[PATCH RFC] pass write value to in_range pointers

Michael S. Tsirkin
2009-06-22T15:17:19Z

It seems that a lot of complexity and trickiness with iosignalfd is
handling the group/item relationship, which comes about because kvm does
not currently let a device on the bus claim a write transaction based on the
value written. This could be greatly simplified if the value written
was passed to the in_range check for write operation. We could then
simply make each kvm_iosignalfd a device on the bus.

What does everyone think of the following lightly tested patch?

-->

Subject: kvm: pass value to in_range callback

For write transactions, pass the value written to in_range checks so
that we can make each iosignalfd a separate device on kvm bus.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

---

diff --git a/virt/kvm/iodev.h b/virt/kvm/iodev.h
index 55e8846..98a25af 100644
--- a/virt/kvm/iodev.h
+++ b/virt/kvm/iodev.h
@@ -28,7 +28,7 @@ struct kvm_io_device {
int len,
const void *val);
int (*in_range)(struct kvm_io_device *this, gpa_t addr, int len,
- int is_write);
+ int is_write, void *write_val);
void (*destructor)(struct kvm_io_device *this);

void *private;
@@ -51,9 +51,10 @@ static inline void kvm_iodevice_write(struct kvm_io_device *dev,
}

static inline int kvm_iodevice_inrange(struct kvm_io_device *dev,
- gpa_t addr, int len, int is_write)
+ gpa_t addr, int len, int is_write,
+ void *write_val)
{
- return dev->in_range(dev, addr, len, is_write);
+ return dev->in_range(dev, addr, len, is_write, write_val);
}

static inline void kvm_iodevice_destructor(struct kvm_io_device *dev)
diff --git a/arch/ia64/kvm/kvm-ia64.c b/arch/ia64/kvm/kvm-ia64.c
index 80c57b0..8cfdf9d 100644
--- a/arch/ia64/kvm/kvm-ia64.c
+++ b/arch/ia64/kvm/kvm-ia64.c
@@ -211,11 +211,13 @@ int kvm_dev_ioctl_check_extension(long ext)
}

static struct kvm_io_device *vcpu_find_mmio_dev(struct kvm_vcpu *vcpu,
- gpa_t addr, int len, int is_write)
+ gpa_t addr, int len, int is_write,
+ void *write_val)
{
struct kvm_io_device *dev;

- dev = kvm_io_bus_find_dev(&vcpu->kvm->mmio_bus, addr, len, is_write);
+ dev = kvm_io_bus_find_dev(&vcpu->kvm->mmio_bus, addr, len, is_write,
+ write_val);

return dev;
}
@@ -247,7 +247,8 @@ static int handle_mmio(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
kvm_run->exit_reason = KVM_EXIT_MMIO;
return 0;
mmio:
- mmio_dev = vcpu_find_mmio_dev(vcpu, p->addr, p->size, !p->dir);
+ mmio_dev = vcpu_find_mmio_dev(vcpu, p->addr, p->size,
+ !p->dir, &p->data);
if (mmio_dev) {
if (!p->dir)
kvm_iodevice_write(mmio_dev, p->addr, p->size,
diff --git a/arch/x86/kvm/i8254.c b/arch/x86/kvm/i8254.c
index 4d6f0d2..5ba21ff 100644
--- a/arch/x86/kvm/i8254.c
+++ b/arch/x86/kvm/i8254.c
@@ -485,7 +485,7 @@ static void pit_ioport_read(struct kvm_io_device *this,
}

static int pit_in_range(struct kvm_io_device *this, gpa_t addr,
- int len, int is_write)
+ int len, int is_write, void *write_val)
{
return ((addr >= KVM_PIT_BASE_ADDRESS) &&
(addr < KVM_PIT_BASE_ADDRESS + KVM_PIT_MEM_LENGTH));
diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
index ae99d83..456fd53 100644
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -721,7 +721,7 @@ static void apic_mmio_write(struct kvm_io_device *this,
}

static int apic_mmio_range(struct kvm_io_device *this, gpa_t addr,
- int len, int size)
+ int len, int is_write, void *write_val)
{
struct kvm_lapic *apic = (struct kvm_lapic *)this->private;
int ret = 0;
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 249540f..9d29017 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -2043,13 +2043,13 @@ static void kvm_init_msr_list(void)
*/
static struct kvm_io_device *vcpu_find_pervcpu_dev(struct kvm_vcpu *vcpu,
gpa_t addr, int len,
- int is_write)
+ int is_write, void *write_val)
{
struct kvm_io_device *dev;

if (vcpu->arch.apic) {
dev = &vcpu->arch.apic->dev;
- if (dev->in_range(dev, addr, len, is_write))
+ if (dev->in_range(dev, addr, len, is_write, write_val))
return dev;
}
return NULL;
@@ -2058,14 +2058,14 @@ static struct kvm_io_device *vcpu_find_pervcpu_dev(struct kvm_vcpu *vcpu,

static struct kvm_io_device *vcpu_find_mmio_dev(struct kvm_vcpu *vcpu,
gpa_t addr, int len,
- int is_write)
+ int is_write, void *write_val)
{
struct kvm_io_device *dev;

- dev = vcpu_find_pervcpu_dev(vcpu, addr, len, is_write);
+ dev = vcpu_find_pervcpu_dev(vcpu, addr, len, is_write, write_val);
if (dev == NULL)
dev = kvm_io_bus_find_dev(&vcpu->kvm->mmio_bus, addr, len,
- is_write);
+ is_write, write_val);
return dev;
}

@@ -2161,7 +2161,7 @@ mmio:
* Is this MMIO handled locally?
*/
mutex_lock(&vcpu->kvm->lock);
- mmio_dev = vcpu_find_mmio_dev(vcpu, gpa, bytes, 0);
+ mmio_dev = vcpu_find_mmio_dev(vcpu, gpa, bytes, 0, NULL);
if (mmio_dev) {
kvm_iodevice_read(mmio_dev, gpa, bytes, val);
mutex_unlock(&vcpu->kvm->lock);
@@ -2216,7 +2216,7 @@ mmio:
* Is this MMIO handled locally?
*/
mutex_lock(&vcpu->kvm->lock);
- mmio_dev = vcpu_find_mmio_dev(vcpu, gpa, bytes, 1);
+ mmio_dev = vcpu_find_mmio_dev(vcpu, gpa, bytes, 1, val);
if (mmio_dev) {
kvm_iodevice_write(mmio_dev, gpa, bytes, val);
mutex_unlock(&vcpu->kvm->lock);
@@ -2576,9 +2576,10 @@ static void pio_string_write(struct kvm_io_device *pio_dev,

static struct kvm_io_device *vcpu_find_pio_dev(struct kvm_vcpu *vcpu,
gpa_t addr, int len,
- int is_write)
+ int is_write, void *write_val)
{
- return kvm_io_bus_find_dev(&vcpu->kvm->pio_bus, addr, len, is_write);
+ return kvm_io_bus_find_dev(&vcpu->kvm->pio_bus, addr, len, is_write,
+ write_val);
}

int kvm_emulate_pio(struct kvm_vcpu *vcpu, struct kvm_run *run, int in,
@@ -2608,7 +2608,8 @@ int kvm_emulate_pio(struct kvm_vcpu *vcpu, struct kvm_run *run, int in,
val = kvm_register_read(vcpu, VCPU_REGS_RAX);
memcpy(vcpu->arch.pio_data, &val, 4);

- pio_dev = vcpu_find_pio_dev(vcpu, port, size, !in);
+ pio_dev = vcpu_find_pio_dev(vcpu, port, size, !in,
+ vcpu->arch.pio_data);
if (pio_dev) {
kernel_pio(pio_dev, vcpu, vcpu->arch.pio_data);
complete_pio(vcpu);
@@ -2624,7 +2625,6 @@ int kvm_emulate_pio_string(struct kvm_vcpu *vcpu, struct kvm_run *run, int in,
{
unsigned now, in_page;
int ret = 0;
- struct kvm_io_device *pio_dev;

vcpu->run->exit_reason = KVM_EXIT_IO;
vcpu->run->io.direction = in ? KVM_EXIT_IO_IN : KVM_EXIT_IO_OUT;
@@ -2672,9 +2672,6 @@ int kvm_emulate_pio_string(struct kvm_vcpu *vcpu, struct kvm_run *run, int in,

vcpu->arch.pio.guest_gva = address;

- pio_dev = vcpu_find_pio_dev(vcpu, port,
- vcpu->arch.pio.cur_count,
- !vcpu->arch.pio.in);
if (!vcpu->arch.pio.in) {
/* string PIO write */
ret = pio_copy_data(vcpu);
@@ -2682,13 +2679,20 @@ int kvm_emulate_pio_string(struct kvm_vcpu *vcpu, struct kvm_run *run, int in,
kvm_inject_gp(vcpu, 0);
return 1;
}
- if (ret == 0 && pio_dev) {
- pio_string_write(pio_dev, vcpu);
- complete_pio(vcpu);
- if (vcpu->arch.pio.count == 0)
- ret = 1;
+ if (ret == 0) {
+ struct kvm_io_device *pio_dev;
+ pio_dev = vcpu_find_pio_dev(vcpu, port,
+ vcpu->arch.pio.cur_count,
+ 1, vcpu->arch.pio_data);
+ if (pio_dev) {
+ pio_string_write(pio_dev, vcpu);
+ complete_pio(vcpu);
+ if (vcpu->arch.pio.count == 0)
+ ret = 1;
+ }
}
- } else if (pio_dev)
+ } else if (vcpu_find_pio_dev(vcpu, port, vcpu->arch.pio.cur_count, 0,
+ NULL))
pr_unimpl(vcpu, "no string pio read support yet, "
"port %x size %d count %ld\n",
port, size, count);
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index aacc544..0fb7938 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -60,7 +60,8 @@ struct kvm_io_bus {
void kvm_io_bus_init(struct kvm_io_bus *bus);
void kvm_io_bus_destroy(struct kvm_io_bus *bus);
struct kvm_io_device *kvm_io_bus_find_dev(struct kvm_io_bus *bus,
- gpa_t addr, int len, int is_write);
+ gpa_t addr, int len, int is_write,
+ void *write_val);
void kvm_io_bus_register_dev(struct kvm_io_bus *bus,
struct kvm_io_device *dev);

diff --git a/virt/kvm/coalesced_mmio.c b/virt/kvm/coalesced_mmio.c
index 5ae620d..3a1cbfd 100644
--- a/virt/kvm/coalesced_mmio.c
+++ b/virt/kvm/coalesced_mmio.c
@@ -15,7 +15,8 @@
#include "coalesced_mmio.h"

static int coalesced_mmio_in_range(struct kvm_io_device *this,
- gpa_t addr, int len, int is_write)
+ gpa_t addr, int len, int is_write,
+ void *write_val)
{
struct kvm_coalesced_mmio_dev *dev =
(struct kvm_coalesced_mmio_dev*)this->private;
diff --git a/virt/kvm/ioapic.c b/virt/kvm/ioapic.c
index 1eddae9..2adbb1b 100644
--- a/virt/kvm/ioapic.c
+++ b/virt/kvm/ioapic.c
@@ -221,7 +221,8 @@ void kvm_ioapic_update_eoi(struct kvm *kvm, int vector, int trigger_mode)
}

static int ioapic_in_range(struct kvm_io_device *this, gpa_t addr,
- int len, int is_write)
+ int len, int is_write,
+ void *write_val)
{
struct kvm_ioapic *ioapic = (struct kvm_ioapic *)this->private;

diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 7645543..b97e390 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -2445,14 +2445,15 @@ void kvm_io_bus_destroy(struct kvm_io_bus *bus)
}

struct kvm_io_device *kvm_io_bus_find_dev(struct kvm_io_bus *bus,
- gpa_t addr, int len, int is_write)
+ gpa_t addr, int len, int is_write,
+ void *write_val)
{
int i;

for (i = 0; i < bus->dev_count; i++) {
struct kvm_io_device *pos = bus->devs[i];

- if (pos->in_range(pos, addr, len, is_write))
+ if (pos->in_range(pos, addr, len, is_write, write_val))
return pos;
}