KVM: s390: Add new reset vcpu API
Janosch Frank
maintainerPATCH v2 1/1 KVM: s390: Add new reset vcpu API
The architecture states that we need to reset local IRQs for all CPU resets. Because the old reset interface did not support the normal CPU reset we never did that.
Now that we have a new interface, let's properly clear out local IRQs and let this commit be a reminder.
--- arch/s390/kvm/kvm-s390.c | 13 +++++++++++++ include/uapi/linux/kvm.h | 4 ++++ 2 files changed, 17 insertions(+)
arch/s390/kvm/kvm-s390.c +13 -0
@@ -529,6 +529,7 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)case KVM_CAP_S390_CMMA_MIGRATION :case KVM_CAP_S390_AIS :case KVM_CAP_S390_AIS_MIGRATION : +case KVM_CAP_S390_VCPU_RESETS : r =1 ;break ;case KVM_CAP_S390_HPAGE_1M :
@@ -3287,6 +3288,13 @@ static int kvm_arch_vcpu_ioctl_set_one_reg(struct kvm_vcpu *vcpu,return r; } +static int kvm_arch_vcpu_ioctl_normal_reset (struct kvm_vcpu *vcpu) +{ +kvm_clear_async_pf_completion_queue (vcpu); +kvm_s390_clear_local_irqs (vcpu); +return 0 ; +} +static int kvm_arch_vcpu_ioctl_initial_reset (struct kvm_vcpu *vcpu) {kvm_s390_vcpu_initial_reset (vcpu);
@@ -4363,7 +4371,12 @@ long kvm_arch_vcpu_ioctl(struct file *filp, r =kvm_arch_vcpu_ioctl_set_initial_psw (vcpu, psw);break ; } +case KVM_S390_NORMAL_RESET : + r =kvm_arch_vcpu_ioctl_normal_reset (vcpu); +break ;case KVM_S390_INITIAL_RESET : +/* fallthrough */ +case KVM_S390_CLEAR_RESET : r =kvm_arch_vcpu_ioctl_initial_reset (vcpu);break ;case KVM_SET_ONE_REG :
include/uapi/linux/kvm.h +4 -0
@@ -1000,6 +1000,7 @@ struct kvm_ppc_resize_hpt {#define KVM_CAP_PMU_EVENT_FILTER 173#define KVM_CAP_ARM_IRQ_LINE_LAYOUT_2 174#define KVM_CAP_HYPERV_DIRECT_TLBFLUSH 175 +#define KVM_CAP_S390_VCPU_RESETS 180#ifdef KVM_CAP_IRQ_ROUTING
@@ -1461,6 +1462,9 @@ struct kvm_enc_region {/* Available with KVM_CAP_ARM_SVE */ #define KVM_ARM_VCPU_FINALIZE _IOW(KVMIO, 0xc2, int) +#define KVM_S390_NORMAL_RESET _IO(KVMIO, 0xc3) +#define KVM_S390_CLEAR_RESET _IO(KVMIO, 0xc4) +/* Secure Encrypted Virtualization command */ enum sev_cmd_id {/* Guest initialization commands */
Signature · 1 line
2.20.1
Quoted 65 lines · Janosch Frank
The architecture states that we need to reset local IRQs for all CPU resets. Because the old reset interface did not support the normal CPU reset we never did that.
Now that we have a new interface, let's properly clear out local IRQs and let this commit be a reminder.
Signed-off-by Janosch Frank <[email protected]>--- arch/s390/kvm/kvm-s390.c | 13 +++++++++++++ include/uapi/linux/kvm.h | 4 ++++ 2 files changed, 17 insertions(+)arch/s390/kvm/kvm-s390.c +13
-0@@ -529,6 +529,7 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)case KVM_CAP_S390_CMMA_MIGRATION :case KVM_CAP_S390_AIS :case KVM_CAP_S390_AIS_MIGRATION : +case KVM_CAP_S390_VCPU_RESETS : r =1 ;break ;case KVM_CAP_S390_HPAGE_1M :@@ -3287,6 +3288,13 @@ static int kvm_arch_vcpu_ioctl_set_one_reg(struct kvm_vcpu *vcpu,return r; } +static int kvm_arch_vcpu_ioctl_normal_reset (struct kvm_vcpu *vcpu) +{ +kvm_clear_async_pf_completion_queue (vcpu); +kvm_s390_clear_local_irqs (vcpu); +return 0 ; +} +static int kvm_arch_vcpu_ioctl_initial_reset (struct kvm_vcpu *vcpu) {kvm_s390_vcpu_initial_reset (vcpu);@@ -4363,7 +4371,12 @@ long kvm_arch_vcpu_ioctl(struct file *filp, r =kvm_arch_vcpu_ioctl_set_initial_psw (vcpu, psw);break ; } +case KVM_S390_NORMAL_RESET : + r =kvm_arch_vcpu_ioctl_normal_reset (vcpu); +break ;case KVM_S390_INITIAL_RESET : +/* fallthrough */ +case KVM_S390_CLEAR_RESET : r =kvm_arch_vcpu_ioctl_initial_reset (vcpu);break ;case KVM_SET_ONE_REG :include/uapi/linux/kvm.h +1
-0@@ -1000,6 +1000,7 @@ struct kvm_ppc_resize_hpt {#define KVM_CAP_PMU_EVENT_FILTER 173#define KVM_CAP_ARM_IRQ_LINE_LAYOUT_2 174#define KVM_CAP_HYPERV_DIRECT_TLBFLUSH 175 +#define KVM_CAP_S390_VCPU_RESETS 180#ifdef KVM_CAP_IRQ_ROUTING
include/uapi/linux/kvm.h struct kvm_enc_region { · line 1464
Quoted 3 lines
include/uapi/linux/kvm.h +0
-0@@ -1461,6 +1462,9 @@ struct kvm_enc_region {/* Available with KVM_CAP_ARM_SVE */ #define KVM_ARM_VCPU_FINALIZE _IOW(KVMIO, 0xc2, int)
Maybe also a comment like
"Available with KVM_CAP_S390_VCPU_RESETS" ?
include/uapi/linux/kvm.h struct kvm_enc_region { · line 1470
Quoted 7 lines
include/uapi/linux/kvm.h +3
-0+#define KVM_S390_NORMAL_RESET _IO(KVMIO, 0xc3) +#define KVM_S390_CLEAR_RESET _IO(KVMIO, 0xc4) +/* Secure Encrypted Virtualization command */ enum sev_cmd_id {/* Guest initialization commands */
Signature · 3 lines
Thanks, David / dhildenb
Quoted 6 lines · On Tue, 3 Dec 2019 11:20:55 -0500 Janosch Frank <[email protected]> wrote:
The architecture states that we need to reset local IRQs for all CPU resets. Because the old reset interface did not support the normal CPU reset we never did that.
Now that we have a new interface, let's properly clear out local IRQs and let this commit be a reminder.
Well, the new interface did not appear magically, this patch introduces it :) (The whole sentence is a bit confusing; what is this commit supposed to remind us of?)
Quoted 34 lines
Signed-off-by Janosch Frank <[email protected]>--- arch/s390/kvm/kvm-s390.c | 13 +++++++++++++ include/uapi/linux/kvm.h | 4 ++++ 2 files changed, 17 insertions(+)arch/s390/kvm/kvm-s390.c +8
-0@@ -529,6 +529,7 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)case KVM_CAP_S390_CMMA_MIGRATION :case KVM_CAP_S390_AIS :case KVM_CAP_S390_AIS_MIGRATION : +case KVM_CAP_S390_VCPU_RESETS : r =1 ;break ;case KVM_CAP_S390_HPAGE_1M :@@ -3287,6 +3288,13 @@ static int kvm_arch_vcpu_ioctl_set_one_reg(struct kvm_vcpu *vcpu,return r; } +static int kvm_arch_vcpu_ioctl_normal_reset (struct kvm_vcpu *vcpu) +{ +kvm_clear_async_pf_completion_queue (vcpu); +kvm_s390_clear_local_irqs (vcpu); +return 0 ; +} +static int kvm_arch_vcpu_ioctl_initial_reset (struct kvm_vcpu *vcpu) {kvm_s390_vcpu_initial_reset (vcpu);
arch/s390/kvm/kvm-s390.c long kvm_arch_vcpu_ioctl(struct file *filp, · line 4380
Quoted 10 lines
arch/s390/kvm/kvm-s390.c +5
-0@@ -4363,7 +4371,12 @@ long kvm_arch_vcpu_ioctl(struct file *filp, r =kvm_arch_vcpu_ioctl_set_initial_psw (vcpu, psw);break ; } +case KVM_S390_NORMAL_RESET : + r =kvm_arch_vcpu_ioctl_normal_reset (vcpu); +break ;case KVM_S390_INITIAL_RESET : +/* fallthrough */ +case KVM_S390_CLEAR_RESET : r =kvm_arch_vcpu_ioctl_initial_reset (vcpu);
The cover letter probably should also mention that clear reset falls back to initial reset for now?
Quoted 15 lines
arch/s390/kvm/kvm-s390.c +0
-0break ;case KVM_SET_ONE_REG :include/uapi/linux/kvm.h +1
-0@@ -1000,6 +1000,7 @@ struct kvm_ppc_resize_hpt {#define KVM_CAP_PMU_EVENT_FILTER 173#define KVM_CAP_ARM_IRQ_LINE_LAYOUT_2 174#define KVM_CAP_HYPERV_DIRECT_TLBFLUSH 175 +#define KVM_CAP_S390_VCPU_RESETS 180#ifdef KVM_CAP_IRQ_ROUTING
include/uapi/linux/kvm.h struct kvm_enc_region { · line 1470
Quoted 9 lines
include/uapi/linux/kvm.h +3
-0@@ -1461,6 +1462,9 @@ struct kvm_enc_region {/* Available with KVM_CAP_ARM_SVE */ #define KVM_ARM_VCPU_FINALIZE _IOW(KVMIO, 0xc2, int) +#define KVM_S390_NORMAL_RESET _IO(KVMIO, 0xc3) +#define KVM_S390_CLEAR_RESET _IO(KVMIO, 0xc4) +/* Secure Encrypted Virtualization command */ enum sev_cmd_id {/* Guest initialization commands */
Looks sane, but please also document the new ioctls and the new cap.
Quoted 41 lines · Janosch Frank
The architecture states that we need to reset local IRQs for all CPU resets. Because the old reset interface did not support the normal CPU reset we never did that.
Now that we have a new interface, let's properly clear out local IRQs and let this commit be a reminder.
Signed-off-by Janosch Frank <[email protected]>--- arch/s390/kvm/kvm-s390.c | 13 +++++++++++++ include/uapi/linux/kvm.h | 4 ++++ 2 files changed, 17 insertions(+)arch/s390/kvm/kvm-s390.c +8
-0@@ -529,6 +529,7 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)case KVM_CAP_S390_CMMA_MIGRATION :case KVM_CAP_S390_AIS :case KVM_CAP_S390_AIS_MIGRATION : +case KVM_CAP_S390_VCPU_RESETS : r =1 ;break ;case KVM_CAP_S390_HPAGE_1M :@@ -3287,6 +3288,13 @@ static int kvm_arch_vcpu_ioctl_set_one_reg(struct kvm_vcpu *vcpu,return r; } +static int kvm_arch_vcpu_ioctl_normal_reset (struct kvm_vcpu *vcpu) +{ +kvm_clear_async_pf_completion_queue (vcpu); +kvm_s390_clear_local_irqs (vcpu); +return 0 ; +} +static int kvm_arch_vcpu_ioctl_initial_reset (struct kvm_vcpu *vcpu) {kvm_s390_vcpu_initial_reset (vcpu);@@ -4363,7 +4371,12 @@ long kvm_arch_vcpu_ioctl(struct file *filp, r =kvm_arch_vcpu_ioctl_set_initial_psw (vcpu, psw);
arch/s390/kvm/kvm-s390.c long kvm_arch_vcpu_ioctl(struct file *filp, · line 4381
Quoted 10 lines
arch/s390/kvm/kvm-s390.c +5
-0break ; } +case KVM_S390_NORMAL_RESET : + r =kvm_arch_vcpu_ioctl_normal_reset (vcpu); +break ;case KVM_S390_INITIAL_RESET : +/* fallthrough */ +case KVM_S390_CLEAR_RESET : r =kvm_arch_vcpu_ioctl_initial_reset (vcpu);break ;
Isn't clear reset supposed to do more than the initial reset? If so, I'd rather expect it the other way round:
case KVM_S390_CLEAR_RESET: /* fallthrough */ case KVM_S390_INITIAL_RESET: r = kvm_arch_vcpu_ioctl_initial_reset(vcpu); break;
... so you can later add the additional stuff before the "/* fallthrough */"?
Thomas
Janosch Frank
maintainerQuoted 47 lines · Thomas Huth
Quoted 46 lines · Janosch Frank
The architecture states that we need to reset local IRQs for all CPU resets. Because the old reset interface did not support the normal CPU reset we never did that.
Now that we have a new interface, let's properly clear out local IRQs and let this commit be a reminder.
Signed-off-by Janosch Frank <[email protected]>--- arch/s390/kvm/kvm-s390.c | 13 +++++++++++++ include/uapi/linux/kvm.h | 4 ++++ 2 files changed, 17 insertions(+)arch/s390/kvm/kvm-s390.c +11
-0@@ -529,6 +529,7 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)case KVM_CAP_S390_CMMA_MIGRATION :case KVM_CAP_S390_AIS :case KVM_CAP_S390_AIS_MIGRATION : +case KVM_CAP_S390_VCPU_RESETS : r =1 ;break ;case KVM_CAP_S390_HPAGE_1M :@@ -3287,6 +3288,13 @@ static int kvm_arch_vcpu_ioctl_set_one_reg(struct kvm_vcpu *vcpu,return r; } +static int kvm_arch_vcpu_ioctl_normal_reset (struct kvm_vcpu *vcpu) +{ +kvm_clear_async_pf_completion_queue (vcpu); +kvm_s390_clear_local_irqs (vcpu); +return 0 ; +} +static int kvm_arch_vcpu_ioctl_initial_reset (struct kvm_vcpu *vcpu) {kvm_s390_vcpu_initial_reset (vcpu);@@ -4363,7 +4371,12 @@ long kvm_arch_vcpu_ioctl(struct file *filp, r =kvm_arch_vcpu_ioctl_set_initial_psw (vcpu, psw);break ; } +case KVM_S390_NORMAL_RESET : + r =kvm_arch_vcpu_ioctl_normal_reset (vcpu); +break ;
Quoted 8 lines
arch/s390/kvm/kvm-s390.c long kvm_arch_vcpu_ioctl(struct file *filp, · line 4381
Quoted 5 lines
arch/s390/kvm/kvm-s390.c +2
-0case KVM_S390_INITIAL_RESET : +/* fallthrough */ +case KVM_S390_CLEAR_RESET : r =kvm_arch_vcpu_ioctl_initial_reset (vcpu);break ;Isn't clear reset supposed to do more than the initial reset? If so, I'd rather expect it the other way round:
In the PV patch I remove the fallthrough and add a function for the clear reset. I add the UV reset calls into the kvm_arch_vcpu_ioctl_*_reset() functions, therefore I can't fallthrough because the Ultravisor does currently not allow staged resets (i.e. first initial then clear if a clear reset is needed)
Quoted 12 lines
case KVM_S390_CLEAR_RESET: /* fallthrough */ case KVM_S390_INITIAL_RESET: r = kvm_arch_vcpu_ioctl_initial_reset(vcpu); break;... so you can later add the additional stuff before the "/* fallthrough */"?
Thomas
Quoted 57 lines · Janosch Frank
Quoted 47 lines · Thomas Huth
Quoted 46 lines · Janosch Frank
The architecture states that we need to reset local IRQs for all CPU resets. Because the old reset interface did not support the normal CPU reset we never did that.
Now that we have a new interface, let's properly clear out local IRQs and let this commit be a reminder.
Signed-off-by Janosch Frank <[email protected]>--- arch/s390/kvm/kvm-s390.c | 13 +++++++++++++ include/uapi/linux/kvm.h | 4 ++++ 2 files changed, 17 insertions(+)arch/s390/kvm/kvm-s390.c +11
-0@@ -529,6 +529,7 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)case KVM_CAP_S390_CMMA_MIGRATION :case KVM_CAP_S390_AIS :case KVM_CAP_S390_AIS_MIGRATION : +case KVM_CAP_S390_VCPU_RESETS : r =1 ;break ;case KVM_CAP_S390_HPAGE_1M :@@ -3287,6 +3288,13 @@ static int kvm_arch_vcpu_ioctl_set_one_reg(struct kvm_vcpu *vcpu,return r; } +static int kvm_arch_vcpu_ioctl_normal_reset (struct kvm_vcpu *vcpu) +{ +kvm_clear_async_pf_completion_queue (vcpu); +kvm_s390_clear_local_irqs (vcpu); +return 0 ; +} +static int kvm_arch_vcpu_ioctl_initial_reset (struct kvm_vcpu *vcpu) {kvm_s390_vcpu_initial_reset (vcpu);@@ -4363,7 +4371,12 @@ long kvm_arch_vcpu_ioctl(struct file *filp, r =kvm_arch_vcpu_ioctl_set_initial_psw (vcpu, psw);break ; } +case KVM_S390_NORMAL_RESET : + r =kvm_arch_vcpu_ioctl_normal_reset (vcpu); +break ;Quoted 8 lines
arch/s390/kvm/kvm-s390.c long kvm_arch_vcpu_ioctl(struct file *filp, · line 4381
Quoted 5 lines
arch/s390/kvm/kvm-s390.c +2
-0case KVM_S390_INITIAL_RESET : +/* fallthrough */ +case KVM_S390_CLEAR_RESET : r =kvm_arch_vcpu_ioctl_initial_reset (vcpu);break ;Isn't clear reset supposed to do more than the initial reset? If so, I'd rather expect it the other way round:
Quoted 5 lines
In the PV patch I remove the fallthrough and add a function for the clear reset. I add the UV reset calls into the kvm_arch_vcpu_ioctl_*_reset() functions, therefore I can't fallthrough because the Ultravisor does currently not allow staged resets (i.e. first initial then clear if a clear reset is needed)
Ok, then it's fine. But in case you respin your patch, it's maybe less confusing if you swap it.
Thomas