Re: [PATCH kvmtool 05/16] ioport: pci: Move port allocations to PCI devices

[Andre Przywara <andre.przywara@arm.com>]

On Thu, 7 Mar 2019 08:36:06 +0000
Julien Thierry <julien.thierry@arm.com> wrote:

Hi,

> The dynamic ioport allocation with IOPORT_EMPTY is currently only used
> by PCI devices. Other devices use fixed ports for which they request
> registration to the ioport API.
> 
> PCI ports need to be in the PCI IO space and there is no reason ioport
> API should know a PCI port is being allocated and needs to be placed in
> PCI IO space. This currently just happens to be the case.
> 
> Move the responsability of dynamic allocation of ioports from the ioport
> API to PCI.
> 
> In the future, if other types of devices also need dynamic ioport
> allocation, they'll have to figure out the range of ports they are
> allowed to use.
> 
> Signed-off-by: Julien Thierry <julien.thierry@arm.com>
> ---
>  hw/pci-shmem.c       |  3 ++-
>  hw/vesa.c            |  4 ++--
>  include/kvm/ioport.h |  3 ---
>  include/kvm/pci.h    |  2 ++
>  ioport.c             | 18 ------------------
>  pci.c                |  8 ++++++++
>  vfio/core.c          |  6 ++++--
>  virtio/pci.c         |  3 ++-
>  8 files changed, 20 insertions(+), 27 deletions(-)
> 
> diff --git a/hw/pci-shmem.c b/hw/pci-shmem.c
> index f92bc75..a0c5ba8 100644
> --- a/hw/pci-shmem.c
> +++ b/hw/pci-shmem.c
> @@ -357,7 +357,8 @@ int pci_shmem__init(struct kvm *kvm)
>  		return 0;
>  
>  	/* Register MMIO space for MSI-X */
> -	r = ioport__register(kvm, IOPORT_EMPTY, &shmem_pci__io_ops, IOPORT_SIZE, NULL);
> +	r = pci_get_io_port_block(IOPORT_SIZE);
> +	r = ioport__register(kvm, r, &shmem_pci__io_ops, IOPORT_SIZE, NULL);
>  	if (r < 0)
>  		return r;
>  	ivshmem_registers = (u16)r;
> diff --git a/hw/vesa.c b/hw/vesa.c
> index f3c5114..404a8a3 100644
> --- a/hw/vesa.c
> +++ b/hw/vesa.c
> @@ -60,8 +60,8 @@ struct framebuffer *vesa__init(struct kvm *kvm)
>  
>  	if (!kvm->cfg.vnc && !kvm->cfg.sdl && !kvm->cfg.gtk)
>  		return NULL;
> -
> -	r = ioport__register(kvm, IOPORT_EMPTY, &vesa_io_ops, IOPORT_SIZE, NULL);
> +	r = pci_get_io_space_block(IOPORT_SIZE);

I am confused. This is still registering I/O ports, right? And this
(misnamed) function is about MMIO?
So should it read r = pci_get_io_port_block(IOPORT_SIZE); ?

> +	r = ioport__register(kvm, r, &vesa_io_ops, IOPORT_SIZE, NULL);
>  	if (r < 0)
>  		return ERR_PTR(r);
>  
> diff --git a/include/kvm/ioport.h b/include/kvm/ioport.h
> index db52a47..b10fcd5 100644
> --- a/include/kvm/ioport.h
> +++ b/include/kvm/ioport.h
> @@ -14,11 +14,8 @@
>  
>  /* some ports we reserve for own use */
>  #define IOPORT_DBG			0xe0
> -#define IOPORT_START			0x6200
>  #define IOPORT_SIZE			0x400
>  
> -#define IOPORT_EMPTY			USHRT_MAX
> -
>  struct kvm;
>  
>  struct ioport {
> diff --git a/include/kvm/pci.h b/include/kvm/pci.h
> index a86c15a..bdbd183 100644
> --- a/include/kvm/pci.h
> +++ b/include/kvm/pci.h
> @@ -19,6 +19,7 @@
>  #define PCI_CONFIG_DATA		0xcfc
>  #define PCI_CONFIG_BUS_FORWARD	0xcfa
>  #define PCI_IO_SIZE		0x100
> +#define PCI_IOPORT_START	0x6200
>  #define PCI_CFG_SIZE		(1ULL << 24)
>  
>  struct kvm;
> @@ -153,6 +154,7 @@ int pci__init(struct kvm *kvm);
>  int pci__exit(struct kvm *kvm);
>  struct pci_device_header *pci__find_dev(u8 dev_num);
>  u32 pci_get_io_space_block(u32 size);

So I think this was already misnamed, but with your new function below
becomes utterly confusing. Can we rename this to pci_get_mmio_space_block?

> +u16 pci_get_io_port_block(u32 size);
>  void pci__assign_irq(struct device_header *dev_hdr);
>  void pci__config_wr(struct kvm *kvm, union pci_config_address addr, void *data, int size);
>  void pci__config_rd(struct kvm *kvm, union pci_config_address addr, void *data, int size);
> diff --git a/ioport.c b/ioport.c
> index a6dc65e..a72e403 100644
> --- a/ioport.c
> +++ b/ioport.c
> @@ -16,24 +16,8 @@
>  
>  #define ioport_node(n) rb_entry(n, struct ioport, node)
>  
> -DEFINE_MUTEX(ioport_mutex);
> -
> -static u16			free_io_port_idx; /* protected by ioport_mutex */
> -
>  static struct rb_root		ioport_tree = RB_ROOT;
>  
> -static u16 ioport__find_free_port(void)
> -{
> -	u16 free_port;
> -
> -	mutex_lock(&ioport_mutex);
> -	free_port = IOPORT_START + free_io_port_idx * IOPORT_SIZE;
> -	free_io_port_idx++;
> -	mutex_unlock(&ioport_mutex);
> -
> -	return free_port;
> -}
> -
>  static struct ioport *ioport_search(struct rb_root *root, u64 addr)
>  {
>  	struct rb_int_node *node;
> @@ -85,8 +69,6 @@ int ioport__register(struct kvm *kvm, u16 port, struct ioport_operations *ops, i
>  	int r;
>  
>  	br_write_lock(kvm);
> -	if (port == IOPORT_EMPTY)
> -		port = ioport__find_free_port();
>  
>  	entry = ioport_search(&ioport_tree, port);
>  	if (entry) {
> diff --git a/pci.c b/pci.c
> index 9edefa5..cd749db 100644
> --- a/pci.c
> +++ b/pci.c
> @@ -19,6 +19,14 @@ static u32 pci_config_address_bits;
>   * PCI isn't currently supported.)
>   */
>  static u32 io_space_blocks		= KVM_PCI_MMIO_AREA;
> +static u16 io_port_blocks		= PCI_IOPORT_START;
> +
> +u16 pci_get_io_port_block(u32 size)
> +{
> +	u16 port = ALIGN(io_port_blocks, IOPORT_SIZE);

Nit: Can we please have an empty line after the variable declaration?

Cheers,
Andre.

> +	io_port_blocks = port + size;
> +	return port;
> +}
>  
>  /*
>   * BARs must be naturally aligned, so enforce this in the allocator.
> diff --git a/vfio/core.c b/vfio/core.c
> index 17b5b0c..0ed1e6f 100644
> --- a/vfio/core.c
> +++ b/vfio/core.c
> @@ -202,8 +202,10 @@ static int vfio_setup_trap_region(struct kvm *kvm, struct vfio_device *vdev,
>  				  struct vfio_region *region)
>  {
>  	if (region->is_ioport) {
> -		int port = ioport__register(kvm, IOPORT_EMPTY, &vfio_ioport_ops,
> -					    region->info.size, region);
> +		int port = pci_get_io_port_block(region->info.size);
> +
> +		port = ioport__register(kvm, port, &vfio_ioport_ops,
> +					region->info.size, region);
>  		if (port < 0)
>  			return port;
>  
> diff --git a/virtio/pci.c b/virtio/pci.c
> index 5a5fc6e..c8e16dd 100644
> --- a/virtio/pci.c
> +++ b/virtio/pci.c
> @@ -420,7 +420,8 @@ int virtio_pci__init(struct kvm *kvm, void *dev, struct virtio_device *vdev,
>  	vpci->kvm = kvm;
>  	vpci->dev = dev;
>  
> -	r = ioport__register(kvm, IOPORT_EMPTY, &virtio_pci__io_ops, IOPORT_SIZE, vdev);
> +	r = pci_get_io_port_block(IOPORT_SIZE);
> +	r = ioport__register(kvm, r, &virtio_pci__io_ops, IOPORT_SIZE, vdev);
>  	if (r < 0)
>  		return r;
>  	vpci->port_addr = (u16)r;