From 47ae4b05d0fa2f2a998ebaf34d2dcbffca56a9db Mon Sep 17 00:00:00 2001 From: Juergen Gross Date: Mon, 29 Aug 2016 08:48:43 +0200 Subject: virt, sched: Add generic vCPU pinning support 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 Signed-off-by: Peter Zijlstra (Intel) Cc: Douglas_Warzecha@dell.com Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: akataria@vmware.com Cc: boris.ostrovsky@oracle.com Cc: chrisw@sous-sol.org Cc: david.vrabel@citrix.com Cc: hpa@zytor.com Cc: jdelvare@suse.com Cc: jeremy@goop.org Cc: linux@roeck-us.net Cc: pali.rohar@gmail.com Cc: rusty@rustcorp.com.au Cc: virtualization@lists.linux-foundation.org Cc: xen-devel@lists.xenproject.org Link: http://lkml.kernel.org/r/1472453327-19050-3-git-send-email-jgross@suse.com Signed-off-by: Ingo Molnar --- arch/x86/include/asm/hypervisor.h | 4 ++++ arch/x86/kernel/cpu/hypervisor.c | 11 +++++++++++ 2 files changed, 15 insertions(+) (limited to 'arch') diff --git a/arch/x86/include/asm/hypervisor.h b/arch/x86/include/asm/hypervisor.h index 055ea9941dd5..67942b6ad4b7 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 27e46658ebe3..35691a6b0d32 100644 --- a/arch/x86/kernel/cpu/hypervisor.c +++ b/arch/x86/kernel/cpu/hypervisor.c @@ -86,3 +86,14 @@ 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"); +} -- cgit v1.2.3 From 99bc67536d04bcb9133546284acfb15d033b8bfe Mon Sep 17 00:00:00 2001 From: Juergen Gross Date: Mon, 29 Aug 2016 08:48:45 +0200 Subject: xen: Add xen_pin_vcpu() to support calling functions on a dedicated pCPU Some hardware models (e.g. Dell Studio 1555 laptops) require calls to the firmware to be issued on CPU 0 only. As Dom0 might have to use these calls, add xen_pin_vcpu() to achieve this functionality. In case either the domain doesn't have the privilege to make the related hypercall or the hypervisor isn't supporting it, issue a warning once and disable further pinning attempts. Signed-off-by: Juergen Gross Signed-off-by: Peter Zijlstra (Intel) Acked-by: David Vrabel Cc: Douglas_Warzecha@dell.com Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: akataria@vmware.com Cc: boris.ostrovsky@oracle.com Cc: chrisw@sous-sol.org Cc: hpa@zytor.com Cc: jdelvare@suse.com Cc: jeremy@goop.org Cc: linux@roeck-us.net Cc: pali.rohar@gmail.com Cc: rusty@rustcorp.com.au Cc: virtualization@lists.linux-foundation.org Cc: xen-devel@lists.xenproject.org Link: http://lkml.kernel.org/r/1472453327-19050-5-git-send-email-jgross@suse.com Signed-off-by: Ingo Molnar --- arch/x86/xen/enlighten.c | 40 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 40 insertions(+) (limited to 'arch') diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c index b86ebb1a9a7f..bc9aaba01a22 100644 --- a/arch/x86/xen/enlighten.c +++ b/arch/x86/xen/enlighten.c @@ -1925,6 +1925,45 @@ static void xen_set_cpu_features(struct cpuinfo_x86 *c) } } +static void xen_pin_vcpu(int cpu) +{ + static bool disable_pinning; + struct sched_pin_override pin_override; + int ret; + + if (disable_pinning) + return; + + pin_override.pcpu = cpu; + ret = HYPERVISOR_sched_op(SCHEDOP_pin_override, &pin_override); + + /* Ignore errors when removing override. */ + if (cpu < 0) + return; + + switch (ret) { + case -ENOSYS: + pr_warn("Unable to pin on physical cpu %d. In case of problems consider vcpu pinning.\n", + cpu); + disable_pinning = true; + break; + case -EPERM: + WARN(1, "Trying to pin vcpu without having privilege to do so\n"); + disable_pinning = true; + break; + case -EINVAL: + case -EBUSY: + pr_warn("Physical cpu %d not available for pinning. Check Xen cpu configuration.\n", + cpu); + break; + case 0: + break; + default: + WARN(1, "rc %d while trying to pin vcpu\n", ret); + disable_pinning = true; + } +} + const struct hypervisor_x86 x86_hyper_xen = { .name = "Xen", .detect = xen_platform, @@ -1933,6 +1972,7 @@ const struct hypervisor_x86 x86_hyper_xen = { #endif .x2apic_available = xen_x2apic_para_available, .set_cpu_features = xen_set_cpu_features, + .pin_vcpu = xen_pin_vcpu, }; EXPORT_SYMBOL(x86_hyper_xen); -- cgit v1.2.3