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Commit 126a5af5 authored by Cornelia Huck's avatar Cornelia Huck Committed by Paolo Bonzini
Browse files

KVM: kvm-io: support cookies 



Add new functions kvm_io_bus_{read,write}_cookie() that allows users of
the kvm io infrastructure to use a cookie value to speed up lookup of a
device on an io bus.

Signed-off-by: default avatarCornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: default avatarGleb Natapov <gleb@redhat.com>
parent 1c118b82

include/linux/kvm_host.h

+4 −0
Original line number Original line Diff line number Diff line
@@ -160,8 +160,12 @@ enum kvm_bus { 




int kvm_io_bus_write(struct kvm *kvm, enum kvm_bus bus_idx, gpa_t addr,

int kvm_io_bus_write(struct kvm *kvm, enum kvm_bus bus_idx, gpa_t addr,

		     int len, const void *val);

		     int len, const void *val);

int kvm_io_bus_write_cookie(struct kvm *kvm, enum kvm_bus bus_idx, gpa_t addr,

			    int len, const void *val, long cookie);

int kvm_io_bus_read(struct kvm *kvm, enum kvm_bus bus_idx, gpa_t addr, int len,

int kvm_io_bus_read(struct kvm *kvm, enum kvm_bus bus_idx, gpa_t addr, int len,

		    void *val);

		    void *val);

int kvm_io_bus_read_cookie(struct kvm *kvm, enum kvm_bus bus_idx, gpa_t addr,

			   int len, void *val, long cookie);

int kvm_io_bus_register_dev(struct kvm *kvm, enum kvm_bus bus_idx, gpa_t addr,

int kvm_io_bus_register_dev(struct kvm *kvm, enum kvm_bus bus_idx, gpa_t addr,

			    int len, struct kvm_io_device *dev);

			    int len, struct kvm_io_device *dev);

int kvm_io_bus_unregister_dev(struct kvm *kvm, enum kvm_bus bus_idx,

int kvm_io_bus_unregister_dev(struct kvm *kvm, enum kvm_bus bus_idx,

virt/kvm/kvm_main.c

+92 −16
Original line number Original line Diff line number Diff line
@@ -2863,11 +2863,48 @@ static int kvm_io_bus_get_first_dev(struct kvm_io_bus *bus, 
	return off;

	return off;

}

}





static int __kvm_io_bus_write(struct kvm_io_bus *bus,

			      struct kvm_io_range *range, const void *val)

{

	int idx;



	idx = kvm_io_bus_get_first_dev(bus, range->addr, range->len);

	if (idx < 0)

		return -EOPNOTSUPP;



	while (idx < bus->dev_count &&

		kvm_io_bus_sort_cmp(range, &bus->range[idx]) == 0) {

		if (!kvm_iodevice_write(bus->range[idx].dev, range->addr,

					range->len, val))

			return idx;

		idx++;

	}



	return -EOPNOTSUPP;

}



/* kvm_io_bus_write - called under kvm->slots_lock */

/* kvm_io_bus_write - called under kvm->slots_lock */

int kvm_io_bus_write(struct kvm *kvm, enum kvm_bus bus_idx, gpa_t addr,

int kvm_io_bus_write(struct kvm *kvm, enum kvm_bus bus_idx, gpa_t addr,

		     int len, const void *val)

		     int len, const void *val)

{

{

	int idx;

	struct kvm_io_bus *bus;

	struct kvm_io_range range;

	int r;



	range = (struct kvm_io_range) {

		.addr = addr,

		.len = len,

	};



	bus = srcu_dereference(kvm->buses[bus_idx], &kvm->srcu);

	r = __kvm_io_bus_write(bus, &range, val);

	return r < 0 ? r : 0;

}



/* kvm_io_bus_write_cookie - called under kvm->slots_lock */

int kvm_io_bus_write_cookie(struct kvm *kvm, enum kvm_bus bus_idx, gpa_t addr,

			    int len, const void *val, long cookie)

{

	struct kvm_io_bus *bus;

	struct kvm_io_bus *bus;

	struct kvm_io_range range;

	struct kvm_io_range range;
@@ -2877,14 +2914,35 @@ int kvm_io_bus_write(struct kvm *kvm, enum kvm_bus bus_idx, gpa_t addr, 
	};

	};





	bus = srcu_dereference(kvm->buses[bus_idx], &kvm->srcu);

	bus = srcu_dereference(kvm->buses[bus_idx], &kvm->srcu);

	idx = kvm_io_bus_get_first_dev(bus, addr, len);



	/* First try the device referenced by cookie. */

	if ((cookie >= 0) && (cookie < bus->dev_count) &&

	    (kvm_io_bus_sort_cmp(&range, &bus->range[cookie]) == 0))

		if (!kvm_iodevice_write(bus->range[cookie].dev, addr, len,

					val))

			return cookie;



	/*

	 * cookie contained garbage; fall back to search and return the

	 * correct cookie value.

	 */

	return __kvm_io_bus_write(bus, &range, val);

}



static int __kvm_io_bus_read(struct kvm_io_bus *bus, struct kvm_io_range *range,

			     void *val)

{

	int idx;



	idx = kvm_io_bus_get_first_dev(bus, range->addr, range->len);

	if (idx < 0)

	if (idx < 0)

		return -EOPNOTSUPP;

		return -EOPNOTSUPP;





	while (idx < bus->dev_count &&

	while (idx < bus->dev_count &&

		kvm_io_bus_sort_cmp(&range, &bus->range[idx]) == 0) {

		kvm_io_bus_sort_cmp(range, &bus->range[idx]) == 0) {

		if (!kvm_iodevice_write(bus->range[idx].dev, addr, len, val))

		if (!kvm_iodevice_read(bus->range[idx].dev, range->addr,

			return 0;

				       range->len, val))

			return idx;

		idx++;

		idx++;

	}

	}
@@ -2895,9 +2953,9 @@ int kvm_io_bus_write(struct kvm *kvm, enum kvm_bus bus_idx, gpa_t addr, 
int kvm_io_bus_read(struct kvm *kvm, enum kvm_bus bus_idx, gpa_t addr,

int kvm_io_bus_read(struct kvm *kvm, enum kvm_bus bus_idx, gpa_t addr,

		    int len, void *val)

		    int len, void *val)

{

{

	int idx;

	struct kvm_io_bus *bus;

	struct kvm_io_bus *bus;

	struct kvm_io_range range;

	struct kvm_io_range range;

	int r;





	range = (struct kvm_io_range) {

	range = (struct kvm_io_range) {

		.addr = addr,

		.addr = addr,
@@ -2905,18 +2963,36 @@ int kvm_io_bus_read(struct kvm *kvm, enum kvm_bus bus_idx, gpa_t addr, 
	};

	};





	bus = srcu_dereference(kvm->buses[bus_idx], &kvm->srcu);

	bus = srcu_dereference(kvm->buses[bus_idx], &kvm->srcu);

	idx = kvm_io_bus_get_first_dev(bus, addr, len);

	r = __kvm_io_bus_read(bus, &range, val);

	if (idx < 0)

	return r < 0 ? r : 0;

		return -EOPNOTSUPP;



	while (idx < bus->dev_count &&

		kvm_io_bus_sort_cmp(&range, &bus->range[idx]) == 0) {

		if (!kvm_iodevice_read(bus->range[idx].dev, addr, len, val))

			return 0;

		idx++;

}

}





	return -EOPNOTSUPP;

/* kvm_io_bus_read_cookie - called under kvm->slots_lock */

int kvm_io_bus_read_cookie(struct kvm *kvm, enum kvm_bus bus_idx, gpa_t addr,

			   int len, void *val, long cookie)

{

	struct kvm_io_bus *bus;

	struct kvm_io_range range;



	range = (struct kvm_io_range) {

		.addr = addr,

		.len = len,

	};



	bus = srcu_dereference(kvm->buses[bus_idx], &kvm->srcu);



	/* First try the device referenced by cookie. */

	if ((cookie >= 0) && (cookie < bus->dev_count) &&

	    (kvm_io_bus_sort_cmp(&range, &bus->range[cookie]) == 0))

		if (!kvm_iodevice_read(bus->range[cookie].dev, addr, len,

				       val))

			return cookie;



	/*

	 * cookie contained garbage; fall back to search and return the

	 * correct cookie value.

	 */

	return __kvm_io_bus_read(bus, &range, val);

}

}





/* Caller must hold slots_lock. */

/* Caller must hold slots_lock. */