Re: [PATCH 4.4 12/50] KVM: s390: wire up bpb feature

[Christian Borntraeger <borntraeger@de.ibm.com>]

On 04/30/2018 08:17 PM, Greg Kroah-Hartman wrote:
> On Sun, Apr 29, 2018 at 09:51:27AM +0200, Martin Schwidefsky wrote:
>> On Fri, 27 Apr 2018 17:53:46 +0200
>> Christian Borntraeger <borntraeger@de.ibm.com> wrote:
>>
>>> On 04/27/2018 05:46 PM, Greg Kroah-Hartman wrote:
>>>> On Fri, Apr 27, 2018 at 05:17:15PM +0200, Greg Kroah-Hartman wrote:  
>>>>> On Fri, Apr 27, 2018 at 05:10:04PM +0200, Christian Borntraeger wrote:  
>>>>>>
>>>>>>
>>>>>> On 04/27/2018 03:58 PM, Greg Kroah-Hartman wrote:  
>>>>>>> 4.4-stable review patch.  If anyone has any objections, please let me know.
>>>>>>>
>>>>>>> ------------------
>>>>>>>
>>>>>>> From: Martin Schwidefsky <schwidefsky@de.ibm.com>
>>>>>>>
>>>>>>>
>>>>>>> From: Christian Borntraeger <borntraeger@de.ibm.com>  
>>>>>
>>>>> Ick, that is wrong right there, my scripts messed up, this should not
>>>>> have 2 author lines :(
>>>>>
>>>>> I'll go look at all of these, odds are it made the same error
>>>>> everywhere...  
>>>>
>>>> Yes, I've now fixed that up in the queue.  
>>>
>>> As this patch backport was also functionally incorrect and Martin is already away
>>> do you want me to send an updated version?
>>
>> Checked my 4.4 backport git branch and indeed the hunk is misplaced.
>> Sometime I wonder about the patch tool and the hickups it can produce.
>>
>> My take on the replacement patch looks as follows:
>>
>> ---
>> >From 82f20b6237a8d04378c8f4a1614bf32a6c8d8a8b Mon Sep 17 00:00:00 2001
>> From: Christian Borntraeger <borntraeger@de.ibm.com>
>> Date: Wed, 17 Jan 2018 14:44:34 +0100
>> Subject: [PATCH 03/18] KVM: s390: wire up bpb feature
>> MIME-Version: 1.0
>> Content-Type: text/plain; charset=UTF-8
>> Content-Transfer-Encoding: 8bit
>>
>> [ Upstream commit 35b3fde6203b932b2b1a5b53b3d8808abc9c4f60 ]
>>
>> The new firmware interfaces for branch prediction behaviour changes
>> are transparently available for the guest. Nevertheless, there is
>> new state attached that should be migrated and properly resetted.
>> Provide a mechanism for handling reset, migration and VSIE.
>>
>> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
>> Reviewed-by: David Hildenbrand <david@redhat.com>
>> Reviewed-by: Cornelia Huck <cohuck@redhat.com>
>> [Changed capability number to 152. - Radim]
>> Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
>> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
>> ---
>>  arch/s390/include/asm/kvm_host.h |  3 ++-
>>  arch/s390/include/uapi/asm/kvm.h |  3 +++
>>  arch/s390/kvm/kvm-s390.c         | 12 ++++++++++++
>>  include/uapi/linux/kvm.h         |  1 +
>>  4 files changed, 18 insertions(+), 1 deletion(-)
>>
>> diff --git a/arch/s390/include/asm/kvm_host.h b/arch/s390/include/asm/kvm_host.h
>> index e9a983f40a24..7d9c5917da2b 100644
>> --- a/arch/s390/include/asm/kvm_host.h
>> +++ b/arch/s390/include/asm/kvm_host.h
>> @@ -136,7 +136,8 @@ struct kvm_s390_sie_block {
>>  	__u16	ipa;			/* 0x0056 */
>>  	__u32	ipb;			/* 0x0058 */
>>  	__u32	scaoh;			/* 0x005c */
>> -	__u8	reserved60;		/* 0x0060 */
>> +#define FPF_BPBC 	0x20
>> +	__u8	fpf;			/* 0x0060 */
>>  	__u8	ecb;			/* 0x0061 */
>>  	__u8    ecb2;                   /* 0x0062 */
>>  #define ECB3_AES 0x04
>> diff --git a/arch/s390/include/uapi/asm/kvm.h b/arch/s390/include/uapi/asm/kvm.h
>> index ef1a5fcc6c66..3aec52253c04 100644
>> --- a/arch/s390/include/uapi/asm/kvm.h
>> +++ b/arch/s390/include/uapi/asm/kvm.h
>> @@ -151,6 +151,7 @@ struct kvm_guest_debug_arch {
>>  #define KVM_SYNC_ARCH0  (1UL << 4)
>>  #define KVM_SYNC_PFAULT (1UL << 5)
>>  #define KVM_SYNC_VRS    (1UL << 6)
>> +#define KVM_SYNC_BPBC	(1UL << 10)
>>  /* definition of registers in kvm_run */
>>  struct kvm_sync_regs {
>>  	__u64 prefix;	/* prefix register */
>> @@ -168,6 +169,8 @@ struct kvm_sync_regs {
>>  	__u64 vrs[32][2];	/* vector registers */
>>  	__u8  reserved[512];	/* for future vector expansion */
>>  	__u32 fpc;	/* only valid with vector registers */
>> +	__u8 bpbc : 1;		/* bp mode */
>> +	__u8 reserved2 : 7;
>>  };
>>  
>>  #define KVM_REG_S390_TODPR	(KVM_REG_S390 | KVM_REG_SIZE_U32 | 0x1)
>> diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
>> index 23e3f5d77a24..ca03c847127a 100644
>> --- a/arch/s390/kvm/kvm-s390.c
>> +++ b/arch/s390/kvm/kvm-s390.c
>> @@ -257,6 +257,9 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
>>  	case KVM_CAP_S390_VECTOR_REGISTERS:
>>  		r = MACHINE_HAS_VX;
>>  		break;
>> +	case KVM_CAP_S390_BPB:
>> +		r = test_facility(82);
>> +		break;
>>  	default:
>>  		r = 0;
>>  	}
>> @@ -1262,6 +1265,8 @@ int kvm_arch_vcpu_init(struct kvm_vcpu *vcpu)
>>  				    KVM_SYNC_CRS |
>>  				    KVM_SYNC_ARCH0 |
>>  				    KVM_SYNC_PFAULT;
>> +	if (test_kvm_facility(vcpu->kvm, 82))
>> +		vcpu->run->kvm_valid_regs |= KVM_SYNC_BPBC;
>>  	if (test_kvm_facility(vcpu->kvm, 129))
>>  		vcpu->run->kvm_valid_regs |= KVM_SYNC_VRS;
>>  
>> @@ -1327,6 +1332,7 @@ static void kvm_s390_vcpu_initial_reset(struct kvm_vcpu *vcpu)
>>  	current->thread.fpu.fpc = 0;
>>  	vcpu->arch.sie_block->gbea = 1;
>>  	vcpu->arch.sie_block->pp = 0;
>> +	vcpu->arch.sie_block->fpf &= ~FPF_BPBC;
>>  	vcpu->arch.pfault_token = KVM_S390_PFAULT_TOKEN_INVALID;
>>  	kvm_clear_async_pf_completion_queue(vcpu);
>>  	if (!kvm_s390_user_cpu_state_ctrl(vcpu->kvm))
>> @@ -2145,6 +2151,11 @@ static void sync_regs(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
>>  		if (vcpu->arch.pfault_token == KVM_S390_PFAULT_TOKEN_INVALID)
>>  			kvm_clear_async_pf_completion_queue(vcpu);
>>  	}
>> +	if ((kvm_run->kvm_dirty_regs & KVM_SYNC_BPBC) &&
>> +	    test_kvm_facility(vcpu->kvm, 82)) {
>> +		vcpu->arch.sie_block->fpf &= ~FPF_BPBC;
>> +		vcpu->arch.sie_block->fpf |= kvm_run->s.regs.bpbc ? FPF_BPBC : 0;
>> +	}
>>  	kvm_run->kvm_dirty_regs = 0;
>>  }
>>  
>> @@ -2162,6 +2173,7 @@ static void store_regs(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
>>  	kvm_run->s.regs.pft = vcpu->arch.pfault_token;
>>  	kvm_run->s.regs.pfs = vcpu->arch.pfault_select;
>>  	kvm_run->s.regs.pfc = vcpu->arch.pfault_compare;
>> +	kvm_run->s.regs.bpbc = (vcpu->arch.sie_block->fpf & FPF_BPBC) == FPF_BPBC;
>>  }
>>  
>>  int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
>> diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
>> index 03f3618612aa..376d0ab5b9f2 100644
>> --- a/include/uapi/linux/kvm.h
>> +++ b/include/uapi/linux/kvm.h
>> @@ -831,6 +831,7 @@ struct kvm_ppc_smmu_info {
>>  #define KVM_CAP_GUEST_DEBUG_HW_WPS 120
>>  #define KVM_CAP_SPLIT_IRQCHIP 121
>>  #define KVM_CAP_IOEVENTFD_ANY_LENGTH 122
>> +#define KVM_CAP_S390_BPB 152
>>  
>>  #ifdef KVM_CAP_IRQ_ROUTING
>>  
> 
> Did I include the correct version in the latest release, or do I need to
> do a revert and add this one in?

Martins backport and my backport looks almost identical, so you can keep mine.