Hi Andre, On 2/25/21 12:58 AM, Andre Przywara wrote: > In their core functionality MMIO and I/O port traps are not really > different, yet we still have two totally separate code paths for > handling them. Devices need to decide on one conduit or need to provide > different handler functions for each of them. > > Extend the existing MMIO emulation to also cover ioport handlers. > This just adds another RB tree root for holding the I/O port handlers, > but otherwise uses the same tree population and lookup code. > "ioport" or "mmio" just become a flag in the registration function. > Provide wrappers to not break existing users, and allow an easy > transition for the existing ioport handlers. > > This also means that ioport handlers now can use the same emulation > callback prototype as MMIO handlers, which means we have to migrate them > over. To allow a smooth transition, we hook up the new I/O emulate > function to the end of the existing ioport emulation code. > > Signed-off-by: Andre Przywara <[email protected]> > --- > include/kvm/kvm.h | 49 ++++++++++++++++++++++++++++++++--- > ioport.c | 4 +-- > mmio.c | 65 +++++++++++++++++++++++++++++++++++++++-------- > 3 files changed, 102 insertions(+), 16 deletions(-) > > diff --git a/include/kvm/kvm.h b/include/kvm/kvm.h > index f1f0afd7..306b258a 100644 > --- a/include/kvm/kvm.h > +++ b/include/kvm/kvm.h > @@ -27,10 +27,23 @@ > #define PAGE_SIZE (sysconf(_SC_PAGE_SIZE)) > #endif > > +/* > + * We are reusing the existing DEVICE_BUS_MMIO and DEVICE_BUS_IOPORT > constants > + * from kvm/devices.h to differentiate between registering an I/O port and an > + * MMIO region. > + * To avoid collisions with future additions of more bus types, we reserve > + * a generous 4 bits for the bus mask here. > + */ > +#define IOTRAP_BUS_MASK 0xf > +#define IOTRAP_COALESCE (1U << 4) > + > #define DEFINE_KVM_EXT(ext) \ > .name = #ext, \ > .code = ext > > +struct kvm_cpu; > +typedef void (*mmio_handler_fn)(struct kvm_cpu *vcpu, u64 addr, u8 *data, > + u32 len, u8 is_write, void *ptr); > typedef void (*fdt_irq_fn)(void *fdt, u8 irq, enum irq_type irq_type); > > enum { > @@ -113,6 +126,8 @@ void kvm__irq_line(struct kvm *kvm, int irq, int level); > void kvm__irq_trigger(struct kvm *kvm, int irq); > bool kvm__emulate_io(struct kvm_cpu *vcpu, u16 port, void *data, int > direction, int size, u32 count); > bool kvm__emulate_mmio(struct kvm_cpu *vcpu, u64 phys_addr, u8 *data, u32 > len, u8 is_write); > +bool kvm__emulate_pio(struct kvm_cpu *vcpu, u16 port, void *data, > + int direction, int size, u32 count); > int kvm__destroy_mem(struct kvm *kvm, u64 guest_phys, u64 size, void > *userspace_addr); > int kvm__register_mem(struct kvm *kvm, u64 guest_phys, u64 size, void > *userspace_addr, > enum kvm_mem_type type); > @@ -136,10 +151,36 @@ static inline int kvm__reserve_mem(struct kvm *kvm, u64 > guest_phys, u64 size) > KVM_MEM_TYPE_RESERVED); > } > > -int __must_check kvm__register_mmio(struct kvm *kvm, u64 phys_addr, u64 > phys_addr_len, bool coalesce, > - void (*mmio_fn)(struct kvm_cpu *vcpu, u64 > addr, u8 *data, u32 len, u8 is_write, void *ptr), > - void *ptr); > -bool kvm__deregister_mmio(struct kvm *kvm, u64 phys_addr); > +int __must_check kvm__register_iotrap(struct kvm *kvm, u64 phys_addr, u64 > len, > + mmio_handler_fn mmio_fn, void *ptr, > + unsigned int flags); > + > +static inline > +int __must_check kvm__register_mmio(struct kvm *kvm, u64 phys_addr, > + u64 phys_addr_len, bool coalesce, > + mmio_handler_fn mmio_fn, void *ptr) > +{ > + return kvm__register_iotrap(kvm, phys_addr, phys_addr_len, mmio_fn, ptr, > + DEVICE_BUS_MMIO | (coalesce ? IOTRAP_COALESCE : 0)); > +} > +static inline > +int __must_check kvm__register_pio(struct kvm *kvm, u16 port, u16 len, > + mmio_handler_fn mmio_fn, void *ptr) > +{ > + return kvm__register_iotrap(kvm, port, len, mmio_fn, ptr, > + DEVICE_BUS_IOPORT); > +} > + > +bool kvm__deregister_iotrap(struct kvm *kvm, u64 phys_addr, unsigned int > flags); > +static inline bool kvm__deregister_mmio(struct kvm *kvm, u64 phys_addr) > +{ > + return kvm__deregister_iotrap(kvm, phys_addr, DEVICE_BUS_MMIO); > +} > +static inline bool kvm__deregister_pio(struct kvm *kvm, u16 port) > +{ > + return kvm__deregister_iotrap(kvm, port, DEVICE_BUS_IOPORT); > +} > + > void kvm__reboot(struct kvm *kvm); > void kvm__pause(struct kvm *kvm); > void kvm__continue(struct kvm *kvm); > diff --git a/ioport.c b/ioport.c > index e0123f27..ce29e7e7 100644 > --- a/ioport.c > +++ b/ioport.c > @@ -162,7 +162,8 @@ bool kvm__emulate_io(struct kvm_cpu *vcpu, u16 port, void > *data, int direction, > > entry = ioport_get(&ioport_tree, port); > if (!entry) > - goto out; > + return kvm__emulate_pio(vcpu, port, data, direction, > + size, count); > > ops = entry->ops; > > @@ -177,7 +178,6 @@ bool kvm__emulate_io(struct kvm_cpu *vcpu, u16 port, void > *data, int direction, > > ioport_put(&ioport_tree, entry); > > -out: > if (ret) > return true; > > diff --git a/mmio.c b/mmio.c > index cd141cd3..75de04ad 100644 > --- a/mmio.c > +++ b/mmio.c > @@ -19,13 +19,14 @@ static DEFINE_MUTEX(mmio_lock); > > struct mmio_mapping { > struct rb_int_node node; > - void (*mmio_fn)(struct kvm_cpu *vcpu, u64 addr, u8 > *data, u32 len, u8 is_write, void *ptr); > + mmio_handler_fn mmio_fn; > void *ptr; > u32 refcount; > bool remove; > }; > > static struct rb_root mmio_tree = RB_ROOT; > +static struct rb_root pio_tree = RB_ROOT; > > static struct mmio_mapping *mmio_search(struct rb_root *root, u64 addr, u64 > len) > { > @@ -103,9 +104,14 @@ static void mmio_put(struct kvm *kvm, struct rb_root > *root, struct mmio_mapping > mutex_unlock(&mmio_lock); > } > > -int kvm__register_mmio(struct kvm *kvm, u64 phys_addr, u64 phys_addr_len, > bool coalesce, > - void (*mmio_fn)(struct kvm_cpu *vcpu, u64 addr, u8 > *data, u32 len, u8 is_write, void *ptr), > - void *ptr) > +static bool trap_is_mmio(unsigned int flags) > +{ > + return (flags & IOTRAP_BUS_MASK) == DEVICE_BUS_MMIO; > +} > + > +int kvm__register_iotrap(struct kvm *kvm, u64 phys_addr, u64 phys_addr_len, > + mmio_handler_fn mmio_fn, void *ptr, > + unsigned int flags) > { > struct mmio_mapping *mmio; > struct kvm_coalesced_mmio_zone zone; > @@ -127,7 +133,7 @@ int kvm__register_mmio(struct kvm *kvm, u64 phys_addr, > u64 phys_addr_len, bool c > .remove = false, > }; > > - if (coalesce) { > + if (trap_is_mmio(flags) && (flags & IOTRAP_COALESCE)) { > zone = (struct kvm_coalesced_mmio_zone) { > .addr = phys_addr, > .size = phys_addr_len, > @@ -138,19 +144,29 @@ int kvm__register_mmio(struct kvm *kvm, u64 phys_addr, > u64 phys_addr_len, bool c > return -errno; > } > } > + > mutex_lock(&mmio_lock); > - ret = mmio_insert(&mmio_tree, mmio); > + if (trap_is_mmio(flags)) > + ret = mmio_insert(&mmio_tree, mmio); > + else > + ret = mmio_insert(&pio_tree, mmio); > mutex_unlock(&mmio_lock); > > return ret; > } > > -bool kvm__deregister_mmio(struct kvm *kvm, u64 phys_addr) > +bool kvm__deregister_iotrap(struct kvm *kvm, u64 phys_addr, unsigned int > flags) > { > struct mmio_mapping *mmio; > + struct rb_root *tree; > + > + if ((flags & IOTRAP_BUS_MASK) == DEVICE_BUS_IOPORT) > + tree = &pio_tree; > + else > + tree = &mmio_tree;
We could swap the conditional branches and use trap_is_mmio(flags) like we do above. Regardless, the patch looks really good: Reviewed-by: Alexandru Elisei <[email protected]> Thanks, Alex > > mutex_lock(&mmio_lock); > - mmio = mmio_search_single(&mmio_tree, phys_addr); > + mmio = mmio_search_single(tree, phys_addr); > if (mmio == NULL) { > mutex_unlock(&mmio_lock); > return false; > @@ -167,7 +183,7 @@ bool kvm__deregister_mmio(struct kvm *kvm, u64 phys_addr) > * called mmio_put(). This will trigger use-after-free errors on VCPU0. > */ > if (mmio->refcount == 0) > - mmio_deregister(kvm, &mmio_tree, mmio); > + mmio_deregister(kvm, tree, mmio); > else > mmio->remove = true; > mutex_unlock(&mmio_lock); > @@ -175,7 +191,8 @@ bool kvm__deregister_mmio(struct kvm *kvm, u64 phys_addr) > return true; > } > > -bool kvm__emulate_mmio(struct kvm_cpu *vcpu, u64 phys_addr, u8 *data, u32 > len, u8 is_write) > +bool kvm__emulate_mmio(struct kvm_cpu *vcpu, u64 phys_addr, u8 *data, > + u32 len, u8 is_write) > { > struct mmio_mapping *mmio; > > @@ -194,3 +211,31 @@ bool kvm__emulate_mmio(struct kvm_cpu *vcpu, u64 > phys_addr, u8 *data, u32 len, u > out: > return true; > } > + > +bool kvm__emulate_pio(struct kvm_cpu *vcpu, u16 port, void *data, > + int direction, int size, u32 count) > +{ > + struct mmio_mapping *mmio; > + bool is_write = direction == KVM_EXIT_IO_OUT; > + > + mmio = mmio_get(&pio_tree, port, size); > + if (!mmio) { > + if (vcpu->kvm->cfg.ioport_debug) { > + fprintf(stderr, "IO error: %s port=%x, size=%d, > count=%u\n", > + to_direction(direction), port, size, count); > + > + return false; > + } > + return true; > + } > + > + while (count--) { > + mmio->mmio_fn(vcpu, port, data, size, is_write, mmio->ptr); > + > + data += size; > + } > + > + mmio_put(vcpu->kvm, &pio_tree, mmio); > + > + return true; > +} _______________________________________________ kvmarm mailing list [email protected] https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
