky, david.vrabel
On Wed, 6 Jul 2016, Juergen Gross wrote:
> Up to now reading the stolen time of a remote cpu was not possible in a
> performant way under Xen. This made support of runqueue steal time via
> paravirt_steal_rq_enabled impossible.
>
> With the addition of an appropriate hypervisor interface this is now
> possible, so add the support.
>
> Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
> V2: removed static variable as requested by Stefano Stabellini
> ---
> drivers/xen/time.c | 40 +++++++++++++++++++++++-----------------
> 1 file changed, 23 insertions(+), 17 deletions(-)
>
> diff --git a/drivers/xen/time.c b/drivers/xen/time.c
> index 2257b66..a7fe35b 100644
> --- a/drivers/xen/time.c
> +++ b/drivers/xen/time.c
> @@ -47,27 +47,31 @@ static u64 get64(const u64 *p)
> return ret;
> }
>
> -/*
> - * Runstate accounting
> - */
> -void xen_get_runstate_snapshot(struct vcpu_runstate_info *res)
> +static void xen_get_runstate_snapshot_cpu(struct vcpu_runstate_info *res,
> + unsigned int cpu)
> {
> u64 state_time;
> struct vcpu_runstate_info *state;
>
> BUG_ON(preemptible());
>
> - state = this_cpu_ptr(&xen_runstate);
> + state = per_cpu_ptr(&xen_runstate, cpu);
>
> - /*
> - * The runstate info is always updated by the hypervisor on
> - * the current CPU, so there's no need to use anything
> - * stronger than a compiler barrier when fetching it.
> - */
> do {
> state_time = get64(&state->state_entry_time);
> + rmb(); /* Hypervisor might update data. */
> *res = READ_ONCE(*state);
> - } while (get64(&state->state_entry_time) != state_time);
> + rmb(); /* Hypervisor might update data. */
> + } while (get64(&state->state_entry_time) != state_time ||
> + (state_time & XEN_RUNSTATE_UPDATE));
> +}
> +
> +/*
> + * Runstate accounting
> + */
> +void xen_get_runstate_snapshot(struct vcpu_runstate_info *res)
> +{
> + xen_get_runstate_snapshot_cpu(res, smp_processor_id());
> }
>
> /* return true when a vcpu could run but has no real cpu to run on */
> @@ -80,8 +84,7 @@ static u64 xen_steal_clock(int cpu)
> {
> struct vcpu_runstate_info state;
>
> - BUG_ON(cpu != smp_processor_id());
> - xen_get_runstate_snapshot(&state);
> + xen_get_runstate_snapshot_cpu(&state, cpu);
> return state.time[RUNSTATE_runnable] + state.time[RUNSTATE_offline];
> }
>
> @@ -98,11 +101,14 @@ void xen_setup_runstate_info(int cpu)
>
> void __init xen_time_setup_guest(void)
> {
> + bool xen_runstate_remote;
> +
> + xen_runstate_remote = !HYPERVISOR_vm_assist(VMASST_CMD_enable,
> + VMASST_TYPE_runstate_update_flag);
> +
> pv_time_ops.steal_clock = xen_steal_clock;
>
> static_key_slow_inc(¶virt_steal_enabled);
> - /*
> - * We can't set paravirt_steal_rq_enabled as this would require the
> - * capability to read another cpu's runstate info.
> - */
> + if (xen_runstate_remote)
> + static_key_slow_inc(¶virt_steal_rq_enabled);
> }
> --
> 2.6.6
>
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [Xen-devel] [PATCH v2 0/3] xen: add full support for CONFIG_PARAVIRT_TIME_ACCOUNTING
2016-07-06 5:00 [PATCH v2 0/3] xen: add full support for CONFIG_PARAVIRT_TIME_ACCOUNTING Juergen Gross
` (2 preceding siblings ...)
2016-07-06 5:00 ` [PATCH v2 3/3] xen: support runqueue steal time on xen Juergen Gross
@ 2016-07-06 12:06 ` David Vrabel
3 siblings, 0 replies; 6+ messages in thread
From: David Vrabel @ 2016-07-06 12:06 UTC (permalink / raw)
To: Juergen Gross, xen-devel, linux-kernel
Cc: boris.ostrovsky, sstabellini, david.vrabel
On 06/07/16 06:00, Juergen Gross wrote:
> With most recent Xen hypervisor (4.8) it is now possible to add full
> support of CONFIG_PARAVIRT_TIME_ACCOUNTING.
>
> To be applied on top of commit ed2f61fdd2356c2a1d1239aa1507ce4e2e059306
> "xen: add steal_clock support on x86" of kernel/git/xen/tip.git
>
> Runtime tested on x86_64, compile tested on arm64.
Applied to for-linus-4.8, thanks.
David
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2016-07-06 12:06 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
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2016-07-06 5:00 [PATCH v2 0/3] xen: add full support for CONFIG_PARAVIRT_TIME_ACCOUNTING Juergen Gross
2016-07-06 5:00 ` [PATCH v2 1/3] xen: update xen headers Juergen Gross
2016-07-06 5:00 ` [PATCH v2 2/3] arm/xen: add support for vm_assist hypercall Juergen Gross
2016-07-06 5:00 ` [PATCH v2 3/3] xen: support runqueue steal time on xen Juergen Gross
2016-07-06 10:03 ` Stefano Stabellini
2016-07-06 12:06 ` [Xen-devel] [PATCH v2 0/3] xen: add full support for CONFIG_PARAVIRT_TIME_ACCOUNTING David Vrabel
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