[SLOF] [PATCH v1 07/27] virtio: add virtio 1.0 capability parsing

Alexey Kardashevskiy aik at ozlabs.ru
Fri Jan 15 11:31:21 AEDT 2016


On 01/14/2016 09:45 PM, Nikunj A Dadhania wrote:
> Alexey Kardashevskiy <aik at ozlabs.ru> writes:
>
>> On 01/13/2016 10:16 PM, Nikunj A Dadhania wrote:
>>> Signed-off-by: Nikunj A Dadhania <nikunj at linux.vnet.ibm.com>
>>> ---
>>>    lib/libvirtio/virtio.c | 135 +++++++++++++++++++++++++++++++++++++++++++++++++
>>>    lib/libvirtio/virtio.h |   3 +-
>>>    2 files changed, 137 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/lib/libvirtio/virtio.c b/lib/libvirtio/virtio.c
>>> index 7e0d6a3..bcf050b 100644
>>> --- a/lib/libvirtio/virtio.c
>>> +++ b/lib/libvirtio/virtio.c
>>> @@ -14,6 +14,7 @@
>>>    #include <stdbool.h>
>>>    #include <stdlib.h>
>>>    #include <string.h>
>>> +#include <stddef.h>
>>>    #include <cpu.h>
>>>    #include <cache.h>
>>>    #include <byteorder.h>
>>> @@ -31,6 +32,140 @@
>>>    #define VIRTIOHDR_ISR_STATUS		19
>>>    #define VIRTIOHDR_DEVICE_CONFIG 	20
>>>
>>> +/* PCI defines */
>>> +#define PCI_BASE_ADDR_SPACE_IO	0x01
>>> +#define PCI_BASE_ADDR_SPACE_MEM	0x00
>>> +#define PCI_BASE_ADDR_MEM_MASK	(~0x0fUL)
>>> +#define PCI_BASE_ADDR_IO_MASK	(~0x03UL)
>>> +
>>> +#define PCI_BASE_ADDR_REG_0	0x10
>>> +#define PCI_CONFIG_CAP_REG	0x34
>>> +
>>> +#define PCI_CAP_ID_VNDR		0x9
>>> +
>>> +#define VIRTIO_PCI_CAP_COMMON 1
>>> +#define VIRTIO_PCI_CAP_NOTIFY 2
>>> +#define VIRTIO_PCI_CAP_ISR    3
>>> +#define VIRTIO_PCI_CAP_DEVICE 4
>>> +#define VIRTIO_PCI_CAP_PCI    5
>>> +
>>> +#define VIRTIO_CAP_VNDR     0
>>> +#define VIRTIO_CAP_NEXT     1
>>> +#define VIRTIO_CAP_LEN      2
>>> +#define VIRTIO_CAP_CFG_TYPE 3
>>> +#define VIRTIO_CAP_BAR      4
>>> +#define VIRTIO_CAP_OFFSET   8
>>> +#define VIRTIO_CAP_LENGTH  12
>>
>>
>> VIRTIO_CAP_LEN and VIRTIO_CAP_LENGTH - how are they different? I could not
>> figure out from the code as they are not used at all.
>
> VIRTIO_CAP_LEN -    Capability length
> VIRTIO_CAP_LENGTH - Length of the virtio structure pointed by
> "addr[bar]+ offset"


Are these the same as VIRTIO_PCI_CAP_xxx from the kernel's 
include/uapi/linux/virtio_pci.h ? Why change their names?

Same comment about the entire "PCI defines" - use the same macro names, 
easier to grep in the kernel tree.



>  From the virtio 1.0 spec
>
> struct virtio_pci_cap {
> u8 cap_vndr; /* Generic PCI field: PCI_CAP_ID_VNDR */
> u8 cap_next; /* Generic PCI field: next ptr. */
> u8 cap_len;  /* Generic PCI field: capability length */
> u8 cfg_type; /* Identifies the structure. */
> u8 bar;      /* Where to find it. */
> u8 padding[3]; /* Pad to full dword. */
> le32 offset;   /* Offset within the bar. */
> le32 length; /* Length of the structure, in bytes. */
> };
>
>>
>>
>>> +
>>> +#define le64 uint64_t
>>> +#define le32 uint32_t
>>> +#define le16 uint16_t
>>
>>
>> I'd use:
>>
>> typedef __u16 __bitwise __le16;
>> typedef __u16 __bitwise __be16;
>> typedef __u32 __bitwise __le32;
>> typedef __u32 __bitwise __be32;
>> typedef __u64 __bitwise __le64;
>> typedef __u64 __bitwise __be64;
>>
>> as include/uapi/linux/types.h does in the kernel.
>
> Sure. I can take that.
>
>>
>>> +
>>> +struct virtio_dev_common {
>>> +	le32 dev_features_sel;
>>> +	le32 dev_features;
>>> +	le32 drv_features_sel;
>>> +	le32 drv_features;
>>> +	le16 msix_config;
>>> +	le16 num_queues;
>>> +	uint8_t dev_status;
>>> +	uint8_t cfg_generation;
>>> +
>>> +	le16 q_select;
>>> +	le16 q_size;
>>> +	le16 q_msix_vec;
>>> +	le16 q_enable;
>>> +	le16 q_notify_off;
>>> +	le64 q_desc;
>>> +	le64 q_avail;
>>> +	le64 q_used;
>>> +} __attribute__ ((packed));
>>> +
>>> +static void virtio_process_cap(struct virtio_device *dev, uint8_t cap_ptr)
>>> +{
>>> +	struct virtio_cap *cap;
>>> +	uint8_t cfg_type, bar;
>>> +	uint32_t offset;
>>> +	uint64_t addr = 0;
>>> +
>>> +	cfg_type = SLOF_pci_config_read8(cap_ptr + VIRTIO_CAP_CFG_TYPE);
>>> +	bar = SLOF_pci_config_read8(cap_ptr + VIRTIO_CAP_BAR);
>>> +	offset = SLOF_pci_config_read32(cap_ptr + VIRTIO_CAP_OFFSET);
>>> +
>>> +	switch(cfg_type) {
>>> +	case VIRTIO_PCI_CAP_COMMON:
>>> +		cap = &dev->common;
>>> +		break;
>>> +	case VIRTIO_PCI_CAP_NOTIFY:
>>> +		cap = &dev->notify;
>>> +		dev->notify_off_mul = SLOF_pci_config_read32(cap_ptr + sizeof(struct virtio_cap));
>>> +		break;
>>> +	case VIRTIO_PCI_CAP_ISR:
>>> +		cap = &dev->isr;
>>> +		break;
>>> +	case VIRTIO_PCI_CAP_DEVICE:
>>> +		cap = &dev->device;
>>> +		break;
>>> +	default:
>>> +		cap = NULL;
>>> +	}
>>> +
>>> +	if (cap && cfg_type) {
>>> +		cap->bar = bar;
>>> +		addr = SLOF_pci_config_read32(PCI_BASE_ADDR_REG_0 + 4 * cap->bar);
>>> +		if (addr & PCI_BASE_ADDR_SPACE_IO) {
>>> +			cap->is_io = 1;
>>> +			addr = addr & PCI_BASE_ADDR_IO_MASK;
>>> +		} else if (addr & 4) {
>>> +			addr = SLOF_pci_config_read32(PCI_BASE_ADDR_REG_0 + 4 * cap->bar) |
>>> +				(SLOF_pci_config_read32(PCI_BASE_ADDR_REG_0 + 4 * (cap->bar + 1)) << 32);
>>> +			addr = (uint64_t)SLOF_translate_my_address((void *)addr);
>>> +			addr = addr & PCI_BASE_ADDR_MEM_MASK;
>>> +		}
>>> +		else {
>>> +			cap->is_io = 0;
>>> +			addr = addr & PCI_BASE_ADDR_MEM_MASK;
>>> +		}
>>> +		cap->addr = (void *)addr + offset;
>>> +		cap->cap_id = cfg_type;
>>> +	}
>>> +	return;
>>> +}
>>> +/**
>>> + * Setup virtio device details, gets called from SLOF routines
>>> + * Determines legacy or modern device.
>>> + */
>>> +void virtio_setup_device(struct virtio_device *dev)
>>
>>
>> s/virtio_setup_device/virtio_parse_capabilities/ ? This function does not
>> set up anything...w
>
> Sure.
>
>>
>>
>>> +{
>>> +	uint8_t cap_ptr, cap_vndr;
>>> +	uint64_t addr = 0;
>>> +
>>> +	cap_ptr = SLOF_pci_config_read8(PCI_CONFIG_CAP_REG);
>>> +	while (cap_ptr != 0)
>>> +	{
>>> +		cap_vndr = SLOF_pci_config_read8(cap_ptr + VIRTIO_CAP_VNDR);
>>> +		if (cap_vndr == PCI_CAP_ID_VNDR)
>>> +			virtio_process_cap(dev, cap_ptr);
>>> +		cap_ptr = SLOF_pci_config_read8(cap_ptr+VIRTIO_CAP_NEXT);
>>> +	}
>>> +	if (dev->common.cap_id && dev->notify.cap_id && dev->isr.cap_id && dev->device.cap_id)
>>> +		dev->is_modern = 1;
>>> +	else {
>>> +		dev->is_modern = 0;
>>> +		dev->legacy.cap_id = 0;
>>> +		dev->legacy.bar = 0;
>>> +		addr = SLOF_pci_config_read32(PCI_BASE_ADDR_REG_0);
>>> +		if (addr & PCI_BASE_ADDR_SPACE_IO) {
>>> +			dev->legacy.is_io = 1;
>>> +			addr = addr & PCI_BASE_ADDR_IO_MASK;
>>> +		} else {
>>> +			dev->legacy.is_io = 0;
>>> +			addr = addr & PCI_BASE_ADDR_MEM_MASK;
>>> +		}
>>> +		dev->legacy.addr = (void *)addr;
>>> +	}
>>> +	return;
>>> +}
>>>
>>>    /**
>>>     * Calculate ring size according to queue size number
>>> diff --git a/lib/libvirtio/virtio.h b/lib/libvirtio/virtio.h
>>> index 56e044b..eee3144 100644
>>> --- a/lib/libvirtio/virtio.h
>>> +++ b/lib/libvirtio/virtio.h
>>> @@ -74,7 +74,7 @@ struct vring_used {
>>>
>>>    /* Structure shared with SLOF and is 16bytes */
>>>    struct virtio_cap {
>>> -	uint64_t addr;
>>> +	void *addr;
>>>    	uint8_t bar;
>>>    	uint8_t is_io;
>>>    	uint8_t cap_id;
>>> @@ -116,6 +116,7 @@ extern void virtio_fill_desc(struct vring_desc *desc,
>>>                                 uint16_t flags, uint16_t next);
>>>    extern int virtio_queue_init_vq(struct virtio_device *dev, struct vqs *vq, unsigned int id);
>>>
>>> +extern void virtio_setup_device(struct virtio_device *dev);
>>>    extern void virtio_reset_device(struct virtio_device *dev);
>>>    extern void virtio_queue_notify(struct virtio_device *dev, int queue);
>>>    extern void virtio_set_status(struct virtio_device *dev, int status);
>>>
>>
>>
>> The whole patch seems to belong to 18/27.
>
> why ?


Because this is where this new code gets used. Before 18/27, this one is 
not needed, used. When I was reading 18/27, I had to search for this one in 
order to understand what this new virtio_setup_device() actually does.



-- 
Alexey


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