From 6d28f789bf81540d4069342b1a28bfd41dab38a3 Mon Sep 17 00:00:00 2001 From: Halil Pasic Date: Mon, 25 Jan 2016 19:10:40 +0100 Subject: [PATCH] KVM: s390: add clear I/O irq operation for FLIC Introduce a FLIC operation for clearing I/O interrupts for a subchannel. Rationale: According to the platform specification, pending I/O interruption requests have to be revoked in certain situations. For instance, according to the Principles of Operation (page 17-27), a subchannel put into the installed parameters initialized state is in the same state as after an I/O system reset (just parameters possibly changed). This implies that any I/O interrupts for that subchannel are no longer pending (as I/O system resets clear I/O interrupts). Therefore, we need an interface to clear pending I/O interrupts. Signed-off-by: Halil Pasic Reviewed-by: Cornelia Huck Reviewed-by: Christian Borntraeger Signed-off-by: Christian Borntraeger Signed-off-by: Cornelia Huck --- .../virtual/kvm/devices/s390_flic.txt | 6 +++++ arch/s390/include/uapi/asm/kvm.h | 1 + arch/s390/kvm/interrupt.c | 25 +++++++++++++++++++ 3 files changed, 32 insertions(+) diff --git a/Documentation/virtual/kvm/devices/s390_flic.txt b/Documentation/virtual/kvm/devices/s390_flic.txt index 646f47470f98..8478de1c0192 100644 --- a/Documentation/virtual/kvm/devices/s390_flic.txt +++ b/Documentation/virtual/kvm/devices/s390_flic.txt @@ -11,6 +11,7 @@ FLIC provides support to - add interrupts (KVM_DEV_FLIC_ENQUEUE) - inspect currently pending interrupts (KVM_FLIC_GET_ALL_IRQS) - purge all pending floating interrupts (KVM_DEV_FLIC_CLEAR_IRQS) +- purge one pending floating I/O interrupt (KVM_DEV_FLIC_CLEAR_IO_IRQ) - enable/disable for the guest transparent async page faults - register and modify adapter interrupt sources (KVM_DEV_FLIC_ADAPTER_*) @@ -40,6 +41,11 @@ Groups: Simply deletes all elements from the list of currently pending floating interrupts. No interrupts are injected into the guest. + KVM_DEV_FLIC_CLEAR_IO_IRQ + Deletes one (if any) I/O interrupt for a subchannel identified by the + subsystem identification word passed via the buffer specified by + attr->addr (address) and attr->attr (length). + KVM_DEV_FLIC_APF_ENABLE Enables async page faults for the guest. So in case of a major page fault the host is allowed to handle this async and continues the guest. diff --git a/arch/s390/include/uapi/asm/kvm.h b/arch/s390/include/uapi/asm/kvm.h index 347fe5afa419..3b8e99ef9d58 100644 --- a/arch/s390/include/uapi/asm/kvm.h +++ b/arch/s390/include/uapi/asm/kvm.h @@ -25,6 +25,7 @@ #define KVM_DEV_FLIC_APF_DISABLE_WAIT 5 #define KVM_DEV_FLIC_ADAPTER_REGISTER 6 #define KVM_DEV_FLIC_ADAPTER_MODIFY 7 +#define KVM_DEV_FLIC_CLEAR_IO_IRQ 8 /* * We can have up to 4*64k pending subchannels + 8 adapter interrupts, * as well as up to ASYNC_PF_PER_VCPU*KVM_MAX_VCPUS pfault done interrupts. diff --git a/arch/s390/kvm/interrupt.c b/arch/s390/kvm/interrupt.c index 4c2cdb2dcfc8..e55040467eb5 100644 --- a/arch/s390/kvm/interrupt.c +++ b/arch/s390/kvm/interrupt.c @@ -2034,6 +2034,27 @@ static int modify_io_adapter(struct kvm_device *dev, return ret; } +static int clear_io_irq(struct kvm *kvm, struct kvm_device_attr *attr) + +{ + const u64 isc_mask = 0xffUL << 24; /* all iscs set */ + u32 schid; + + if (attr->flags) + return -EINVAL; + if (attr->attr != sizeof(schid)) + return -EINVAL; + if (copy_from_user(&schid, (void __user *) attr->addr, sizeof(schid))) + return -EFAULT; + kfree(kvm_s390_get_io_int(kvm, isc_mask, schid)); + /* + * If userspace is conforming to the architecture, we can have at most + * one pending I/O interrupt per subchannel, so this is effectively a + * clear all. + */ + return 0; +} + static int flic_set_attr(struct kvm_device *dev, struct kvm_device_attr *attr) { int r = 0; @@ -2067,6 +2088,9 @@ static int flic_set_attr(struct kvm_device *dev, struct kvm_device_attr *attr) case KVM_DEV_FLIC_ADAPTER_MODIFY: r = modify_io_adapter(dev, attr); break; + case KVM_DEV_FLIC_CLEAR_IO_IRQ: + r = clear_io_irq(dev->kvm, attr); + break; default: r = -EINVAL; } @@ -2085,6 +2109,7 @@ static int flic_has_attr(struct kvm_device *dev, case KVM_DEV_FLIC_APF_DISABLE_WAIT: case KVM_DEV_FLIC_ADAPTER_REGISTER: case KVM_DEV_FLIC_ADAPTER_MODIFY: + case KVM_DEV_FLIC_CLEAR_IO_IRQ: return 0; } return -ENXIO;