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Commit 84223598 authored by Cornelia Huck's avatar Cornelia Huck
Browse files

KVM: s390: irq routing for adapter interrupts. 



Introduce a new interrupt class for s390 adapter interrupts and enable
irqfds for s390.

This is depending on a new s390 specific vm capability, KVM_CAP_S390_IRQCHIP,
that needs to be enabled by userspace.

Acked-by: default avatarChristian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: default avatarCornelia Huck <cornelia.huck@de.ibm.com>
parent 841b91c5

Documentation/virtual/kvm/api.txt

+17 −4
Original line number Diff line number Diff line
@@ -586,8 +586,8 @@ struct kvm_fpu { 


4.24 KVM_CREATE_IRQCHIP



Capability: KVM_CAP_IRQCHIP

Architectures: x86, ia64, ARM, arm64

Capability: KVM_CAP_IRQCHIP, KVM_CAP_S390_IRQCHIP (s390)

Architectures: x86, ia64, ARM, arm64, s390

Type: vm ioctl

Parameters: none

Returns: 0 on success, -1 on error
@@ -596,7 +596,10 @@ Creates an interrupt controller model in the kernel. On x86, creates a virtual 
ioapic, a virtual PIC (two PICs, nested), and sets up future vcpus to have a

local APIC.  IRQ routing for GSIs 0-15 is set to both PIC and IOAPIC; GSI 16-23

only go to the IOAPIC.  On ia64, a IOSAPIC is created. On ARM/arm64, a GIC is

created.

created. On s390, a dummy irq routing table is created.



Note that on s390 the KVM_CAP_S390_IRQCHIP vm capability needs to be enabled

before KVM_CREATE_IRQCHIP can be used.





4.25 KVM_IRQ_LINE
@@ -1336,7 +1339,7 @@ KVM_ASSIGN_DEV_IRQ. Partial deassignment of host or guest IRQ is allowed. 
4.52 KVM_SET_GSI_ROUTING



Capability: KVM_CAP_IRQ_ROUTING

Architectures: x86 ia64

Architectures: x86 ia64 s390

Type: vm ioctl

Parameters: struct kvm_irq_routing (in)

Returns: 0 on success, -1 on error
@@ -1359,6 +1362,7 @@ struct kvm_irq_routing_entry { 
	union {

		struct kvm_irq_routing_irqchip irqchip;

		struct kvm_irq_routing_msi msi;

		struct kvm_irq_routing_s390_adapter adapter;

		__u32 pad[8];

	} u;

};
@@ -1366,6 +1370,7 @@ struct kvm_irq_routing_entry { 
/* gsi routing entry types */

#define KVM_IRQ_ROUTING_IRQCHIP 1

#define KVM_IRQ_ROUTING_MSI 2

#define KVM_IRQ_ROUTING_S390_ADAPTER 3



No flags are specified so far, the corresponding field must be set to zero.
@@ -1381,6 +1386,14 @@ struct kvm_irq_routing_msi { 
	__u32 pad;

};



struct kvm_irq_routing_s390_adapter {

	__u64 ind_addr;

	__u64 summary_addr;

	__u64 ind_offset;

	__u32 summary_offset;

	__u32 adapter_id;

};





4.53 KVM_ASSIGN_SET_MSIX_NR

arch/s390/include/asm/kvm_host.h

+9 −0
Original line number Diff line number Diff line
@@ -24,6 +24,14 @@ 
#define KVM_MAX_VCPUS 64

#define KVM_USER_MEM_SLOTS 32



/*

 * These seem to be used for allocating ->chip in the routing table,

 * which we don't use. 4096 is an out-of-thin-air value. If we need

 * to look at ->chip later on, we'll need to revisit this.

 */

#define KVM_NR_IRQCHIPS 1

#define KVM_IRQCHIP_NUM_PINS 4096



struct sca_entry {

	atomic_t scn;

	__u32	reserved;
@@ -274,6 +282,7 @@ struct kvm_arch{ 
	struct kvm_device *flic;

	struct gmap *gmap;

	int css_support;

	int use_irqchip;

	struct s390_io_adapter *adapters[MAX_S390_IO_ADAPTERS];

};

arch/s390/kvm/Kconfig

+2 −0
Original line number Diff line number Diff line
@@ -25,6 +25,8 @@ config KVM 
	select HAVE_KVM_EVENTFD

	select KVM_ASYNC_PF

	select KVM_ASYNC_PF_SYNC

	select HAVE_KVM_IRQCHIP

	select HAVE_KVM_IRQ_ROUTING

	---help---

	  Support hosting paravirtualized guest machines using the SIE

	  virtualization capability on the mainframe. This should work

arch/s390/kvm/Makefile

+1 −1
Original line number Diff line number Diff line
@@ -7,7 +7,7 @@ 
# as published by the Free Software Foundation.



KVM := ../../../virt/kvm

common-objs = $(KVM)/kvm_main.o $(KVM)/eventfd.o  $(KVM)/async_pf.o

common-objs = $(KVM)/kvm_main.o $(KVM)/eventfd.o  $(KVM)/async_pf.o $(KVM)/irqchip.o



ccflags-y := -Ivirt/kvm -Iarch/s390/kvm

arch/s390/kvm/interrupt.c

+121 −0
Original line number Diff line number Diff line
@@ -13,6 +13,7 @@ 
#include <linux/interrupt.h>

#include <linux/kvm_host.h>

#include <linux/hrtimer.h>

#include <linux/mmu_context.h>

#include <linux/signal.h>

#include <linux/slab.h>

#include <asm/asm-offsets.h>
@@ -1284,3 +1285,123 @@ struct kvm_device_ops kvm_flic_ops = { 
	.create = flic_create,

	.destroy = flic_destroy,

};



static unsigned long get_ind_bit(__u64 addr, unsigned long bit_nr, bool swap)

{

	unsigned long bit;



	bit = bit_nr + (addr % PAGE_SIZE) * 8;



	return swap ? (bit ^ (BITS_PER_LONG - 1)) : bit;

}



static struct s390_map_info *get_map_info(struct s390_io_adapter *adapter,

					  u64 addr)

{

	struct s390_map_info *map;



	if (!adapter)

		return NULL;



	list_for_each_entry(map, &adapter->maps, list) {

		if (map->guest_addr == addr)

			return map;

	}

	return NULL;

}



static int adapter_indicators_set(struct kvm *kvm,

				  struct s390_io_adapter *adapter,

				  struct kvm_s390_adapter_int *adapter_int)

{

	unsigned long bit;

	int summary_set, idx;

	struct s390_map_info *info;

	void *map;



	info = get_map_info(adapter, adapter_int->ind_addr);

	if (!info)

		return -1;

	map = page_address(info->page);

	bit = get_ind_bit(info->addr, adapter_int->ind_offset, adapter->swap);

	set_bit(bit, map);

	idx = srcu_read_lock(&kvm->srcu);

	mark_page_dirty(kvm, info->guest_addr >> PAGE_SHIFT);

	set_page_dirty_lock(info->page);

	info = get_map_info(adapter, adapter_int->summary_addr);

	if (!info) {

		srcu_read_unlock(&kvm->srcu, idx);

		return -1;

	}

	map = page_address(info->page);

	bit = get_ind_bit(info->addr, adapter_int->summary_offset,

			  adapter->swap);

	summary_set = test_and_set_bit(bit, map);

	mark_page_dirty(kvm, info->guest_addr >> PAGE_SHIFT);

	set_page_dirty_lock(info->page);

	srcu_read_unlock(&kvm->srcu, idx);

	return summary_set ? 0 : 1;

}



/*

 * < 0 - not injected due to error

 * = 0 - coalesced, summary indicator already active

 * > 0 - injected interrupt

 */

static int set_adapter_int(struct kvm_kernel_irq_routing_entry *e,

			   struct kvm *kvm, int irq_source_id, int level,

			   bool line_status)

{

	int ret;

	struct s390_io_adapter *adapter;



	/* We're only interested in the 0->1 transition. */

	if (!level)

		return 0;

	adapter = get_io_adapter(kvm, e->adapter.adapter_id);

	if (!adapter)

		return -1;

	down_read(&adapter->maps_lock);

	ret = adapter_indicators_set(kvm, adapter, &e->adapter);

	up_read(&adapter->maps_lock);

	if ((ret > 0) && !adapter->masked) {

		struct kvm_s390_interrupt s390int = {

			.type = KVM_S390_INT_IO(1, 0, 0, 0),

			.parm = 0,

			.parm64 = (adapter->isc << 27) | 0x80000000,

		};

		ret = kvm_s390_inject_vm(kvm, &s390int);

		if (ret == 0)

			ret = 1;

	}

	return ret;

}



int kvm_set_routing_entry(struct kvm_irq_routing_table *rt,

			  struct kvm_kernel_irq_routing_entry *e,

			  const struct kvm_irq_routing_entry *ue)

{

	int ret;



	switch (ue->type) {

	case KVM_IRQ_ROUTING_S390_ADAPTER:

		e->set = set_adapter_int;

		e->adapter.summary_addr = ue->u.adapter.summary_addr;

		e->adapter.ind_addr = ue->u.adapter.ind_addr;

		e->adapter.summary_offset = ue->u.adapter.summary_offset;

		e->adapter.ind_offset = ue->u.adapter.ind_offset;

		e->adapter.adapter_id = ue->u.adapter.adapter_id;

		ret = 0;

		break;

	default:

		ret = -EINVAL;

	}



	return ret;

}



int kvm_set_msi(struct kvm_kernel_irq_routing_entry *e, struct kvm *kvm,

		int irq_source_id, int level, bool line_status)

{

	return -EINVAL;

}