Commit 8a242234 authored by Heiko Carstens's avatar Heiko Carstens Committed by Christian Borntraeger
Browse files

KVM: s390: make use of ipte lock 



Signed-off-by: default avatarHeiko Carstens <heiko.carstens@de.ibm.com>
Reviewed-by: default avatarThomas Huth <thuth@linux.vnet.ibm.com>
Signed-off-by: default avatarChristian Borntraeger <borntraeger@de.ibm.com>
parent 217a4406

arch/s390/include/asm/kvm_host.h

+11 −1
Original line number Diff line number Diff line
@@ -39,9 +39,17 @@ struct sca_entry { 
	__u64	reserved2[2];

} __attribute__((packed));



union ipte_control {

	unsigned long val;

	struct {

		unsigned long k  : 1;

		unsigned long kh : 31;

		unsigned long kg : 32;

	};

};



struct sca_block {

	__u64	ipte_control;

	union ipte_control ipte_control;

	__u64	reserved[5];

	__u64	mcn;

	__u64	reserved2;
@@ -167,6 +175,7 @@ struct kvm_vcpu_stat { 
	u32 instruction_stpx;

	u32 instruction_stap;

	u32 instruction_storage_key;

	u32 instruction_ipte_interlock;

	u32 instruction_stsch;

	u32 instruction_chsc;

	u32 instruction_stsi;
@@ -336,6 +345,7 @@ struct kvm_arch{ 
	int use_irqchip;

	int use_cmma;

	struct s390_io_adapter *adapters[MAX_S390_IO_ADAPTERS];

	wait_queue_head_t ipte_wq;

};



#define KVM_HVA_ERR_BAD		(-1UL)

arch/s390/kvm/gaccess.c

+109 −0
Original line number Diff line number Diff line
@@ -207,6 +207,107 @@ union raddress { 
	unsigned long pfra : 52; /* Page-Frame Real Address */

};



static int ipte_lock_count;

static DEFINE_MUTEX(ipte_mutex);



int ipte_lock_held(struct kvm_vcpu *vcpu)

{

	union ipte_control *ic = &vcpu->kvm->arch.sca->ipte_control;



	if (vcpu->arch.sie_block->eca & 1)

		return ic->kh != 0;

	return ipte_lock_count != 0;

}



static void ipte_lock_simple(struct kvm_vcpu *vcpu)

{

	union ipte_control old, new, *ic;



	mutex_lock(&ipte_mutex);

	ipte_lock_count++;

	if (ipte_lock_count > 1)

		goto out;

	ic = &vcpu->kvm->arch.sca->ipte_control;

	do {

		old = ACCESS_ONCE(*ic);

		while (old.k) {

			cond_resched();

			old = ACCESS_ONCE(*ic);

		}

		new = old;

		new.k = 1;

	} while (cmpxchg(&ic->val, old.val, new.val) != old.val);

out:

	mutex_unlock(&ipte_mutex);

}



static void ipte_unlock_simple(struct kvm_vcpu *vcpu)

{

	union ipte_control old, new, *ic;



	mutex_lock(&ipte_mutex);

	ipte_lock_count--;

	if (ipte_lock_count)

		goto out;

	ic = &vcpu->kvm->arch.sca->ipte_control;

	do {

		new = old = ACCESS_ONCE(*ic);

		new.k = 0;

	} while (cmpxchg(&ic->val, old.val, new.val) != old.val);

	if (!ipte_lock_count)

		wake_up(&vcpu->kvm->arch.ipte_wq);

out:

	mutex_unlock(&ipte_mutex);

}



static void ipte_lock_siif(struct kvm_vcpu *vcpu)

{

	union ipte_control old, new, *ic;



	ic = &vcpu->kvm->arch.sca->ipte_control;

	do {

		old = ACCESS_ONCE(*ic);

		while (old.kg) {

			cond_resched();

			old = ACCESS_ONCE(*ic);

		}

		new = old;

		new.k = 1;

		new.kh++;

	} while (cmpxchg(&ic->val, old.val, new.val) != old.val);

}



static void ipte_unlock_siif(struct kvm_vcpu *vcpu)

{

	union ipte_control old, new, *ic;



	ic = &vcpu->kvm->arch.sca->ipte_control;

	do {

		new = old = ACCESS_ONCE(*ic);

		new.kh--;

		if (!new.kh)

			new.k = 0;

	} while (cmpxchg(&ic->val, old.val, new.val) != old.val);

	if (!new.kh)

		wake_up(&vcpu->kvm->arch.ipte_wq);

}



static void ipte_lock(struct kvm_vcpu *vcpu)

{

	if (vcpu->arch.sie_block->eca & 1)

		ipte_lock_siif(vcpu);

	else

		ipte_lock_simple(vcpu);

}



static void ipte_unlock(struct kvm_vcpu *vcpu)

{

	if (vcpu->arch.sie_block->eca & 1)

		ipte_unlock_siif(vcpu);

	else

		ipte_unlock_simple(vcpu);

}



static unsigned long get_vcpu_asce(struct kvm_vcpu *vcpu)

{

	switch (psw_bits(vcpu->arch.sie_block->gpsw).as) {
@@ -485,6 +586,8 @@ int access_guest(struct kvm_vcpu *vcpu, unsigned long ga, void *data, 
	unsigned long _len, nr_pages, gpa, idx;

	unsigned long pages_array[2];

	unsigned long *pages;

	int need_ipte_lock;

	union asce asce;

	int rc;



	if (!len)
@@ -498,6 +601,10 @@ int access_guest(struct kvm_vcpu *vcpu, unsigned long ga, void *data, 
		pages = vmalloc(nr_pages * sizeof(unsigned long));

	if (!pages)

		return -ENOMEM;

	asce.val = get_vcpu_asce(vcpu);

	need_ipte_lock = psw_bits(*psw).t && !asce.r;

	if (need_ipte_lock)

		ipte_lock(vcpu);

	rc = guest_page_range(vcpu, ga, pages, nr_pages, write);

	for (idx = 0; idx < nr_pages && !rc; idx++) {

		gpa = *(pages + idx) + (ga & ~PAGE_MASK);
@@ -510,6 +617,8 @@ int access_guest(struct kvm_vcpu *vcpu, unsigned long ga, void *data, 
		ga += _len;

		data += _len;

	}

	if (need_ipte_lock)

		ipte_unlock(vcpu);

	if (nr_pages > ARRAY_SIZE(pages_array))

		vfree(pages);

	return rc;

arch/s390/kvm/gaccess.h

+2 −0
Original line number Diff line number Diff line
@@ -397,4 +397,6 @@ int read_guest_real(struct kvm_vcpu *vcpu, unsigned long gra, void *data, 
	return access_guest_real(vcpu, gra, data, len, 0);

}



int ipte_lock_held(struct kvm_vcpu *vcpu);



#endif /* __KVM_S390_GACCESS_H */

arch/s390/kvm/kvm-s390.c

+2 −0
Original line number Diff line number Diff line
@@ -67,6 +67,7 @@ struct kvm_stats_debugfs_item debugfs_entries[] = { 
	{ "instruction_stpx", VCPU_STAT(instruction_stpx) },

	{ "instruction_stap", VCPU_STAT(instruction_stap) },

	{ "instruction_storage_key", VCPU_STAT(instruction_storage_key) },

	{ "instruction_ipte_interlock", VCPU_STAT(instruction_ipte_interlock) },

	{ "instruction_stsch", VCPU_STAT(instruction_stsch) },

	{ "instruction_chsc", VCPU_STAT(instruction_chsc) },

	{ "instruction_essa", VCPU_STAT(instruction_essa) },
@@ -437,6 +438,7 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type) 


	spin_lock_init(&kvm->arch.float_int.lock);

	INIT_LIST_HEAD(&kvm->arch.float_int.list);

	init_waitqueue_head(&kvm->arch.ipte_wq);



	debug_register_view(kvm->arch.dbf, &debug_sprintf_view);

	VM_EVENT(kvm, 3, "%s", "vm created");

arch/s390/kvm/priv.c

+18 −0
Original line number Diff line number Diff line
@@ -173,6 +173,19 @@ static int handle_skey(struct kvm_vcpu *vcpu) 
	return 0;

}



static int handle_ipte_interlock(struct kvm_vcpu *vcpu)

{

	psw_t *psw = &vcpu->arch.sie_block->gpsw;



	vcpu->stat.instruction_ipte_interlock++;

	if (psw_bits(*psw).p)

		return kvm_s390_inject_program_int(vcpu, PGM_PRIVILEGED_OP);

	wait_event(vcpu->kvm->arch.ipte_wq, !ipte_lock_held(vcpu));

	psw->addr = __rewind_psw(*psw, 4);

	VCPU_EVENT(vcpu, 4, "%s", "retrying ipte interlock operation");

	return 0;

}



static int handle_test_block(struct kvm_vcpu *vcpu)

{

	unsigned long hva;
@@ -509,6 +522,7 @@ static const intercept_handler_t b2_handlers[256] = { 
	[0x10] = handle_set_prefix,

	[0x11] = handle_store_prefix,

	[0x12] = handle_store_cpu_address,

	[0x21] = handle_ipte_interlock,

	[0x29] = handle_skey,

	[0x2a] = handle_skey,

	[0x2b] = handle_skey,
@@ -526,6 +540,7 @@ static const intercept_handler_t b2_handlers[256] = { 
	[0x3a] = handle_io_inst,

	[0x3b] = handle_io_inst,

	[0x3c] = handle_io_inst,

	[0x50] = handle_ipte_interlock,

	[0x5f] = handle_io_inst,

	[0x74] = handle_io_inst,

	[0x76] = handle_io_inst,
@@ -686,7 +701,10 @@ static int handle_essa(struct kvm_vcpu *vcpu) 
}



static const intercept_handler_t b9_handlers[256] = {

	[0x8a] = handle_ipte_interlock,

	[0x8d] = handle_epsw,

	[0x8e] = handle_ipte_interlock,

	[0x8f] = handle_ipte_interlock,

	[0xab] = handle_essa,

	[0xaf] = handle_pfmf,

};

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