* [PATCH v3 0/2] Enable PV qspinlock for Hyper-V @ 2018-09-27 6:01 Yi Sun 2018-09-27 6:01 ` [PATCH v3 1/2] X86/Hyper-V: Add Guest IDLE MSR support Yi Sun 2018-09-27 6:01 ` [PATCH v3 2/2] locking/pvqspinlock, hv: Enable PV qspinlock for Hyper-V Yi Sun 0 siblings, 2 replies; 10+ messages in thread From: Yi Sun @ 2018-09-27 6:01 UTC (permalink / raw) To: linux-kernel Cc: x86, tglx, chao.p.peng, chao.gao, isaku.yamahata, michael.h.kelley, tianyu.lan, Yi Sun, K. Y. Srinivasan, Haiyang Zhang, Stephen Hemminger, Jonathan Corbet, Michael Kelley (EOSG) v2->v3: - use "Hyper-V: " as the message prefix - remove unnecessary header files - remove unnecessary check in 'hv_qlock_wait' - fix compilation error on different platforms v1->v2: - compile hv_spinlock.c only when CONFIG_PARAVIRT_SPINLOCKS enabled - merge v1 patch 2/3 to single patch - remove part of the boilerplate in hv_spinlock.c - declare hv_pvspin as __initdata - remove spin_wait_info and hv_notify_long_spin_wait because SpinWaitInfo is a standalone feature. - add comments for reading HV_X64_MSR_GUEST_IDLE - replace pr_warn to pr_info - use pr_fmt instead of the 'hv:' prefix - register callback function for smp_ops.smp_prepare_boot_cpu to initialize hyper-v spinlock This patch adds the necessary Hyper-V specific code to allow PV qspinlock work on Hyper-V. In wait callback function, read HV_X64_MSR_GUEST_IDLE MSR to trigger the guest's transition to the idle power state which can be exited by an IPI even if IF flag is disabled. In kick callback function, just send platform IPI to make waiting vcpu exit idle state. In vcpu_is_preempted callback function, return false directly because Hyper-V does not provide such interface so far. Cc: "K. Y. Srinivasan" <kys@microsoft.com> Cc: Haiyang Zhang <haiyangz@microsoft.com> Cc: Stephen Hemminger <sthemmin@microsoft.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Michael Kelley (EOSG) <Michael.H.Kelley@microsoft.com> Yi Sun (2): X86/Hyper-V: Add Guest IDLE MSR support locking/pvqspinlock, hv: Enable PV qspinlock for Hyper-V Documentation/admin-guide/kernel-parameters.txt | 5 ++ arch/x86/hyperv/Makefile | 4 ++ arch/x86/hyperv/hv_spinlock.c | 76 +++++++++++++++++++++++++ arch/x86/include/asm/hyperv-tlfs.h | 5 ++ arch/x86/include/asm/mshyperv.h | 1 + arch/x86/kernel/cpu/mshyperv.c | 14 +++++ 6 files changed, 105 insertions(+) create mode 100644 arch/x86/hyperv/hv_spinlock.c -- 1.9.1 ^ permalink raw reply [flat|nested] 10+ messages in thread
* [PATCH v3 1/2] X86/Hyper-V: Add Guest IDLE MSR support 2018-09-27 6:01 [PATCH v3 0/2] Enable PV qspinlock for Hyper-V Yi Sun @ 2018-09-27 6:01 ` Yi Sun 2018-10-02 11:27 ` [tip:x86/hyperv] x86/hyperv: Add GUEST_IDLE_MSR support tip-bot for Yi Sun 2018-10-09 12:27 ` [tip:x86/paravirt] " tip-bot for Yi Sun 2018-09-27 6:01 ` [PATCH v3 2/2] locking/pvqspinlock, hv: Enable PV qspinlock for Hyper-V Yi Sun 1 sibling, 2 replies; 10+ messages in thread From: Yi Sun @ 2018-09-27 6:01 UTC (permalink / raw) To: linux-kernel Cc: x86, tglx, chao.p.peng, chao.gao, isaku.yamahata, michael.h.kelley, tianyu.lan, Yi Sun, K. Y. Srinivasan, Haiyang Zhang, Stephen Hemminger Hyper-V may expose a HV_X64_MSR_GUEST_IDLE MSR. We can read HYPERV_CPUID_FEATURES eax to check it. Read this MSR can trigger the guest's transition to the idle power state which can be exited by an IPI even if IF flag is disabled. Cc: "K. Y. Srinivasan" <kys@microsoft.com> Cc: Haiyang Zhang <haiyangz@microsoft.com> Cc: Stephen Hemminger <sthemmin@microsoft.com> Reviewed-by: Michael Kelley <mikelley@microsoft.com> Signed-off-by: Yi Sun <yi.y.sun@linux.intel.com> --- arch/x86/include/asm/hyperv-tlfs.h | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/arch/x86/include/asm/hyperv-tlfs.h b/arch/x86/include/asm/hyperv-tlfs.h index 00e01d2..4139f76 100644 --- a/arch/x86/include/asm/hyperv-tlfs.h +++ b/arch/x86/include/asm/hyperv-tlfs.h @@ -38,6 +38,8 @@ #define HV_MSR_TIME_REF_COUNT_AVAILABLE (1 << 1) /* Partition reference TSC MSR is available */ #define HV_MSR_REFERENCE_TSC_AVAILABLE (1 << 9) +/* Partition Guest IDLE MSR is available */ +#define HV_X64_MSR_GUEST_IDLE_AVAILABLE (1 << 10) /* A partition's reference time stamp counter (TSC) page */ #define HV_X64_MSR_REFERENCE_TSC 0x40000021 @@ -246,6 +248,9 @@ #define HV_X64_MSR_STIMER3_CONFIG 0x400000B6 #define HV_X64_MSR_STIMER3_COUNT 0x400000B7 +/* Hyper-V guest idle MSR */ +#define HV_X64_MSR_GUEST_IDLE 0x400000F0 + /* Hyper-V guest crash notification MSR's */ #define HV_X64_MSR_CRASH_P0 0x40000100 #define HV_X64_MSR_CRASH_P1 0x40000101 -- 1.9.1 ^ permalink raw reply related [flat|nested] 10+ messages in thread
* [tip:x86/hyperv] x86/hyperv: Add GUEST_IDLE_MSR support 2018-09-27 6:01 ` [PATCH v3 1/2] X86/Hyper-V: Add Guest IDLE MSR support Yi Sun @ 2018-10-02 11:27 ` tip-bot for Yi Sun 2018-10-09 12:27 ` [tip:x86/paravirt] " tip-bot for Yi Sun 1 sibling, 0 replies; 10+ messages in thread From: tip-bot for Yi Sun @ 2018-10-02 11:27 UTC (permalink / raw) To: linux-tip-commits Cc: hpa, linux-kernel, mingo, sthemmin, haiyangz, mikelley, yi.y.sun, kys, tglx Commit-ID: 10d02e13385ce1e90abb49ef1e9a366a5d968157 Gitweb: https://git.kernel.org/tip/10d02e13385ce1e90abb49ef1e9a366a5d968157 Author: Yi Sun <yi.y.sun@linux.intel.com> AuthorDate: Thu, 27 Sep 2018 14:01:43 +0800 Committer: Thomas Gleixner <tglx@linutronix.de> CommitDate: Tue, 2 Oct 2018 13:21:52 +0200 x86/hyperv: Add GUEST_IDLE_MSR support Hyper-V may expose a HV_X64_MSR_GUEST_IDLE MSR via HYPERV_CPUID_FEATURES. Reading this MSR triggers the host to transition the guest vCPU into an idle state. This state can be exited via an IPI even if the read in the guest happened from an interrupt disabled section. Signed-off-by: Yi Sun <yi.y.sun@linux.intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Michael Kelley <mikelley@microsoft.com> Cc: chao.p.peng@intel.com Cc: chao.gao@intel.com Cc: isaku.yamahata@intel.com Cc: tianyu.lan@microsoft.com Cc: "K. Y. Srinivasan" <kys@microsoft.com> Cc: Haiyang Zhang <haiyangz@microsoft.com> Cc: Stephen Hemminger <sthemmin@microsoft.com> Link: https://lkml.kernel.org/r/1538028104-114050-2-git-send-email-yi.y.sun@linux.intel.com --- arch/x86/include/asm/hyperv-tlfs.h | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/arch/x86/include/asm/hyperv-tlfs.h b/arch/x86/include/asm/hyperv-tlfs.h index 00e01d215f74..4139f7650fe5 100644 --- a/arch/x86/include/asm/hyperv-tlfs.h +++ b/arch/x86/include/asm/hyperv-tlfs.h @@ -38,6 +38,8 @@ #define HV_MSR_TIME_REF_COUNT_AVAILABLE (1 << 1) /* Partition reference TSC MSR is available */ #define HV_MSR_REFERENCE_TSC_AVAILABLE (1 << 9) +/* Partition Guest IDLE MSR is available */ +#define HV_X64_MSR_GUEST_IDLE_AVAILABLE (1 << 10) /* A partition's reference time stamp counter (TSC) page */ #define HV_X64_MSR_REFERENCE_TSC 0x40000021 @@ -246,6 +248,9 @@ #define HV_X64_MSR_STIMER3_CONFIG 0x400000B6 #define HV_X64_MSR_STIMER3_COUNT 0x400000B7 +/* Hyper-V guest idle MSR */ +#define HV_X64_MSR_GUEST_IDLE 0x400000F0 + /* Hyper-V guest crash notification MSR's */ #define HV_X64_MSR_CRASH_P0 0x40000100 #define HV_X64_MSR_CRASH_P1 0x40000101 ^ permalink raw reply related [flat|nested] 10+ messages in thread
* [tip:x86/paravirt] x86/hyperv: Add GUEST_IDLE_MSR support 2018-09-27 6:01 ` [PATCH v3 1/2] X86/Hyper-V: Add Guest IDLE MSR support Yi Sun 2018-10-02 11:27 ` [tip:x86/hyperv] x86/hyperv: Add GUEST_IDLE_MSR support tip-bot for Yi Sun @ 2018-10-09 12:27 ` tip-bot for Yi Sun 1 sibling, 0 replies; 10+ messages in thread From: tip-bot for Yi Sun @ 2018-10-09 12:27 UTC (permalink / raw) To: linux-tip-commits Cc: kys, tglx, linux-kernel, yi.y.sun, haiyangz, mingo, mikelley, sthemmin, hpa Commit-ID: f726c4620df39055f060537a8ed183c18a2c504b Gitweb: https://git.kernel.org/tip/f726c4620df39055f060537a8ed183c18a2c504b Author: Yi Sun <yi.y.sun@linux.intel.com> AuthorDate: Thu, 27 Sep 2018 14:01:43 +0800 Committer: Thomas Gleixner <tglx@linutronix.de> CommitDate: Tue, 9 Oct 2018 14:14:49 +0200 x86/hyperv: Add GUEST_IDLE_MSR support Hyper-V may expose a HV_X64_MSR_GUEST_IDLE MSR via HYPERV_CPUID_FEATURES. Reading this MSR triggers the host to transition the guest vCPU into an idle state. This state can be exited via an IPI even if the read in the guest happened from an interrupt disabled section. Signed-off-by: Yi Sun <yi.y.sun@linux.intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Michael Kelley <mikelley@microsoft.com> Cc: chao.p.peng@intel.com Cc: chao.gao@intel.com Cc: isaku.yamahata@intel.com Cc: tianyu.lan@microsoft.com Cc: "K. Y. Srinivasan" <kys@microsoft.com> Cc: Haiyang Zhang <haiyangz@microsoft.com> Cc: Stephen Hemminger <sthemmin@microsoft.com> Link: https://lkml.kernel.org/r/1538028104-114050-2-git-send-email-yi.y.sun@linux.intel.com --- arch/x86/include/asm/hyperv-tlfs.h | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/arch/x86/include/asm/hyperv-tlfs.h b/arch/x86/include/asm/hyperv-tlfs.h index e977b6b3a538..2a2fa170caf1 100644 --- a/arch/x86/include/asm/hyperv-tlfs.h +++ b/arch/x86/include/asm/hyperv-tlfs.h @@ -38,6 +38,8 @@ #define HV_MSR_TIME_REF_COUNT_AVAILABLE (1 << 1) /* Partition reference TSC MSR is available */ #define HV_MSR_REFERENCE_TSC_AVAILABLE (1 << 9) +/* Partition Guest IDLE MSR is available */ +#define HV_X64_MSR_GUEST_IDLE_AVAILABLE (1 << 10) /* A partition's reference time stamp counter (TSC) page */ #define HV_X64_MSR_REFERENCE_TSC 0x40000021 @@ -246,6 +248,9 @@ #define HV_X64_MSR_STIMER3_CONFIG 0x400000B6 #define HV_X64_MSR_STIMER3_COUNT 0x400000B7 +/* Hyper-V guest idle MSR */ +#define HV_X64_MSR_GUEST_IDLE 0x400000F0 + /* Hyper-V guest crash notification MSR's */ #define HV_X64_MSR_CRASH_P0 0x40000100 #define HV_X64_MSR_CRASH_P1 0x40000101 ^ permalink raw reply related [flat|nested] 10+ messages in thread
* [PATCH v3 2/2] locking/pvqspinlock, hv: Enable PV qspinlock for Hyper-V 2018-09-27 6:01 [PATCH v3 0/2] Enable PV qspinlock for Hyper-V Yi Sun 2018-09-27 6:01 ` [PATCH v3 1/2] X86/Hyper-V: Add Guest IDLE MSR support Yi Sun @ 2018-09-27 6:01 ` Yi Sun 2018-09-28 22:09 ` Michael Kelley (EOSG) 2018-10-02 11:28 ` [tip:x86/hyperv] x86/hyperv: " tip-bot for Yi Sun 1 sibling, 2 replies; 10+ messages in thread From: Yi Sun @ 2018-09-27 6:01 UTC (permalink / raw) To: linux-kernel Cc: x86, tglx, chao.p.peng, chao.gao, isaku.yamahata, michael.h.kelley, tianyu.lan, Yi Sun, K. Y. Srinivasan, Haiyang Zhang, Stephen Hemminger, Michael Kelley (EOSG) Follow PV spinlock mechanism to implement the callback functions to allow the CPU idling and kicking operations on Hyper-V. Cc: "K. Y. Srinivasan" <kys@microsoft.com> Cc: Haiyang Zhang <haiyangz@microsoft.com> Cc: Stephen Hemminger <sthemmin@microsoft.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Michael Kelley (EOSG) <Michael.H.Kelley@microsoft.com> Signed-off-by: Yi Sun <yi.y.sun@linux.intel.com> --- v2->v3: - use "Hyper-V: " as the message prefix (suggested by Michael Kelley) - remove unnecessary header files (suggested by Michael Kelley) - remove unnecessary check in 'hv_qlock_wait' (suggested by Michael Kelley) - fix compilation error on different platforms (suggested by Thomas Gleixner) --- Documentation/admin-guide/kernel-parameters.txt | 5 ++ arch/x86/hyperv/Makefile | 4 ++ arch/x86/hyperv/hv_spinlock.c | 76 +++++++++++++++++++++++++ arch/x86/include/asm/mshyperv.h | 1 + arch/x86/kernel/cpu/mshyperv.c | 14 +++++ 5 files changed, 100 insertions(+) create mode 100644 arch/x86/hyperv/hv_spinlock.c diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 92eb1f4..0fc8448 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -1385,6 +1385,11 @@ hvc_iucv_allow= [S390] Comma-separated list of z/VM user IDs. If specified, z/VM IUCV HVC accepts connections from listed z/VM user IDs only. + + hv_nopvspin [X86,HYPER_V] + Disables the ticketlock slowpath using HYPER-V PV + optimizations. + keep_bootcon [KNL] Do not unregister boot console at start. This is only useful for debugging when something happens in the window diff --git a/arch/x86/hyperv/Makefile b/arch/x86/hyperv/Makefile index b21ee65..1c11f94 100644 --- a/arch/x86/hyperv/Makefile +++ b/arch/x86/hyperv/Makefile @@ -1,2 +1,6 @@ obj-y := hv_init.o mmu.o nested.o obj-$(CONFIG_X86_64) += hv_apic.o + +ifdef CONFIG_X86_64 +obj-$(CONFIG_PARAVIRT_SPINLOCKS) += hv_spinlock.o +endif diff --git a/arch/x86/hyperv/hv_spinlock.c b/arch/x86/hyperv/hv_spinlock.c new file mode 100644 index 0000000..e8fe997 --- /dev/null +++ b/arch/x86/hyperv/hv_spinlock.c @@ -0,0 +1,76 @@ +// SPDX-License-Identifier: GPL-2.0 + +/* + * Hyper-V specific spinlock code. + * + * Copyright (C) 2018, Intel, Inc. + * + * Author : Yi Sun <yi.y.sun@intel.com> + */ + +#define pr_fmt(fmt) "Hyper-V: " fmt + +#include <linux/spinlock.h> + +#include <asm/mshyperv.h> +#include <asm/hyperv-tlfs.h> +#include <asm/paravirt.h> +#include <asm/qspinlock.h> +#include <asm/apic.h> + +static bool __initdata hv_pvspin = true; + +static void hv_qlock_kick(int cpu) +{ + apic->send_IPI(cpu, X86_PLATFORM_IPI_VECTOR); +} + +static void hv_qlock_wait(u8 *byte, u8 val) +{ + unsigned long msr_val; + + if (READ_ONCE(*byte) != val) + return; + + /* + * Read HV_X64_MSR_GUEST_IDLE MSR can trigger the guest's + * transition to the idle power state which can be exited + * by an IPI even if IF flag is disabled. + */ + rdmsrl(HV_X64_MSR_GUEST_IDLE, msr_val); +} + +/* + * Hyper-V does not support this so far. + */ +bool hv_vcpu_is_preempted(int vcpu) +{ + return false; +} +PV_CALLEE_SAVE_REGS_THUNK(hv_vcpu_is_preempted); + +void __init hv_init_spinlocks(void) +{ + if (!hv_pvspin || + !apic || + !(ms_hyperv.hints & HV_X64_CLUSTER_IPI_RECOMMENDED) || + !(ms_hyperv.features & HV_X64_MSR_GUEST_IDLE_AVAILABLE)) { + pr_info("PV spinlocks disabled\n"); + return; + } + pr_info("PV spinlocks enabled\n"); + + __pv_init_lock_hash(); + pv_lock_ops.queued_spin_lock_slowpath = __pv_queued_spin_lock_slowpath; + pv_lock_ops.queued_spin_unlock = PV_CALLEE_SAVE(__pv_queued_spin_unlock); + pv_lock_ops.wait = hv_qlock_wait; + pv_lock_ops.kick = hv_qlock_kick; + pv_lock_ops.vcpu_is_preempted = PV_CALLEE_SAVE(hv_vcpu_is_preempted); +} + +static __init int hv_parse_nopvspin(char *arg) +{ + hv_pvspin = false; + return 0; +} +early_param("hv_nopvspin", hv_parse_nopvspin); diff --git a/arch/x86/include/asm/mshyperv.h b/arch/x86/include/asm/mshyperv.h index f377044..759cfd2 100644 --- a/arch/x86/include/asm/mshyperv.h +++ b/arch/x86/include/asm/mshyperv.h @@ -351,6 +351,7 @@ static inline int cpumask_to_vpset(struct hv_vpset *vpset, #ifdef CONFIG_X86_64 void hv_apic_init(void); +void __init hv_init_spinlocks(void); #else static inline void hv_apic_init(void) {} #endif diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c index ad12733..a5cc219 100644 --- a/arch/x86/kernel/cpu/mshyperv.c +++ b/arch/x86/kernel/cpu/mshyperv.c @@ -199,6 +199,16 @@ static unsigned long hv_get_tsc_khz(void) return freq / 1000; } +#if defined(CONFIG_SMP) && IS_ENABLED(CONFIG_HYPERV) +static void __init hv_smp_prepare_boot_cpu(void) +{ + native_smp_prepare_boot_cpu(); +#if defined(CONFIG_X86_64) && defined(CONFIG_PARAVIRT_SPINLOCKS) + hv_init_spinlocks(); +#endif +} +#endif + static void __init ms_hyperv_init_platform(void) { int hv_host_info_eax; @@ -303,6 +313,10 @@ static void __init ms_hyperv_init_platform(void) if (ms_hyperv.misc_features & HV_STIMER_DIRECT_MODE_AVAILABLE) alloc_intr_gate(HYPERV_STIMER0_VECTOR, hv_stimer0_callback_vector); + +#if defined(CONFIG_SMP) + smp_ops.smp_prepare_boot_cpu = hv_smp_prepare_boot_cpu; +#endif #endif } -- 1.9.1 ^ permalink raw reply related [flat|nested] 10+ messages in thread
* RE: [PATCH v3 2/2] locking/pvqspinlock, hv: Enable PV qspinlock for Hyper-V 2018-09-27 6:01 ` [PATCH v3 2/2] locking/pvqspinlock, hv: Enable PV qspinlock for Hyper-V Yi Sun @ 2018-09-28 22:09 ` Michael Kelley (EOSG) 2018-10-02 11:28 ` [tip:x86/hyperv] x86/hyperv: " tip-bot for Yi Sun 1 sibling, 0 replies; 10+ messages in thread From: Michael Kelley (EOSG) @ 2018-09-28 22:09 UTC (permalink / raw) To: Yi Sun, linux-kernel Cc: x86, tglx, chao.p.peng, chao.gao, isaku.yamahata, Tianyu Lan, KY Srinivasan, Haiyang Zhang, Stephen Hemminger From: Yi Sun <yi.y.sun@linux.intel.com> Sent: Wednesday, September 26, 2018 11:02 PM > Follow PV spinlock mechanism to implement the callback functions > to allow the CPU idling and kicking operations on Hyper-V. > > Cc: "K. Y. Srinivasan" <kys@microsoft.com> > Cc: Haiyang Zhang <haiyangz@microsoft.com> > Cc: Stephen Hemminger <sthemmin@microsoft.com> > Cc: Thomas Gleixner <tglx@linutronix.de> > Cc: Michael Kelley (EOSG) <Michael.H.Kelley@microsoft.com> > Signed-off-by: Yi Sun <yi.y.sun@linux.intel.com> > --- Reviewed-by: Michael Kelley <mikelley@microsoft.com> ^ permalink raw reply [flat|nested] 10+ messages in thread
* [tip:x86/hyperv] x86/hyperv: Enable PV qspinlock for Hyper-V 2018-09-27 6:01 ` [PATCH v3 2/2] locking/pvqspinlock, hv: Enable PV qspinlock for Hyper-V Yi Sun 2018-09-28 22:09 ` Michael Kelley (EOSG) @ 2018-10-02 11:28 ` tip-bot for Yi Sun 2018-10-02 11:38 ` Juergen Gross 1 sibling, 1 reply; 10+ messages in thread From: tip-bot for Yi Sun @ 2018-10-02 11:28 UTC (permalink / raw) To: linux-tip-commits Cc: mingo, tglx, linux-kernel, sthemmin, mikelley, haiyangz, kys, hpa, yi.y.sun Commit-ID: aaa7fc34c003bd8133a49f7634480cef6288ad55 Gitweb: https://git.kernel.org/tip/aaa7fc34c003bd8133a49f7634480cef6288ad55 Author: Yi Sun <yi.y.sun@linux.intel.com> AuthorDate: Thu, 27 Sep 2018 14:01:44 +0800 Committer: Thomas Gleixner <tglx@linutronix.de> CommitDate: Tue, 2 Oct 2018 13:22:06 +0200 x86/hyperv: Enable PV qspinlock for Hyper-V Implement the necessary callbacks for PV spinlocks which allow vCPU idling and kicking operations when running as a guest on Hyper-V Signed-off-by: Yi Sun <yi.y.sun@linux.intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Michael Kelley <mikelley@microsoft.com> Cc: chao.p.peng@intel.com Cc: chao.gao@intel.com Cc: isaku.yamahata@intel.com Cc: tianyu.lan@microsoft.com Cc: "K. Y. Srinivasan" <kys@microsoft.com> Cc: Haiyang Zhang <haiyangz@microsoft.com> Cc: Stephen Hemminger <sthemmin@microsoft.com> Link: https://lkml.kernel.org/r/1538028104-114050-3-git-send-email-yi.y.sun@linux.intel.com --- Documentation/admin-guide/kernel-parameters.txt | 5 ++ arch/x86/hyperv/Makefile | 4 ++ arch/x86/hyperv/hv_spinlock.c | 75 +++++++++++++++++++++++++ arch/x86/include/asm/mshyperv.h | 1 + arch/x86/kernel/cpu/mshyperv.c | 14 +++++ 5 files changed, 99 insertions(+) diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 92eb1f42240d..0fc8448a85ea 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -1385,6 +1385,11 @@ hvc_iucv_allow= [S390] Comma-separated list of z/VM user IDs. If specified, z/VM IUCV HVC accepts connections from listed z/VM user IDs only. + + hv_nopvspin [X86,HYPER_V] + Disables the ticketlock slowpath using HYPER-V PV + optimizations. + keep_bootcon [KNL] Do not unregister boot console at start. This is only useful for debugging when something happens in the window diff --git a/arch/x86/hyperv/Makefile b/arch/x86/hyperv/Makefile index b21ee65c4101..1c11f9420a82 100644 --- a/arch/x86/hyperv/Makefile +++ b/arch/x86/hyperv/Makefile @@ -1,2 +1,6 @@ obj-y := hv_init.o mmu.o nested.o obj-$(CONFIG_X86_64) += hv_apic.o + +ifdef CONFIG_X86_64 +obj-$(CONFIG_PARAVIRT_SPINLOCKS) += hv_spinlock.o +endif diff --git a/arch/x86/hyperv/hv_spinlock.c b/arch/x86/hyperv/hv_spinlock.c new file mode 100644 index 000000000000..6d3221322d0d --- /dev/null +++ b/arch/x86/hyperv/hv_spinlock.c @@ -0,0 +1,75 @@ +// SPDX-License-Identifier: GPL-2.0 + +/* + * Hyper-V specific spinlock code. + * + * Copyright (C) 2018, Intel, Inc. + * + * Author : Yi Sun <yi.y.sun@intel.com> + */ + +#define pr_fmt(fmt) "Hyper-V: " fmt + +#include <linux/spinlock.h> + +#include <asm/mshyperv.h> +#include <asm/hyperv-tlfs.h> +#include <asm/paravirt.h> +#include <asm/qspinlock.h> +#include <asm/apic.h> + +static bool __initdata hv_pvspin = true; + +static void hv_qlock_kick(int cpu) +{ + apic->send_IPI(cpu, X86_PLATFORM_IPI_VECTOR); +} + +static void hv_qlock_wait(u8 *byte, u8 val) +{ + unsigned long msr_val; + + if (READ_ONCE(*byte) != val) + return; + + /* + * Read HV_X64_MSR_GUEST_IDLE MSR can trigger the guest's + * transition to the idle power state which can be exited + * by an IPI even if IF flag is disabled. + */ + rdmsrl(HV_X64_MSR_GUEST_IDLE, msr_val); +} + +/* + * Hyper-V does not support this so far. + */ +static bool hv_vcpu_is_preempted(int vcpu) +{ + return false; +} +PV_CALLEE_SAVE_REGS_THUNK(hv_vcpu_is_preempted); + +void __init hv_init_spinlocks(void) +{ + if (!hv_pvspin || !apic || + !(ms_hyperv.hints & HV_X64_CLUSTER_IPI_RECOMMENDED) || + !(ms_hyperv.features & HV_X64_MSR_GUEST_IDLE_AVAILABLE)) { + pr_info("PV spinlocks disabled\n"); + return; + } + pr_info("PV spinlocks enabled\n"); + + __pv_init_lock_hash(); + pv_lock_ops.queued_spin_lock_slowpath = __pv_queued_spin_lock_slowpath; + pv_lock_ops.queued_spin_unlock = PV_CALLEE_SAVE(__pv_queued_spin_unlock); + pv_lock_ops.wait = hv_qlock_wait; + pv_lock_ops.kick = hv_qlock_kick; + pv_lock_ops.vcpu_is_preempted = PV_CALLEE_SAVE(hv_vcpu_is_preempted); +} + +static __init int hv_parse_nopvspin(char *arg) +{ + hv_pvspin = false; + return 0; +} +early_param("hv_nopvspin", hv_parse_nopvspin); diff --git a/arch/x86/include/asm/mshyperv.h b/arch/x86/include/asm/mshyperv.h index f37704497d8f..759cfd214eb9 100644 --- a/arch/x86/include/asm/mshyperv.h +++ b/arch/x86/include/asm/mshyperv.h @@ -351,6 +351,7 @@ int hyperv_flush_guest_mapping(u64 as); #ifdef CONFIG_X86_64 void hv_apic_init(void); +void __init hv_init_spinlocks(void); #else static inline void hv_apic_init(void) {} #endif diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c index ad12733f6058..1c72f3819eb1 100644 --- a/arch/x86/kernel/cpu/mshyperv.c +++ b/arch/x86/kernel/cpu/mshyperv.c @@ -199,6 +199,16 @@ static unsigned long hv_get_tsc_khz(void) return freq / 1000; } +#if defined(CONFIG_SMP) && IS_ENABLED(CONFIG_HYPERV) +static void __init hv_smp_prepare_boot_cpu(void) +{ + native_smp_prepare_boot_cpu(); +#if defined(CONFIG_X86_64) && defined(CONFIG_PARAVIRT_SPINLOCKS) + hv_init_spinlocks(); +#endif +} +#endif + static void __init ms_hyperv_init_platform(void) { int hv_host_info_eax; @@ -303,6 +313,10 @@ static void __init ms_hyperv_init_platform(void) if (ms_hyperv.misc_features & HV_STIMER_DIRECT_MODE_AVAILABLE) alloc_intr_gate(HYPERV_STIMER0_VECTOR, hv_stimer0_callback_vector); + +# ifdef CONFIG_SMP + smp_ops.smp_prepare_boot_cpu = hv_smp_prepare_boot_cpu; +# endif #endif } ^ permalink raw reply related [flat|nested] 10+ messages in thread
* Re: [tip:x86/hyperv] x86/hyperv: Enable PV qspinlock for Hyper-V 2018-10-02 11:28 ` [tip:x86/hyperv] x86/hyperv: " tip-bot for Yi Sun @ 2018-10-02 11:38 ` Juergen Gross 2018-10-02 12:13 ` Thomas Gleixner 2018-10-08 8:12 ` Yi Sun 0 siblings, 2 replies; 10+ messages in thread From: Juergen Gross @ 2018-10-02 11:38 UTC (permalink / raw) To: linux-kernel, tglx, mingo, sthemmin, mikelley, kys, haiyangz, yi.y.sun, hpa Sorry for noticing this only now, but I have been fighting with Xen PV qspinlocks last weekend: On 02/10/2018 13:28, tip-bot for Yi Sun wrote: > Commit-ID: aaa7fc34c003bd8133a49f7634480cef6288ad55 > Gitweb: https://git.kernel.org/tip/aaa7fc34c003bd8133a49f7634480cef6288ad55 > Author: Yi Sun <yi.y.sun@linux.intel.com> > AuthorDate: Thu, 27 Sep 2018 14:01:44 +0800 > Committer: Thomas Gleixner <tglx@linutronix.de> > CommitDate: Tue, 2 Oct 2018 13:22:06 +0200 > > x86/hyperv: Enable PV qspinlock for Hyper-V > > Implement the necessary callbacks for PV spinlocks which allow vCPU idling > and kicking operations when running as a guest on Hyper-V > > Signed-off-by: Yi Sun <yi.y.sun@linux.intel.com> > Signed-off-by: Thomas Gleixner <tglx@linutronix.de> > Reviewed-by: Michael Kelley <mikelley@microsoft.com> > Cc: chao.p.peng@intel.com > Cc: chao.gao@intel.com > Cc: isaku.yamahata@intel.com > Cc: tianyu.lan@microsoft.com > Cc: "K. Y. Srinivasan" <kys@microsoft.com> > Cc: Haiyang Zhang <haiyangz@microsoft.com> > Cc: Stephen Hemminger <sthemmin@microsoft.com> > Link: https://lkml.kernel.org/r/1538028104-114050-3-git-send-email-yi.y.sun@linux.intel.com > --- > Documentation/admin-guide/kernel-parameters.txt | 5 ++ > arch/x86/hyperv/Makefile | 4 ++ > arch/x86/hyperv/hv_spinlock.c | 75 +++++++++++++++++++++++++ > arch/x86/include/asm/mshyperv.h | 1 + > arch/x86/kernel/cpu/mshyperv.c | 14 +++++ > 5 files changed, 99 insertions(+) > ... > diff --git a/arch/x86/hyperv/hv_spinlock.c b/arch/x86/hyperv/hv_spinlock.c > new file mode 100644 > index 000000000000..6d3221322d0d > --- /dev/null > +++ b/arch/x86/hyperv/hv_spinlock.c > @@ -0,0 +1,75 @@ > +// SPDX-License-Identifier: GPL-2.0 > + > +/* > + * Hyper-V specific spinlock code. > + * > + * Copyright (C) 2018, Intel, Inc. > + * > + * Author : Yi Sun <yi.y.sun@intel.com> > + */ > + > +#define pr_fmt(fmt) "Hyper-V: " fmt > + > +#include <linux/spinlock.h> > + > +#include <asm/mshyperv.h> > +#include <asm/hyperv-tlfs.h> > +#include <asm/paravirt.h> > +#include <asm/qspinlock.h> > +#include <asm/apic.h> > + > +static bool __initdata hv_pvspin = true; > + > +static void hv_qlock_kick(int cpu) > +{ > + apic->send_IPI(cpu, X86_PLATFORM_IPI_VECTOR); > +} > + > +static void hv_qlock_wait(u8 *byte, u8 val) > +{ > + unsigned long msr_val; > + > + if (READ_ONCE(*byte) != val) > + return; > + > + /* > + * Read HV_X64_MSR_GUEST_IDLE MSR can trigger the guest's > + * transition to the idle power state which can be exited > + * by an IPI even if IF flag is disabled. > + */ What if interrupts are enabled? Won't a kick happening here just interrupt and then the following rdmsr result in a hang? I believe the correct way would be to: - disable interrupts before above READ_ONCE() and restore them after the rdmsrl() - return early if in_nmi() similar as the kvm specific variant is doing it. Juergen ^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [tip:x86/hyperv] x86/hyperv: Enable PV qspinlock for Hyper-V 2018-10-02 11:38 ` Juergen Gross @ 2018-10-02 12:13 ` Thomas Gleixner 2018-10-08 8:12 ` Yi Sun 1 sibling, 0 replies; 10+ messages in thread From: Thomas Gleixner @ 2018-10-02 12:13 UTC (permalink / raw) To: Juergen Gross Cc: linux-kernel, mingo, sthemmin, mikelley, kys, haiyangz, yi.y.sun, hpa On Tue, 2 Oct 2018, Juergen Gross wrote: > Sorry for noticing this only now, but I have been fighting with > Xen PV qspinlocks last weekend: > > > + /* > > + * Read HV_X64_MSR_GUEST_IDLE MSR can trigger the guest's > > + * transition to the idle power state which can be exited > > + * by an IPI even if IF flag is disabled. > > + */ > > What if interrupts are enabled? Won't a kick happening here just > interrupt and then the following rdmsr result in a hang? > > I believe the correct way would be to: > > - disable interrupts before above READ_ONCE() and restore them > after the rdmsrl() > > - return early if in_nmi() > > similar as the kvm specific variant is doing it. Interesting question. I zapped the last commit for now until this is clarified. Thanks, tglx ^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [tip:x86/hyperv] x86/hyperv: Enable PV qspinlock for Hyper-V 2018-10-02 11:38 ` Juergen Gross 2018-10-02 12:13 ` Thomas Gleixner @ 2018-10-08 8:12 ` Yi Sun 1 sibling, 0 replies; 10+ messages in thread From: Yi Sun @ 2018-10-08 8:12 UTC (permalink / raw) To: Juergen Gross Cc: linux-kernel, tglx, mingo, sthemmin, mikelley, kys, haiyangz, hpa On 18-10-02 13:38:55, Juergen Gross wrote: > > +static void hv_qlock_wait(u8 *byte, u8 val) > > +{ > > + unsigned long msr_val; > > + > > + if (READ_ONCE(*byte) != val) > > + return; > > + > > + /* > > + * Read HV_X64_MSR_GUEST_IDLE MSR can trigger the guest's > > + * transition to the idle power state which can be exited > > + * by an IPI even if IF flag is disabled. > > + */ > > What if interrupts are enabled? Won't a kick happening here just > interrupt and then the following rdmsr result in a hang? > > I believe the correct way would be to: > > - disable interrupts before above READ_ONCE() and restore them > after the rdmsrl() > > - return early if in_nmi() > > similar as the kvm specific variant is doing it. > > > Juergen Thank you for the suggestion! That is a possible case. I will submit a new version in soon. BRs, Yi Sun ^ permalink raw reply [flat|nested] 10+ messages in thread
end of thread, other threads:[~2018-10-09 12:28 UTC | newest] Thread overview: 10+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2018-09-27 6:01 [PATCH v3 0/2] Enable PV qspinlock for Hyper-V Yi Sun 2018-09-27 6:01 ` [PATCH v3 1/2] X86/Hyper-V: Add Guest IDLE MSR support Yi Sun 2018-10-02 11:27 ` [tip:x86/hyperv] x86/hyperv: Add GUEST_IDLE_MSR support tip-bot for Yi Sun 2018-10-09 12:27 ` [tip:x86/paravirt] " tip-bot for Yi Sun 2018-09-27 6:01 ` [PATCH v3 2/2] locking/pvqspinlock, hv: Enable PV qspinlock for Hyper-V Yi Sun 2018-09-28 22:09 ` Michael Kelley (EOSG) 2018-10-02 11:28 ` [tip:x86/hyperv] x86/hyperv: " tip-bot for Yi Sun 2018-10-02 11:38 ` Juergen Gross 2018-10-02 12:13 ` Thomas Gleixner 2018-10-08 8:12 ` Yi Sun
This is an external index of several public inboxes, see mirroring instructions on how to clone and mirror all data and code used by this external index.