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* [PATCH 0/2] Fix the allocation of pv cpu mask
@ 2020-09-14  9:11 lihaiwei.kernel
  2020-09-14  9:11 ` [PATCH 1/2] KVM: Fix the build error lihaiwei.kernel
  2020-09-14  9:11 ` [PATCH 2/2] KVM: Check if __pv_cpu_mask was allocated instead of assigning ops too late lihaiwei.kernel
  0 siblings, 2 replies; 6+ messages in thread
From: lihaiwei.kernel @ 2020-09-14  9:11 UTC (permalink / raw)
  To: linux-kernel, kvm, x86
  Cc: pbonzini, sean.j.christopherson, vkuznets, wanpengli, jmattson,
	joro, tglx, mingo, bp, hpa, lihaiwei

From: Haiwei Li <lihaiwei@tencent.com>

Hi,

There is a old version patch of 'KVM: Check the allocation of pv cpu mask'
in upstream. The v2 and what is discussed is in url:

https://lore.kernel.org/kvm/87o8mlooki.fsf@vitty.brq.redhat.com/

In this patch, i fix the build error and make changes as suggested.

Haiwei Li (2):
  KVM: Fix the build error
  KVM: Check if __pv_cpu_mask was allocated instead of assigning ops too
    late

 arch/x86/kernel/kvm.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

-- 
2.18.4


^ permalink raw reply	[flat|nested] 6+ messages in thread

* [PATCH 1/2] KVM: Fix the build error
  2020-09-14  9:11 [PATCH 0/2] Fix the allocation of pv cpu mask lihaiwei.kernel
@ 2020-09-14  9:11 ` lihaiwei.kernel
  2020-09-20 13:09   ` Paolo Bonzini
  2020-09-14  9:11 ` [PATCH 2/2] KVM: Check if __pv_cpu_mask was allocated instead of assigning ops too late lihaiwei.kernel
  1 sibling, 1 reply; 6+ messages in thread
From: lihaiwei.kernel @ 2020-09-14  9:11 UTC (permalink / raw)
  To: linux-kernel, kvm, x86
  Cc: pbonzini, sean.j.christopherson, vkuznets, wanpengli, jmattson,
	joro, tglx, mingo, bp, hpa, lihaiwei, kernel test robot

From: Haiwei Li <lihaiwei@tencent.com>

When CONFIG_SMP is not set, an build error occurs with message "error:
use of undeclared identifier 'kvm_send_ipi_mask_allbutself'"

Fixes: 0f990222108d ("KVM: Check the allocation of pv cpu mask", 2020-09-01)
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Haiwei Li <lihaiwei@tencent.com>
---
 arch/x86/kernel/kvm.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c
index 1b51b727b140..7e8be0421720 100644
--- a/arch/x86/kernel/kvm.c
+++ b/arch/x86/kernel/kvm.c
@@ -797,7 +797,9 @@ static __init int kvm_alloc_cpumask(void)
 			}
 		}
 
+#if defined(CONFIG_SMP)
 	apic->send_IPI_mask_allbutself = kvm_send_ipi_mask_allbutself;
+#endif
 	pv_ops.mmu.flush_tlb_others = kvm_flush_tlb_others;
 	return 0;
 
-- 
2.18.4


^ permalink raw reply	[flat|nested] 6+ messages in thread

* [PATCH 2/2] KVM: Check if __pv_cpu_mask was allocated instead of assigning ops too late
  2020-09-14  9:11 [PATCH 0/2] Fix the allocation of pv cpu mask lihaiwei.kernel
  2020-09-14  9:11 ` [PATCH 1/2] KVM: Fix the build error lihaiwei.kernel
@ 2020-09-14  9:11 ` lihaiwei.kernel
  1 sibling, 0 replies; 6+ messages in thread
From: lihaiwei.kernel @ 2020-09-14  9:11 UTC (permalink / raw)
  To: linux-kernel, kvm, x86
  Cc: pbonzini, sean.j.christopherson, vkuznets, wanpengli, jmattson,
	joro, tglx, mingo, bp, hpa, lihaiwei

From: Haiwei Li <lihaiwei@tencent.com>

Without this patch, kvm_flush_tlb_others is not called. We can always check
if __pv_cpu_mask was allocated and revert back to the architectural path if
not.

Suggested-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Haiwei Li <lihaiwei@tencent.com>
---
 arch/x86/kernel/kvm.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c
index 7e8be0421720..3c6c516d9828 100644
--- a/arch/x86/kernel/kvm.c
+++ b/arch/x86/kernel/kvm.c
@@ -553,7 +553,6 @@ static void kvm_send_ipi_mask_allbutself(const struct cpumask *mask, int vector)
 static void kvm_setup_pv_ipi(void)
 {
 	apic->send_IPI_mask = kvm_send_ipi_mask;
-	apic->send_IPI_mask_allbutself = kvm_send_ipi_mask_allbutself;
 	pr_info("setup PV IPIs\n");
 }
 
@@ -619,6 +618,11 @@ static void kvm_flush_tlb_others(const struct cpumask *cpumask,
 	struct kvm_steal_time *src;
 	struct cpumask *flushmask = this_cpu_cpumask_var_ptr(__pv_cpu_mask);
 
+	if (unlikely(!flushmask)) {
+		native_flush_tlb_others(cpumask, info);
+		return;
+	}
+
 	cpumask_copy(flushmask, cpumask);
 	/*
 	 * We have to call flush only on online vCPUs. And
@@ -652,6 +656,7 @@ static void __init kvm_guest_init(void)
 	}
 
 	if (pv_tlb_flush_supported()) {
+		pv_ops.mmu.flush_tlb_others = kvm_flush_tlb_others;
 		pv_ops.mmu.tlb_remove_table = tlb_remove_table;
 		pr_info("KVM setup pv remote TLB flush\n");
 	}
@@ -800,7 +805,6 @@ static __init int kvm_alloc_cpumask(void)
 #if defined(CONFIG_SMP)
 	apic->send_IPI_mask_allbutself = kvm_send_ipi_mask_allbutself;
 #endif
-	pv_ops.mmu.flush_tlb_others = kvm_flush_tlb_others;
 	return 0;
 
 zalloc_cpumask_fail:
-- 
2.18.4


^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH 1/2] KVM: Fix the build error
  2020-09-14  9:11 ` [PATCH 1/2] KVM: Fix the build error lihaiwei.kernel
@ 2020-09-20 13:09   ` Paolo Bonzini
  2020-09-21  0:23     ` Haiwei Li
  2020-09-23  5:02     ` Haiwei Li
  0 siblings, 2 replies; 6+ messages in thread
From: Paolo Bonzini @ 2020-09-20 13:09 UTC (permalink / raw)
  To: lihaiwei.kernel, linux-kernel, kvm, x86
  Cc: sean.j.christopherson, vkuznets, wanpengli, jmattson, joro, tglx,
	mingo, bp, hpa, lihaiwei, kernel test robot

On 14/09/20 11:11, lihaiwei.kernel@gmail.com wrote:
> From: Haiwei Li <lihaiwei@tencent.com>
> 
> When CONFIG_SMP is not set, an build error occurs with message "error:
> use of undeclared identifier 'kvm_send_ipi_mask_allbutself'"
> 
> Fixes: 0f990222108d ("KVM: Check the allocation of pv cpu mask", 2020-09-01)
> Reported-by: kernel test robot <lkp@intel.com>
> Signed-off-by: Haiwei Li <lihaiwei@tencent.com>
> ---
>  arch/x86/kernel/kvm.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c
> index 1b51b727b140..7e8be0421720 100644
> --- a/arch/x86/kernel/kvm.c
> +++ b/arch/x86/kernel/kvm.c
> @@ -797,7 +797,9 @@ static __init int kvm_alloc_cpumask(void)
>  			}
>  		}
>  
> +#if defined(CONFIG_SMP)
>  	apic->send_IPI_mask_allbutself = kvm_send_ipi_mask_allbutself;
> +#endif
>  	pv_ops.mmu.flush_tlb_others = kvm_flush_tlb_others;
>  	return 0;
>  
> 

If CONFIG_SMP is not set you don't need kvm_alloc_cpumask or
pv_ops.mmu.flush_tlb_others at all.  Can you squash these two into the
original patch and re-submit for 5.10?

Paolo


^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH 1/2] KVM: Fix the build error
  2020-09-20 13:09   ` Paolo Bonzini
@ 2020-09-21  0:23     ` Haiwei Li
  2020-09-23  5:02     ` Haiwei Li
  1 sibling, 0 replies; 6+ messages in thread
From: Haiwei Li @ 2020-09-21  0:23 UTC (permalink / raw)
  To: Paolo Bonzini, linux-kernel, kvm, x86
  Cc: sean.j.christopherson, vkuznets, wanpengli, jmattson, joro, tglx,
	mingo, bp, hpa, lihaiwei, kernel test robot



On 20/9/20 21:09, Paolo Bonzini wrote:
> On 14/09/20 11:11, lihaiwei.kernel@gmail.com wrote:
>> From: Haiwei Li <lihaiwei@tencent.com>
>>
>> When CONFIG_SMP is not set, an build error occurs with message "error:
>> use of undeclared identifier 'kvm_send_ipi_mask_allbutself'"
>>
>> Fixes: 0f990222108d ("KVM: Check the allocation of pv cpu mask", 2020-09-01)
>> Reported-by: kernel test robot <lkp@intel.com>
>> Signed-off-by: Haiwei Li <lihaiwei@tencent.com>
>> ---
>>   arch/x86/kernel/kvm.c | 2 ++
>>   1 file changed, 2 insertions(+)
>>
>> diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c
>> index 1b51b727b140..7e8be0421720 100644
>> --- a/arch/x86/kernel/kvm.c
>> +++ b/arch/x86/kernel/kvm.c
>> @@ -797,7 +797,9 @@ static __init int kvm_alloc_cpumask(void)
>>   			}
>>   		}
>>   
>> +#if defined(CONFIG_SMP)
>>   	apic->send_IPI_mask_allbutself = kvm_send_ipi_mask_allbutself;
>> +#endif
>>   	pv_ops.mmu.flush_tlb_others = kvm_flush_tlb_others;
>>   	return 0;
>>   
>>
> 
> If CONFIG_SMP is not set you don't need kvm_alloc_cpumask or
> pv_ops.mmu.flush_tlb_others at all.  Can you squash these two into the
> original patch and re-submit for 5.10?

I will, thanks.

Haiwei Li

^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH 1/2] KVM: Fix the build error
  2020-09-20 13:09   ` Paolo Bonzini
  2020-09-21  0:23     ` Haiwei Li
@ 2020-09-23  5:02     ` Haiwei Li
  1 sibling, 0 replies; 6+ messages in thread
From: Haiwei Li @ 2020-09-23  5:02 UTC (permalink / raw)
  To: Paolo Bonzini, linux-kernel, kvm, x86
  Cc: sean.j.christopherson, vkuznets, wanpengli, jmattson, joro, tglx,
	mingo, bp, hpa, lihaiwei, kernel test robot

On 20/9/20 21:09, Paolo Bonzini wrote:
> On 14/09/20 11:11, lihaiwei.kernel@gmail.com wrote:
>> From: Haiwei Li <lihaiwei@tencent.com>
>>
>> When CONFIG_SMP is not set, an build error occurs with message "error:
>> use of undeclared identifier 'kvm_send_ipi_mask_allbutself'"
>>
>> Fixes: 0f990222108d ("KVM: Check the allocation of pv cpu mask", 2020-09-01)
>> Reported-by: kernel test robot <lkp@intel.com>
>> Signed-off-by: Haiwei Li <lihaiwei@tencent.com>
>> ---
>>   arch/x86/kernel/kvm.c | 2 ++
>>   1 file changed, 2 insertions(+)
>>
>> diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c
>> index 1b51b727b140..7e8be0421720 100644
>> --- a/arch/x86/kernel/kvm.c
>> +++ b/arch/x86/kernel/kvm.c
>> @@ -797,7 +797,9 @@ static __init int kvm_alloc_cpumask(void)
>>   			}
>>   		}
>>   
>> +#if defined(CONFIG_SMP)
>>   	apic->send_IPI_mask_allbutself = kvm_send_ipi_mask_allbutself;
>> +#endif
>>   	pv_ops.mmu.flush_tlb_others = kvm_flush_tlb_others;
>>   	return 0;
>>   
>>
> 
> If CONFIG_SMP is not set you don't need kvm_alloc_cpumask or
> pv_ops.mmu.flush_tlb_others at all.  Can you squash these two into the
> original patch and re-submit for 5.10?

Hi, Paolo

I'm a little confused. Function kvm_flush_tlb_others doesn't seem to be 
related to CONFIG_SMP.

And my patch like:

---
  arch/x86/kernel/kvm.c | 27 ++++++++++++++++++++++++---
  1 file changed, 24 insertions(+), 3 deletions(-)

diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c
index 9663ba31347c..1e5da6db519c 100644
--- a/arch/x86/kernel/kvm.c
+++ b/arch/x86/kernel/kvm.c
@@ -553,7 +553,6 @@ static void kvm_send_ipi_mask_allbutself(const 
struct cpumask *mask, int vector)
  static void kvm_setup_pv_ipi(void)
  {
  	apic->send_IPI_mask = kvm_send_ipi_mask;
-	apic->send_IPI_mask_allbutself = kvm_send_ipi_mask_allbutself;
  	pr_info("setup PV IPIs\n");
  }

@@ -619,6 +618,11 @@ static void kvm_flush_tlb_others(const struct 
cpumask *cpumask,
  	struct kvm_steal_time *src;
  	struct cpumask *flushmask = this_cpu_cpumask_var_ptr(__pv_cpu_mask);

+	if (unlikely(!flushmask)) {
+		native_flush_tlb_others(cpumask, info);
+		return;
+	}
+
  	cpumask_copy(flushmask, cpumask);
  	/*
  	 * We have to call flush only on online vCPUs. And
@@ -765,6 +769,14 @@ static __init int activate_jump_labels(void)
  }
  arch_initcall(activate_jump_labels);

+static void kvm_free_cpumask(void)
+{
+	unsigned int cpu;
+
+	for_each_possible_cpu(cpu)
+		free_cpumask_var(per_cpu(__pv_cpu_mask, cpu));
+}
+
  static __init int kvm_alloc_cpumask(void)
  {
  	int cpu;
@@ -783,11 +795,20 @@ static __init int kvm_alloc_cpumask(void)

  	if (alloc)
  		for_each_possible_cpu(cpu) {
-			zalloc_cpumask_var_node(per_cpu_ptr(&__pv_cpu_mask, cpu),
-				GFP_KERNEL, cpu_to_node(cpu));
+			if (!zalloc_cpumask_var_node(
+				per_cpu_ptr(&__pv_cpu_mask, cpu),
+				GFP_KERNEL, cpu_to_node(cpu)))
+				goto zalloc_cpumask_fail;
  		}

+#if defined(CONFIG_SMP)
+	apic->send_IPI_mask_allbutself = kvm_send_ipi_mask_allbutself;
+#endif
  	return 0;
+
+zalloc_cpumask_fail:
+	kvm_free_cpumask();
+	return -ENOMEM;
  }
  arch_initcall(kvm_alloc_cpumask);

--
2.18.4

Do you have any suggestion? Thanks.

     Haiwei

^ permalink raw reply	[flat|nested] 6+ messages in thread

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Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-09-14  9:11 [PATCH 0/2] Fix the allocation of pv cpu mask lihaiwei.kernel
2020-09-14  9:11 ` [PATCH 1/2] KVM: Fix the build error lihaiwei.kernel
2020-09-20 13:09   ` Paolo Bonzini
2020-09-21  0:23     ` Haiwei Li
2020-09-23  5:02     ` Haiwei Li
2020-09-14  9:11 ` [PATCH 2/2] KVM: Check if __pv_cpu_mask was allocated instead of assigning ops too late lihaiwei.kernel

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