pc-bios/s390-ccw/virtio.c - qemu - Git at Google

 /*
  * Virtio driver bits
  *
  * Copyright (c) 2013 Alexander Graf <agraf@suse.de>
  *
  * This work is licensed under the terms of the GNU GPL, version 2 or (at
  * your option) any later version. See the COPYING file in the top-level
  * directory.
  */

 #include "s390-ccw.h"
 #include "virtio.h"

 struct vring block;

 static char chsc_page[PAGE_SIZE] __attribute__((__aligned__(PAGE_SIZE)));

 static long kvm_hypercall(unsigned long nr, unsigned long param1,
                           unsigned long param2)
 {
 	register ulong r_nr asm("1") = nr;
 	register ulong r_param1 asm("2") = param1;
 	register ulong r_param2 asm("3") = param2;
 	register long retval asm("2");

 	asm volatile ("diag 2,4,0x500"
 		      : "=d" (retval)
 		      : "d" (r_nr), "0" (r_param1), "r"(r_param2)
 		      : "memory", "cc");

 	return retval;
 }

 static void virtio_notify(struct subchannel_id schid)
 {
     kvm_hypercall(KVM_S390_VIRTIO_CCW_NOTIFY, *(u32*)&schid, 0);
 }

 /***********************************************
  *             Virtio functions                *
  ***********************************************/

 static int drain_irqs(struct subchannel_id schid)
 {
     struct irb irb = {};
     int r = 0;

     while (1) {
         /* FIXME: make use of TPI, for that enable subchannel and isc */
         if (tsch(schid, &irb)) {
             /* Might want to differentiate error codes later on. */
             if (irb.scsw.cstat) {
                 r = -EIO;
             } else if (irb.scsw.dstat != 0xc) {
                 r = -EIO;
             }
             return r;
         }
     }
 }

 static int run_ccw(struct subchannel_id schid, int cmd, void *ptr, int len)
 {
     struct ccw1 ccw = {};
     struct cmd_orb orb = {};
     struct schib schib;
     int r;

     /* start command processing */
     stsch_err(schid, &schib);
     schib.scsw.ctrl = SCSW_FCTL_START_FUNC;
     msch(schid, &schib);

     /* start subchannel command */
     orb.fmt = 1;
     orb.cpa = (u32)(long)&ccw;
     orb.lpm = 0x80;

     ccw.cmd_code = cmd;
     ccw.cda = (long)ptr;
     ccw.count = len;

     r = ssch(schid, &orb);
     /*
      * XXX Wait until device is done processing the CCW. For now we can
      *     assume that a simple tsch will have finished the CCW processing,
      *     but the architecture allows for asynchronous operation
      */
     if (!r) {
         r = drain_irqs(schid);
     }
     return r;
 }

 static void virtio_set_status(struct subchannel_id schid,
                               unsigned long dev_addr)
 {
     unsigned char status = dev_addr;
     if (run_ccw(schid, CCW_CMD_WRITE_STATUS, &status, sizeof(status))) {
         virtio_panic("Could not write status to host!\n");
     }
 }

 static void virtio_reset(struct subchannel_id schid)
 {
     run_ccw(schid, CCW_CMD_VDEV_RESET, NULL, 0);
 }

 static void vring_init(struct vring *vr, unsigned int num, void *p,
                        unsigned long align)
 {
     debug_print_addr("init p", p);
     vr->num = num;
     vr->desc = p;
     vr->avail = p + num*sizeof(struct vring_desc);
     vr->used = (void *)(((unsigned long)&vr->avail->ring[num] + align-1)
                 & ~(align - 1));

     /* Zero out all relevant field */
     vr->avail->flags = 0;
     vr->avail->idx = 0;

     /* We're running with interrupts off anyways, so don't bother */
     vr->used->flags = VRING_USED_F_NO_NOTIFY;
     vr->used->idx = 0;
     vr->used_idx = 0;
     vr->next_idx = 0;

     debug_print_addr("init vr", vr);
 }

 static void vring_notify(struct subchannel_id schid)
 {
     virtio_notify(schid);
 }

 static void vring_send_buf(struct vring *vr, void *p, int len, int flags)
 {
     /* For follow-up chains we need to keep the first entry point */
     if (!(flags & VRING_HIDDEN_IS_CHAIN)) {
         vr->avail->ring[vr->avail->idx % vr->num] = vr->next_idx;
     }

     vr->desc[vr->next_idx].addr = (ulong)p;
     vr->desc[vr->next_idx].len = len;
     vr->desc[vr->next_idx].flags = flags & ~VRING_HIDDEN_IS_CHAIN;
     vr->desc[vr->next_idx].next = vr->next_idx;
     vr->desc[vr->next_idx].next++;
     vr->next_idx++;

     /* Chains only have a single ID */
     if (!(flags & VRING_DESC_F_NEXT)) {
         vr->avail->idx++;
     }
 }

 static u64 get_clock(void)
 {
     u64 r;

     asm volatile("stck %0" : "=Q" (r) : : "cc");
     return r;
 }

 static ulong get_second(void)
 {
     return (get_clock() >> 12) / 1000000;
 }

 /*
  * Wait for the host to reply.
  *
  * timeout is in seconds if > 0.
  *
  * Returns 0 on success, 1 on timeout.
  */
 static int vring_wait_reply(struct vring *vr, int timeout)
 {
     ulong target_second = get_second() + timeout;
     struct subchannel_id schid = vr->schid;
     int r = 0;

     /* Wait until the used index has moved. */
     while (vr->used->idx == vr->used_idx) {
         vring_notify(schid);
         if (timeout && (get_second() >= target_second)) {
             r = 1;
             break;
         }
         yield();
     }

     vr->used_idx = vr->used->idx;
     vr->next_idx = 0;
     vr->desc[0].len = 0;
     vr->desc[0].flags = 0;

     return r;
 }

 /***********************************************
  *               Virtio block                  *
  ***********************************************/

 static int virtio_read_many(ulong sector, void *load_addr, int sec_num)
 {
     struct virtio_blk_outhdr out_hdr;
     u8 status;
     int r;

     /* Tell the host we want to read */
     out_hdr.type = VIRTIO_BLK_T_IN;
     out_hdr.ioprio = 99;
     out_hdr.sector = sector;

     vring_send_buf(&block, &out_hdr, sizeof(out_hdr), VRING_DESC_F_NEXT);

     /* This is where we want to receive data */
     vring_send_buf(&block, load_addr, SECTOR_SIZE * sec_num,
                    VRING_DESC_F_WRITE | VRING_HIDDEN_IS_CHAIN |
                    VRING_DESC_F_NEXT);

     /* status field */
     vring_send_buf(&block, &status, sizeof(u8), VRING_DESC_F_WRITE |
                    VRING_HIDDEN_IS_CHAIN);

     /* Now we can tell the host to read */
     vring_wait_reply(&block, 0);

     r = drain_irqs(block.schid);
     if (r) {
         /* Well, whatever status is supposed to contain... */
         status = 1;
     }
     return status;
 }

 unsigned long virtio_load_direct(ulong rec_list1, ulong rec_list2,
 				 ulong subchan_id, void *load_addr)
 {
     u8 status;
     int sec = rec_list1;
     int sec_num = ((rec_list2 >> 32) & 0xffff) + 1;
     int sec_len = rec_list2 >> 48;
     ulong addr = (ulong)load_addr;

     if (sec_len != SECTOR_SIZE) {
         return -1;
     }

     sclp_print(".");
     status = virtio_read_many(sec, (void*)addr, sec_num);
     if (status) {
         virtio_panic("I/O Error");
     }
     addr += sec_num * SECTOR_SIZE;

     return addr;
 }

 int virtio_read(ulong sector, void *load_addr)
 {
     return virtio_read_many(sector, load_addr, 1);
 }

 void virtio_setup_block(struct subchannel_id schid)
 {
     struct vq_info_block info;
     struct vq_config_block config = {};

     virtio_reset(schid);

     config.index = 0;
     if (run_ccw(schid, CCW_CMD_READ_VQ_CONF, &config, sizeof(config))) {
         virtio_panic("Could not get block device configuration\n");
     }
     vring_init(&block, config.num, (void*)(100 * 1024 * 1024),
                KVM_S390_VIRTIO_RING_ALIGN);

     info.queue = (100ULL * 1024ULL* 1024ULL);
     info.align = KVM_S390_VIRTIO_RING_ALIGN;
     info.index = 0;
     info.num = config.num;
     block.schid = schid;

     if (!run_ccw(schid, CCW_CMD_SET_VQ, &info, sizeof(info))) {
         virtio_set_status(schid, VIRTIO_CONFIG_S_DRIVER_OK);
     }
 }

 bool virtio_is_blk(struct subchannel_id schid)
 {
     int r;
     struct senseid senseid = {};

     /* run sense id command */
     r = run_ccw(schid, CCW_CMD_SENSE_ID, &senseid, sizeof(senseid));
     if (r) {
         return false;
     }
     if ((senseid.cu_type != 0x3832) || (senseid.cu_model != VIRTIO_ID_BLOCK)) {
         return false;
     }

     return true;
 }

 int enable_mss_facility(void)
 {
     int ret;
     struct chsc_area_sda *sda_area = (struct chsc_area_sda *) chsc_page;

     memset(sda_area, 0, PAGE_SIZE);
     sda_area->request.length = 0x0400;
     sda_area->request.code = 0x0031;
     sda_area->operation_code = 0x2;

     ret = chsc(sda_area);
     if ((ret == 0) && (sda_area->response.code == 0x0001)) {
         return 0;
     }
     return -EIO;
 }
	/*
	* Virtio driver bits
	*
	* Copyright (c) 2013 Alexander Graf <agraf@suse.de>
	*
	* This work is licensed under the terms of the GNU GPL, version 2 or (at
	* your option) any later version. See the COPYING file in the top-level
	* directory.
	*/

	#include "s390-ccw.h"
	#include "virtio.h"

	struct vring block;

	static char chsc_page[PAGE_SIZE] __attribute__((__aligned__(PAGE_SIZE)));

	static long kvm_hypercall(unsigned long nr, unsigned long param1,
	unsigned long param2)
	{
	register ulong r_nr asm("1") = nr;
	register ulong r_param1 asm("2") = param1;
	register ulong r_param2 asm("3") = param2;
	register long retval asm("2");

	asm volatile ("diag 2,4,0x500"
	: "=d" (retval)
	: "d" (r_nr), "0" (r_param1), "r"(r_param2)
	: "memory", "cc");

	return retval;
	}

	static void virtio_notify(struct subchannel_id schid)
	{
	kvm_hypercall(KVM_S390_VIRTIO_CCW_NOTIFY, (u32)&schid, 0);
	}

	/***********************************************
	* Virtio functions *
	***********************************************/

	static int drain_irqs(struct subchannel_id schid)
	{
	struct irb irb = {};
	int r = 0;

	while (1) {
	/* FIXME: make use of TPI, for that enable subchannel and isc */
	if (tsch(schid, &irb)) {
	/* Might want to differentiate error codes later on. */
	if (irb.scsw.cstat) {
	r = -EIO;
	} else if (irb.scsw.dstat != 0xc) {
	r = -EIO;
	}
	return r;
	}
	}
	}

	static int run_ccw(struct subchannel_id schid, int cmd, void *ptr, int len)
	{
	struct ccw1 ccw = {};
	struct cmd_orb orb = {};
	struct schib schib;
	int r;

	/* start command processing */
	stsch_err(schid, &schib);
	schib.scsw.ctrl = SCSW_FCTL_START_FUNC;
	msch(schid, &schib);

	/* start subchannel command */
	orb.fmt = 1;
	orb.cpa = (u32)(long)&ccw;
	orb.lpm = 0x80;

	ccw.cmd_code = cmd;
	ccw.cda = (long)ptr;
	ccw.count = len;

	r = ssch(schid, &orb);
	/*
	* XXX Wait until device is done processing the CCW. For now we can
	* assume that a simple tsch will have finished the CCW processing,
	* but the architecture allows for asynchronous operation
	*/
	if (!r) {
	r = drain_irqs(schid);
	}
	return r;
	}

	static void virtio_set_status(struct subchannel_id schid,
	unsigned long dev_addr)
	{
	unsigned char status = dev_addr;
	if (run_ccw(schid, CCW_CMD_WRITE_STATUS, &status, sizeof(status))) {
	virtio_panic("Could not write status to host!\n");
	}
	}

	static void virtio_reset(struct subchannel_id schid)
	{
	run_ccw(schid, CCW_CMD_VDEV_RESET, NULL, 0);
	}

	static void vring_init(struct vring vr, unsigned int num, void p,
	unsigned long align)
	{
	debug_print_addr("init p", p);
	vr->num = num;
	vr->desc = p;
	vr->avail = p + num*sizeof(struct vring_desc);
	vr->used = (void *)(((unsigned long)&vr->avail->ring[num] + align-1)
	& ~(align - 1));

	/* Zero out all relevant field */
	vr->avail->flags = 0;
	vr->avail->idx = 0;

	/* We're running with interrupts off anyways, so don't bother */
	vr->used->flags = VRING_USED_F_NO_NOTIFY;
	vr->used->idx = 0;
	vr->used_idx = 0;
	vr->next_idx = 0;

	debug_print_addr("init vr", vr);
	}

	static void vring_notify(struct subchannel_id schid)
	{
	virtio_notify(schid);
	}

	static void vring_send_buf(struct vring vr, void p, int len, int flags)
	{
	/* For follow-up chains we need to keep the first entry point */
	if (!(flags & VRING_HIDDEN_IS_CHAIN)) {
	vr->avail->ring[vr->avail->idx % vr->num] = vr->next_idx;
	}

	vr->desc[vr->next_idx].addr = (ulong)p;
	vr->desc[vr->next_idx].len = len;
	vr->desc[vr->next_idx].flags = flags & ~VRING_HIDDEN_IS_CHAIN;
	vr->desc[vr->next_idx].next = vr->next_idx;
	vr->desc[vr->next_idx].next++;
	vr->next_idx++;

	/* Chains only have a single ID */
	if (!(flags & VRING_DESC_F_NEXT)) {
	vr->avail->idx++;
	}
	}

	static u64 get_clock(void)
	{
	u64 r;

	asm volatile("stck %0" : "=Q" (r) : : "cc");
	return r;
	}

	static ulong get_second(void)
	{
	return (get_clock() >> 12) / 1000000;
	}

	/*
	* Wait for the host to reply.
	*
	* timeout is in seconds if > 0.
	*
	* Returns 0 on success, 1 on timeout.
	*/
	static int vring_wait_reply(struct vring *vr, int timeout)
	{
	ulong target_second = get_second() + timeout;
	struct subchannel_id schid = vr->schid;
	int r = 0;

	/* Wait until the used index has moved. */
	while (vr->used->idx == vr->used_idx) {
	vring_notify(schid);
	if (timeout && (get_second() >= target_second)) {
	r = 1;
	break;
	}
	yield();
	}

	vr->used_idx = vr->used->idx;
	vr->next_idx = 0;
	vr->desc[0].len = 0;
	vr->desc[0].flags = 0;

	return r;
	}

	/***********************************************
	* Virtio block *
	***********************************************/

	static int virtio_read_many(ulong sector, void *load_addr, int sec_num)
	{
	struct virtio_blk_outhdr out_hdr;
	u8 status;
	int r;

	/* Tell the host we want to read */
	out_hdr.type = VIRTIO_BLK_T_IN;
	out_hdr.ioprio = 99;
	out_hdr.sector = sector;

	vring_send_buf(&block, &out_hdr, sizeof(out_hdr), VRING_DESC_F_NEXT);

	/* This is where we want to receive data */
	vring_send_buf(&block, load_addr, SECTOR_SIZE * sec_num,
	VRING_DESC_F_WRITE \| VRING_HIDDEN_IS_CHAIN \|
	VRING_DESC_F_NEXT);

	/* status field */
	vring_send_buf(&block, &status, sizeof(u8), VRING_DESC_F_WRITE \|
	VRING_HIDDEN_IS_CHAIN);

	/* Now we can tell the host to read */
	vring_wait_reply(&block, 0);

	r = drain_irqs(block.schid);
	if (r) {
	/* Well, whatever status is supposed to contain... */
	status = 1;
	}
	return status;
	}

	unsigned long virtio_load_direct(ulong rec_list1, ulong rec_list2,
	ulong subchan_id, void *load_addr)
	{
	u8 status;
	int sec = rec_list1;
	int sec_num = ((rec_list2 >> 32) & 0xffff) + 1;
	int sec_len = rec_list2 >> 48;
	ulong addr = (ulong)load_addr;

	if (sec_len != SECTOR_SIZE) {
	return -1;
	}

	sclp_print(".");
	status = virtio_read_many(sec, (void*)addr, sec_num);
	if (status) {
	virtio_panic("I/O Error");
	}
	addr += sec_num * SECTOR_SIZE;

	return addr;
	}

	int virtio_read(ulong sector, void *load_addr)
	{
	return virtio_read_many(sector, load_addr, 1);
	}

	void virtio_setup_block(struct subchannel_id schid)
	{
	struct vq_info_block info;
	struct vq_config_block config = {};

	virtio_reset(schid);

	config.index = 0;
	if (run_ccw(schid, CCW_CMD_READ_VQ_CONF, &config, sizeof(config))) {
	virtio_panic("Could not get block device configuration\n");
	}
	vring_init(&block, config.num, (void)(100 1024 * 1024),
	KVM_S390_VIRTIO_RING_ALIGN);

	info.queue = (100ULL * 1024ULL* 1024ULL);
	info.align = KVM_S390_VIRTIO_RING_ALIGN;
	info.index = 0;
	info.num = config.num;
	block.schid = schid;

	if (!run_ccw(schid, CCW_CMD_SET_VQ, &info, sizeof(info))) {
	virtio_set_status(schid, VIRTIO_CONFIG_S_DRIVER_OK);
	}
	}

	bool virtio_is_blk(struct subchannel_id schid)
	{
	int r;
	struct senseid senseid = {};

	/* run sense id command */
	r = run_ccw(schid, CCW_CMD_SENSE_ID, &senseid, sizeof(senseid));
	if (r) {
	return false;
	}
	if ((senseid.cu_type != 0x3832) \|\| (senseid.cu_model != VIRTIO_ID_BLOCK)) {
	return false;
	}

	return true;
	}

	int enable_mss_facility(void)
	{
	int ret;
	struct chsc_area_sda sda_area = (struct chsc_area_sda ) chsc_page;

	memset(sda_area, 0, PAGE_SIZE);
	sda_area->request.length = 0x0400;
	sda_area->request.code = 0x0031;
	sda_area->operation_code = 0x2;

	ret = chsc(sda_area);
	if ((ret == 0) && (sda_area->response.code == 0x0001)) {
	return 0;
	}
	return -EIO;
	}