On 06/04/16 16:17, Juergen Gross wrote:
Add generic virtualization support for pinning the current vcpu to a
specified physical cpu. As this operation isn't performance critical
(a very limited set of operations like BIOS calls and SMIs is expected
to need this) just add a hypervisor specific indirection.
Signed-off-by: Juergen Gross <jgross@xxxxxxxx>
Could please some maintainer comment on this patch?
Juergen
---
V4: move this patch some places up in the series
WARN_ONCE in case platform doesn't support pinning as requested by
Peter Zijlstra
V3: use getc_cpu()/put_cpu() as suggested by David Vrabel
V2: adapt to using workqueues
add include/linux/hypervisor.h to hide architecture specific stuff
from generic kernel code
In case paravirt maintainers don't want to be responsible for
include/linux/hypervisor.h I could take it.
---
MAINTAINERS | 1 +
arch/x86/include/asm/hypervisor.h | 4 ++++
arch/x86/kernel/cpu/hypervisor.c | 11 +++++++++++
include/linux/hypervisor.h | 17 +++++++++++++++++
kernel/smp.c | 1 +
kernel/up.c | 1 +
6 files changed, 35 insertions(+)
create mode 100644 include/linux/hypervisor.h
diff --git a/MAINTAINERS b/MAINTAINERS
index 40eb1db..d3bde4f 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -8330,6 +8330,7 @@ S: Supported
F: Documentation/virtual/paravirt_ops.txt
F: arch/*/kernel/paravirt*
F: arch/*/include/asm/paravirt.h
+F: include/linux/hypervisor.h
PARIDE DRIVERS FOR PARALLEL PORT IDE DEVICES
M: Tim Waugh <tim@xxxxxxxxxxxx>
diff --git a/arch/x86/include/asm/hypervisor.h b/arch/x86/include/asm/hypervisor.h
index 055ea99..67942b6 100644
--- a/arch/x86/include/asm/hypervisor.h
+++ b/arch/x86/include/asm/hypervisor.h
@@ -43,6 +43,9 @@ struct hypervisor_x86 {
/* X2APIC detection (run once per boot) */
bool (*x2apic_available)(void);
+
+ /* pin current vcpu to specified physical cpu (run rarely) */
+ void (*pin_vcpu)(int);
};
extern const struct hypervisor_x86 *x86_hyper;
@@ -56,6 +59,7 @@ extern const struct hypervisor_x86 x86_hyper_kvm;
extern void init_hypervisor(struct cpuinfo_x86 *c);
extern void init_hypervisor_platform(void);
extern bool hypervisor_x2apic_available(void);
+extern void hypervisor_pin_vcpu(int cpu);
#else
static inline void init_hypervisor(struct cpuinfo_x86 *c) { }
static inline void init_hypervisor_platform(void) { }
diff --git a/arch/x86/kernel/cpu/hypervisor.c b/arch/x86/kernel/cpu/hypervisor.c
index 73d391a..ff108f8 100644
--- a/arch/x86/kernel/cpu/hypervisor.c
+++ b/arch/x86/kernel/cpu/hypervisor.c
@@ -85,3 +85,14 @@ bool __init hypervisor_x2apic_available(void)
x86_hyper->x2apic_available &&
x86_hyper->x2apic_available();
}
+
+void hypervisor_pin_vcpu(int cpu)
+{
+ if (!x86_hyper)
+ return;
+
+ if (x86_hyper->pin_vcpu)
+ x86_hyper->pin_vcpu(cpu);
+ else
+ WARN_ONCE(1, "vcpu pinning requested but not supported!\n");
+}
diff --git a/include/linux/hypervisor.h b/include/linux/hypervisor.h
new file mode 100644
index 0000000..3fa5ef2
--- /dev/null
+++ b/include/linux/hypervisor.h
@@ -0,0 +1,17 @@
+#ifndef __LINUX_HYPEVISOR_H
+#define __LINUX_HYPEVISOR_H
+
+/*
+ * Generic Hypervisor support
+ * Juergen Gross <jgross@xxxxxxxx>
+ */
+
+#ifdef CONFIG_HYPERVISOR_GUEST
+#include <asm/hypervisor.h>
+#else
+static inline void hypervisor_pin_vcpu(int cpu)
+{
+}
+#endif
+
+#endif /* __LINUX_HYPEVISOR_H */
diff --git a/kernel/smp.c b/kernel/smp.c
index 7416544..9388064 100644
--- a/kernel/smp.c
+++ b/kernel/smp.c
@@ -14,6 +14,7 @@
#include <linux/smp.h>
#include <linux/cpu.h>
#include <linux/sched.h>
+#include <linux/hypervisor.h>
#include "smpboot.h"
diff --git a/kernel/up.c b/kernel/up.c
index 1760bf3..3ccee2b 100644
--- a/kernel/up.c
+++ b/kernel/up.c
@@ -6,6 +6,7 @@
#include <linux/kernel.h>
#include <linux/export.h>
#include <linux/smp.h>
+#include <linux/hypervisor.h>
int smp_call_function_single(int cpu, void (*func) (void *info), void *info,
int wait)
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