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xen: add steal_clock support on x86

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The pv_time_ops structure contains a function pointer for the
"steal_clock" functionality used only by KVM and Xen on ARM. Xen on x86
uses its own mechanism to account for the "stolen" time a thread wasn't
able to run due to hypervisor scheduling.

Add support in Xen arch independent time handling for this feature by
moving it out of the arm arch into drivers/xen and remove the x86 Xen
hack.

Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
This commit is contained in:
Juergen Gross
2016-05-20 09:26:48 +02:00
committed by David Vrabel
parent c7ebf9d9c6
commit ecb23dc6f2
6 changed files with 25 additions and 69 deletions
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20
drivers/xen/time.c
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@@ -6,6 +6,7 @@
#include <linux/math64.h>
#include <linux/gfp.h>
#include <asm/paravirt.h>
#include <asm/xen/hypervisor.h>
#include <asm/xen/hypercall.h>
@@ -75,6 +76,15 @@ bool xen_vcpu_stolen(int vcpu)
return per_cpu(xen_runstate, vcpu).state == RUNSTATE_runnable;
}
static u64 xen_steal_clock(int cpu)
{
struct vcpu_runstate_info state;
BUG_ON(cpu != smp_processor_id());
xen_get_runstate_snapshot(&state);
return state.time[RUNSTATE_runnable] + state.time[RUNSTATE_offline];
}
void xen_setup_runstate_info(int cpu)
{
struct vcpu_register_runstate_memory_area area;
@@ -86,3 +96,13 @@ void xen_setup_runstate_info(int cpu)
BUG();
}
void __init xen_time_setup_guest(void)
{
pv_time_ops.steal_clock = xen_steal_clock;
static_key_slow_inc(&paravirt_steal_enabled);
/*
* We can't set paravirt_steal_rq_enabled as this would require the
* capability to read another cpu's runstate info.
*/
}