[PATCH 00/12] KVM: PPC: Nested APIv2 : Performance improvements

[PATCH 00/12] KVM: PPC: Nested APIv2 : Performance improvements

[Vaibhav Jain]

From: vaibhav <vajain21@vajain21.in.ibm.com>


This patch series introduces series of performance improvements to recently
added support for Nested APIv2 PPC64 Guests via [1]. Details for Nested
APIv2 for PPC64 Guests is available in Documentation/powerpc/kvm-nested.rst.

This patch series introduces various optimizations for a Nested APIv2
guests namely:

* Reduce the number times L1 hypervisor requests for L2 state from L0.
* Register the L2 VPA with L1
* Optimizing interrupt delivery of some interrupt types.
* Optimize emulation of mmio loads/stores for L2 in L1.

The hcalls needed for testing these patches have been implemented in the
spapr qemu model and is available at [2].

There are scripts available to assist in setting up an environment for
testing nested guests at [3].

These patches are consequence of insights from on going performance
engineering effort for improving performance of Nested APIv2
Guests. Special thanks goes to:
* Gautam Menghani
* Jordan Niethe
* Nicholas Piggin
* Vaidyanathan Srinivasan

Refs:
[1] https://lore.kernel.org/all/20230905034658.82835-1-jniethe5@gmail.com
[2] https://github.com/planetharsh/qemu/tree/upstream-0714-kop
[3] https://github.com/iamjpn/kvm-powervm-test

Jordan Niethe (11):
  KVM: PPC: Book3S HV nestedv2: Invalidate RPT before deleting a guest
  KVM: PPC: Book3S HV nestedv2: Avoid reloading the tb offset
  KVM: PPC: Book3S HV nestedv2: Do not check msr on hcalls
  KVM: PPC: Book3S HV nestedv2: Get the PID only if needed to copy
    tofrom a guest
  KVM: PPC: Book3S HV nestedv2: Ensure LPCR_MER bit is passed to the L0
  KVM: PPC: Book3S HV nestedv2: Do not inject certain interrupts
  KVM: PPC: Book3S HV nestedv2: Avoid msr check in
    kvmppc_handle_exit_hv()
  KVM: PPC: Book3S HV nestedv2: Do not call H_COPY_TOFROM_GUEST
  KVM: PPC: Book3S HV nestedv2: Register the VPA with the L0
  KVM: PPC: Reduce reliance on analyse_instr() in mmio emulation
  KVM: PPC: Book3S HV nestedv2: Do not cancel pending decrementer
    exception

Nicholas Piggin (1):
  KVM: PPC: Book3S HV: Handle pending exceptions on guest entry with
    MSR_EE

 arch/powerpc/include/asm/kvm_book3s.h    | 10 +++-
 arch/powerpc/include/asm/kvm_book3s_64.h |  1 +
 arch/powerpc/kvm/book3s.c                |  4 +-
 arch/powerpc/kvm/book3s_64_mmu_radix.c   |  7 ++-
 arch/powerpc/kvm/book3s_hv.c             | 72 +++++++++++++++++-------
 arch/powerpc/kvm/book3s_hv_nested.c      |  2 +-
 arch/powerpc/kvm/book3s_hv_nestedv2.c    | 29 ++++++++++
 arch/powerpc/kvm/emulate_loadstore.c     | 21 ++++---
 8 files changed, 107 insertions(+), 39 deletions(-)

-- 
2.42.0

[PATCH 01/12] KVM: PPC: Book3S HV nestedv2: Invalidate RPT before deleting a guest

[Vaibhav Jain]

From: Jordan Niethe <jniethe5@gmail.com>

An L0 must invalidate the L2's RPT during H_GUEST_DELETE if this has not
already been done. This is a slow operation that means H_GUEST_DELETE
must return H_BUSY multiple times before completing. Invalidating the
tables before deleting the guest so there is less work for the L0 to do.

Signed-off-by: Jordan Niethe <jniethe5@gmail.com>
---
 arch/powerpc/include/asm/kvm_book3s.h | 1 +
 arch/powerpc/kvm/book3s_hv.c          | 6 ++++--
 arch/powerpc/kvm/book3s_hv_nested.c   | 2 +-
 3 files changed, 6 insertions(+), 3 deletions(-)

diff --git a/arch/powerpc/include/asm/kvm_book3s.h b/arch/powerpc/include/asm/kvm_book3s.h
index 4f527d09c92b..a37736ed3728 100644
--- a/arch/powerpc/include/asm/kvm_book3s.h
+++ b/arch/powerpc/include/asm/kvm_book3s.h
@@ -302,6 +302,7 @@ void kvmhv_nested_exit(void);
 void kvmhv_vm_nested_init(struct kvm *kvm);
 long kvmhv_set_partition_table(struct kvm_vcpu *vcpu);
 long kvmhv_copy_tofrom_guest_nested(struct kvm_vcpu *vcpu);
+void kvmhv_flush_lpid(u64 lpid);
 void kvmhv_set_ptbl_entry(u64 lpid, u64 dw0, u64 dw1);
 void kvmhv_release_all_nested(struct kvm *kvm);
 long kvmhv_enter_nested_guest(struct kvm_vcpu *vcpu);
diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c
index 1ed6ec140701..5543e8490cd9 100644
--- a/arch/powerpc/kvm/book3s_hv.c
+++ b/arch/powerpc/kvm/book3s_hv.c
@@ -5691,10 +5691,12 @@ static void kvmppc_core_destroy_vm_hv(struct kvm *kvm)
 			kvmhv_set_ptbl_entry(kvm->arch.lpid, 0, 0);
 	}
 
-	if (kvmhv_is_nestedv2())
+	if (kvmhv_is_nestedv2()) {
+		kvmhv_flush_lpid(kvm->arch.lpid);
 		plpar_guest_delete(0, kvm->arch.lpid);
-	else
+	} else {
 		kvmppc_free_lpid(kvm->arch.lpid);
+	}
 
 	kvmppc_free_pimap(kvm);
 }
diff --git a/arch/powerpc/kvm/book3s_hv_nested.c b/arch/powerpc/kvm/book3s_hv_nested.c
index 3b658b8696bc..5c375ec1a3c6 100644
--- a/arch/powerpc/kvm/book3s_hv_nested.c
+++ b/arch/powerpc/kvm/book3s_hv_nested.c
@@ -503,7 +503,7 @@ void kvmhv_nested_exit(void)
 	}
 }
 
-static void kvmhv_flush_lpid(u64 lpid)
+void kvmhv_flush_lpid(u64 lpid)
 {
 	long rc;
 
-- 
2.42.0

Re: [PATCH 01/12] KVM: PPC: Book3S HV nestedv2: Invalidate RPT before deleting a guest

[Aneesh Kumar K.V]

Vaibhav Jain <vaibhav@linux.ibm.com> writes:

> From: Jordan Niethe <jniethe5@gmail.com>
>
> An L0 must invalidate the L2's RPT during H_GUEST_DELETE if this has not
> already been done. This is a slow operation that means H_GUEST_DELETE
> must return H_BUSY multiple times before completing. Invalidating the
> tables before deleting the guest so there is less work for the L0 to do.
>
> Signed-off-by: Jordan Niethe <jniethe5@gmail.com>
> ---
>  arch/powerpc/include/asm/kvm_book3s.h | 1 +
>  arch/powerpc/kvm/book3s_hv.c          | 6 ++++--
>  arch/powerpc/kvm/book3s_hv_nested.c   | 2 +-
>  3 files changed, 6 insertions(+), 3 deletions(-)
>
> diff --git a/arch/powerpc/include/asm/kvm_book3s.h b/arch/powerpc/include/asm/kvm_book3s.h
> index 4f527d09c92b..a37736ed3728 100644
> --- a/arch/powerpc/include/asm/kvm_book3s.h
> +++ b/arch/powerpc/include/asm/kvm_book3s.h
> @@ -302,6 +302,7 @@ void kvmhv_nested_exit(void);
>  void kvmhv_vm_nested_init(struct kvm *kvm);
>  long kvmhv_set_partition_table(struct kvm_vcpu *vcpu);
>  long kvmhv_copy_tofrom_guest_nested(struct kvm_vcpu *vcpu);
> +void kvmhv_flush_lpid(u64 lpid);
>  void kvmhv_set_ptbl_entry(u64 lpid, u64 dw0, u64 dw1);
>  void kvmhv_release_all_nested(struct kvm *kvm);
>  long kvmhv_enter_nested_guest(struct kvm_vcpu *vcpu);
> diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c
> index 1ed6ec140701..5543e8490cd9 100644
> --- a/arch/powerpc/kvm/book3s_hv.c
> +++ b/arch/powerpc/kvm/book3s_hv.c
> @@ -5691,10 +5691,12 @@ static void kvmppc_core_destroy_vm_hv(struct kvm *kvm)
>  			kvmhv_set_ptbl_entry(kvm->arch.lpid, 0, 0);
>  	}
>  
> -	if (kvmhv_is_nestedv2())
> +	if (kvmhv_is_nestedv2()) {
> +		kvmhv_flush_lpid(kvm->arch.lpid);
>  		plpar_guest_delete(0, kvm->arch.lpid);
>

I am not sure I follow the optimization here. I would expect the
hypervisor to kill all the translation caches as part of guest_delete.
What is the benefit of doing a lpid flush outside the guest delete?

> -	else
> +	} else {
>  		kvmppc_free_lpid(kvm->arch.lpid);
> +	}
>  
>  	kvmppc_free_pimap(kvm);
>  }
> diff --git a/arch/powerpc/kvm/book3s_hv_nested.c b/arch/powerpc/kvm/book3s_hv_nested.c
> index 3b658b8696bc..5c375ec1a3c6 100644
> --- a/arch/powerpc/kvm/book3s_hv_nested.c
> +++ b/arch/powerpc/kvm/book3s_hv_nested.c
> @@ -503,7 +503,7 @@ void kvmhv_nested_exit(void)
>  	}
>  }
>  
> -static void kvmhv_flush_lpid(u64 lpid)
> +void kvmhv_flush_lpid(u64 lpid)
>  {
>  	long rc;
>  
> -- 
> 2.42.0

Re: [PATCH 01/12] KVM: PPC: Book3S HV nestedv2: Invalidate RPT before deleting a guest

[Vaibhav Jain]

Hi Aneesh,

Thanks for looking into this patch. My responses inline below:

"Aneesh Kumar K.V (IBM)" <aneesh.kumar@kernel.org> writes:

> Vaibhav Jain <vaibhav@linux.ibm.com> writes:
>
>> From: Jordan Niethe <jniethe5@gmail.com>
>>
>> An L0 must invalidate the L2's RPT during H_GUEST_DELETE if this has not
>> already been done. This is a slow operation that means H_GUEST_DELETE
>> must return H_BUSY multiple times before completing. Invalidating the
>> tables before deleting the guest so there is less work for the L0 to do.
>>
>> Signed-off-by: Jordan Niethe <jniethe5@gmail.com>
>> ---
>>  arch/powerpc/include/asm/kvm_book3s.h | 1 +
>>  arch/powerpc/kvm/book3s_hv.c          | 6 ++++--
>>  arch/powerpc/kvm/book3s_hv_nested.c   | 2 +-
>>  3 files changed, 6 insertions(+), 3 deletions(-)
>>
>> diff --git a/arch/powerpc/include/asm/kvm_book3s.h b/arch/powerpc/include/asm/kvm_book3s.h
>> index 4f527d09c92b..a37736ed3728 100644
>> --- a/arch/powerpc/include/asm/kvm_book3s.h
>> +++ b/arch/powerpc/include/asm/kvm_book3s.h
>> @@ -302,6 +302,7 @@ void kvmhv_nested_exit(void);
>>  void kvmhv_vm_nested_init(struct kvm *kvm);
>>  long kvmhv_set_partition_table(struct kvm_vcpu *vcpu);
>>  long kvmhv_copy_tofrom_guest_nested(struct kvm_vcpu *vcpu);
>> +void kvmhv_flush_lpid(u64 lpid);
>>  void kvmhv_set_ptbl_entry(u64 lpid, u64 dw0, u64 dw1);
>>  void kvmhv_release_all_nested(struct kvm *kvm);
>>  long kvmhv_enter_nested_guest(struct kvm_vcpu *vcpu);
>> diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c
>> index 1ed6ec140701..5543e8490cd9 100644
>> --- a/arch/powerpc/kvm/book3s_hv.c
>> +++ b/arch/powerpc/kvm/book3s_hv.c
>> @@ -5691,10 +5691,12 @@ static void kvmppc_core_destroy_vm_hv(struct kvm *kvm)
>>  			kvmhv_set_ptbl_entry(kvm->arch.lpid, 0, 0);
>>  	}
>>  
>> -	if (kvmhv_is_nestedv2())
>> +	if (kvmhv_is_nestedv2()) {
>> +		kvmhv_flush_lpid(kvm->arch.lpid);
>>  		plpar_guest_delete(0, kvm->arch.lpid);
>>
>
> I am not sure I follow the optimization here. I would expect the
> hypervisor to kill all the translation caches as part of guest_delete.
> What is the benefit of doing a lpid flush outside the guest delete?
>
Thats right. However without this optimization the H_GUEST_DELETE hcall
in plpar_guest_delete() returns H_BUSY multiple times resulting in
multiple hcalls to the hypervisor until it finishes. Flushing the guest
translation cache upfront reduces the number of HCALLs L1 guests has to
make to delete a L2 guest via H_GUEST_DELETE.

>> -	else
>> +	} else {
>>  		kvmppc_free_lpid(kvm->arch.lpid);
>> +	}
>>  
>>  	kvmppc_free_pimap(kvm);
>>  }
>> diff --git a/arch/powerpc/kvm/book3s_hv_nested.c b/arch/powerpc/kvm/book3s_hv_nested.c
>> index 3b658b8696bc..5c375ec1a3c6 100644
>> --- a/arch/powerpc/kvm/book3s_hv_nested.c
>> +++ b/arch/powerpc/kvm/book3s_hv_nested.c
>> @@ -503,7 +503,7 @@ void kvmhv_nested_exit(void)
>>  	}
>>  }
>>  
>> -static void kvmhv_flush_lpid(u64 lpid)
>> +void kvmhv_flush_lpid(u64 lpid)
>>  {
>>  	long rc;
>>  
>> -- 
>> 2.42.0

-- 
Cheers
~ Vaibhav

Re: [PATCH 01/12] KVM: PPC: Book3S HV nestedv2: Invalidate RPT before deleting a guest

[Aneesh Kumar K.V]

Vaibhav Jain <vaibhav@linux.ibm.com> writes:

> Hi Aneesh,
>
> Thanks for looking into this patch. My responses inline below:
>
> "Aneesh Kumar K.V (IBM)" <aneesh.kumar@kernel.org> writes:
>
>> Vaibhav Jain <vaibhav@linux.ibm.com> writes:
>>
>>> From: Jordan Niethe <jniethe5@gmail.com>
>>>
>>> An L0 must invalidate the L2's RPT during H_GUEST_DELETE if this has not
>>> already been done. This is a slow operation that means H_GUEST_DELETE
>>> must return H_BUSY multiple times before completing. Invalidating the
>>> tables before deleting the guest so there is less work for the L0 to do.
>>>
>>> Signed-off-by: Jordan Niethe <jniethe5@gmail.com>
>>> ---
>>>  arch/powerpc/include/asm/kvm_book3s.h | 1 +
>>>  arch/powerpc/kvm/book3s_hv.c          | 6 ++++--
>>>  arch/powerpc/kvm/book3s_hv_nested.c   | 2 +-
>>>  3 files changed, 6 insertions(+), 3 deletions(-)
>>>
>>> diff --git a/arch/powerpc/include/asm/kvm_book3s.h b/arch/powerpc/include/asm/kvm_book3s.h
>>> index 4f527d09c92b..a37736ed3728 100644
>>> --- a/arch/powerpc/include/asm/kvm_book3s.h
>>> +++ b/arch/powerpc/include/asm/kvm_book3s.h
>>> @@ -302,6 +302,7 @@ void kvmhv_nested_exit(void);
>>>  void kvmhv_vm_nested_init(struct kvm *kvm);
>>>  long kvmhv_set_partition_table(struct kvm_vcpu *vcpu);
>>>  long kvmhv_copy_tofrom_guest_nested(struct kvm_vcpu *vcpu);
>>> +void kvmhv_flush_lpid(u64 lpid);
>>>  void kvmhv_set_ptbl_entry(u64 lpid, u64 dw0, u64 dw1);
>>>  void kvmhv_release_all_nested(struct kvm *kvm);
>>>  long kvmhv_enter_nested_guest(struct kvm_vcpu *vcpu);
>>> diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c
>>> index 1ed6ec140701..5543e8490cd9 100644
>>> --- a/arch/powerpc/kvm/book3s_hv.c
>>> +++ b/arch/powerpc/kvm/book3s_hv.c
>>> @@ -5691,10 +5691,12 @@ static void kvmppc_core_destroy_vm_hv(struct kvm *kvm)
>>>  			kvmhv_set_ptbl_entry(kvm->arch.lpid, 0, 0);
>>>  	}
>>>  
>>> -	if (kvmhv_is_nestedv2())
>>> +	if (kvmhv_is_nestedv2()) {
>>> +		kvmhv_flush_lpid(kvm->arch.lpid);
>>>  		plpar_guest_delete(0, kvm->arch.lpid);
>>>
>>
>> I am not sure I follow the optimization here. I would expect the
>> hypervisor to kill all the translation caches as part of guest_delete.
>> What is the benefit of doing a lpid flush outside the guest delete?
>>
> Thats right. However without this optimization the H_GUEST_DELETE hcall
> in plpar_guest_delete() returns H_BUSY multiple times resulting in
> multiple hcalls to the hypervisor until it finishes. Flushing the guest
> translation cache upfront reduces the number of HCALLs L1 guests has to
> make to delete a L2 guest via H_GUEST_DELETE.
>

can we add that as a comment above that kvmhv_flush_lpid()?

-aneesh

Re: [PATCH 01/12] KVM: PPC: Book3S HV nestedv2: Invalidate RPT before deleting a guest

[Vaibhav Jain]

"Aneesh Kumar K.V" <aneesh.kumar@kernel.org> writes:

> Vaibhav Jain <vaibhav@linux.ibm.com> writes:
>
>> Hi Aneesh,
>>
>> Thanks for looking into this patch. My responses inline below:
>>
>> "Aneesh Kumar K.V (IBM)" <aneesh.kumar@kernel.org> writes:
>>
>>> Vaibhav Jain <vaibhav@linux.ibm.com> writes:
>>>
>>>> From: Jordan Niethe <jniethe5@gmail.com>
>>>>
>>>> An L0 must invalidate the L2's RPT during H_GUEST_DELETE if this has not
>>>> already been done. This is a slow operation that means H_GUEST_DELETE
>>>> must return H_BUSY multiple times before completing. Invalidating the
>>>> tables before deleting the guest so there is less work for the L0 to do.
>>>>
>>>> Signed-off-by: Jordan Niethe <jniethe5@gmail.com>
>>>> ---
>>>>  arch/powerpc/include/asm/kvm_book3s.h | 1 +
>>>>  arch/powerpc/kvm/book3s_hv.c          | 6 ++++--
>>>>  arch/powerpc/kvm/book3s_hv_nested.c   | 2 +-
>>>>  3 files changed, 6 insertions(+), 3 deletions(-)
>>>>
>>>> diff --git a/arch/powerpc/include/asm/kvm_book3s.h b/arch/powerpc/include/asm/kvm_book3s.h
>>>> index 4f527d09c92b..a37736ed3728 100644
>>>> --- a/arch/powerpc/include/asm/kvm_book3s.h
>>>> +++ b/arch/powerpc/include/asm/kvm_book3s.h
>>>> @@ -302,6 +302,7 @@ void kvmhv_nested_exit(void);
>>>>  void kvmhv_vm_nested_init(struct kvm *kvm);
>>>>  long kvmhv_set_partition_table(struct kvm_vcpu *vcpu);
>>>>  long kvmhv_copy_tofrom_guest_nested(struct kvm_vcpu *vcpu);
>>>> +void kvmhv_flush_lpid(u64 lpid);
>>>>  void kvmhv_set_ptbl_entry(u64 lpid, u64 dw0, u64 dw1);
>>>>  void kvmhv_release_all_nested(struct kvm *kvm);
>>>>  long kvmhv_enter_nested_guest(struct kvm_vcpu *vcpu);
>>>> diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c
>>>> index 1ed6ec140701..5543e8490cd9 100644
>>>> --- a/arch/powerpc/kvm/book3s_hv.c
>>>> +++ b/arch/powerpc/kvm/book3s_hv.c
>>>> @@ -5691,10 +5691,12 @@ static void kvmppc_core_destroy_vm_hv(struct kvm *kvm)
>>>>  			kvmhv_set_ptbl_entry(kvm->arch.lpid, 0, 0);
>>>>  	}
>>>>  
>>>> -	if (kvmhv_is_nestedv2())
>>>> +	if (kvmhv_is_nestedv2()) {
>>>> +		kvmhv_flush_lpid(kvm->arch.lpid);
>>>>  		plpar_guest_delete(0, kvm->arch.lpid);
>>>>
>>>
>>> I am not sure I follow the optimization here. I would expect the
>>> hypervisor to kill all the translation caches as part of guest_delete.
>>> What is the benefit of doing a lpid flush outside the guest delete?
>>>
>> Thats right. However without this optimization the H_GUEST_DELETE hcall
>> in plpar_guest_delete() returns H_BUSY multiple times resulting in
>> multiple hcalls to the hypervisor until it finishes. Flushing the guest
>> translation cache upfront reduces the number of HCALLs L1 guests has to
>> make to delete a L2 guest via H_GUEST_DELETE.
>>
>
> can we add that as a comment above that kvmhv_flush_lpid()?
Sure, I will put up a comment with that detail in v2 of the patch
series.

>
> -aneesh

-- 
Cheers
~ Vaibhav

[PATCH 02/12] KVM: PPC: Book3S HV nestedv2: Avoid reloading the tb offset

[Vaibhav Jain]

From: Jordan Niethe <jniethe5@gmail.com>

The kvmppc_get_tb_offset() getter reloads KVMPPC_GSID_TB_OFFSET from the
L0 for nestedv2 host. This is unnecessary as the value does not change.
KVMPPC_GSID_TB_OFFSET also need not be reloaded in
kvmppc_{s,g}et_dec_expires().

Signed-off-by: Jordan Niethe <jniethe5@gmail.com>
---
 arch/powerpc/include/asm/kvm_book3s.h | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/arch/powerpc/include/asm/kvm_book3s.h b/arch/powerpc/include/asm/kvm_book3s.h
index a37736ed3728..3e1e2a698c9e 100644
--- a/arch/powerpc/include/asm/kvm_book3s.h
+++ b/arch/powerpc/include/asm/kvm_book3s.h
@@ -594,13 +594,17 @@ static inline u##size kvmppc_get_##reg(struct kvm_vcpu *vcpu)		\
 
 
 KVMPPC_BOOK3S_VCORE_ACCESSOR(vtb, 64, KVMPPC_GSID_VTB)
-KVMPPC_BOOK3S_VCORE_ACCESSOR(tb_offset, 64, KVMPPC_GSID_TB_OFFSET)
 KVMPPC_BOOK3S_VCORE_ACCESSOR_GET(arch_compat, 32, KVMPPC_GSID_LOGICAL_PVR)
 KVMPPC_BOOK3S_VCORE_ACCESSOR_GET(lpcr, 64, KVMPPC_GSID_LPCR)
+KVMPPC_BOOK3S_VCORE_ACCESSOR_SET(tb_offset, 64, KVMPPC_GSID_TB_OFFSET)
+
+static inline u64 kvmppc_get_tb_offset(struct kvm_vcpu *vcpu)
+{
+	return vcpu->arch.vcore->tb_offset;
+}
 
 static inline u64 kvmppc_get_dec_expires(struct kvm_vcpu *vcpu)
 {
-	WARN_ON(kvmhv_nestedv2_cached_reload(vcpu, KVMPPC_GSID_TB_OFFSET) < 0);
 	WARN_ON(kvmhv_nestedv2_cached_reload(vcpu, KVMPPC_GSID_DEC_EXPIRY_TB) < 0);
 	return vcpu->arch.dec_expires;
 }
@@ -608,7 +612,6 @@ static inline u64 kvmppc_get_dec_expires(struct kvm_vcpu *vcpu)
 static inline void kvmppc_set_dec_expires(struct kvm_vcpu *vcpu, u64 val)
 {
 	vcpu->arch.dec_expires = val;
-	WARN_ON(kvmhv_nestedv2_cached_reload(vcpu, KVMPPC_GSID_TB_OFFSET) < 0);
 	kvmhv_nestedv2_mark_dirty(vcpu, KVMPPC_GSID_DEC_EXPIRY_TB);
 }
 
-- 
2.42.0

[PATCH 03/12] KVM: PPC: Book3S HV nestedv2: Do not check msr on hcalls

[Vaibhav Jain]

From: Jordan Niethe <jniethe5@gmail.com>

The check for a hcall coming from userspace is done for KVM-PR. This is
not supported for nestedv2 and the L0 will directly inject the necessary
exception to the L2 if userspace performs a hcall. Avoid checking the
MSR and thus avoid a H_GUEST_GET_STATE hcall in the L1.

Signed-off-by: Jordan Niethe <jniethe5@gmail.com>
---
 arch/powerpc/kvm/book3s_hv.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c
index 5543e8490cd9..069c336b6f3c 100644
--- a/arch/powerpc/kvm/book3s_hv.c
+++ b/arch/powerpc/kvm/book3s_hv.c
@@ -1688,7 +1688,7 @@ static int kvmppc_handle_exit_hv(struct kvm_vcpu *vcpu,
 	{
 		int i;
 
-		if (unlikely(__kvmppc_get_msr_hv(vcpu) & MSR_PR)) {
+		if (!kvmhv_is_nestedv2() && unlikely(__kvmppc_get_msr_hv(vcpu) & MSR_PR)) {
 			/*
 			 * Guest userspace executed sc 1. This can only be
 			 * reached by the P9 path because the old path
@@ -4949,7 +4949,7 @@ static int kvmppc_vcpu_run_hv(struct kvm_vcpu *vcpu)
 		if (run->exit_reason == KVM_EXIT_PAPR_HCALL) {
 			accumulate_time(vcpu, &vcpu->arch.hcall);
 
-			if (WARN_ON_ONCE(__kvmppc_get_msr_hv(vcpu) & MSR_PR)) {
+			if (!kvmhv_is_nestedv2() && WARN_ON_ONCE(__kvmppc_get_msr_hv(vcpu) & MSR_PR)) {
 				/*
 				 * These should have been caught reflected
 				 * into the guest by now. Final sanity check:
-- 
2.42.0

[PATCH 04/12] KVM: PPC: Book3S HV nestedv2: Get the PID only if needed to copy tofrom a guest

[Vaibhav Jain]

From: Jordan Niethe <jniethe5@gmail.com>

kvmhv_copy_tofrom_guest_radix() gets the PID at the start of the
function. If pid is not used, then this is a wasteful H_GUEST_GET_STATE
hcall for nestedv2 hosts. Move the assignment to where pid will be used.

Suggested-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Jordan Niethe <jniethe5@gmail.com>
---
 arch/powerpc/kvm/book3s_64_mmu_radix.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/kvm/book3s_64_mmu_radix.c b/arch/powerpc/kvm/book3s_64_mmu_radix.c
index 175a8eb2681f..916af6c153a5 100644
--- a/arch/powerpc/kvm/book3s_64_mmu_radix.c
+++ b/arch/powerpc/kvm/book3s_64_mmu_radix.c
@@ -97,7 +97,7 @@ static long kvmhv_copy_tofrom_guest_radix(struct kvm_vcpu *vcpu, gva_t eaddr,
 					  void *to, void *from, unsigned long n)
 {
 	int lpid = vcpu->kvm->arch.lpid;
-	int pid = kvmppc_get_pid(vcpu);
+	int pid;
 
 	/* This would cause a data segment intr so don't allow the access */
 	if (eaddr & (0x3FFUL << 52))
@@ -110,6 +110,8 @@ static long kvmhv_copy_tofrom_guest_radix(struct kvm_vcpu *vcpu, gva_t eaddr,
 	/* If accessing quadrant 3 then pid is expected to be 0 */
 	if (((eaddr >> 62) & 0x3) == 0x3)
 		pid = 0;
+	else
+		pid = kvmppc_get_pid(vcpu);
 
 	eaddr &= ~(0xFFFUL << 52);
 
-- 
2.42.0

[PATCH 05/12] KVM: PPC: Book3S HV nestedv2: Ensure LPCR_MER bit is passed to the L0

[Vaibhav Jain]

From: Jordan Niethe <jniethe5@gmail.com>

LPCR_MER is conditionally set during entry to a guest if there is a
pending external interrupt. In the nestedv2 case, this change is not
being communicated to the L0, which means it is not being set in the L2.
Ensure the updated LPCR value is passed to the L0.

Signed-off-by: Jordan Niethe <jniethe5@gmail.com>
---
 arch/powerpc/kvm/book3s_hv.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c
index 069c336b6f3c..6d1f0bca27aa 100644
--- a/arch/powerpc/kvm/book3s_hv.c
+++ b/arch/powerpc/kvm/book3s_hv.c
@@ -4084,6 +4084,8 @@ static int kvmhv_vcpu_entry_nestedv2(struct kvm_vcpu *vcpu, u64 time_limit,
 	if (rc < 0)
 		return -EINVAL;
 
+	kvmppc_gse_put_u64(io->vcpu_run_input, KVMPPC_GSID_LPCR, lpcr);
+
 	accumulate_time(vcpu, &vcpu->arch.in_guest);
 	rc = plpar_guest_run_vcpu(0, vcpu->kvm->arch.lpid, vcpu->vcpu_id,
 				  &trap, &i);
-- 
2.42.0

[PATCH 06/12] KVM: PPC: Book3S HV: Handle pending exceptions on guest entry with MSR_EE

[Vaibhav Jain]

From: Nicholas Piggin <npiggin@gmail.com>

Commit 026728dc5d41 ("KVM: PPC: Book3S HV P9: Inject pending xive
interrupts at guest entry") changed guest entry so that if external
interrupts are enabled, BOOK3S_IRQPRIO_EXTERNAL is not tested for. Test
for this regardless of MSR_EE.

For an L1 host, do not inject an interrupt, but always
use LPCR_MER. If the L0 desires it can inject an interrupt.

Fixes: 026728dc5d41 ("KVM: PPC: Book3S HV P9: Inject pending xive interrupts at guest entry")
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
[jpn: use kvmpcc_get_msr(), write commit message]
Signed-off-by: Jordan Niethe <jniethe5@gmail.com>
---
 arch/powerpc/kvm/book3s_hv.c | 18 ++++++++++++------
 1 file changed, 12 insertions(+), 6 deletions(-)

diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c
index 6d1f0bca27aa..4dc6a928073f 100644
--- a/arch/powerpc/kvm/book3s_hv.c
+++ b/arch/powerpc/kvm/book3s_hv.c
@@ -4738,13 +4738,19 @@ int kvmhv_run_single_vcpu(struct kvm_vcpu *vcpu, u64 time_limit,
 
 	if (!nested) {
 		kvmppc_core_prepare_to_enter(vcpu);
-		if (__kvmppc_get_msr_hv(vcpu) & MSR_EE) {
-			if (xive_interrupt_pending(vcpu))
+		if (test_bit(BOOK3S_IRQPRIO_EXTERNAL,
+			     &vcpu->arch.pending_exceptions) ||
+		    xive_interrupt_pending(vcpu)) {
+			/*
+			 * For nested HV, don't synthesize but always pass MER,
+			 * the L0 will be able to optimise that more
+			 * effectively than manipulating registers directly.
+			 */
+			if (!kvmhv_on_pseries() && (__kvmppc_get_msr_hv(vcpu) & MSR_EE))
 				kvmppc_inject_interrupt_hv(vcpu,
-						BOOK3S_INTERRUPT_EXTERNAL, 0);
-		} else if (test_bit(BOOK3S_IRQPRIO_EXTERNAL,
-			     &vcpu->arch.pending_exceptions)) {
-			lpcr |= LPCR_MER;
+							   BOOK3S_INTERRUPT_EXTERNAL, 0);
+			else
+				lpcr |= LPCR_MER;
 		}
 	} else if (vcpu->arch.pending_exceptions ||
 		   vcpu->arch.doorbell_request ||
-- 
2.42.0

[PATCH 07/12] KVM: PPC: Book3S HV nestedv2: Do not inject certain interrupts

[Vaibhav Jain]

From: Jordan Niethe <jniethe5@gmail.com>

There is no need to inject an external interrupt in
kvmppc_book3s_irqprio_deliver() as the test for BOOK3S_IRQPRIO_EXTERNAL
in kvmhv_run_single_vcpu() before guest entry will raise LPCR_MER if
needed. There is also no need to inject the decrementer interrupt as
this will be raised within the L2 if needed. Avoiding these injections
reduces H_GUEST_GET_STATE hcalls by the L1.

Suggested-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Jordan Niethe <jniethe5@gmail.com>
---
 arch/powerpc/kvm/book3s.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/powerpc/kvm/book3s.c b/arch/powerpc/kvm/book3s.c
index 6cd20ab9e94e..8acec144120e 100644
--- a/arch/powerpc/kvm/book3s.c
+++ b/arch/powerpc/kvm/book3s.c
@@ -302,11 +302,11 @@ static int kvmppc_book3s_irqprio_deliver(struct kvm_vcpu *vcpu,
 
 	switch (priority) {
 	case BOOK3S_IRQPRIO_DECREMENTER:
-		deliver = (kvmppc_get_msr(vcpu) & MSR_EE) && !crit;
+		deliver = !kvmhv_is_nestedv2() && (kvmppc_get_msr(vcpu) & MSR_EE) && !crit;
 		vec = BOOK3S_INTERRUPT_DECREMENTER;
 		break;
 	case BOOK3S_IRQPRIO_EXTERNAL:
-		deliver = (kvmppc_get_msr(vcpu) & MSR_EE) && !crit;
+		deliver = !kvmhv_is_nestedv2() && (kvmppc_get_msr(vcpu) & MSR_EE) && !crit;
 		vec = BOOK3S_INTERRUPT_EXTERNAL;
 		break;
 	case BOOK3S_IRQPRIO_SYSTEM_RESET:
-- 
2.42.0

[PATCH 08/12] KVM: PPC: Book3S HV nestedv2: Avoid msr check in kvmppc_handle_exit_hv()

[Vaibhav Jain]

From: Jordan Niethe <jniethe5@gmail.com>

The msr check in kvmppc_handle_exit_hv() is not needed for nestedv2 hosts,
skip the check to avoid a H_GUEST_GET_STATE hcall.

Signed-off-by: Jordan Niethe <jniethe5@gmail.com>
---
 arch/powerpc/kvm/book3s_hv.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c
index 4dc6a928073f..47fe470375df 100644
--- a/arch/powerpc/kvm/book3s_hv.c
+++ b/arch/powerpc/kvm/book3s_hv.c
@@ -1597,7 +1597,7 @@ static int kvmppc_handle_exit_hv(struct kvm_vcpu *vcpu,
 	 * That can happen due to a bug, or due to a machine check
 	 * occurring at just the wrong time.
 	 */
-	if (__kvmppc_get_msr_hv(vcpu) & MSR_HV) {
+	if (!kvmhv_is_nestedv2() && (__kvmppc_get_msr_hv(vcpu) & MSR_HV)) {
 		printk(KERN_EMERG "KVM trap in HV mode!\n");
 		printk(KERN_EMERG "trap=0x%x | pc=0x%lx | msr=0x%llx\n",
 			vcpu->arch.trap, kvmppc_get_pc(vcpu),
-- 
2.42.0

[PATCH 09/12] KVM: PPC: Book3S HV nestedv2: Do not call H_COPY_TOFROM_GUEST

[Vaibhav Jain]

From: Jordan Niethe <jniethe5@gmail.com>

H_COPY_TOFROM_GUEST is part of the nestedv1 API and so should not be
called by a nestedv2 host. Do not attempt to call it.

Signed-off-by: Jordan Niethe <jniethe5@gmail.com>
---
 arch/powerpc/kvm/book3s_64_mmu_radix.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/arch/powerpc/kvm/book3s_64_mmu_radix.c b/arch/powerpc/kvm/book3s_64_mmu_radix.c
index 916af6c153a5..4a1abb9f7c05 100644
--- a/arch/powerpc/kvm/book3s_64_mmu_radix.c
+++ b/arch/powerpc/kvm/book3s_64_mmu_radix.c
@@ -40,6 +40,9 @@ unsigned long __kvmhv_copy_tofrom_guest_radix(int lpid, int pid,
 	unsigned long quadrant, ret = n;
 	bool is_load = !!to;
 
+	if (kvmhv_is_nestedv2())
+		return H_UNSUPPORTED;
+
 	/* Can't access quadrants 1 or 2 in non-HV mode, call the HV to do it */
 	if (kvmhv_on_pseries())
 		return plpar_hcall_norets(H_COPY_TOFROM_GUEST, lpid, pid, eaddr,
-- 
2.42.0

Re: [PATCH 09/12] KVM: PPC: Book3S HV nestedv2: Do not call H_COPY_TOFROM_GUEST

[Aneesh Kumar K.V]

Vaibhav Jain <vaibhav@linux.ibm.com> writes:

> From: Jordan Niethe <jniethe5@gmail.com>
>
> H_COPY_TOFROM_GUEST is part of the nestedv1 API and so should not be
> called by a nestedv2 host. Do not attempt to call it.
>

May be we should use
firmware_has_feature(FW_FEATURE_H_COPY_TOFROM_GUEST))?

the nestedv2 can end up using the above hcall if it is supported by the
hypervisor right? In its absence we will have to translate the guest ea
using xlate and then use kvm_guest_read to read location using the guest
real address right? That xlate will also involves multiple kvm_guest_read.


> Signed-off-by: Jordan Niethe <jniethe5@gmail.com>
> ---
>  arch/powerpc/kvm/book3s_64_mmu_radix.c | 3 +++
>  1 file changed, 3 insertions(+)
>
> diff --git a/arch/powerpc/kvm/book3s_64_mmu_radix.c b/arch/powerpc/kvm/book3s_64_mmu_radix.c
> index 916af6c153a5..4a1abb9f7c05 100644
> --- a/arch/powerpc/kvm/book3s_64_mmu_radix.c
> +++ b/arch/powerpc/kvm/book3s_64_mmu_radix.c
> @@ -40,6 +40,9 @@ unsigned long __kvmhv_copy_tofrom_guest_radix(int lpid, int pid,
>  	unsigned long quadrant, ret = n;
>  	bool is_load = !!to;
>  
> +	if (kvmhv_is_nestedv2())
> +		return H_UNSUPPORTED;
> +
>  	/* Can't access quadrants 1 or 2 in non-HV mode, call the HV to do it */
>  	if (kvmhv_on_pseries())
>  		return plpar_hcall_norets(H_COPY_TOFROM_GUEST, lpid, pid, eaddr,
> -- 
> 2.42.0

Re: [PATCH 09/12] KVM: PPC: Book3S HV nestedv2: Do not call H_COPY_TOFROM_GUEST

[Vaibhav Jain]

Hi Aneesh,

Thanks for looking into this patch. My responses inline:

"Aneesh Kumar K.V (IBM)" <aneesh.kumar@kernel.org> writes:

<snip>
> May be we should use
> firmware_has_feature(FW_FEATURE_H_COPY_TOFROM_GUEST))?
>
> the nestedv2 can end up using the above hcall if it is supported by the
> hypervisor right? In its absence we will have to translate the guest ea
> using xlate and then use kvm_guest_read to read location using the guest
> real address right? That xlate will also involves multiple kvm_guest_read.
>
>
Yes, Agreed and thats a nice suggestion. However ATM the hypervisor
supporting Nestedv2 doesnt have support for this hcall. In future once
we have support for this hcall for nestedv2 from the hypervisor we can
replace this branch with a firmware_has_feature() test.

>> Signed-off-by: Jordan Niethe <jniethe5@gmail.com>
>> ---
>>  arch/powerpc/kvm/book3s_64_mmu_radix.c | 3 +++
>>  1 file changed, 3 insertions(+)
>>
>> diff --git a/arch/powerpc/kvm/book3s_64_mmu_radix.c b/arch/powerpc/kvm/book3s_64_mmu_radix.c
>> index 916af6c153a5..4a1abb9f7c05 100644
>> --- a/arch/powerpc/kvm/book3s_64_mmu_radix.c
>> +++ b/arch/powerpc/kvm/book3s_64_mmu_radix.c
>> @@ -40,6 +40,9 @@ unsigned long __kvmhv_copy_tofrom_guest_radix(int lpid, int pid,
>>  	unsigned long quadrant, ret = n;
>>  	bool is_load = !!to;
>>  
>> +	if (kvmhv_is_nestedv2())
>> +		return H_UNSUPPORTED;
>> +
>>  	/* Can't access quadrants 1 or 2 in non-HV mode, call the HV to do it */
>>  	if (kvmhv_on_pseries())
>>  		return plpar_hcall_norets(H_COPY_TOFROM_GUEST, lpid, pid, eaddr,
>> -- 
>> 2.42.0

-- 
Cheers
~ Vaibhav

Re: [PATCH 09/12] KVM: PPC: Book3S HV nestedv2: Do not call H_COPY_TOFROM_GUEST

[Aneesh Kumar K.V]

On 12/11/23 9:26 AM, Vaibhav Jain wrote:
> Hi Aneesh,
> 
> Thanks for looking into this patch. My responses inline:
> 
> "Aneesh Kumar K.V (IBM)" <aneesh.kumar@kernel.org> writes:
> 
> <snip>
>> May be we should use 
>> firmware_has_feature(FW_FEATURE_H_COPY_TOFROM_GUEST))?
>> 
>> the nestedv2 can end up using the above hcall if it is supported by
>> the hypervisor right? In its absence we will have to translate the
>> guest ea using xlate and then use kvm_guest_read to read location
>> using the guest real address right? That xlate will also involves
>> multiple kvm_guest_read.
>> 
>> 
> Yes, Agreed and thats a nice suggestion. However ATM the hypervisor 
> supporting Nestedv2 doesnt have support for this hcall. In future
> once we have support for this hcall for nestedv2 from the hypervisor
> we can replace this branch with a firmware_has_feature() test.
> 

What I am suggesting is we convert that conditional to firmware_has_feature so that
later when hypervisor supports this hcall all older kernel can make
use of the copy_tofrom_guest without any code change.

>>> Signed-off-by: Jordan Niethe <jniethe5@gmail.com> --- 
>>> arch/powerpc/kvm/book3s_64_mmu_radix.c | 3 +++ 1 file changed, 3
>>> insertions(+)
>>> 
>>> diff --git a/arch/powerpc/kvm/book3s_64_mmu_radix.c
>>> b/arch/powerpc/kvm/book3s_64_mmu_radix.c index
>>> 916af6c153a5..4a1abb9f7c05 100644 ---
>>> a/arch/powerpc/kvm/book3s_64_mmu_radix.c +++
>>> b/arch/powerpc/kvm/book3s_64_mmu_radix.c @@ -40,6 +40,9 @@
>>> unsigned long __kvmhv_copy_tofrom_guest_radix(int lpid, int pid, 
>>> unsigned long quadrant, ret = n; bool is_load = !!to;
>>> 
>>> +	if (kvmhv_is_nestedv2()) +		return H_UNSUPPORTED; + /* Can't
>>> access quadrants 1 or 2 in non-HV mode, call the HV to do it */ 
>>> if (kvmhv_on_pseries()) return
>>> plpar_hcall_norets(H_COPY_TOFROM_GUEST, lpid, pid, eaddr, -- 
>>> 2.42.0
> 

Re: [PATCH 09/12] KVM: PPC: Book3S HV nestedv2: Do not call H_COPY_TOFROM_GUEST

[Vaibhav Jain]

Hi Aneesh,

"Aneesh Kumar K.V" <aneesh.kumar@kernel.org> writes:

<snip>
>> Yes, Agreed and thats a nice suggestion. However ATM the hypervisor 
>> supporting Nestedv2 doesnt have support for this hcall. In future
>> once we have support for this hcall for nestedv2 from the hypervisor
>> we can replace this branch with a firmware_has_feature() test.
>> 
>
> What I am suggesting is we convert that conditional to firmware_has_feature so that
> later when hypervisor supports this hcall all older kernel can make
> use of the copy_tofrom_guest without any code change.

AFAIK for firmware_has_feature to work we either need:
- A way to call this hcall with some invalid args. However lpid/pid for
guest arent allocated during boot.

- A way for hypervisor to advertise support for this hcall before the L1
kernel boots.

ATM L0 dosent support for any of these two ways. I can do a follow up
patch later when we have a clarity on how we want to advertise support
for this hcall. For now current kernel supporting nestedv2 wont be
using this hcall assuming its not supported. Future kernels can use one
of the two ways above to set the firmware_has_feature flag to take
advantage of this hcall.


-- 
Cheers
~ Vaibhav

Re: [PATCH 09/12] KVM: PPC: Book3S HV nestedv2: Do not call H_COPY_TOFROM_GUEST

[Aneesh Kumar K.V]

Vaibhav Jain <vaibhav@linux.ibm.com> writes:

> Hi Aneesh,
>
> "Aneesh Kumar K.V" <aneesh.kumar@kernel.org> writes:
>
> <snip>
>>> Yes, Agreed and thats a nice suggestion. However ATM the hypervisor 
>>> supporting Nestedv2 doesnt have support for this hcall. In future
>>> once we have support for this hcall for nestedv2 from the hypervisor
>>> we can replace this branch with a firmware_has_feature() test.
>>> 
>>
>> What I am suggesting is we convert that conditional to firmware_has_feature so that
>> later when hypervisor supports this hcall all older kernel can make
>> use of the copy_tofrom_guest without any code change.
>
> AFAIK for firmware_has_feature to work we either need:
> - A way to call this hcall with some invalid args. However lpid/pid for
> guest arent allocated during boot.
>
> - A way for hypervisor to advertise support for this hcall before the L1
> kernel boots.
>
> ATM L0 dosent support for any of these two ways. I can do a follow up
> patch later when we have a clarity on how we want to advertise support
> for this hcall. For now current kernel supporting nestedv2 wont be
> using this hcall assuming its not supported. Future kernels can use one
> of the two ways above to set the firmware_has_feature flag to take
> advantage of this hcall.
>

We can use the second option and have L0 publish the firmware feature
when it adds the new hcall. The good part about this is that all
existing L1 kernels will automatically use the new hcall. Something
like.

diff --git a/arch/powerpc/include/asm/firmware.h b/arch/powerpc/include/asm/firmware.h
index 69ae9cf57d50..0ef97b56f999 100644
--- a/arch/powerpc/include/asm/firmware.h
+++ b/arch/powerpc/include/asm/firmware.h
@@ -57,6 +57,7 @@
 #define FW_FEATURE_ENERGY_SCALE_INFO ASM_CONST(0x0000040000000000)
 #define FW_FEATURE_WATCHDOG	ASM_CONST(0x0000080000000000)
 #define FW_FEATURE_PLPKS	ASM_CONST(0x0000100000000000)
+#define FW_FEATURE_H_COPY_TOFROM_GUEST	ASM_CONST(0x0000200000000000)
 
 #ifndef __ASSEMBLY__
 
diff --git a/arch/powerpc/kvm/book3s_64_mmu_radix.c b/arch/powerpc/kvm/book3s_64_mmu_radix.c
index 282d1b54b073..8fc598b4767a 100644
--- a/arch/powerpc/kvm/book3s_64_mmu_radix.c
+++ b/arch/powerpc/kvm/book3s_64_mmu_radix.c
@@ -39,6 +39,9 @@ unsigned long __kvmhv_copy_tofrom_guest_radix(int lpid, int pid,
 	unsigned long quadrant, ret = n;
 	bool is_load = !!to;
 
+	if (!firmware_has_feature(FW_FEATURE_H_COPY_TOFROM_GUEST))
+		return H_UNSUPPORTED;
+
 	/* Can't access quadrants 1 or 2 in non-HV mode, call the HV to do it */
 	if (kvmhv_on_pseries())
 		return plpar_hcall_norets(H_COPY_TOFROM_GUEST, lpid, pid, eaddr,
diff --git a/arch/powerpc/platforms/pseries/firmware.c b/arch/powerpc/platforms/pseries/firmware.c
index 18447e5fa17d..d49b5c52e7b8 100644
--- a/arch/powerpc/platforms/pseries/firmware.c
+++ b/arch/powerpc/platforms/pseries/firmware.c
@@ -69,6 +69,8 @@ hypertas_fw_features_table[] = {
 	{FW_FEATURE_ENERGY_SCALE_INFO,	"hcall-energy-scale-info"},
 	{FW_FEATURE_WATCHDOG,		"hcall-watchdog"},
 	{FW_FEATURE_PLPKS,		"hcall-pks"},
+	{FW_FEATURE_H_COPY_TOFROM_GUEST,
+					"hcall-h-copy_tofrom-guest"},
 };
 
 /* Build up the firmware features bitmask using the contents of

[PATCH 10/12] KVM: PPC: Book3S HV nestedv2: Register the VPA with the L0

[Vaibhav Jain]

From: Jordan Niethe <jniethe5@gmail.com>

In the nestedv2 case, the L1 may register the L2's VPA with the L0. This
allows the L0 to manage the L2's dispatch count, as well as enable
possible performance optimisations by seeing if certain resources are
not being used by the L2 (such as the PMCs).

Use the H_GUEST_SET_STATE call to inform the L0 of the L2's VPA
address. This can not be done in the H_GUEST_VCPU_RUN input buffer.

Signed-off-by: Jordan Niethe <jniethe5@gmail.com>
---
 arch/powerpc/include/asm/kvm_book3s_64.h |  1 +
 arch/powerpc/kvm/book3s_hv.c             | 38 ++++++++++++++++++------
 arch/powerpc/kvm/book3s_hv_nestedv2.c    | 29 ++++++++++++++++++
 3 files changed, 59 insertions(+), 9 deletions(-)

diff --git a/arch/powerpc/include/asm/kvm_book3s_64.h b/arch/powerpc/include/asm/kvm_book3s_64.h
index 2477021bff54..d8729ec81ca0 100644
--- a/arch/powerpc/include/asm/kvm_book3s_64.h
+++ b/arch/powerpc/include/asm/kvm_book3s_64.h
@@ -682,6 +682,7 @@ void kvmhv_nestedv2_vcpu_free(struct kvm_vcpu *vcpu, struct kvmhv_nestedv2_io *i
 int kvmhv_nestedv2_flush_vcpu(struct kvm_vcpu *vcpu, u64 time_limit);
 int kvmhv_nestedv2_set_ptbl_entry(unsigned long lpid, u64 dw0, u64 dw1);
 int kvmhv_nestedv2_parse_output(struct kvm_vcpu *vcpu);
+int kvmhv_nestedv2_set_vpa(struct kvm_vcpu *vcpu, unsigned long vpa);
 
 #endif /* CONFIG_KVM_BOOK3S_HV_POSSIBLE */
 
diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c
index 47fe470375df..2ee3f2478570 100644
--- a/arch/powerpc/kvm/book3s_hv.c
+++ b/arch/powerpc/kvm/book3s_hv.c
@@ -650,7 +650,8 @@ static unsigned long do_h_register_vpa(struct kvm_vcpu *vcpu,
 	return err;
 }
 
-static void kvmppc_update_vpa(struct kvm_vcpu *vcpu, struct kvmppc_vpa *vpap)
+static void kvmppc_update_vpa(struct kvm_vcpu *vcpu, struct kvmppc_vpa *vpap,
+			       struct kvmppc_vpa *old_vpap)
 {
 	struct kvm *kvm = vcpu->kvm;
 	void *va;
@@ -690,9 +691,8 @@ static void kvmppc_update_vpa(struct kvm_vcpu *vcpu, struct kvmppc_vpa *vpap)
 		kvmppc_unpin_guest_page(kvm, va, gpa, false);
 		va = NULL;
 	}
-	if (vpap->pinned_addr)
-		kvmppc_unpin_guest_page(kvm, vpap->pinned_addr, vpap->gpa,
-					vpap->dirty);
+	*old_vpap = *vpap;
+
 	vpap->gpa = gpa;
 	vpap->pinned_addr = va;
 	vpap->dirty = false;
@@ -702,6 +702,9 @@ static void kvmppc_update_vpa(struct kvm_vcpu *vcpu, struct kvmppc_vpa *vpap)
 
 static void kvmppc_update_vpas(struct kvm_vcpu *vcpu)
 {
+	struct kvm *kvm = vcpu->kvm;
+	struct kvmppc_vpa old_vpa = { 0 };
+
 	if (!(vcpu->arch.vpa.update_pending ||
 	      vcpu->arch.slb_shadow.update_pending ||
 	      vcpu->arch.dtl.update_pending))
@@ -709,17 +712,34 @@ static void kvmppc_update_vpas(struct kvm_vcpu *vcpu)
 
 	spin_lock(&vcpu->arch.vpa_update_lock);
 	if (vcpu->arch.vpa.update_pending) {
-		kvmppc_update_vpa(vcpu, &vcpu->arch.vpa);
-		if (vcpu->arch.vpa.pinned_addr)
+		kvmppc_update_vpa(vcpu, &vcpu->arch.vpa, &old_vpa);
+		if (old_vpa.pinned_addr) {
+			if (kvmhv_is_nestedv2())
+				kvmhv_nestedv2_set_vpa(vcpu, ~0ull);
+			kvmppc_unpin_guest_page(kvm, old_vpa.pinned_addr, old_vpa.gpa,
+						old_vpa.dirty);
+		}
+		if (vcpu->arch.vpa.pinned_addr) {
 			init_vpa(vcpu, vcpu->arch.vpa.pinned_addr);
+			if (kvmhv_is_nestedv2())
+				kvmhv_nestedv2_set_vpa(vcpu, __pa(vcpu->arch.vpa.pinned_addr));
+		}
 	}
 	if (vcpu->arch.dtl.update_pending) {
-		kvmppc_update_vpa(vcpu, &vcpu->arch.dtl);
+		kvmppc_update_vpa(vcpu, &vcpu->arch.dtl, &old_vpa);
+		if (old_vpa.pinned_addr)
+			kvmppc_unpin_guest_page(kvm, old_vpa.pinned_addr, old_vpa.gpa,
+						old_vpa.dirty);
 		vcpu->arch.dtl_ptr = vcpu->arch.dtl.pinned_addr;
 		vcpu->arch.dtl_index = 0;
 	}
-	if (vcpu->arch.slb_shadow.update_pending)
-		kvmppc_update_vpa(vcpu, &vcpu->arch.slb_shadow);
+	if (vcpu->arch.slb_shadow.update_pending) {
+		kvmppc_update_vpa(vcpu, &vcpu->arch.slb_shadow, &old_vpa);
+		if (old_vpa.pinned_addr)
+			kvmppc_unpin_guest_page(kvm, old_vpa.pinned_addr, old_vpa.gpa,
+						old_vpa.dirty);
+	}
+
 	spin_unlock(&vcpu->arch.vpa_update_lock);
 }
 
diff --git a/arch/powerpc/kvm/book3s_hv_nestedv2.c b/arch/powerpc/kvm/book3s_hv_nestedv2.c
index fd3c4f2d9480..5378eb40b162 100644
--- a/arch/powerpc/kvm/book3s_hv_nestedv2.c
+++ b/arch/powerpc/kvm/book3s_hv_nestedv2.c
@@ -855,6 +855,35 @@ int kvmhv_nestedv2_set_ptbl_entry(unsigned long lpid, u64 dw0, u64 dw1)
 }
 EXPORT_SYMBOL_GPL(kvmhv_nestedv2_set_ptbl_entry);
 
+/**
+ * kvmhv_nestedv2_set_vpa() - register L2 VPA with L0
+ * @vcpu: vcpu
+ * @vpa: L1 logical real address
+ */
+int kvmhv_nestedv2_set_vpa(struct kvm_vcpu *vcpu, unsigned long vpa)
+{
+	struct kvmhv_nestedv2_io *io;
+	struct kvmppc_gs_buff *gsb;
+	int rc = 0;
+
+	io = &vcpu->arch.nestedv2_io;
+	gsb = io->vcpu_run_input;
+
+	kvmppc_gsb_reset(gsb);
+	rc = kvmppc_gse_put_u64(gsb, KVMPPC_GSID_VPA, vpa);
+	if (rc < 0)
+		goto out;
+
+	rc = kvmppc_gsb_send(gsb, 0);
+	if (rc < 0)
+		pr_err("KVM-NESTEDv2: couldn't register the L2 VPA (rc=%d)\n", rc);
+
+out:
+	kvmppc_gsb_reset(gsb);
+	return rc;
+}
+EXPORT_SYMBOL_GPL(kvmhv_nestedv2_set_vpa);
+
 /**
  * kvmhv_nestedv2_parse_output() - receive values from H_GUEST_RUN_VCPU output
  * @vcpu: vcpu
-- 
2.42.0

[PATCH 11/12] KVM: PPC: Reduce reliance on analyse_instr() in mmio emulation

[Vaibhav Jain]

From: Jordan Niethe <jniethe5@gmail.com>

Commit 709236039964 ("KVM: PPC: Reimplement non-SIMD LOAD/STORE
instruction mmio emulation with analyse_instr() input") and
commit 2b33cb585f94 ("KVM: PPC: Reimplement LOAD_FP/STORE_FP instruction
mmio emulation with analyse_instr() input") made
kvmppc_emulate_loadstore() use the results from analyse_instr() for
instruction emulation. In particular the effective address from
analyse_instr() is used for UPDATE type instructions and fact that
op.val is all ready endian corrected is used in the STORE case.

However, these changes now have some negative implications for the
nestedv2 case.  For analyse_instr() to determine the correct effective
address, the GPRs must be loaded from the L0. This is not needed as
vcpu->arch.vaddr_accessed is already set. Change back to using
vcpu->arch.vaddr_accessed.

In the STORE case, use kvmppc_get_gpr() value instead of the op.val.
kvmppc_get_gpr() will reload from the L0 if needed in the nestedv2 case.
This means if a byte reversal is needed must now be passed to
kvmppc_handle_store() like in the kvmppc_handle_load() case.

This means the call to kvmhv_nestedv2_reload_ptregs() can be avoided as
there is no concern about op.val being stale. Drop the call to
kvmhv_nestedv2_mark_dirty_ptregs() as without the call to
kvmhv_nestedv2_reload_ptregs(), stale state could be marked as valid.

This is fine as the required marking things dirty is already handled for
the UPDATE case by the call to kvmppc_set_gpr(). For LOADs, it is
handled in kvmppc_complete_mmio_load(). This is called either directly
in __kvmppc_handle_load() if the load can be handled in KVM, or on the
next kvm_arch_vcpu_ioctl_run() if an exit was required.

Signed-off-by: Jordan Niethe <jniethe5@gmail.com>
---
 arch/powerpc/kvm/emulate_loadstore.c | 21 ++++++++++-----------
 1 file changed, 10 insertions(+), 11 deletions(-)

diff --git a/arch/powerpc/kvm/emulate_loadstore.c b/arch/powerpc/kvm/emulate_loadstore.c
index 077fd88a0b68..ec60c7979718 100644
--- a/arch/powerpc/kvm/emulate_loadstore.c
+++ b/arch/powerpc/kvm/emulate_loadstore.c
@@ -93,7 +93,6 @@ int kvmppc_emulate_loadstore(struct kvm_vcpu *vcpu)
 
 	emulated = EMULATE_FAIL;
 	vcpu->arch.regs.msr = kvmppc_get_msr(vcpu);
-	kvmhv_nestedv2_reload_ptregs(vcpu, &vcpu->arch.regs);
 	if (analyse_instr(&op, &vcpu->arch.regs, inst) == 0) {
 		int type = op.type & INSTR_TYPE_MASK;
 		int size = GETSIZE(op.type);
@@ -112,7 +111,7 @@ int kvmppc_emulate_loadstore(struct kvm_vcpu *vcpu)
 						op.reg, size, !instr_byte_swap);
 
 			if ((op.type & UPDATE) && (emulated != EMULATE_FAIL))
-				kvmppc_set_gpr(vcpu, op.update_reg, op.ea);
+				kvmppc_set_gpr(vcpu, op.update_reg, vcpu->arch.vaddr_accessed);
 
 			break;
 		}
@@ -132,7 +131,7 @@ int kvmppc_emulate_loadstore(struct kvm_vcpu *vcpu)
 					     KVM_MMIO_REG_FPR|op.reg, size, 1);
 
 			if ((op.type & UPDATE) && (emulated != EMULATE_FAIL))
-				kvmppc_set_gpr(vcpu, op.update_reg, op.ea);
+				kvmppc_set_gpr(vcpu, op.update_reg, vcpu->arch.vaddr_accessed);
 
 			break;
 #endif
@@ -224,16 +223,17 @@ int kvmppc_emulate_loadstore(struct kvm_vcpu *vcpu)
 			break;
 		}
 #endif
-		case STORE:
-			/* if need byte reverse, op.val has been reversed by
-			 * analyse_instr().
-			 */
-			emulated = kvmppc_handle_store(vcpu, op.val, size, 1);
+		case STORE: {
+			int instr_byte_swap = op.type & BYTEREV;
+
+			emulated = kvmppc_handle_store(vcpu, kvmppc_get_gpr(vcpu, op.reg),
+						       size, !instr_byte_swap);
 
 			if ((op.type & UPDATE) && (emulated != EMULATE_FAIL))
-				kvmppc_set_gpr(vcpu, op.update_reg, op.ea);
+				kvmppc_set_gpr(vcpu, op.update_reg, vcpu->arch.vaddr_accessed);
 
 			break;
+		}
 #ifdef CONFIG_PPC_FPU
 		case STORE_FP:
 			if (kvmppc_check_fp_disabled(vcpu))
@@ -254,7 +254,7 @@ int kvmppc_emulate_loadstore(struct kvm_vcpu *vcpu)
 					kvmppc_get_fpr(vcpu, op.reg), size, 1);
 
 			if ((op.type & UPDATE) && (emulated != EMULATE_FAIL))
-				kvmppc_set_gpr(vcpu, op.update_reg, op.ea);
+				kvmppc_set_gpr(vcpu, op.update_reg, vcpu->arch.vaddr_accessed);
 
 			break;
 #endif
@@ -358,7 +358,6 @@ int kvmppc_emulate_loadstore(struct kvm_vcpu *vcpu)
 	}
 
 	trace_kvm_ppc_instr(ppc_inst_val(inst), kvmppc_get_pc(vcpu), emulated);
-	kvmhv_nestedv2_mark_dirty_ptregs(vcpu, &vcpu->arch.regs);
 
 	/* Advance past emulated instruction. */
 	if (emulated != EMULATE_FAIL)
-- 
2.42.0

[PATCH 12/12] KVM: PPC: Book3S HV nestedv2: Do not cancel pending decrementer exception

[Vaibhav Jain]

From: Jordan Niethe <jniethe5@gmail.com>

In the nestedv2 case, if there is a pending decrementer exception, the
L1 must get the L2's timebase from the L0 to see if the exception should
be cancelled. This adds the overhead of a H_GUEST_GET_STATE call to the
likely case in which the decrementer should not be cancelled.

Avoid this logic for the nestedv2 case.

Signed-off-by: Jordan Niethe <jniethe5@gmail.com>
---
 arch/powerpc/kvm/book3s_hv.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c
index 2ee3f2478570..e48126a59ba7 100644
--- a/arch/powerpc/kvm/book3s_hv.c
+++ b/arch/powerpc/kvm/book3s_hv.c
@@ -4834,7 +4834,7 @@ int kvmhv_run_single_vcpu(struct kvm_vcpu *vcpu, u64 time_limit,
 	 * entering a nested guest in which case the decrementer is now owned
 	 * by L2 and the L1 decrementer is provided in hdec_expires
 	 */
-	if (kvmppc_core_pending_dec(vcpu) &&
+	if (!kvmhv_is_nestedv2() && kvmppc_core_pending_dec(vcpu) &&
 			((tb < kvmppc_dec_expires_host_tb(vcpu)) ||
 			 (trap == BOOK3S_INTERRUPT_SYSCALL &&
 			  kvmppc_get_gpr(vcpu, 3) == H_ENTER_NESTED)))
-- 
2.42.0

Re: [PATCH 00/12] KVM: PPC: Nested APIv2 : Performance improvements

[Michael Ellerman]

On Fri, 01 Dec 2023 18:56:05 +0530, Vaibhav Jain wrote:
> This patch series introduces series of performance improvements to recently
> added support for Nested APIv2 PPC64 Guests via [1]. Details for Nested
> APIv2 for PPC64 Guests is available in Documentation/powerpc/kvm-nested.rst.
> 
> This patch series introduces various optimizations for a Nested APIv2
> guests namely:
> 
> [...]

Applied to powerpc/topic/ppc-kvm.

[01/12] KVM: PPC: Book3S HV nestedv2: Invalidate RPT before deleting a guest
        https://git.kernel.org/powerpc/c/7d370e1812b9a5f5cc68aaa5991bf7d31d8ff52c
[02/12] KVM: PPC: Book3S HV nestedv2: Avoid reloading the tb offset
        https://git.kernel.org/powerpc/c/e0d4acbcba3f2d63dc15bc5432c8e26fc9e19675
[03/12] KVM: PPC: Book3S HV nestedv2: Do not check msr on hcalls
        https://git.kernel.org/powerpc/c/63ccae78cd88b52fb1d598ae33fa8408ce067b30
[04/12] KVM: PPC: Book3S HV nestedv2: Get the PID only if needed to copy tofrom a guest
        https://git.kernel.org/powerpc/c/e678748a8dca5b57041a84a66577f6168587b3f7
[05/12] KVM: PPC: Book3S HV nestedv2: Ensure LPCR_MER bit is passed to the L0
        https://git.kernel.org/powerpc/c/ec0f6639fa8853cf6bfdfc3588aada7eeb7e5e37
[06/12] KVM: PPC: Book3S HV: Handle pending exceptions on guest entry with MSR_EE
        https://git.kernel.org/powerpc/c/ecd10702baae5c16a91d139bde7eff84ce55daee
[07/12] KVM: PPC: Book3S HV nestedv2: Do not inject certain interrupts
        https://git.kernel.org/powerpc/c/df938a5576f3f3b08e1f217c660385c0d58a0b91
[08/12] KVM: PPC: Book3S HV nestedv2: Avoid msr check in kvmppc_handle_exit_hv()
        https://git.kernel.org/powerpc/c/a9a3de530d7531bf6cd3f6ccda769cd94c1105a0
[09/12] KVM: PPC: Book3S HV nestedv2: Do not call H_COPY_TOFROM_GUEST
        https://git.kernel.org/powerpc/c/4bc8ff6f170c78f64446c5d5f9ef6771eefd3416
[10/12] KVM: PPC: Book3S HV nestedv2: Register the VPA with the L0
        https://git.kernel.org/powerpc/c/db1dcfae1dae3c042f348175ac0394e2fc14b1b3
[11/12] KVM: PPC: Reduce reliance on analyse_instr() in mmio emulation
        https://git.kernel.org/powerpc/c/797a5af8fc7297b19e5c6b1713956ebf1e6c1cde
[12/12] KVM: PPC: Book3S HV nestedv2: Do not cancel pending decrementer exception
        https://git.kernel.org/powerpc/c/180c6b072bf360b686e53d893d8dcf7dbbaec6bb

cheers