Re: [PATCH v2 0/6] KVM: arm64: VCPU preempted check support
On 2020/1/15 22:14, Marc Zyngier wrote: > On 2020-01-13 12:12, Will Deacon wrote: >> [+PeterZ] >> >> On Thu, Dec 26, 2019 at 09:58:27PM +0800, Zengruan Ye wrote: >>> This patch set aims to support the vcpu_is_preempted() functionality >>> under KVM/arm64, which allowing the guest to obtain the VCPU is >>> currently running or not. This will enhance lock performance on >>> overcommitted hosts (more runnable VCPUs than physical CPUs in the >>> system) as doing busy waits for preempted VCPUs will hurt system >>> performance far worse than early yielding. >>> >>> We have observed some performace improvements in uninx benchmark tests. >>> >>> unix benchmark result: >>> host: kernel 5.5.0-rc1, HiSilicon Kunpeng920, 8 CPUs >>> guest: kernel 5.5.0-rc1, 16 VCPUs >>> >>> test-case | after-patch | before-patch >>> +---+-- >>> Dhrystone 2 using register variables | 334600751.0 lps | 335319028.3 >>> lps >>> Double-Precision Whetstone | 32856.1 MWIPS | 32849.6 >>> MWIPS >>> Execl Throughput | 3662.1 lps | 2718.0 >>> lps >>> File Copy 1024 bufsize 2000 maxblocks | 432906.4 KBps | 158011.8 >>> KBps >>> File Copy 256 bufsize 500 maxblocks | 116023.0 KBps | 37664.0 >>> KBps >>> File Copy 4096 bufsize 8000 maxblocks | 1432769.8 KBps | 441108.8 >>> KBps >>> Pipe Throughput | 6405029.6 lps | 6021457.6 >>> lps >>> Pipe-based Context Switching | 185872.7 lps | 184255.3 >>> lps >>> Process Creation | 4025.7 lps | 3706.6 >>> lps >>> Shell Scripts (1 concurrent) | 6745.6 lpm | 6436.1 >>> lpm >>> Shell Scripts (8 concurrent) | 998.7 lpm | 931.1 >>> lpm >>> System Call Overhead | 3913363.1 lps | 3883287.8 >>> lps >>> +---+-- >>> System Benchmarks Index Score | 1835.1 | 1327.6 >> >> Interesting, thanks for the numbers. >> >> So it looks like there is a decent improvement to be had from targetted vCPU >> wakeup, but I really dislike the explicit PV interface and it's already been >> shown to interact badly with the WFE-based polling in smp_cond_load_*(). >> >> Rather than expose a divergent interface, I would instead like to explore an >> improvement to smp_cond_load_*() and see how that performs before we commit >> to something more intrusive. Marc and I looked at this very briefly in the >> past, and the basic idea is to register all of the WFE sites with the >> hypervisor, indicating which register contains the address being spun on >> and which register contains the "bad" value. That way, you don't bother >> rescheduling a vCPU if the value at the address is still bad, because you >> know it will exit immediately. >> >> Of course, the devil is in the details because when I say "address", that's >> a guest virtual address, so you need to play some tricks in the hypervisor >> so that you have a separate mapping for the lockword (it's enough to keep >> track of the physical address). >> >> Our hacks are here but we basically ran out of time to work on them beyond >> an unoptimised and hacky prototype: >> >> https://git.kernel.org/pub/scm/linux/kernel/git/maz/arm-platforms.git/log/?h=kvm-arm64/pvcy >> >> Marc -- how would you prefer to handle this? > > Let me try and rebase this thing to a modern kernel (I doubt it applies > without > conflicts to mainline). We can then have discussion about its merit on the > list > once I post it. It'd be good to have a pointer to the benchamrks that have > been > used here. > > Thanks, > > M. Hi Marc, Will, My apologies for the slow reply. Just checking what is the latest on this PV cond yield prototype? https://git.kernel.org/pub/scm/linux/kernel/git/maz/arm-platforms.git/log/?h=kvm-arm64/pvcy The following are the unixbench test results of PV cond yield prototype: unix benchmark result: host: kernel 5.10.0-rc6, HiSilicon Kunpeng920, 8 CPUs guest: kernel 5.10.0-rc6, 16 VCPUs | 5.10.0-rc6 | pv_cond_yield | vcpu_is_preempted System Benchmarks Index Values|INDEX | INDEX| INDEX ---++---+--- Dhrystone 2 using register variables | 29164.0 |29156.9|29207.2 Double-Precision Whetstone| 6807.6 | 6789.2| 6912.1 Execl Throughput |856.7 | 1195.6| 863.1 File Copy 1024 bufsize 2000 maxblocks |189.9 | 923.5| 1094.2 File Copy 256 bufsize 500 maxblocks |121.9 | 578.4| 588.7 File Copy 4096 bufsize 8000 maxblocks |419.9 | 1992.0| 2733.7
Re: [PATCH v2 0/6] KVM: arm64: VCPU preempted check support
On 2020/1/15 22:14, Marc Zyngier wrote: > On 2020-01-13 12:12, Will Deacon wrote: >> [+PeterZ] >> >> On Thu, Dec 26, 2019 at 09:58:27PM +0800, Zengruan Ye wrote: >>> This patch set aims to support the vcpu_is_preempted() functionality >>> under KVM/arm64, which allowing the guest to obtain the VCPU is >>> currently running or not. This will enhance lock performance on >>> overcommitted hosts (more runnable VCPUs than physical CPUs in the >>> system) as doing busy waits for preempted VCPUs will hurt system >>> performance far worse than early yielding. >>> >>> We have observed some performace improvements in uninx benchmark tests. >>> >>> unix benchmark result: >>> host: kernel 5.5.0-rc1, HiSilicon Kunpeng920, 8 CPUs >>> guest: kernel 5.5.0-rc1, 16 VCPUs >>> >>> test-case | after-patch | before-patch >>> +---+-- >>> Dhrystone 2 using register variables | 334600751.0 lps | 335319028.3 >>> lps >>> Double-Precision Whetstone | 32856.1 MWIPS | 32849.6 >>> MWIPS >>> Execl Throughput | 3662.1 lps | 2718.0 >>> lps >>> File Copy 1024 bufsize 2000 maxblocks | 432906.4 KBps | 158011.8 >>> KBps >>> File Copy 256 bufsize 500 maxblocks | 116023.0 KBps | 37664.0 >>> KBps >>> File Copy 4096 bufsize 8000 maxblocks | 1432769.8 KBps | 441108.8 >>> KBps >>> Pipe Throughput | 6405029.6 lps | 6021457.6 >>> lps >>> Pipe-based Context Switching | 185872.7 lps | 184255.3 >>> lps >>> Process Creation | 4025.7 lps | 3706.6 >>> lps >>> Shell Scripts (1 concurrent) | 6745.6 lpm | 6436.1 >>> lpm >>> Shell Scripts (8 concurrent) | 998.7 lpm | 931.1 >>> lpm >>> System Call Overhead | 3913363.1 lps | 3883287.8 >>> lps >>> +---+-- >>> System Benchmarks Index Score | 1835.1 | 1327.6 >> >> Interesting, thanks for the numbers. >> >> So it looks like there is a decent improvement to be had from targetted vCPU >> wakeup, but I really dislike the explicit PV interface and it's already been >> shown to interact badly with the WFE-based polling in smp_cond_load_*(). >> >> Rather than expose a divergent interface, I would instead like to explore an >> improvement to smp_cond_load_*() and see how that performs before we commit >> to something more intrusive. Marc and I looked at this very briefly in the >> past, and the basic idea is to register all of the WFE sites with the >> hypervisor, indicating which register contains the address being spun on >> and which register contains the "bad" value. That way, you don't bother >> rescheduling a vCPU if the value at the address is still bad, because you >> know it will exit immediately. >> >> Of course, the devil is in the details because when I say "address", that's >> a guest virtual address, so you need to play some tricks in the hypervisor >> so that you have a separate mapping for the lockword (it's enough to keep >> track of the physical address). >> >> Our hacks are here but we basically ran out of time to work on them beyond >> an unoptimised and hacky prototype: >> >> https://git.kernel.org/pub/scm/linux/kernel/git/maz/arm-platforms.git/log/?h=kvm-arm64/pvcy >> >> Marc -- how would you prefer to handle this? > > Let me try and rebase this thing to a modern kernel (I doubt it applies > without > conflicts to mainline). We can then have discussion about its merit on the > list > once I post it. It'd be good to have a pointer to the benchamrks that have > been > used here. Hi Marc, Will, My apologies for the slow reply. Just checking what is the latest on this PV cond yield prototype? https://git.kernel.org/pub/scm/linux/kernel/git/maz/arm-platforms.git/log/?h=kvm-arm64/pvcy Recently, I re-doed the unixbench test comparison between vCPU preempted check and PV cond yield. The results are as follows: unix benchmark result: host: kernel 5.10.0-rc6, HiSilicon Kunpeng920, 8 CPUs guest: kernel 5.10.0-rc6, 16 VCPUs | 5.10.0-rc6 | pv_cond_yield | vcpu_is_preempted System Benchmarks Index Values | INDEX | INDEX | INDEX ---++---+--- Dhrystone 2 using register variables | 29164.0 | 29156.9 | 29207.2 Double-Precision Whetstone | 6807.6 | 6789.2 | 6912.1 Execl Throughput | 856.7 | 1195.6 | 863.1 File Copy 1024 bufsize 2000 maxblocks | 189.9 | 923.5 | 1094.2 File Copy 256 bufsize 500 maxblocks | 121.9 | 578.4 | 588.7 File Copy 4096 bufsize 8000 maxblocks | 419.9 |
Re: [PATCH v2 6/6] KVM: arm64: Support the VCPU preemption check
Hi Steve,
On 2020/1/9 23:09, Steven Price wrote:
> On 26/12/2019 13:58, Zengruan Ye wrote:
>> Support the vcpu_is_preempted() functionality under KVM/arm64. This will
>> enhance lock performance on overcommitted hosts (more runnable VCPUs
>> than physical CPUs in the system) as doing busy waits for preempted
>> VCPUs will hurt system performance far worse than early yielding.
>>
>> unix benchmark result:
>> host: kernel 5.5.0-rc1, HiSilicon Kunpeng920, 8 CPUs
>> guest: kernel 5.5.0-rc1, 16 VCPUs
>>
>> test-case | after-patch | before-patch
>> +---+--
>> Dhrystone 2 using register variables | 334600751.0 lps | 335319028.3
>> lps
>> Double-Precision Whetstone | 32856.1 MWIPS | 32849.6
>> MWIPS
>> Execl Throughput | 3662.1 lps | 2718.0
>> lps
>> File Copy 1024 bufsize 2000 maxblocks | 432906.4 KBps | 158011.8
>> KBps
>> File Copy 256 bufsize 500 maxblocks | 116023.0 KBps | 37664.0
>> KBps
>> File Copy 4096 bufsize 8000 maxblocks | 1432769.8 KBps | 441108.8
>> KBps
>> Pipe Throughput | 6405029.6 lps | 6021457.6
>> lps
>> Pipe-based Context Switching | 185872.7 lps | 184255.3
>> lps
>> Process Creation | 4025.7 lps | 3706.6
>> lps
>> Shell Scripts (1 concurrent) | 6745.6 lpm | 6436.1
>> lpm
>> Shell Scripts (8 concurrent) | 998.7 lpm | 931.1
>> lpm
>> System Call Overhead | 3913363.1 lps | 3883287.8
>> lps
>> +---+--
>> System Benchmarks Index Score | 1835.1 | 1327.6
>>
>> Signed-off-by: Zengruan Ye
>> ---
>> arch/arm64/include/asm/paravirt.h | 3 +
>> arch/arm64/kernel/paravirt.c | 117 ++
>> arch/arm64/kernel/setup.c | 2 +
>> include/linux/cpuhotplug.h | 1 +
>> 4 files changed, 123 insertions(+)
>>
>> diff --git a/arch/arm64/include/asm/paravirt.h
>> b/arch/arm64/include/asm/paravirt.h
>> index 7b1c81b544bb..ca3a2c7881f3 100644
>> --- a/arch/arm64/include/asm/paravirt.h
>> +++ b/arch/arm64/include/asm/paravirt.h
>> @@ -29,6 +29,8 @@ static inline u64 paravirt_steal_clock(int cpu)
>> int __init pv_time_init(void);
>> +int __init pv_lock_init(void);
>> +
>> __visible bool __native_vcpu_is_preempted(int cpu);
>> static inline bool pv_vcpu_is_preempted(int cpu)
>> @@ -39,6 +41,7 @@ static inline bool pv_vcpu_is_preempted(int cpu)
>> #else
>> #define pv_time_init() do {} while (0)
>> +#define pv_lock_init() do {} while (0)
>> #endif // CONFIG_PARAVIRT
>> diff --git a/arch/arm64/kernel/paravirt.c b/arch/arm64/kernel/paravirt.c
>> index d8f1ba8c22ce..bd2ad6a17a26 100644
>> --- a/arch/arm64/kernel/paravirt.c
>> +++ b/arch/arm64/kernel/paravirt.c
>> @@ -22,6 +22,7 @@
>> #include
>> #include
>> #include
>> +#include
>> struct static_key paravirt_steal_enabled;
>> struct static_key paravirt_steal_rq_enabled;
>> @@ -35,6 +36,10 @@ struct pv_time_stolen_time_region {
>> struct pvclock_vcpu_stolen_time *kaddr;
>> };
>> +struct pv_lock_state_region {
>> + struct pvlock_vcpu_state *kaddr;
>> +};
>> +
>> static DEFINE_PER_CPU(struct pv_time_stolen_time_region,
>> stolen_time_region);
>> static bool steal_acc = true;
>> @@ -158,3 +163,115 @@ int __init pv_time_init(void)
>> return 0;
>> }
>> +
>> +static DEFINE_PER_CPU(struct pv_lock_state_region, lock_state_region);
>> +
>> +static bool kvm_vcpu_is_preempted(int cpu)
>> +{
>> + struct pv_lock_state_region *reg;
>> + __le64 preempted_le;
>> +
>> + reg = per_cpu_ptr(_state_region, cpu);
>> + if (!reg->kaddr) {
>> + pr_warn_once("PV lock enabled but not configured for cpu %d\n",
>> + cpu);
>> + return false;
>> + }
>> +
>> + preempted_le = le64_to_cpu(READ_ONCE(reg->kaddr->preempted));
>> +
>> + return !!(preempted_le & 1);
>
> According to the documentation preempted != 0 means preempted, but here you
> are checking the LSB. You need to be consistent about the ABI.
Thanks for posting this. I'll update the code.
>
>> +}
>> +
>> +static int pvlock_vcpu_state_dying_cpu(unsigned int cpu)
>> +{
>> + struct pv_lock_state_region *reg;
>> +
>> + reg = this_cpu_ptr(_state_region);
>> + if (!reg->kaddr)
>> + return 0;
>> +
>> + memunmap(reg->kaddr);
>> + memset(reg, 0, sizeof(*reg));
>> +
>> + return 0;
>> +}
>> +
>> +static int init_pvlock_vcpu_state(unsigned int cpu)
>> +{
>> + struct pv_lock_state_region *reg;
>> + struct arm_smccc_res res;
>> +
>> + reg = this_cpu_ptr(_state_region);
>> +
>> + arm_smccc_1_1_invoke(ARM_SMCCC_HV_PV_LOCK_PREEMPTED, );
>> +
>> + if (res.a0 ==
Re: [PATCH v2 3/6] KVM: arm64: Support pvlock preempted via shared structure
Hi Steve,
On 2020/1/9 23:02, Steven Price wrote:
> On 26/12/2019 13:58, Zengruan Ye wrote:
>> Implement the service call for configuring a shared structure between a
>> VCPU and the hypervisor in which the hypervisor can tell the VCPU is
>> running or not.
>>
>> The preempted field is zero if 1) some old KVM deos not support this filed.
>
> NIT: s/deos/does/
Thanks for posting this.
>
> However, I would hope that the service call will fail if it's an old KVM not
> simply return zero.
Sorry, I'm not sure what you mean. The service call will fail if it's an old
KVM, and the Guest will use __native_vcpu_is_preempted.
>
>> 2) the VCPU is not preempted. Other values means the VCPU has been preempted.
>>
>> Signed-off-by: Zengruan Ye
>> ---
>> arch/arm/include/asm/kvm_host.h | 18
>> arch/arm64/include/asm/kvm_host.h | 19 +
>> arch/arm64/kvm/Makefile | 1 +
>> virt/kvm/arm/arm.c | 8 ++
>> virt/kvm/arm/hypercalls.c | 8 ++
>> virt/kvm/arm/pvlock.c | 46 +++
>> 6 files changed, 100 insertions(+)
>> create mode 100644 virt/kvm/arm/pvlock.c
>>
>> diff --git a/arch/arm/include/asm/kvm_host.h
>> b/arch/arm/include/asm/kvm_host.h
>> index 556cd818eccf..dfeaf9204875 100644
>> --- a/arch/arm/include/asm/kvm_host.h
>> +++ b/arch/arm/include/asm/kvm_host.h
>> @@ -356,6 +356,24 @@ static inline bool kvm_arm_is_pvtime_enabled(struct
>> kvm_vcpu_arch *vcpu_arch)
>> return false;
>> }
>> +static inline void kvm_arm_pvlock_preempted_init(struct kvm_vcpu_arch
>> *vcpu_arch)
>> +{
>> +}
>> +
>> +static inline bool kvm_arm_is_pvlock_preempted_ready(struct kvm_vcpu_arch
>> *vcpu_arch)
>> +{
>> + return false;
>> +}
>> +
>> +static inline gpa_t kvm_init_pvlock(struct kvm_vcpu *vcpu)
>> +{
>> + return GPA_INVALID;
>> +}
>> +
>> +static inline void kvm_update_pvlock_preempted(struct kvm_vcpu *vcpu, u64
>> preempted)
>> +{
>> +}
>> +
>> void kvm_mmu_wp_memory_region(struct kvm *kvm, int slot);
>> struct kvm_vcpu *kvm_mpidr_to_vcpu(struct kvm *kvm, unsigned long mpidr);
>> diff --git a/arch/arm64/include/asm/kvm_host.h
>> b/arch/arm64/include/asm/kvm_host.h
>> index c61260cf63c5..2818a2330f92 100644
>> --- a/arch/arm64/include/asm/kvm_host.h
>> +++ b/arch/arm64/include/asm/kvm_host.h
>> @@ -354,6 +354,12 @@ struct kvm_vcpu_arch {
>> u64 last_steal;
>> gpa_t base;
>> } steal;
>> +
>> + /* Guest PV lock state */
>> + struct {
>> + u64 preempted;
>
> I'm not sure why the kernel needs to (separately) track this preempted state?
> It doesn't appear to be used from what I can tell.
Good point, the preempted state field is not actually used, I'll remove it.
>
> Steve
>
>> + gpa_t base;
>> + } pv;
>> };
>> /* Pointer to the vcpu's SVE FFR for sve_{save,load}_state() */
>> @@ -515,6 +521,19 @@ static inline bool kvm_arm_is_pvtime_enabled(struct
>> kvm_vcpu_arch *vcpu_arch)
>> return (vcpu_arch->steal.base != GPA_INVALID);
>> }
>> +static inline void kvm_arm_pvlock_preempted_init(struct kvm_vcpu_arch
>> *vcpu_arch)
>> +{
>> + vcpu_arch->pv.base = GPA_INVALID;
>> +}
>> +
>> +static inline bool kvm_arm_is_pvlock_preempted_ready(struct kvm_vcpu_arch
>> *vcpu_arch)
>> +{
>> + return (vcpu_arch->pv.base != GPA_INVALID);
>> +}
>> +
>> +gpa_t kvm_init_pvlock(struct kvm_vcpu *vcpu);
>> +void kvm_update_pvlock_preempted(struct kvm_vcpu *vcpu, u64 preempted);
>> +
>> void kvm_set_sei_esr(struct kvm_vcpu *vcpu, u64 syndrome);
>> struct kvm_vcpu *kvm_mpidr_to_vcpu(struct kvm *kvm, unsigned long mpidr);
>> diff --git a/arch/arm64/kvm/Makefile b/arch/arm64/kvm/Makefile
>> index 5ffbdc39e780..e4591f56d5f1 100644
>> --- a/arch/arm64/kvm/Makefile
>> +++ b/arch/arm64/kvm/Makefile
>> @@ -15,6 +15,7 @@ kvm-$(CONFIG_KVM_ARM_HOST) += $(KVM)/arm/arm.o
>> $(KVM)/arm/mmu.o $(KVM)/arm/mmio.
>> kvm-$(CONFIG_KVM_ARM_HOST) += $(KVM)/arm/psci.o $(KVM)/arm/perf.o
>> kvm-$(CONFIG_KVM_ARM_HOST) += $(KVM)/arm/hypercalls.o
>> kvm-$(CONFIG_KVM_ARM_HOST) += $(KVM)/arm/pvtime.o
>> +kvm-$(CONFIG_KVM_ARM_HOST) += $(KVM)/arm/pvlock.o
>> kvm-$(CONFIG_KVM_ARM_HOST) += inject_fault.o regmap.o va_layout.o
>> kvm-$(CONFIG_KVM_ARM_HOST) += hyp.o hyp-init.o handle_exit.o
>> diff --git a/virt/kvm/arm/arm.c b/virt/kvm/arm/arm.c
>> index 8de4daf25097..36d57e77d3c4 100644
>> --- a/virt/kvm/arm/arm.c
>> +++ b/virt/kvm/arm/arm.c
>> @@ -383,6 +383,8 @@ int kvm_arch_vcpu_init(struct kvm_vcpu *vcpu)
>> kvm_arm_pvtime_vcpu_init(>arch);
>> + kvm_arm_pvlock_preempted_init(>arch);
>> +
>> return kvm_vgic_vcpu_init(vcpu);
>> }
>> @@ -421,6 +423,9 @@ void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
>> vcpu_set_wfx_traps(vcpu);
>> vcpu_ptrauth_setup_lazy(vcpu);
>> +
>> + if (kvm_arm_is_pvlock_preempted_ready(>arch))
>> + kvm_update_pvlock_preempted(vcpu, 0);
>> }
>> void
Re: [PATCH v2 1/6] KVM: arm64: Document PV-lock interface
Hi Steve, On 2020/1/9 22:53, Steven Price wrote: > On 26/12/2019 13:58, Zengruan Ye wrote: >> Introduce a paravirtualization interface for KVM/arm64 to obtain the VCPU >> is currently running or not. >> >> The PV lock structure of the guest is allocated by user space. >> >> A hypercall interface is provided for the guest to interrogate the >> hypervisor's support for this interface and the location of the shared >> memory structures. >> >> Signed-off-by: Zengruan Ye >> --- >> Documentation/virt/kvm/arm/pvlock.rst | 63 + >> Documentation/virt/kvm/devices/vcpu.txt | 14 ++ >> 2 files changed, 77 insertions(+) >> create mode 100644 Documentation/virt/kvm/arm/pvlock.rst >> >> diff --git a/Documentation/virt/kvm/arm/pvlock.rst >> b/Documentation/virt/kvm/arm/pvlock.rst >> new file mode 100644 >> index ..58b3b8ee7537 >> --- /dev/null >> +++ b/Documentation/virt/kvm/arm/pvlock.rst >> @@ -0,0 +1,63 @@ >> +.. SPDX-License-Identifier: GPL-2.0 >> + >> +Paravirtualized lock support for arm64 >> +== >> + >> +KVM/arm64 provides some hypervisor service calls to support a >> paravirtualized >> +guest obtaining the VCPU is currently running or not. > NIT: ^ whether Thanks for posting this. > >> + >> +Two new SMCCC compatible hypercalls are defined: >> + >> +* PV_LOCK_FEATURES: 0xC620 >> +* PV_LOCK_PREEMPTED: 0xC621 >> + >> +The existence of the PV_LOCK hypercall should be probed using the SMCCC 1.1 >> +ARCH_FEATURES mechanism before calling it. > > Since these are within the "vendor specific" SMCCC region ideally you should > also check that you are talking to KVM. (Other hypervisors could allocate > SMCCC IDs differently within this block). Will has a patch on a branch which > gives an example of how this could work [1] > > [1] > https://git.kernel.org/pub/scm/linux/kernel/git/will/linux.git/commit/?h=kvm/hvc=464f5a1741e5959c3e4d2be1966ae0093b4dce06 OK, I will add "vendor specific" check next version. > >> + >> +PV_LOCK_FEATURES >> + = == >> + Function ID: (uint32) 0xC620 >> + PV_call_id: (uint32) The function to query for support. >> + Return value: (int64) NOT_SUPPORTED (-1) or SUCCESS (0) if the >> relevant >> + PV-lock feature is supported by the >> hypervisor. >> + = == >> + >> +PV_LOCK_PREEMPTED >> + = == >> + Function ID: (uint32) 0xC621 >> + Return value: (int64) NOT_SUPPORTED (-1) or SUCCESS (0) if the IPA >> of >> + this VCPU's pv data structure is configured by >> + the hypervisor. >> + = == > > PV_LOCK_PREEMPTED also needs to return the address of this data structure. > Either by returning this in another register, or by e.g. treating a positive > return as an address and a negative value as an error. This is somewhat embarrassing. The code does what you say, but the doc doesn't. Thanks for pointing it out to me! I'll update the doc to match. > >> + >> +The IPA returned by PV_LOCK_PREEMPTED should be mapped by the guest as >> normal >> +memory with inner and outer write back caching attributes, in the inner >> +shareable domain. >> + >> +PV_LOCK_PREEMPTED returns the structure for the calling VCPU. >> + >> +PV lock state >> +- >> + >> +The structure pointed to by the PV_LOCK_PREEMPTED hypercall is as follows: >> + >> ++---+-+-+-+ >> +| Field | Byte Length | Byte Offset | Description | >> ++===+=+=+=+ >> +| preempted | 8 | 0 | Indicate the VCPU who owns this | > > NIT: s/Indicate/Indicates that/. Also more common English would be "the VCPU > *that* owns" Will update. > >> +| | | | struct is running or not. | >> +| | | | Non-zero values mean the VCPU | >> +| | | | has been preempted. Zero means | >> +| | | | the VCPU is not preempted. | >> ++---+-+-+-+ >> + >> +The preempted field will be updated to 1 by the hypervisor prior to >> scheduling >> +a VCPU. When the VCPU is scheduled out, the preempted field will be updated >> +to 0 by the hypervisor. >> + >> +The structure will be present within a reserved region of the normal memory >> +given to the guest. The guest should not attempt to write into this memory. >> +There is a structure per VCPU of the guest. > > I think it would be worth mentioning in this document that the structure is > guaranteed to be 64-byte aligned. Good point, I'll update the doc. > >
Re: [PATCH v2 5/6] KVM: arm64: Add interface to support VCPU preempted check
Hi,
On 2019/12/27 2:51, kbuild test robot wrote:
> Hi Zengruan,
>
> Thank you for the patch! Yet something to improve:
>
> [auto build test ERROR on kvmarm/next]
> [also build test ERROR on kvm/linux-next linus/master v5.5-rc3 next-20191220]
> [cannot apply to arm64/for-next/core]
> [if your patch is applied to the wrong git tree, please drop us a note to help
> improve the system. BTW, we also suggest to use '--base' option to specify the
> base tree in git format-patch, please see
> https://stackoverflow.com/a/37406982]
>
> url:
> https://github.com/0day-ci/linux/commits/Zengruan-Ye/KVM-arm64-VCPU-preempted-check-support/20191227-000637
> base: https://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm.git next
> config: arm64-alldefconfig (attached as .config)
> compiler: aarch64-linux-gcc (GCC) 7.5.0
> reproduce:
> wget
> https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O
> ~/bin/make.cross
> chmod +x ~/bin/make.cross
> # save the attached .config to linux build tree
> GCC_VERSION=7.5.0 make.cross ARCH=arm64
>
> If you fix the issue, kindly add following tag
> Reported-by: kbuild test robot
>
> All errors (new ones prefixed by >>):
>
>In file included from include/linux/spinlock.h:89:0,
> from include/linux/radix-tree.h:16,
> from include/linux/idr.h:15,
> from include/linux/kernfs.h:13,
> from include/linux/sysfs.h:16,
> from include/linux/kobject.h:20,
> from include/linux/of.h:17,
> from include/linux/irqdomain.h:35,
> from include/linux/acpi.h:13,
> from include/acpi/apei.h:9,
> from include/acpi/ghes.h:5,
> from include/linux/arm_sdei.h:8,
> from arch/arm64/kernel/asm-offsets.c:10:
>arch/arm64/include/asm/spinlock.h: In function 'vcpu_is_preempted':
>>> arch/arm64/include/asm/spinlock.h:18:9: error: implicit declaration of
>>> function 'pv_vcpu_is_preempted'; did you mean 'vcpu_is_preempted'?
>>> [-Werror=implicit-function-declaration]
> return pv_vcpu_is_preempted(cpu);
> ^~~~
> vcpu_is_preempted
>cc1: some warnings being treated as errors
>make[2]: *** [arch/arm64/kernel/asm-offsets.s] Error 1
>make[2]: Target '__build' not remade because of errors.
>make[1]: *** [prepare0] Error 2
>make[1]: Target 'prepare' not remade because of errors.
>make: *** [sub-make] Error 2
>27 real 5 user 7 sys 48.63% cpu make prepare
>
> vim +18 arch/arm64/include/asm/spinlock.h
>
> 14
> 15#define vcpu_is_preempted vcpu_is_preempted
> 16static inline bool vcpu_is_preempted(long cpu)
> 17{
> > 18return pv_vcpu_is_preempted(cpu);
> 19}
> 20
>
> ---
> 0-DAY kernel test infrastructure Open Source Technology Center
> https://lists.01.org/hyperkitty/list/kbuild-...@lists.01.org Intel Corporation
>
Thanks for posting this, I'll update the code to fix this issue.
Thanks,
Zengruan
---
arch/arm64/include/asm/spinlock.h | 2 ++
1 file changed, 2 insertions(+)
diff --git a/arch/arm64/include/asm/spinlock.h
b/arch/arm64/include/asm/spinlock.h
index 45ff1b2949a6..b5d1982414c5 100644
--- a/arch/arm64/include/asm/spinlock.h
+++ b/arch/arm64/include/asm/spinlock.h
@@ -12,10 +12,12 @@
/* See include/linux/spinlock.h */
#define smp_mb__after_spinlock() smp_mb()
+#ifdef CONFIG_PARAVIRT
#define vcpu_is_preempted vcpu_is_preempted
static inline bool vcpu_is_preempted(long cpu)
{
return pv_vcpu_is_preempted(cpu);
}
+#endif // CONFIG_PARAVIRT
#endif /* __ASM_SPINLOCK_H */
--
2.19.1
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Re: [PATCH 5/5] KVM: arm64: Support the vcpu preemption check
Hi Steve,
On 2019/12/17 22:40, Steven Price wrote:
> On Tue, Dec 17, 2019 at 01:55:49PM +, yezengr...@huawei.com wrote:
>> From: Zengruan Ye
>>
>> Support the vcpu_is_preempted() functionality under KVM/arm64. This will
>> enhance lock performance on overcommitted hosts (more runnable vcpus
>> than physical cpus in the system) as doing busy waits for preempted
>> vcpus will hurt system performance far worse than early yielding.
>>
>> unix benchmark result:
>> host: kernel 5.5.0-rc1, HiSilicon Kunpeng920, 8 cpus
>> guest: kernel 5.5.0-rc1, 16 vcpus
>>
>>test-case|after-patch| before-patch
>> +---+--
>> Dhrystone 2 using register variables | 334600751.0 lps | 335319028.3 lps
>> Double-Precision Whetstone | 32856.1 MWIPS | 32849.6
>> MWIPS
>> Execl Throughput | 3662.1 lps | 2718.0 lps
>> File Copy 1024 bufsize 2000 maxblocks |432906.4 KBps |158011.8
>> KBps
>> File Copy 256 bufsize 500 maxblocks|116023.0 KBps | 37664.0
>> KBps
>> File Copy 4096 bufsize 8000 maxblocks | 1432769.8 KBps |441108.8
>> KBps
>> Pipe Throughput| 6405029.6 lps | 6021457.6 lps
>> Pipe-based Context Switching |185872.7 lps |184255.3 lps
>> Process Creation | 4025.7 lps | 3706.6 lps
>> Shell Scripts (1 concurrent) | 6745.6 lpm | 6436.1 lpm
>> Shell Scripts (8 concurrent) | 998.7 lpm | 931.1 lpm
>> System Call Overhead | 3913363.1 lps | 3883287.8 lps
>> +---+--
>> System Benchmarks Index Score | 1835.1 | 1327.6
>>
>> Signed-off-by: Zengruan Ye
>> ---
>> arch/arm64/include/asm/paravirt.h | 3 +
>> arch/arm64/kernel/paravirt.c | 91 +++
>> arch/arm64/kernel/setup.c | 2 +
>> include/linux/cpuhotplug.h| 1 +
>> 4 files changed, 97 insertions(+)
>>
>> diff --git a/arch/arm64/include/asm/paravirt.h
>> b/arch/arm64/include/asm/paravirt.h
>> index 7b1c81b544bb..a2cd0183bbef 100644
>> --- a/arch/arm64/include/asm/paravirt.h
>> +++ b/arch/arm64/include/asm/paravirt.h
>> @@ -29,6 +29,8 @@ static inline u64 paravirt_steal_clock(int cpu)
>>
>> int __init pv_time_init(void);
>>
>> +int __init kvm_guest_init(void);
>> +
>
> This is a *very* generic name - I suggest something like pv_lock_init()
> so it's clear what the function actually does.
>
>> __visible bool __native_vcpu_is_preempted(int cpu);
>>
>> static inline bool pv_vcpu_is_preempted(int cpu)
>> @@ -39,6 +41,7 @@ static inline bool pv_vcpu_is_preempted(int cpu)
>> #else
>>
>> #define pv_time_init() do {} while (0)
>> +#define kvm_guest_init() do {} while (0)
>>
>> #endif // CONFIG_PARAVIRT
>>
>> diff --git a/arch/arm64/kernel/paravirt.c b/arch/arm64/kernel/paravirt.c
>> index d8f1ba8c22ce..a86dead40473 100644
>> --- a/arch/arm64/kernel/paravirt.c
>> +++ b/arch/arm64/kernel/paravirt.c
>> @@ -22,6 +22,7 @@
>> #include
>> #include
>> #include
>> +#include
>>
>> struct static_key paravirt_steal_enabled;
>> struct static_key paravirt_steal_rq_enabled;
>> @@ -158,3 +159,93 @@ int __init pv_time_init(void)
>>
>> return 0;
>> }
>> +
>> +DEFINE_PER_CPU(struct pvlock_vcpu_state, pvlock_vcpu_region) __aligned(64);
>> +EXPORT_PER_CPU_SYMBOL(pvlock_vcpu_region);
>> +
>> +static int pvlock_vcpu_state_dying_cpu(unsigned int cpu)
>> +{
>> +struct pvlock_vcpu_state *reg;
>> +
>> +reg = this_cpu_ptr(_vcpu_region);
>> +if (!reg)
>> +return -EFAULT;
>> +
>> +memset(reg, 0, sizeof(*reg));
>
> I might be missing something obvious here - but I don't see the point of
> this. The hypervisor might immediately overwrite the structure again.
> Indeed you should conside a mechanism for the guest to "unregister" the
> region - otherwise you will face issues with the likes of kexec.
>
> For pv_time the memory is allocated by the hypervisor not the guest to
> avoid lifetime issues about kexec.
Thanks for pointing it out to me! I'll update the memory allocation
mechanism of the PV lock structure to avoid lifetime issues about
kexec.
>
>> +
>> +return 0;
>> +}
>> +
>> +static int init_pvlock_vcpu_state(unsigned int cpu)
>> +{
>> +struct pvlock_vcpu_state *reg;
>> +struct arm_smccc_res res;
>> +
>> +reg = this_cpu_ptr(_vcpu_region);
>> +if (!reg)
>> +return -EFAULT;
>> +
>> +/* Pass the memory address to host via hypercall */
>> +arm_smccc_1_1_invoke(ARM_SMCCC_HV_PV_LOCK_PREEMPTED,
>> + virt_to_phys(reg), );
>> +
>> +return 0;
>> +}
>> +
>> +static bool kvm_vcpu_is_preempted(int cpu)
>> +{
>> +struct pvlock_vcpu_state *reg = _cpu(pvlock_vcpu_region, cpu);
Re: [PATCH 3/5] KVM: arm64: Support pvlock preempted via shared structure
Hi Steve,
On 2019/12/17 22:33, Steven Price wrote:
> On Tue, Dec 17, 2019 at 01:55:47PM +, yezengr...@huawei.com wrote:
>> From: Zengruan Ye
>>
>> Implement the service call for configuring a shared structure between a
>> vcpu and the hypervisor in which the hypervisor can tell the vcpu is
>> running or not.
>>
>> The preempted field is zero if 1) some old KVM deos not support this filed.
>> 2) the vcpu is not preempted. Other values means the vcpu has been preempted.
>>
>> Signed-off-by: Zengruan Ye
>> ---
>> arch/arm/include/asm/kvm_host.h | 13 +
>> arch/arm64/include/asm/kvm_host.h | 17 +
>> arch/arm64/kvm/Makefile | 1 +
>> virt/kvm/arm/arm.c| 8
>> virt/kvm/arm/hypercalls.c | 4
>> virt/kvm/arm/pvlock.c | 21 +
>> 6 files changed, 64 insertions(+)
>> create mode 100644 virt/kvm/arm/pvlock.c
>>
>> diff --git a/arch/arm/include/asm/kvm_host.h
>> b/arch/arm/include/asm/kvm_host.h
>> index 556cd818eccf..098375f1c89e 100644
>> --- a/arch/arm/include/asm/kvm_host.h
>> +++ b/arch/arm/include/asm/kvm_host.h
>> @@ -356,6 +356,19 @@ static inline bool kvm_arm_is_pvtime_enabled(struct
>> kvm_vcpu_arch *vcpu_arch)
>> return false;
>> }
>>
>> +static inline void kvm_arm_pvlock_preempted_init(struct kvm_vcpu_arch
>> *vcpu_arch)
>> +{
>> +}
>> +
>> +static inline bool kvm_arm_is_pvlock_preempted_ready(struct kvm_vcpu_arch
>> *vcpu_arch)
>> +{
>> +return false;
>> +}
>> +
>> +static inline void kvm_update_pvlock_preempted(struct kvm_vcpu *vcpu, u64
>> preempted)
>> +{
>> +}
>> +
>> void kvm_mmu_wp_memory_region(struct kvm *kvm, int slot);
>>
>> struct kvm_vcpu *kvm_mpidr_to_vcpu(struct kvm *kvm, unsigned long mpidr);
>> diff --git a/arch/arm64/include/asm/kvm_host.h
>> b/arch/arm64/include/asm/kvm_host.h
>> index c61260cf63c5..d9b2a21a87ac 100644
>> --- a/arch/arm64/include/asm/kvm_host.h
>> +++ b/arch/arm64/include/asm/kvm_host.h
>> @@ -354,6 +354,11 @@ struct kvm_vcpu_arch {
>> u64 last_steal;
>> gpa_t base;
>> } steal;
>> +
>> +/* Guest PV lock state */
>> +struct {
>> +gpa_t base;
>> +} pv;
>> };
>>
>> /* Pointer to the vcpu's SVE FFR for sve_{save,load}_state() */
>> @@ -515,6 +520,18 @@ static inline bool kvm_arm_is_pvtime_enabled(struct
>> kvm_vcpu_arch *vcpu_arch)
>> return (vcpu_arch->steal.base != GPA_INVALID);
>> }
>>
>> +static inline void kvm_arm_pvlock_preempted_init(struct kvm_vcpu_arch
>> *vcpu_arch)
>> +{
>> +vcpu_arch->pv.base = GPA_INVALID;
>> +}
>> +
>> +static inline bool kvm_arm_is_pvlock_preempted_ready(struct kvm_vcpu_arch
>> *vcpu_arch)
>> +{
>> +return (vcpu_arch->pv.base != GPA_INVALID);
>> +}
>> +
>> +void kvm_update_pvlock_preempted(struct kvm_vcpu *vcpu, u64 preempted);
>> +
>> void kvm_set_sei_esr(struct kvm_vcpu *vcpu, u64 syndrome);
>>
>> struct kvm_vcpu *kvm_mpidr_to_vcpu(struct kvm *kvm, unsigned long mpidr);
>> diff --git a/arch/arm64/kvm/Makefile b/arch/arm64/kvm/Makefile
>> index 5ffbdc39e780..e4591f56d5f1 100644
>> --- a/arch/arm64/kvm/Makefile
>> +++ b/arch/arm64/kvm/Makefile
>> @@ -15,6 +15,7 @@ kvm-$(CONFIG_KVM_ARM_HOST) += $(KVM)/arm/arm.o
>> $(KVM)/arm/mmu.o $(KVM)/arm/mmio.
>> kvm-$(CONFIG_KVM_ARM_HOST) += $(KVM)/arm/psci.o $(KVM)/arm/perf.o
>> kvm-$(CONFIG_KVM_ARM_HOST) += $(KVM)/arm/hypercalls.o
>> kvm-$(CONFIG_KVM_ARM_HOST) += $(KVM)/arm/pvtime.o
>> +kvm-$(CONFIG_KVM_ARM_HOST) += $(KVM)/arm/pvlock.o
>>
>> kvm-$(CONFIG_KVM_ARM_HOST) += inject_fault.o regmap.o va_layout.o
>> kvm-$(CONFIG_KVM_ARM_HOST) += hyp.o hyp-init.o handle_exit.o
>> diff --git a/virt/kvm/arm/arm.c b/virt/kvm/arm/arm.c
>> index 12e0280291ce..c562f62fdd45 100644
>> --- a/virt/kvm/arm/arm.c
>> +++ b/virt/kvm/arm/arm.c
>> @@ -383,6 +383,8 @@ int kvm_arch_vcpu_init(struct kvm_vcpu *vcpu)
>>
>> kvm_arm_pvtime_vcpu_init(>arch);
>>
>> +kvm_arm_pvlock_preempted_init(>arch);
>> +
>> return kvm_vgic_vcpu_init(vcpu);
>> }
>>
>> @@ -421,6 +423,9 @@ void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
>> vcpu_set_wfx_traps(vcpu);
>>
>> vcpu_ptrauth_setup_lazy(vcpu);
>> +
>> +if (kvm_arm_is_pvlock_preempted_ready(>arch))
>> +kvm_update_pvlock_preempted(vcpu, 0);
>> }
>>
>> void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu)
>> @@ -434,6 +439,9 @@ void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu)
>> vcpu->cpu = -1;
>>
>> kvm_arm_set_running_vcpu(NULL);
>> +
>> +if (kvm_arm_is_pvlock_preempted_ready(>arch))
>> +kvm_update_pvlock_preempted(vcpu, 1);
>> }
>>
>> static void vcpu_power_off(struct kvm_vcpu *vcpu)
>> diff --git a/virt/kvm/arm/hypercalls.c b/virt/kvm/arm/hypercalls.c
>> index ff13871fd85a..5964982ccd05 100644
>> --- a/virt/kvm/arm/hypercalls.c
>> +++ b/virt/kvm/arm/hypercalls.c
>> @@ -65,6 +65,10 @@ int kvm_hvc_call_handler(struct kvm_vcpu *vcpu)
>> if (gpa != GPA_INVALID)
>>
Re: [PATCH 1/5] KVM: arm64: Document PV-lock interface
Hi Markus, On 2019/12/20 22:32, Markus Elfring wrote: > … >> +++ b/Documentation/virt/kvm/arm/pvlock.rst > … >> +Paravirtualized lock support for arm64 >> +== >> + >> +KVM/arm64 provids some … > … > > I suggest to avoid a typo here. Thanks for posting this. > > Regards, > Markus > Thanks, Zengruan ___ Virtualization mailing list Virtualization@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/virtualization
Re: [PATCH 2/5] KVM: arm64: Implement PV_LOCK_FEATURES call
Hi Steve,
On 2019/12/17 22:28, Steven Price wrote:
> On Tue, Dec 17, 2019 at 01:55:46PM +, yezengr...@huawei.com wrote:
>> From: Zengruan Ye
>>
>> This provides a mechanism for querying which paravirtualized lock
>> features are available in this hypervisor.
>>
>> Also add the header file which defines the ABI for the paravirtualized
>> lock features we're about to add.
>>
>> Signed-off-by: Zengruan Ye
>> ---
>> arch/arm64/include/asm/pvlock-abi.h | 16
>> include/linux/arm-smccc.h | 13 +
>> virt/kvm/arm/hypercalls.c | 3 +++
>> 3 files changed, 32 insertions(+)
>> create mode 100644 arch/arm64/include/asm/pvlock-abi.h
>>
>> diff --git a/arch/arm64/include/asm/pvlock-abi.h
>> b/arch/arm64/include/asm/pvlock-abi.h
>> new file mode 100644
>> index ..06e0c3d7710a
>> --- /dev/null
>> +++ b/arch/arm64/include/asm/pvlock-abi.h
>> @@ -0,0 +1,16 @@
>> +/* SPDX-License-Identifier: GPL-2.0 */
>> +/*
>> + * Copyright(c) 2019 Huawei Technologies Co., Ltd
>> + * Author: Zengruan Ye
>> + */
>> +
>> +#ifndef __ASM_PVLOCK_ABI_H
>> +#define __ASM_PVLOCK_ABI_H
>> +
>> +struct pvlock_vcpu_state {
>> +__le64 preempted;
>
> Somewhere we need to document when 'preempted' is. It looks like it's a
> 1-bit field from the later patches.
Good point, I'll document this in the pvlock doc.
>
>> +/* Structure must be 64 byte aligned, pad to that size */
>> +u8 padding[56];
>> +} __packed;
>> +
>> +#endif
>> diff --git a/include/linux/arm-smccc.h b/include/linux/arm-smccc.h
>> index 59494df0f55b..59e65a951959 100644
>> --- a/include/linux/arm-smccc.h
>> +++ b/include/linux/arm-smccc.h
>> @@ -377,5 +377,18 @@ asmlinkage void __arm_smccc_hvc(unsigned long a0,
>> unsigned long a1,
>> ARM_SMCCC_OWNER_STANDARD_HYP,\
>> 0x21)
>>
>> +/* Paravirtualised lock calls */
>> +#define ARM_SMCCC_HV_PV_LOCK_FEATURES \
>> +ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL, \
>> + ARM_SMCCC_SMC_64,\
>> + ARM_SMCCC_OWNER_STANDARD_HYP,\
>> + 0x40)
>> +
>> +#define ARM_SMCCC_HV_PV_LOCK_PREEMPTED \
>> +ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL, \
>> + ARM_SMCCC_SMC_64,\
>> + ARM_SMCCC_OWNER_STANDARD_HYP,\
>> + 0x41)
>> +
>> #endif /*__ASSEMBLY__*/
>> #endif /*__LINUX_ARM_SMCCC_H*/
>> diff --git a/virt/kvm/arm/hypercalls.c b/virt/kvm/arm/hypercalls.c
>> index 550dfa3e53cd..ff13871fd85a 100644
>> --- a/virt/kvm/arm/hypercalls.c
>> +++ b/virt/kvm/arm/hypercalls.c
>> @@ -52,6 +52,9 @@ int kvm_hvc_call_handler(struct kvm_vcpu *vcpu)
>> case ARM_SMCCC_HV_PV_TIME_FEATURES:
>> val = SMCCC_RET_SUCCESS;
>> break;
>> +case ARM_SMCCC_HV_PV_LOCK_FEATURES:
>> +val = SMCCC_RET_SUCCESS;
>> +break;
>
> Ideally you wouldn't report that PV_LOCK_FEATURES exists until the
> actual hypercalls are wired up to avoid breaking a bisect.
Thanks for pointing it out to me! I'll update the code.
>
> Steve
>
>> }
>> break;
>> case ARM_SMCCC_HV_PV_TIME_FEATURES:
>> --
>> 2.19.1
>>
>>
>
> .
>
Thanks,
Zengruan
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Re: [PATCH 1/5] KVM: arm64: Document PV-lock interface
Hi Steve, On 2019/12/17 22:21, Steven Price wrote: > On Tue, Dec 17, 2019 at 01:55:45PM +, yezengr...@huawei.com wrote: >> From: Zengruan Ye >> >> Introduce a paravirtualization interface for KVM/arm64 to obtain the vcpu >> is currently running or not. >> >> A hypercall interface is provided for the guest to interrogate the >> hypervisor's support for this interface and the location of the shared >> memory structures. >> >> Signed-off-by: Zengruan Ye >> --- >> Documentation/virt/kvm/arm/pvlock.rst | 31 +++ >> 1 file changed, 31 insertions(+) >> create mode 100644 Documentation/virt/kvm/arm/pvlock.rst >> >> diff --git a/Documentation/virt/kvm/arm/pvlock.rst >> b/Documentation/virt/kvm/arm/pvlock.rst >> new file mode 100644 >> index ..eec0c36edf17 >> --- /dev/null >> +++ b/Documentation/virt/kvm/arm/pvlock.rst >> @@ -0,0 +1,31 @@ >> +.. SPDX-License-Identifier: GPL-2.0 >> + >> +Paravirtualized lock support for arm64 >> +== >> + >> +KVM/arm64 provids some hypervisor service calls to support a paravirtualized >> +guest obtaining the vcpu is currently running or not. >> + >> +Two new SMCCC compatible hypercalls are defined: >> + >> +* PV_LOCK_FEATURES: 0xC540 >> +* PV_LOCK_PREEMPTED: 0xC541 > > These values are in the "Standard Hypervisor Service Calls" section of > SMCCC - so is there a document that describes this features such that > other OSes or hypervisors can implement it? I'm also not entirely sure > of the process of ensuring that the IDs picked are non-conflicting. > > Otherwise if this is a KVM specific interface this should probably > belong within the "Vendor Specific Hypervisor Service Calls" section > along with some probing that the hypervisor is actually KVM. Although I > don't see anything KVM specific. Thanks for pointing it out to me! Actually, I also don't see any documents or KVM specific that describes this features. The values in the "Vendor Specific Hypervisor Service Calls" section may be more appropriate, such as the following * PV_LOCK_FEATURES: 0xC620 * PV_LOCK_PREEMPTED: 0xC621 Please let me know if you have any suggestions. > >> + >> +The existence of the PV_LOCK hypercall should be probed using the SMCCC 1.1 >> +ARCH_FEATURES mechanism before calling it. >> + >> +PV_LOCK_FEATURES >> += == >> +Function ID: (uint32)0xC540 >> +PV_call_id: (uint32)The function to query for support. >> +Return value: (int64) NOT_SUPPORTED (-1) or SUCCESS (0) if the >> relevant >> + PV-lock feature is supported by the >> hypervisor. >> += == >> + >> +PV_LOCK_PREEMPTED >> += == >> +Function ID: (uint32)0xC541 >> +Return value: (int64) NOT_SUPPORTED (-1) or SUCCESS (0) if the IPA >> of >> + this vcpu's pv data structure is configured by >> + the hypervisor. >> += == > >>From the code it looks like there's another argument for this SMC - the > physical address (or IPA) of a struct pvlock_vcpu_state. This structure > also needs to be described as it is part of the ABI. Will update. > > Steve > > . > Thanks, Zengruan ___ Virtualization mailing list Virtualization@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/virtualization
[PATCH 1/5] KVM: arm64: Document PV-lock interface
From: Zengruan Ye Introduce a paravirtualization interface for KVM/arm64 to obtain the vcpu is currently running or not. A hypercall interface is provided for the guest to interrogate the hypervisor's support for this interface and the location of the shared memory structures. Signed-off-by: Zengruan Ye --- Documentation/virt/kvm/arm/pvlock.rst | 31 +++ 1 file changed, 31 insertions(+) create mode 100644 Documentation/virt/kvm/arm/pvlock.rst diff --git a/Documentation/virt/kvm/arm/pvlock.rst b/Documentation/virt/kvm/arm/pvlock.rst new file mode 100644 index ..eec0c36edf17 --- /dev/null +++ b/Documentation/virt/kvm/arm/pvlock.rst @@ -0,0 +1,31 @@ +.. SPDX-License-Identifier: GPL-2.0 + +Paravirtualized lock support for arm64 +== + +KVM/arm64 provids some hypervisor service calls to support a paravirtualized +guest obtaining the vcpu is currently running or not. + +Two new SMCCC compatible hypercalls are defined: + +* PV_LOCK_FEATURES: 0xC540 +* PV_LOCK_PREEMPTED: 0xC541 + +The existence of the PV_LOCK hypercall should be probed using the SMCCC 1.1 +ARCH_FEATURES mechanism before calling it. + +PV_LOCK_FEATURES += == +Function ID: (uint32)0xC540 +PV_call_id: (uint32)The function to query for support. +Return value: (int64) NOT_SUPPORTED (-1) or SUCCESS (0) if the relevant + PV-lock feature is supported by the hypervisor. += == + +PV_LOCK_PREEMPTED += == +Function ID: (uint32)0xC541 +Return value: (int64) NOT_SUPPORTED (-1) or SUCCESS (0) if the IPA of + this vcpu's pv data structure is configured by + the hypervisor. += == -- 2.19.1 ___ Virtualization mailing list Virtualization@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/virtualization
[PATCH 5/5] KVM: arm64: Support the vcpu preemption check
From: Zengruan Ye
Support the vcpu_is_preempted() functionality under KVM/arm64. This will
enhance lock performance on overcommitted hosts (more runnable vcpus
than physical cpus in the system) as doing busy waits for preempted
vcpus will hurt system performance far worse than early yielding.
unix benchmark result:
host: kernel 5.5.0-rc1, HiSilicon Kunpeng920, 8 cpus
guest: kernel 5.5.0-rc1, 16 vcpus
test-case|after-patch| before-patch
+---+--
Dhrystone 2 using register variables | 334600751.0 lps | 335319028.3 lps
Double-Precision Whetstone | 32856.1 MWIPS | 32849.6 MWIPS
Execl Throughput | 3662.1 lps | 2718.0 lps
File Copy 1024 bufsize 2000 maxblocks |432906.4 KBps |158011.8 KBps
File Copy 256 bufsize 500 maxblocks|116023.0 KBps | 37664.0 KBps
File Copy 4096 bufsize 8000 maxblocks | 1432769.8 KBps |441108.8 KBps
Pipe Throughput| 6405029.6 lps | 6021457.6 lps
Pipe-based Context Switching |185872.7 lps |184255.3 lps
Process Creation | 4025.7 lps | 3706.6 lps
Shell Scripts (1 concurrent) | 6745.6 lpm | 6436.1 lpm
Shell Scripts (8 concurrent) | 998.7 lpm | 931.1 lpm
System Call Overhead | 3913363.1 lps | 3883287.8 lps
+---+--
System Benchmarks Index Score | 1835.1 | 1327.6
Signed-off-by: Zengruan Ye
---
arch/arm64/include/asm/paravirt.h | 3 +
arch/arm64/kernel/paravirt.c | 91 +++
arch/arm64/kernel/setup.c | 2 +
include/linux/cpuhotplug.h| 1 +
4 files changed, 97 insertions(+)
diff --git a/arch/arm64/include/asm/paravirt.h
b/arch/arm64/include/asm/paravirt.h
index 7b1c81b544bb..a2cd0183bbef 100644
--- a/arch/arm64/include/asm/paravirt.h
+++ b/arch/arm64/include/asm/paravirt.h
@@ -29,6 +29,8 @@ static inline u64 paravirt_steal_clock(int cpu)
int __init pv_time_init(void);
+int __init kvm_guest_init(void);
+
__visible bool __native_vcpu_is_preempted(int cpu);
static inline bool pv_vcpu_is_preempted(int cpu)
@@ -39,6 +41,7 @@ static inline bool pv_vcpu_is_preempted(int cpu)
#else
#define pv_time_init() do {} while (0)
+#define kvm_guest_init() do {} while (0)
#endif // CONFIG_PARAVIRT
diff --git a/arch/arm64/kernel/paravirt.c b/arch/arm64/kernel/paravirt.c
index d8f1ba8c22ce..a86dead40473 100644
--- a/arch/arm64/kernel/paravirt.c
+++ b/arch/arm64/kernel/paravirt.c
@@ -22,6 +22,7 @@
#include
#include
#include
+#include
struct static_key paravirt_steal_enabled;
struct static_key paravirt_steal_rq_enabled;
@@ -158,3 +159,93 @@ int __init pv_time_init(void)
return 0;
}
+
+DEFINE_PER_CPU(struct pvlock_vcpu_state, pvlock_vcpu_region) __aligned(64);
+EXPORT_PER_CPU_SYMBOL(pvlock_vcpu_region);
+
+static int pvlock_vcpu_state_dying_cpu(unsigned int cpu)
+{
+ struct pvlock_vcpu_state *reg;
+
+ reg = this_cpu_ptr(_vcpu_region);
+ if (!reg)
+ return -EFAULT;
+
+ memset(reg, 0, sizeof(*reg));
+
+ return 0;
+}
+
+static int init_pvlock_vcpu_state(unsigned int cpu)
+{
+ struct pvlock_vcpu_state *reg;
+ struct arm_smccc_res res;
+
+ reg = this_cpu_ptr(_vcpu_region);
+ if (!reg)
+ return -EFAULT;
+
+ /* Pass the memory address to host via hypercall */
+ arm_smccc_1_1_invoke(ARM_SMCCC_HV_PV_LOCK_PREEMPTED,
+virt_to_phys(reg), );
+
+ return 0;
+}
+
+static bool kvm_vcpu_is_preempted(int cpu)
+{
+ struct pvlock_vcpu_state *reg = _cpu(pvlock_vcpu_region, cpu);
+
+ if (reg)
+ return !!(reg->preempted & 1);
+
+ return false;
+}
+
+static int kvm_arm_init_pvlock(void)
+{
+ int ret;
+
+ ret = cpuhp_setup_state(CPUHP_AP_ARM_KVM_PVLOCK_STARTING,
+ "hypervisor/arm/pvlock:starting",
+ init_pvlock_vcpu_state,
+ pvlock_vcpu_state_dying_cpu);
+ if (ret < 0)
+ return ret;
+
+ pv_ops.lock.vcpu_is_preempted = kvm_vcpu_is_preempted;
+
+ pr_info("using PV-lock preempted\n");
+
+ return 0;
+}
+
+static bool has_kvm_pvlock(void)
+{
+ struct arm_smccc_res res;
+
+ /* To detect the presence of PV lock support we require SMCCC 1.1+ */
+ if (psci_ops.smccc_version < SMCCC_VERSION_1_1)
+ return false;
+
+ arm_smccc_1_1_invoke(ARM_SMCCC_ARCH_FEATURES_FUNC_ID,
+ARM_SMCCC_HV_PV_LOCK_FEATURES, );
+
+ if (res.a0 != SMCCC_RET_SUCCESS)
+ return false;
+
+ return true;
+}
+
+int __init kvm_guest_init(void)
+{
+
[PATCH 2/5] KVM: arm64: Implement PV_LOCK_FEATURES call
From: Zengruan Ye
This provides a mechanism for querying which paravirtualized lock
features are available in this hypervisor.
Also add the header file which defines the ABI for the paravirtualized
lock features we're about to add.
Signed-off-by: Zengruan Ye
---
arch/arm64/include/asm/pvlock-abi.h | 16
include/linux/arm-smccc.h | 13 +
virt/kvm/arm/hypercalls.c | 3 +++
3 files changed, 32 insertions(+)
create mode 100644 arch/arm64/include/asm/pvlock-abi.h
diff --git a/arch/arm64/include/asm/pvlock-abi.h
b/arch/arm64/include/asm/pvlock-abi.h
new file mode 100644
index ..06e0c3d7710a
--- /dev/null
+++ b/arch/arm64/include/asm/pvlock-abi.h
@@ -0,0 +1,16 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright(c) 2019 Huawei Technologies Co., Ltd
+ * Author: Zengruan Ye
+ */
+
+#ifndef __ASM_PVLOCK_ABI_H
+#define __ASM_PVLOCK_ABI_H
+
+struct pvlock_vcpu_state {
+ __le64 preempted;
+ /* Structure must be 64 byte aligned, pad to that size */
+ u8 padding[56];
+} __packed;
+
+#endif
diff --git a/include/linux/arm-smccc.h b/include/linux/arm-smccc.h
index 59494df0f55b..59e65a951959 100644
--- a/include/linux/arm-smccc.h
+++ b/include/linux/arm-smccc.h
@@ -377,5 +377,18 @@ asmlinkage void __arm_smccc_hvc(unsigned long a0, unsigned
long a1,
ARM_SMCCC_OWNER_STANDARD_HYP,\
0x21)
+/* Paravirtualised lock calls */
+#define ARM_SMCCC_HV_PV_LOCK_FEATURES \
+ ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL, \
+ ARM_SMCCC_SMC_64,\
+ ARM_SMCCC_OWNER_STANDARD_HYP,\
+ 0x40)
+
+#define ARM_SMCCC_HV_PV_LOCK_PREEMPTED \
+ ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL, \
+ ARM_SMCCC_SMC_64,\
+ ARM_SMCCC_OWNER_STANDARD_HYP,\
+ 0x41)
+
#endif /*__ASSEMBLY__*/
#endif /*__LINUX_ARM_SMCCC_H*/
diff --git a/virt/kvm/arm/hypercalls.c b/virt/kvm/arm/hypercalls.c
index 550dfa3e53cd..ff13871fd85a 100644
--- a/virt/kvm/arm/hypercalls.c
+++ b/virt/kvm/arm/hypercalls.c
@@ -52,6 +52,9 @@ int kvm_hvc_call_handler(struct kvm_vcpu *vcpu)
case ARM_SMCCC_HV_PV_TIME_FEATURES:
val = SMCCC_RET_SUCCESS;
break;
+ case ARM_SMCCC_HV_PV_LOCK_FEATURES:
+ val = SMCCC_RET_SUCCESS;
+ break;
}
break;
case ARM_SMCCC_HV_PV_TIME_FEATURES:
--
2.19.1
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[PATCH 0/5] KVM: arm64: vcpu preempted check support
From: Zengruan Ye This patch set aims to support the vcpu_is_preempted() functionality under KVM/arm64, which allowing the guest to obtain the vcpu is currently running or not. This will enhance lock performance on overcommitted hosts (more runnable vcpus than physical cpus in the system) as doing busy waits for preempted vcpus will hurt system performance far worse than early yielding. We have observed some performace improvements in uninx benchmark tests. unix benchmark result: host: kernel 5.5.0-rc1, HiSilicon Kunpeng920, 8 cpus guest: kernel 5.5.0-rc1, 16 vcpus test-case|after-patch| before-patch +---+-- Dhrystone 2 using register variables | 334600751.0 lps | 335319028.3 lps Double-Precision Whetstone | 32856.1 MWIPS | 32849.6 MWIPS Execl Throughput | 3662.1 lps |2718.0 lps File Copy 1024 bufsize 2000 maxblocks |432906.4 KBps | 158011.8 KBps File Copy 256 bufsize 500 maxblocks|116023.0 KBps | 37664.0 KBps File Copy 4096 bufsize 8000 maxblocks | 1432769.8 KBps | 441108.8 KBps Pipe Throughput| 6405029.6 lps | 6021457.6 lps Pipe-based Context Switching |185872.7 lps | 184255.3 lps Process Creation | 4025.7 lps |3706.6 lps Shell Scripts (1 concurrent) | 6745.6 lpm |6436.1 lpm Shell Scripts (8 concurrent) | 998.7 lpm | 931.1 lpm System Call Overhead | 3913363.1 lps | 3883287.8 lps +---+-- System Benchmarks Index Score | 1835.1 |1327.6 Zengruan Ye (5): KVM: arm64: Document PV-lock interface KVM: arm64: Implement PV_LOCK_FEATURES call KVM: arm64: Support pvlock preempted via shared structure KVM: arm64: Add interface to support vcpu preempted check KVM: arm64: Support the vcpu preemption check Documentation/virt/kvm/arm/pvlock.rst | 31 + arch/arm/include/asm/kvm_host.h| 13 arch/arm64/include/asm/kvm_host.h | 17 + arch/arm64/include/asm/paravirt.h | 15 arch/arm64/include/asm/pvlock-abi.h| 16 + arch/arm64/include/asm/spinlock.h | 7 ++ arch/arm64/kernel/Makefile | 2 +- arch/arm64/kernel/paravirt-spinlocks.c | 13 arch/arm64/kernel/paravirt.c | 95 +- arch/arm64/kernel/setup.c | 2 + arch/arm64/kvm/Makefile| 1 + include/linux/arm-smccc.h | 13 include/linux/cpuhotplug.h | 1 + virt/kvm/arm/arm.c | 8 +++ virt/kvm/arm/hypercalls.c | 7 ++ virt/kvm/arm/pvlock.c | 21 ++ 16 files changed, 260 insertions(+), 2 deletions(-) create mode 100644 Documentation/virt/kvm/arm/pvlock.rst create mode 100644 arch/arm64/include/asm/pvlock-abi.h create mode 100644 arch/arm64/kernel/paravirt-spinlocks.c create mode 100644 virt/kvm/arm/pvlock.c -- 2.19.1 ___ Virtualization mailing list Virtualization@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/virtualization
[PATCH 3/5] KVM: arm64: Support pvlock preempted via shared structure
From: Zengruan Ye
Implement the service call for configuring a shared structure between a
vcpu and the hypervisor in which the hypervisor can tell the vcpu is
running or not.
The preempted field is zero if 1) some old KVM deos not support this filed.
2) the vcpu is not preempted. Other values means the vcpu has been preempted.
Signed-off-by: Zengruan Ye
---
arch/arm/include/asm/kvm_host.h | 13 +
arch/arm64/include/asm/kvm_host.h | 17 +
arch/arm64/kvm/Makefile | 1 +
virt/kvm/arm/arm.c| 8
virt/kvm/arm/hypercalls.c | 4
virt/kvm/arm/pvlock.c | 21 +
6 files changed, 64 insertions(+)
create mode 100644 virt/kvm/arm/pvlock.c
diff --git a/arch/arm/include/asm/kvm_host.h b/arch/arm/include/asm/kvm_host.h
index 556cd818eccf..098375f1c89e 100644
--- a/arch/arm/include/asm/kvm_host.h
+++ b/arch/arm/include/asm/kvm_host.h
@@ -356,6 +356,19 @@ static inline bool kvm_arm_is_pvtime_enabled(struct
kvm_vcpu_arch *vcpu_arch)
return false;
}
+static inline void kvm_arm_pvlock_preempted_init(struct kvm_vcpu_arch
*vcpu_arch)
+{
+}
+
+static inline bool kvm_arm_is_pvlock_preempted_ready(struct kvm_vcpu_arch
*vcpu_arch)
+{
+ return false;
+}
+
+static inline void kvm_update_pvlock_preempted(struct kvm_vcpu *vcpu, u64
preempted)
+{
+}
+
void kvm_mmu_wp_memory_region(struct kvm *kvm, int slot);
struct kvm_vcpu *kvm_mpidr_to_vcpu(struct kvm *kvm, unsigned long mpidr);
diff --git a/arch/arm64/include/asm/kvm_host.h
b/arch/arm64/include/asm/kvm_host.h
index c61260cf63c5..d9b2a21a87ac 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -354,6 +354,11 @@ struct kvm_vcpu_arch {
u64 last_steal;
gpa_t base;
} steal;
+
+ /* Guest PV lock state */
+ struct {
+ gpa_t base;
+ } pv;
};
/* Pointer to the vcpu's SVE FFR for sve_{save,load}_state() */
@@ -515,6 +520,18 @@ static inline bool kvm_arm_is_pvtime_enabled(struct
kvm_vcpu_arch *vcpu_arch)
return (vcpu_arch->steal.base != GPA_INVALID);
}
+static inline void kvm_arm_pvlock_preempted_init(struct kvm_vcpu_arch
*vcpu_arch)
+{
+ vcpu_arch->pv.base = GPA_INVALID;
+}
+
+static inline bool kvm_arm_is_pvlock_preempted_ready(struct kvm_vcpu_arch
*vcpu_arch)
+{
+ return (vcpu_arch->pv.base != GPA_INVALID);
+}
+
+void kvm_update_pvlock_preempted(struct kvm_vcpu *vcpu, u64 preempted);
+
void kvm_set_sei_esr(struct kvm_vcpu *vcpu, u64 syndrome);
struct kvm_vcpu *kvm_mpidr_to_vcpu(struct kvm *kvm, unsigned long mpidr);
diff --git a/arch/arm64/kvm/Makefile b/arch/arm64/kvm/Makefile
index 5ffbdc39e780..e4591f56d5f1 100644
--- a/arch/arm64/kvm/Makefile
+++ b/arch/arm64/kvm/Makefile
@@ -15,6 +15,7 @@ kvm-$(CONFIG_KVM_ARM_HOST) += $(KVM)/arm/arm.o
$(KVM)/arm/mmu.o $(KVM)/arm/mmio.
kvm-$(CONFIG_KVM_ARM_HOST) += $(KVM)/arm/psci.o $(KVM)/arm/perf.o
kvm-$(CONFIG_KVM_ARM_HOST) += $(KVM)/arm/hypercalls.o
kvm-$(CONFIG_KVM_ARM_HOST) += $(KVM)/arm/pvtime.o
+kvm-$(CONFIG_KVM_ARM_HOST) += $(KVM)/arm/pvlock.o
kvm-$(CONFIG_KVM_ARM_HOST) += inject_fault.o regmap.o va_layout.o
kvm-$(CONFIG_KVM_ARM_HOST) += hyp.o hyp-init.o handle_exit.o
diff --git a/virt/kvm/arm/arm.c b/virt/kvm/arm/arm.c
index 12e0280291ce..c562f62fdd45 100644
--- a/virt/kvm/arm/arm.c
+++ b/virt/kvm/arm/arm.c
@@ -383,6 +383,8 @@ int kvm_arch_vcpu_init(struct kvm_vcpu *vcpu)
kvm_arm_pvtime_vcpu_init(>arch);
+ kvm_arm_pvlock_preempted_init(>arch);
+
return kvm_vgic_vcpu_init(vcpu);
}
@@ -421,6 +423,9 @@ void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
vcpu_set_wfx_traps(vcpu);
vcpu_ptrauth_setup_lazy(vcpu);
+
+ if (kvm_arm_is_pvlock_preempted_ready(>arch))
+ kvm_update_pvlock_preempted(vcpu, 0);
}
void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu)
@@ -434,6 +439,9 @@ void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu)
vcpu->cpu = -1;
kvm_arm_set_running_vcpu(NULL);
+
+ if (kvm_arm_is_pvlock_preempted_ready(>arch))
+ kvm_update_pvlock_preempted(vcpu, 1);
}
static void vcpu_power_off(struct kvm_vcpu *vcpu)
diff --git a/virt/kvm/arm/hypercalls.c b/virt/kvm/arm/hypercalls.c
index ff13871fd85a..5964982ccd05 100644
--- a/virt/kvm/arm/hypercalls.c
+++ b/virt/kvm/arm/hypercalls.c
@@ -65,6 +65,10 @@ int kvm_hvc_call_handler(struct kvm_vcpu *vcpu)
if (gpa != GPA_INVALID)
val = gpa;
break;
+ case ARM_SMCCC_HV_PV_LOCK_PREEMPTED:
+ vcpu->arch.pv.base = smccc_get_arg1(vcpu);
+ val = SMCCC_RET_SUCCESS;
+ break;
default:
return kvm_psci_call(vcpu);
}
diff --git a/virt/kvm/arm/pvlock.c b/virt/kvm/arm/pvlock.c
new file mode 100644
index ..c3464958b0f5
--- /dev/null
+++ b/virt/kvm/arm/pvlock.c
@@ -0,0 +1,21 @@
+/*
[PATCH 4/5] KVM: arm64: Add interface to support vcpu preempted check
From: Zengruan Ye
This is to fix some lock holder preemption issues. Some other locks
implementation do a spin loop before acquiring the lock itself.
Currently kernel has an interface of bool vcpu_is_preempted(int cpu). It
takes the cpu as parameter and return true if the cpu is preempted.
Then kernel can break the spin loops upon the retval of vcpu_is_preempted.
As kernel has used this interface, So lets support it.
Signed-off-by: Zengruan Ye
---
arch/arm64/include/asm/paravirt.h | 12
arch/arm64/include/asm/spinlock.h | 7 +++
arch/arm64/kernel/Makefile | 2 +-
arch/arm64/kernel/paravirt-spinlocks.c | 13 +
arch/arm64/kernel/paravirt.c | 4 +++-
5 files changed, 36 insertions(+), 2 deletions(-)
create mode 100644 arch/arm64/kernel/paravirt-spinlocks.c
diff --git a/arch/arm64/include/asm/paravirt.h
b/arch/arm64/include/asm/paravirt.h
index cf3a0fd7c1a7..7b1c81b544bb 100644
--- a/arch/arm64/include/asm/paravirt.h
+++ b/arch/arm64/include/asm/paravirt.h
@@ -11,8 +11,13 @@ struct pv_time_ops {
unsigned long long (*steal_clock)(int cpu);
};
+struct pv_lock_ops {
+ bool (*vcpu_is_preempted)(int cpu);
+};
+
struct paravirt_patch_template {
struct pv_time_ops time;
+ struct pv_lock_ops lock;
};
extern struct paravirt_patch_template pv_ops;
@@ -24,6 +29,13 @@ static inline u64 paravirt_steal_clock(int cpu)
int __init pv_time_init(void);
+__visible bool __native_vcpu_is_preempted(int cpu);
+
+static inline bool pv_vcpu_is_preempted(int cpu)
+{
+ return pv_ops.lock.vcpu_is_preempted(cpu);
+}
+
#else
#define pv_time_init() do {} while (0)
diff --git a/arch/arm64/include/asm/spinlock.h
b/arch/arm64/include/asm/spinlock.h
index b093b287babf..45ff1b2949a6 100644
--- a/arch/arm64/include/asm/spinlock.h
+++ b/arch/arm64/include/asm/spinlock.h
@@ -7,8 +7,15 @@
#include
#include
+#include
/* See include/linux/spinlock.h */
#define smp_mb__after_spinlock() smp_mb()
+#define vcpu_is_preempted vcpu_is_preempted
+static inline bool vcpu_is_preempted(long cpu)
+{
+ return pv_vcpu_is_preempted(cpu);
+}
+
#endif /* __ASM_SPINLOCK_H */
diff --git a/arch/arm64/kernel/Makefile b/arch/arm64/kernel/Makefile
index fc6488660f64..b23cdae433a4 100644
--- a/arch/arm64/kernel/Makefile
+++ b/arch/arm64/kernel/Makefile
@@ -50,7 +50,7 @@ obj-$(CONFIG_ARMV8_DEPRECATED)+=
armv8_deprecated.o
obj-$(CONFIG_ACPI) += acpi.o
obj-$(CONFIG_ACPI_NUMA)+= acpi_numa.o
obj-$(CONFIG_ARM64_ACPI_PARKING_PROTOCOL) += acpi_parking_protocol.o
-obj-$(CONFIG_PARAVIRT) += paravirt.o
+obj-$(CONFIG_PARAVIRT) += paravirt.o paravirt-spinlocks.o
obj-$(CONFIG_RANDOMIZE_BASE) += kaslr.o
obj-$(CONFIG_HIBERNATION) += hibernate.o hibernate-asm.o
obj-$(CONFIG_KEXEC_CORE) += machine_kexec.o relocate_kernel.o
\
diff --git a/arch/arm64/kernel/paravirt-spinlocks.c
b/arch/arm64/kernel/paravirt-spinlocks.c
new file mode 100644
index ..718aa773d45c
--- /dev/null
+++ b/arch/arm64/kernel/paravirt-spinlocks.c
@@ -0,0 +1,13 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright(c) 2019 Huawei Technologies Co., Ltd
+ * Author: Zengruan Ye
+ */
+
+#include
+#include
+
+__visible bool __native_vcpu_is_preempted(int cpu)
+{
+ return false;
+}
diff --git a/arch/arm64/kernel/paravirt.c b/arch/arm64/kernel/paravirt.c
index 1ef702b0be2d..d8f1ba8c22ce 100644
--- a/arch/arm64/kernel/paravirt.c
+++ b/arch/arm64/kernel/paravirt.c
@@ -26,7 +26,9 @@
struct static_key paravirt_steal_enabled;
struct static_key paravirt_steal_rq_enabled;
-struct paravirt_patch_template pv_ops;
+struct paravirt_patch_template pv_ops = {
+ .lock.vcpu_is_preempted = __native_vcpu_is_preempted,
+};
EXPORT_SYMBOL_GPL(pv_ops);
struct pv_time_stolen_time_region {
--
2.19.1
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