diff mbox

[1/2] KVM: x86: fix APIC page invalidation

Message ID 20171130180546.4331-1-rkrcmar@redhat.com (mailing list archive)
State New, archived
Headers show

Commit Message

Radim Krčmář Nov. 30, 2017, 6:05 p.m. UTC
Implementation of the unpinned APIC page didn't update the VMCS address
cache when invalidation was done through range mmu notifiers.
This became a problem when the page notifier was removed.

Re-introduce the arch-specific helper and call it from ...range_start.

Fixes: 38b9917350cb ("kvm: vmx: Implement set_apic_access_page_addr")
Fixes: 369ea8242c0f ("mm/rmap: update to new mmu_notifier semantic v2")
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
---
 arch/x86/include/asm/kvm_host.h |  3 +++
 arch/x86/kvm/x86.c              | 14 ++++++++++++++
 virt/kvm/kvm_main.c             |  8 ++++++++
 3 files changed, 25 insertions(+)

Comments

Fabian Grünbichler Dec. 1, 2017, 12:21 p.m. UTC | #1
On Thu, Nov 30, 2017 at 07:05:45PM +0100, Radim Krčmář wrote:
> Implementation of the unpinned APIC page didn't update the VMCS address
> cache when invalidation was done through range mmu notifiers.
> This became a problem when the page notifier was removed.
> 
> Re-introduce the arch-specific helper and call it from ...range_start.
> 
> Fixes: 38b9917350cb ("kvm: vmx: Implement set_apic_access_page_addr")
> Fixes: 369ea8242c0f ("mm/rmap: update to new mmu_notifier semantic v2")
> Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>

Thanks for the fast reaction!

Some initial test rounds with just Patch 1 applied on top of 4.13.8 show
no blue screens, will do more tests also with 4.14.3 on Monday and
report back.

4.15-rc1 crashes for unrelated reasons, but I can re-run the tests once
a stable-enough rc has been cut..
Paolo Bonzini Dec. 1, 2017, 3:27 p.m. UTC | #2
On 30/11/2017 19:05, Radim Krčmář wrote:
> Implementation of the unpinned APIC page didn't update the VMCS address
> cache when invalidation was done through range mmu notifiers.
> This became a problem when the page notifier was removed.
> 
> Re-introduce the arch-specific helper and call it from ...range_start.
> 
> Fixes: 38b9917350cb ("kvm: vmx: Implement set_apic_access_page_addr")
> Fixes: 369ea8242c0f ("mm/rmap: update to new mmu_notifier semantic v2")
> Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
> ---
>  arch/x86/include/asm/kvm_host.h |  3 +++
>  arch/x86/kvm/x86.c              | 14 ++++++++++++++
>  virt/kvm/kvm_main.c             |  8 ++++++++
>  3 files changed, 25 insertions(+)
> 
> diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
> index 977de5fb968b..c16c3f924863 100644
> --- a/arch/x86/include/asm/kvm_host.h
> +++ b/arch/x86/include/asm/kvm_host.h
> @@ -1435,4 +1435,7 @@ static inline int kvm_cpu_get_apicid(int mps_cpu)
>  #define put_smstate(type, buf, offset, val)                      \
>  	*(type *)((buf) + (offset) - 0x7e00) = val
>  
> +void kvm_arch_mmu_notifier_invalidate_range(struct kvm *kvm,
> +		unsigned long start, unsigned long end);
> +
>  #endif /* _ASM_X86_KVM_HOST_H */
> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> index eee8e7faf1af..a219974cdb89 100644
> --- a/arch/x86/kvm/x86.c
> +++ b/arch/x86/kvm/x86.c
> @@ -6778,6 +6778,20 @@ static void kvm_vcpu_flush_tlb(struct kvm_vcpu *vcpu)
>  	kvm_x86_ops->tlb_flush(vcpu);
>  }
>  
> +void kvm_arch_mmu_notifier_invalidate_range(struct kvm *kvm,
> +		unsigned long start, unsigned long end)
> +{
> +	unsigned long apic_address;
> +
> +	/*
> +	 * The physical address of apic access page is stored in the VMCS.
> +	 * Update it when it becomes invalid.
> +	 */
> +	apic_address = gfn_to_hva(kvm, APIC_DEFAULT_PHYS_BASE >> PAGE_SHIFT);
> +	if (start <= apic_address && apic_address < end)
> +		kvm_make_all_cpus_request(kvm, KVM_REQ_APIC_PAGE_RELOAD);
> +}
> +
>  void kvm_vcpu_reload_apic_access_page(struct kvm_vcpu *vcpu)
>  {
>  	struct page *page = NULL;
> diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
> index c01cff064ec5..b7f4689e373f 100644
> --- a/virt/kvm/kvm_main.c
> +++ b/virt/kvm/kvm_main.c
> @@ -135,6 +135,11 @@ static void kvm_uevent_notify_change(unsigned int type, struct kvm *kvm);
>  static unsigned long long kvm_createvm_count;
>  static unsigned long long kvm_active_vms;
>  
> +__weak void kvm_arch_mmu_notifier_invalidate_range(struct kvm *kvm,
> +		unsigned long start, unsigned long end)
> +{
> +}
> +
>  bool kvm_is_reserved_pfn(kvm_pfn_t pfn)
>  {
>  	if (pfn_valid(pfn))
> @@ -360,6 +365,9 @@ static void kvm_mmu_notifier_invalidate_range_start(struct mmu_notifier *mn,
>  		kvm_flush_remote_tlbs(kvm);
>  
>  	spin_unlock(&kvm->mmu_lock);
> +
> +	kvm_arch_mmu_notifier_invalidate_range(kvm, start, end);
> +
>  	srcu_read_unlock(&kvm->srcu, idx);
>  }
>  
> 

Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Andrea Arcangeli Dec. 3, 2017, 5:28 p.m. UTC | #3
On Thu, Nov 30, 2017 at 07:05:45PM +0100, Radim Krčmář wrote:
> Implementation of the unpinned APIC page didn't update the VMCS address
> cache when invalidation was done through range mmu notifiers.
> This became a problem when the page notifier was removed.
> 
> Re-introduce the arch-specific helper and call it from ...range_start.

Reviewed-by: Andrea Arcangeli <aarcange@redhat.com>

Cc: <stable@vger.kernel.org>

Thanks,
Andrea
Wanpeng Li Dec. 6, 2017, 2:32 a.m. UTC | #4
2017-12-01 2:05 GMT+08:00 Radim Krčmář <rkrcmar@redhat.com>:
> Implementation of the unpinned APIC page didn't update the VMCS address
> cache when invalidation was done through range mmu notifiers.
> This became a problem when the page notifier was removed.
>
> Re-introduce the arch-specific helper and call it from ...range_start.
>
> Fixes: 38b9917350cb ("kvm: vmx: Implement set_apic_access_page_addr")
> Fixes: 369ea8242c0f ("mm/rmap: update to new mmu_notifier semantic v2")
> Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>

Tested-by: Wanpeng Li <wanpeng.li@hotmail.com>

I observe the windows 2016 guest hang during boot on a heavy memory
overcommit host, and this commit fixes it.

Regards,
Wanpeng Li

> ---
>  arch/x86/include/asm/kvm_host.h |  3 +++
>  arch/x86/kvm/x86.c              | 14 ++++++++++++++
>  virt/kvm/kvm_main.c             |  8 ++++++++
>  3 files changed, 25 insertions(+)
>
> diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
> index 977de5fb968b..c16c3f924863 100644
> --- a/arch/x86/include/asm/kvm_host.h
> +++ b/arch/x86/include/asm/kvm_host.h
> @@ -1435,4 +1435,7 @@ static inline int kvm_cpu_get_apicid(int mps_cpu)
>  #define put_smstate(type, buf, offset, val)                      \
>         *(type *)((buf) + (offset) - 0x7e00) = val
>
> +void kvm_arch_mmu_notifier_invalidate_range(struct kvm *kvm,
> +               unsigned long start, unsigned long end);
> +
>  #endif /* _ASM_X86_KVM_HOST_H */
> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> index eee8e7faf1af..a219974cdb89 100644
> --- a/arch/x86/kvm/x86.c
> +++ b/arch/x86/kvm/x86.c
> @@ -6778,6 +6778,20 @@ static void kvm_vcpu_flush_tlb(struct kvm_vcpu *vcpu)
>         kvm_x86_ops->tlb_flush(vcpu);
>  }
>
> +void kvm_arch_mmu_notifier_invalidate_range(struct kvm *kvm,
> +               unsigned long start, unsigned long end)
> +{
> +       unsigned long apic_address;
> +
> +       /*
> +        * The physical address of apic access page is stored in the VMCS.
> +        * Update it when it becomes invalid.
> +        */
> +       apic_address = gfn_to_hva(kvm, APIC_DEFAULT_PHYS_BASE >> PAGE_SHIFT);
> +       if (start <= apic_address && apic_address < end)
> +               kvm_make_all_cpus_request(kvm, KVM_REQ_APIC_PAGE_RELOAD);
> +}
> +
>  void kvm_vcpu_reload_apic_access_page(struct kvm_vcpu *vcpu)
>  {
>         struct page *page = NULL;
> diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
> index c01cff064ec5..b7f4689e373f 100644
> --- a/virt/kvm/kvm_main.c
> +++ b/virt/kvm/kvm_main.c
> @@ -135,6 +135,11 @@ static void kvm_uevent_notify_change(unsigned int type, struct kvm *kvm);
>  static unsigned long long kvm_createvm_count;
>  static unsigned long long kvm_active_vms;
>
> +__weak void kvm_arch_mmu_notifier_invalidate_range(struct kvm *kvm,
> +               unsigned long start, unsigned long end)
> +{
> +}
> +
>  bool kvm_is_reserved_pfn(kvm_pfn_t pfn)
>  {
>         if (pfn_valid(pfn))
> @@ -360,6 +365,9 @@ static void kvm_mmu_notifier_invalidate_range_start(struct mmu_notifier *mn,
>                 kvm_flush_remote_tlbs(kvm);
>
>         spin_unlock(&kvm->mmu_lock);
> +
> +       kvm_arch_mmu_notifier_invalidate_range(kvm, start, end);
> +
>         srcu_read_unlock(&kvm->srcu, idx);
>  }
>
> --
> 2.14.2
>
> --
> To unsubscribe, send a message with 'unsubscribe linux-mm' in
> the body to majordomo@kvack.org.  For more info on Linux MM,
> see: http://www.linux-mm.org/ .
> Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
Fabian Grünbichler Dec. 6, 2017, 8:15 a.m. UTC | #5
On Thu, Nov 30, 2017 at 07:05:45PM +0100, Radim Krčmář wrote:
> Implementation of the unpinned APIC page didn't update the VMCS address
> cache when invalidation was done through range mmu notifiers.
> This became a problem when the page notifier was removed.
> 
> Re-introduce the arch-specific helper and call it from ...range_start.
> 
> Fixes: 38b9917350cb ("kvm: vmx: Implement set_apic_access_page_addr")
> Fixes: 369ea8242c0f ("mm/rmap: update to new mmu_notifier semantic v2")
> Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>

Tested-by: Fabian Grünbichler <f.gruenbichler@proxmox.com>

no further issues observed with this patch applied on top of 4.13 and
4.14 - thanks!

> ---
>  arch/x86/include/asm/kvm_host.h |  3 +++
>  arch/x86/kvm/x86.c              | 14 ++++++++++++++
>  virt/kvm/kvm_main.c             |  8 ++++++++
>  3 files changed, 25 insertions(+)
> 
> diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
> index 977de5fb968b..c16c3f924863 100644
> --- a/arch/x86/include/asm/kvm_host.h
> +++ b/arch/x86/include/asm/kvm_host.h
> @@ -1435,4 +1435,7 @@ static inline int kvm_cpu_get_apicid(int mps_cpu)
>  #define put_smstate(type, buf, offset, val)                      \
>  	*(type *)((buf) + (offset) - 0x7e00) = val
>  
> +void kvm_arch_mmu_notifier_invalidate_range(struct kvm *kvm,
> +		unsigned long start, unsigned long end);
> +
>  #endif /* _ASM_X86_KVM_HOST_H */
> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> index eee8e7faf1af..a219974cdb89 100644
> --- a/arch/x86/kvm/x86.c
> +++ b/arch/x86/kvm/x86.c
> @@ -6778,6 +6778,20 @@ static void kvm_vcpu_flush_tlb(struct kvm_vcpu *vcpu)
>  	kvm_x86_ops->tlb_flush(vcpu);
>  }
>  
> +void kvm_arch_mmu_notifier_invalidate_range(struct kvm *kvm,
> +		unsigned long start, unsigned long end)
> +{
> +	unsigned long apic_address;
> +
> +	/*
> +	 * The physical address of apic access page is stored in the VMCS.
> +	 * Update it when it becomes invalid.
> +	 */
> +	apic_address = gfn_to_hva(kvm, APIC_DEFAULT_PHYS_BASE >> PAGE_SHIFT);
> +	if (start <= apic_address && apic_address < end)
> +		kvm_make_all_cpus_request(kvm, KVM_REQ_APIC_PAGE_RELOAD);
> +}
> +
>  void kvm_vcpu_reload_apic_access_page(struct kvm_vcpu *vcpu)
>  {
>  	struct page *page = NULL;
> diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
> index c01cff064ec5..b7f4689e373f 100644
> --- a/virt/kvm/kvm_main.c
> +++ b/virt/kvm/kvm_main.c
> @@ -135,6 +135,11 @@ static void kvm_uevent_notify_change(unsigned int type, struct kvm *kvm);
>  static unsigned long long kvm_createvm_count;
>  static unsigned long long kvm_active_vms;
>  
> +__weak void kvm_arch_mmu_notifier_invalidate_range(struct kvm *kvm,
> +		unsigned long start, unsigned long end)
> +{
> +}
> +
>  bool kvm_is_reserved_pfn(kvm_pfn_t pfn)
>  {
>  	if (pfn_valid(pfn))
> @@ -360,6 +365,9 @@ static void kvm_mmu_notifier_invalidate_range_start(struct mmu_notifier *mn,
>  		kvm_flush_remote_tlbs(kvm);
>  
>  	spin_unlock(&kvm->mmu_lock);
> +
> +	kvm_arch_mmu_notifier_invalidate_range(kvm, start, end);
> +
>  	srcu_read_unlock(&kvm->srcu, idx);
>  }
>  
> -- 
> 2.14.2
> 
>
Jinpu Wang Dec. 6, 2017, 9:50 a.m. UTC | #6
2017-12-06 3:32 GMT+01:00 Wanpeng Li <kernellwp@gmail.com>:
> 2017-12-01 2:05 GMT+08:00 Radim Krčmář <rkrcmar@redhat.com>:
>> Implementation of the unpinned APIC page didn't update the VMCS address
>> cache when invalidation was done through range mmu notifiers.
>> This became a problem when the page notifier was removed.
>>
>> Re-introduce the arch-specific helper and call it from ...range_start.
>>
>> Fixes: 38b9917350cb ("kvm: vmx: Implement set_apic_access_page_addr")
>> Fixes: 369ea8242c0f ("mm/rmap: update to new mmu_notifier semantic v2")
>> Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
So the patch should be backport to v3.18+?

Thanks,
Jack
>
> Tested-by: Wanpeng Li <wanpeng.li@hotmail.com>
>
> I observe the windows 2016 guest hang during boot on a heavy memory
> overcommit host, and this commit fixes it.
>
> Regards,
> Wanpeng Li
>
>> ---
>>  arch/x86/include/asm/kvm_host.h |  3 +++
>>  arch/x86/kvm/x86.c              | 14 ++++++++++++++
>>  virt/kvm/kvm_main.c             |  8 ++++++++
>>  3 files changed, 25 insertions(+)
>>
>> diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
>> index 977de5fb968b..c16c3f924863 100644
>> --- a/arch/x86/include/asm/kvm_host.h
>> +++ b/arch/x86/include/asm/kvm_host.h
>> @@ -1435,4 +1435,7 @@ static inline int kvm_cpu_get_apicid(int mps_cpu)
>>  #define put_smstate(type, buf, offset, val)                      \
>>         *(type *)((buf) + (offset) - 0x7e00) = val
>>
>> +void kvm_arch_mmu_notifier_invalidate_range(struct kvm *kvm,
>> +               unsigned long start, unsigned long end);
>> +
>>  #endif /* _ASM_X86_KVM_HOST_H */
>> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
>> index eee8e7faf1af..a219974cdb89 100644
>> --- a/arch/x86/kvm/x86.c
>> +++ b/arch/x86/kvm/x86.c
>> @@ -6778,6 +6778,20 @@ static void kvm_vcpu_flush_tlb(struct kvm_vcpu *vcpu)
>>         kvm_x86_ops->tlb_flush(vcpu);
>>  }
>>
>> +void kvm_arch_mmu_notifier_invalidate_range(struct kvm *kvm,
>> +               unsigned long start, unsigned long end)
>> +{
>> +       unsigned long apic_address;
>> +
>> +       /*
>> +        * The physical address of apic access page is stored in the VMCS.
>> +        * Update it when it becomes invalid.
>> +        */
>> +       apic_address = gfn_to_hva(kvm, APIC_DEFAULT_PHYS_BASE >> PAGE_SHIFT);
>> +       if (start <= apic_address && apic_address < end)
>> +               kvm_make_all_cpus_request(kvm, KVM_REQ_APIC_PAGE_RELOAD);
>> +}
>> +
>>  void kvm_vcpu_reload_apic_access_page(struct kvm_vcpu *vcpu)
>>  {
>>         struct page *page = NULL;
>> diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
>> index c01cff064ec5..b7f4689e373f 100644
>> --- a/virt/kvm/kvm_main.c
>> +++ b/virt/kvm/kvm_main.c
>> @@ -135,6 +135,11 @@ static void kvm_uevent_notify_change(unsigned int type, struct kvm *kvm);
>>  static unsigned long long kvm_createvm_count;
>>  static unsigned long long kvm_active_vms;
>>
>> +__weak void kvm_arch_mmu_notifier_invalidate_range(struct kvm *kvm,
>> +               unsigned long start, unsigned long end)
>> +{
>> +}
>> +
>>  bool kvm_is_reserved_pfn(kvm_pfn_t pfn)
>>  {
>>         if (pfn_valid(pfn))
>> @@ -360,6 +365,9 @@ static void kvm_mmu_notifier_invalidate_range_start(struct mmu_notifier *mn,
>>                 kvm_flush_remote_tlbs(kvm);
>>
>>         spin_unlock(&kvm->mmu_lock);
>> +
>> +       kvm_arch_mmu_notifier_invalidate_range(kvm, start, end);
>> +
>>         srcu_read_unlock(&kvm->srcu, idx);
>>  }
>>
>> --
>> 2.14.2
>>
>> --
>> To unsubscribe, send a message with 'unsubscribe linux-mm' in
>> the body to majordomo@kvack.org.  For more info on Linux MM,
>> see: http://www.linux-mm.org/ .
>> Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
Paolo Bonzini Dec. 6, 2017, 10 a.m. UTC | #7
On 06/12/2017 10:50, 王金浦 wrote:
> 2017-12-06 3:32 GMT+01:00 Wanpeng Li <kernellwp@gmail.com>:
>> 2017-12-01 2:05 GMT+08:00 Radim Krčmář <rkrcmar@redhat.com>:
>>> Implementation of the unpinned APIC page didn't update the VMCS address
>>> cache when invalidation was done through range mmu notifiers.
>>> This became a problem when the page notifier was removed.
>>>
>>> Re-introduce the arch-specific helper and call it from ...range_start.
>>>
>>> Fixes: 38b9917350cb ("kvm: vmx: Implement set_apic_access_page_addr")
>>> Fixes: 369ea8242c0f ("mm/rmap: update to new mmu_notifier semantic v2")
>>> Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
> So the patch should be backport to v3.18+?

In practice the invalidate_page callback was enough because the APIC
page is allocated with alloc_page().  But it doesn't hurt.

Paolo

> Thanks,
> Jack
>>
>> Tested-by: Wanpeng Li <wanpeng.li@hotmail.com>
>>
>> I observe the windows 2016 guest hang during boot on a heavy memory
>> overcommit host, and this commit fixes it.
>>
>> Regards,
>> Wanpeng Li
>>
>>> ---
>>>  arch/x86/include/asm/kvm_host.h |  3 +++
>>>  arch/x86/kvm/x86.c              | 14 ++++++++++++++
>>>  virt/kvm/kvm_main.c             |  8 ++++++++
>>>  3 files changed, 25 insertions(+)
>>>
>>> diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
>>> index 977de5fb968b..c16c3f924863 100644
>>> --- a/arch/x86/include/asm/kvm_host.h
>>> +++ b/arch/x86/include/asm/kvm_host.h
>>> @@ -1435,4 +1435,7 @@ static inline int kvm_cpu_get_apicid(int mps_cpu)
>>>  #define put_smstate(type, buf, offset, val)                      \
>>>         *(type *)((buf) + (offset) - 0x7e00) = val
>>>
>>> +void kvm_arch_mmu_notifier_invalidate_range(struct kvm *kvm,
>>> +               unsigned long start, unsigned long end);
>>> +
>>>  #endif /* _ASM_X86_KVM_HOST_H */
>>> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
>>> index eee8e7faf1af..a219974cdb89 100644
>>> --- a/arch/x86/kvm/x86.c
>>> +++ b/arch/x86/kvm/x86.c
>>> @@ -6778,6 +6778,20 @@ static void kvm_vcpu_flush_tlb(struct kvm_vcpu *vcpu)
>>>         kvm_x86_ops->tlb_flush(vcpu);
>>>  }
>>>
>>> +void kvm_arch_mmu_notifier_invalidate_range(struct kvm *kvm,
>>> +               unsigned long start, unsigned long end)
>>> +{
>>> +       unsigned long apic_address;
>>> +
>>> +       /*
>>> +        * The physical address of apic access page is stored in the VMCS.
>>> +        * Update it when it becomes invalid.
>>> +        */
>>> +       apic_address = gfn_to_hva(kvm, APIC_DEFAULT_PHYS_BASE >> PAGE_SHIFT);
>>> +       if (start <= apic_address && apic_address < end)
>>> +               kvm_make_all_cpus_request(kvm, KVM_REQ_APIC_PAGE_RELOAD);
>>> +}
>>> +
>>>  void kvm_vcpu_reload_apic_access_page(struct kvm_vcpu *vcpu)
>>>  {
>>>         struct page *page = NULL;
>>> diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
>>> index c01cff064ec5..b7f4689e373f 100644
>>> --- a/virt/kvm/kvm_main.c
>>> +++ b/virt/kvm/kvm_main.c
>>> @@ -135,6 +135,11 @@ static void kvm_uevent_notify_change(unsigned int type, struct kvm *kvm);
>>>  static unsigned long long kvm_createvm_count;
>>>  static unsigned long long kvm_active_vms;
>>>
>>> +__weak void kvm_arch_mmu_notifier_invalidate_range(struct kvm *kvm,
>>> +               unsigned long start, unsigned long end)
>>> +{
>>> +}
>>> +
>>>  bool kvm_is_reserved_pfn(kvm_pfn_t pfn)
>>>  {
>>>         if (pfn_valid(pfn))
>>> @@ -360,6 +365,9 @@ static void kvm_mmu_notifier_invalidate_range_start(struct mmu_notifier *mn,
>>>                 kvm_flush_remote_tlbs(kvm);
>>>
>>>         spin_unlock(&kvm->mmu_lock);
>>> +
>>> +       kvm_arch_mmu_notifier_invalidate_range(kvm, start, end);
>>> +
>>>         srcu_read_unlock(&kvm->srcu, idx);
>>>  }
>>>
>>> --
>>> 2.14.2
>>>
>>> --
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Richard Purdie Dec. 13, 2017, 12:54 p.m. UTC | #8
On Thu, 2017-11-30 at 19:05 +0100, Radim Krčmář wrote:
> Implementation of the unpinned APIC page didn't update the VMCS
> address
> cache when invalidation was done through range mmu notifiers.
> This became a problem when the page notifier was removed.
> 
> Re-introduce the arch-specific helper and call it from
> ...range_start.
> 
> Fixes: 38b9917350cb ("kvm: vmx: Implement set_apic_access_page_addr")
> Fixes: 369ea8242c0f ("mm/rmap: update to new mmu_notifier semantic
> v2")
> Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
> ---
>  arch/x86/include/asm/kvm_host.h |  3 +++
>  arch/x86/kvm/x86.c              | 14 ++++++++++++++
>  virt/kvm/kvm_main.c             |  8 ++++++++
>  3 files changed, 25 insertions(+)

Thanks for this. I've been chasing APIC related hangs booting images
with qemu-system-x86_64 on 4.13 and 4.14 host kernels where the guest
doesn't have x2apic enabled.

I can confirm this fixes issues the Yocto Project automated testing
infrastructure was seeing.

I'd like to add support for backporting this in stable.

Tested-by: Richard Purdie <richard.purdie@linuxfoundation.org>

Cheers,

Richard
diff mbox

Patch

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 977de5fb968b..c16c3f924863 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -1435,4 +1435,7 @@  static inline int kvm_cpu_get_apicid(int mps_cpu)
 #define put_smstate(type, buf, offset, val)                      \
 	*(type *)((buf) + (offset) - 0x7e00) = val
 
+void kvm_arch_mmu_notifier_invalidate_range(struct kvm *kvm,
+		unsigned long start, unsigned long end);
+
 #endif /* _ASM_X86_KVM_HOST_H */
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index eee8e7faf1af..a219974cdb89 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -6778,6 +6778,20 @@  static void kvm_vcpu_flush_tlb(struct kvm_vcpu *vcpu)
 	kvm_x86_ops->tlb_flush(vcpu);
 }
 
+void kvm_arch_mmu_notifier_invalidate_range(struct kvm *kvm,
+		unsigned long start, unsigned long end)
+{
+	unsigned long apic_address;
+
+	/*
+	 * The physical address of apic access page is stored in the VMCS.
+	 * Update it when it becomes invalid.
+	 */
+	apic_address = gfn_to_hva(kvm, APIC_DEFAULT_PHYS_BASE >> PAGE_SHIFT);
+	if (start <= apic_address && apic_address < end)
+		kvm_make_all_cpus_request(kvm, KVM_REQ_APIC_PAGE_RELOAD);
+}
+
 void kvm_vcpu_reload_apic_access_page(struct kvm_vcpu *vcpu)
 {
 	struct page *page = NULL;
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index c01cff064ec5..b7f4689e373f 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -135,6 +135,11 @@  static void kvm_uevent_notify_change(unsigned int type, struct kvm *kvm);
 static unsigned long long kvm_createvm_count;
 static unsigned long long kvm_active_vms;
 
+__weak void kvm_arch_mmu_notifier_invalidate_range(struct kvm *kvm,
+		unsigned long start, unsigned long end)
+{
+}
+
 bool kvm_is_reserved_pfn(kvm_pfn_t pfn)
 {
 	if (pfn_valid(pfn))
@@ -360,6 +365,9 @@  static void kvm_mmu_notifier_invalidate_range_start(struct mmu_notifier *mn,
 		kvm_flush_remote_tlbs(kvm);
 
 	spin_unlock(&kvm->mmu_lock);
+
+	kvm_arch_mmu_notifier_invalidate_range(kvm, start, end);
+
 	srcu_read_unlock(&kvm->srcu, idx);
 }