[Qemu-devel] Re: [PATCH 09/15] xen: Initialize event channels and io rings

[Anthony Liguori <anthony@codemonkey.ws>]

On 08/12/2010 09:09 AM, stefano.stabellini@eu.citrix.com wrote:
> From: Anthony PERARD<anthony.perard@citrix.com>
>
> Open and bind event channels; map ioreq and buffered ioreq rings.
>
> Signed-off-by: Anthony PERARD<anthony.perard@citrix.com>
> Signed-off-by: Stefano Stabellini<stefano.stabellini@eu.citrix.com>
> ---
>   hw/xen_machine_fv.c   |   25 ++++
>   target-xen/cpu.h      |    1 +
>   target-xen/helper.c   |  362 +++++++++++++++++++++++++++++++++++++++++++++++++
>   target-xen/qemu-xen.h |    2 +
>   4 files changed, 390 insertions(+), 0 deletions(-)
>
> diff --git a/hw/xen_machine_fv.c b/hw/xen_machine_fv.c
> index a6e778a..b1bc88d 100644
> --- a/hw/xen_machine_fv.c
> +++ b/hw/xen_machine_fv.c
> @@ -22,6 +22,9 @@
>    * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
>    * THE SOFTWARE.
>    */
> +#include "config.h"
> +
> +#include<sys/mman.h>
>
>   #include "hw.h"
>   #include "pc.h"
> @@ -71,12 +74,34 @@ static void xen_init_fv(ram_addr_t ram_size,
>
>       CPUState *env;
>
> +    unsigned long ioreq_pfn;
> +    extern void *shared_page;
> +    extern void *buffered_io_page;
> +
>       /* Initialize backend core&  drivers */
>       if (xen_dm_init() != 0) {
>           fprintf(stderr, "%s: xen backend core setup failed\n", __FUNCTION__);
>           exit(1);
>       }
>
> +    xc_get_hvm_param(xen_xc, xen_domid, HVM_PARAM_IOREQ_PFN,&ioreq_pfn);
> +    fprintf(stderr, "shared page at pfn %lx\n", ioreq_pfn);
> +    shared_page = xc_map_foreign_range(xen_xc, xen_domid, XC_PAGE_SIZE,
> +            PROT_READ|PROT_WRITE, ioreq_pfn);
> +    if (shared_page == NULL) {
> +        fprintf(stderr, "map shared IO page returned error %d handle=%p\n", errno, xen_xc);
> +        exit(-1);
> +    }
> +
> +    xc_get_hvm_param(xen_xc, xen_domid, HVM_PARAM_BUFIOREQ_PFN,&ioreq_pfn);
> +    fprintf(stderr, "buffered io page at pfn %lx\n", ioreq_pfn);
> +    buffered_io_page = xc_map_foreign_range(xen_xc, xen_domid, XC_PAGE_SIZE,
> +                                            PROT_READ|PROT_WRITE, ioreq_pfn);
> +    if (buffered_io_page == NULL) {
> +        fprintf(logfile, "map buffered IO page returned error %d\n", errno);
> +        exit(-1);
> +    }
> +
>       /* Initialize a dummy CPU */
>       if (cpu_model == NULL) {
>   #ifdef TARGET_X86_64
> diff --git a/target-xen/cpu.h b/target-xen/cpu.h
> index 5a45d1c..573241f 100644
> --- a/target-xen/cpu.h
> +++ b/target-xen/cpu.h
> @@ -72,6 +72,7 @@ typedef struct CPUXenState {
>
>   CPUXenState *cpu_xen_init(const char *cpu_model);
>   int cpu_xen_exec(CPUXenState *s);
> +void cpu_xen_close(CPUXenState *s);
>
>   int cpu_get_pic_interrupt(CPUXenState *s);
>   void cpu_set_ferr(CPUX86State *s);
> diff --git a/target-xen/helper.c b/target-xen/helper.c
> index 8cb7771..4571ac0 100644
> --- a/target-xen/helper.c
> +++ b/target-xen/helper.c
> @@ -18,25 +18,77 @@
>    * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
>    */
>
> +#include "config.h"
> +
> +#include<inttypes.h>
> +
> +#include<xenctrl.h>
> +#include<xen/hvm/ioreq.h>
> +
>   #include "cpu.h"
>   #include "qemu-xen.h"
>   #include "xenstore.h"
> +#include "hw/xen_backend.h"
> +
> +long time_offset = 0;
> +
> +shared_iopage_t *shared_page = NULL;
> +
> +#define BUFFER_IO_MAX_DELAY  100
> +buffered_iopage_t *buffered_io_page = NULL;
> +QEMUTimer *buffered_io_timer;
> +
> +/* the evtchn fd for polling */
> +int xce_handle = -1;
> +
> +/* which vcpu we are serving */
> +int send_vcpu = 0;
> +
> +/* the evtchn port for polling the notification, */
> +evtchn_port_t *ioreq_local_port;
>
>   CPUXenState *cpu_xen_init(const char *cpu_model)
>   {
>       CPUXenState *env = NULL;
>       static int inited;
> +    int i, rc;
>
>       env = qemu_mallocz(sizeof(CPUXenState));
>       if (!env)
>           return NULL;
>       cpu_exec_init(env);
>
> +    /* There is no shared_page for PV, we're done now */
> +    if (shared_page == NULL)
> +        return env;
> +
> +    ioreq_local_port =
> +        (evtchn_port_t *)qemu_mallocz(smp_cpus * sizeof(evtchn_port_t));
> +    if (!ioreq_local_port)
> +        return NULL;
> +
>    

You don't need to check for NULL.  There's numerous CODING_STYLE issues 
in this file too (like C99 comments).

Regards,

Anthony Liguori

>       /* init various static tables */
>       if (!inited) {
>           inited = 1;
>
>           cpu_single_env = env;
> +
> +        xce_handle = xc_evtchn_open();
> +        if (xce_handle == -1) {
> +            perror("open");
> +            return NULL;
> +        }
> +
> +        /* FIXME: how about if we overflow the page here? */
> +        for (i = 0; i<  smp_cpus; i++) {
> +            rc = xc_evtchn_bind_interdomain(
> +                    xce_handle, xen_domid, shared_page->vcpu_ioreq[i].vp_eport);
> +            if (rc == -1) {
> +                fprintf(stderr, "bind interdomain ioctl error %d\n", errno);
> +                return NULL;
> +            }
> +            ioreq_local_port[i] = rc;
> +        }
>       }
>
>       return env;
> @@ -70,7 +122,317 @@ target_phys_addr_t cpu_get_phys_page_debug(CPUState *env, target_ulong addr)
>       return addr;
>   }
>
> +// get the ioreq packets from share mem
> +static ioreq_t *__cpu_get_ioreq(int vcpu)
> +{
> +    ioreq_t *req =&shared_page->vcpu_ioreq[vcpu];
> +
> +    if (req->state != STATE_IOREQ_READY) {
> +        fprintf(stderr, "I/O request not ready: "
> +                "%x, ptr: %x, port: %"PRIx64", "
> +                "data: %"PRIx64", count: %u, size: %u\n",
> +                req->state, req->data_is_ptr, req->addr,
> +                req->data, req->count, req->size);
> +        return NULL;
> +    }
> +
> +    xen_rmb(); /* see IOREQ_READY /then/ read contents of ioreq */
> +
> +    req->state = STATE_IOREQ_INPROCESS;
> +    return req;
> +}
> +
> +// use poll to get the port notification
> +// ioreq_vec--out,the
> +// retval--the number of ioreq packet
> +static ioreq_t *cpu_get_ioreq(void)
> +{
> +    int i;
> +    evtchn_port_t port;
> +
> +    port = xc_evtchn_pending(xce_handle);
> +    if (port != -1) {
> +        for ( i = 0; i<  smp_cpus; i++ )
> +            if ( ioreq_local_port[i] == port )
> +                break;
> +
> +        if ( i == smp_cpus ) {
> +            fprintf(stderr, "Fatal error while trying to get io event!\n");
> +            exit(1);
> +        }
> +
> +        // unmask the wanted port again
> +        xc_evtchn_unmask(xce_handle, port);
> +
> +        // get the io packet from shared memory
> +        send_vcpu = i;
> +        return __cpu_get_ioreq(i);
> +    }
> +
> +    // read error or read nothing
> +    return NULL;
> +}
> +
> +static unsigned long do_inp(CPUState *env, unsigned long addr,
> +        unsigned long size)
> +{
> +    switch(size) {
> +        case 1:
> +            return cpu_inb(addr);
> +        case 2:
> +            return cpu_inw(addr);
> +        case 4:
> +            return cpu_inl(addr);
> +        default:
> +            fprintf(stderr, "inp: bad size: %lx %lx\n", addr, size);
> +            exit(-1);
> +    }
> +}
> +
> +static void do_outp(CPUState *env, unsigned long addr,
> +        unsigned long size, unsigned long val)
> +{
> +    switch(size) {
> +        case 1:
> +            return cpu_outb(addr, val);
> +        case 2:
> +            return cpu_outw(addr, val);
> +        case 4:
> +            return cpu_outl(addr, val);
> +        default:
> +            fprintf(stderr, "outp: bad size: %lx %lx\n", addr, size);
> +            exit(-1);
> +    }
> +}
> +
> +static inline void read_physical(uint64_t addr, unsigned long size, void *val)
> +{
> +    return cpu_physical_memory_rw((target_phys_addr_t)addr, val, size, 0);
> +}
> +
> +static inline void write_physical(uint64_t addr, unsigned long size, void *val)
> +{
> +    return cpu_physical_memory_rw((target_phys_addr_t)addr, val, size, 1);
> +}
> +
> +static void cpu_ioreq_pio(CPUState *env, ioreq_t *req)
> +{
> +    int i, sign;
> +
> +    sign = req->df ? -1 : 1;
> +
> +    if (req->dir == IOREQ_READ) {
> +        if (!req->data_is_ptr) {
> +            req->data = do_inp(env, req->addr, req->size);
> +        } else {
> +            unsigned long tmp;
> +
> +            for (i = 0; i<  req->count; i++) {
> +                tmp = do_inp(env, req->addr, req->size);
> +                write_physical((target_phys_addr_t) req->data
> +                        + (sign * i * req->size),
> +                        req->size,&tmp);
> +            }
> +        }
> +    } else if (req->dir == IOREQ_WRITE) {
> +        if (!req->data_is_ptr) {
> +            do_outp(env, req->addr, req->size, req->data);
> +        } else {
> +            for (i = 0; i<  req->count; i++) {
> +                unsigned long tmp = 0;
> +
> +                read_physical((target_phys_addr_t) req->data
> +                        + (sign * i * req->size),
> +                        req->size,&tmp);
> +                do_outp(env, req->addr, req->size, tmp);
> +            }
> +        }
> +    }
> +}
> +
> +static void cpu_ioreq_move(CPUState *env, ioreq_t *req)
> +{
> +    int i, sign;
> +
> +    sign = req->df ? -1 : 1;
> +
> +    if (!req->data_is_ptr) {
> +        if (req->dir == IOREQ_READ) {
> +            for (i = 0; i<  req->count; i++) {
> +                read_physical(req->addr
> +                        + (sign * i * req->size),
> +                        req->size,&req->data);
> +            }
> +        } else if (req->dir == IOREQ_WRITE) {
> +            for (i = 0; i<  req->count; i++) {
> +                write_physical(req->addr
> +                        + (sign * i * req->size),
> +                        req->size,&req->data);
> +            }
> +        }
> +    } else {
> +        target_ulong tmp;
> +
> +        if (req->dir == IOREQ_READ) {
> +            for (i = 0; i<  req->count; i++) {
> +                read_physical(req->addr
> +                        + (sign * i * req->size),
> +                        req->size,&tmp);
> +                write_physical((target_phys_addr_t )req->data
> +                        + (sign * i * req->size),
> +                        req->size,&tmp);
> +            }
> +        } else if (req->dir == IOREQ_WRITE) {
> +            for (i = 0; i<  req->count; i++) {
> +                read_physical((target_phys_addr_t) req->data
> +                        + (sign * i * req->size),
> +                        req->size,&tmp);
> +                write_physical(req->addr
> +                        + (sign * i * req->size),
> +                        req->size,&tmp);
> +            }
> +        }
> +    }
> +}
> +
> +static void cpu_ioreq_timeoffset(CPUState *env, ioreq_t *req)
> +{
> +    char b[64];
> +
> +    time_offset += (unsigned long)req->data;
> +
> +    fprintf(stderr, "Time offset set %ld, added offset %"PRId64"\n",
> +            time_offset, req->data);
> +    sprintf(b, "%ld", time_offset);
> +    xenstore_vm_write(xen_domid, "rtc/timeoffset", b);
> +}
> +
> +static void __handle_ioreq(CPUState *env, ioreq_t *req)
> +{
> +    if (!req->data_is_ptr&&  (req->dir == IOREQ_WRITE)&&
> +            (req->size<  sizeof(target_ulong)))
> +        req->data&= ((target_ulong)1<<  (8 * req->size)) - 1;
> +
> +    switch (req->type) {
> +        case IOREQ_TYPE_PIO:
> +            cpu_ioreq_pio(env, req);
> +            break;
> +        case IOREQ_TYPE_COPY:
> +            cpu_ioreq_move(env, req);
> +            break;
> +        case IOREQ_TYPE_TIMEOFFSET:
> +            cpu_ioreq_timeoffset(env, req);
> +            break;
> +        case IOREQ_TYPE_INVALIDATE:
> +            qemu_invalidate_map_cache();
> +            break;
> +        default:
> +            hw_error("Invalid ioreq type 0x%x\n", req->type);
> +    }
> +}
> +
> +static void __handle_buffered_iopage(CPUState *env)
> +{
> +    buf_ioreq_t *buf_req = NULL;
> +    ioreq_t req;
> +    int qw;
> +
> +    if (!buffered_io_page)
> +        return;
> +
> +    while (buffered_io_page->read_pointer !=
> +            buffered_io_page->write_pointer) {
> +        buf_req =&buffered_io_page->buf_ioreq[
> +            buffered_io_page->read_pointer % IOREQ_BUFFER_SLOT_NUM];
> +        req.size = 1UL<<  buf_req->size;
> +        req.count = 1;
> +        req.addr = buf_req->addr;
> +        req.data = buf_req->data;
> +        req.state = STATE_IOREQ_READY;
> +        req.dir = buf_req->dir;
> +        req.df = 1;
> +        req.type = buf_req->type;
> +        req.data_is_ptr = 0;
> +        qw = (req.size == 8);
> +        if (qw) {
> +            buf_req =&buffered_io_page->buf_ioreq[
> +                (buffered_io_page->read_pointer+1) % IOREQ_BUFFER_SLOT_NUM];
> +            req.data |= ((uint64_t)buf_req->data)<<  32;
> +        }
> +
> +        __handle_ioreq(env,&req);
> +
> +        xen_mb();
> +        buffered_io_page->read_pointer += qw ? 2 : 1;
> +    }
> +}
> +
> +static void handle_buffered_io(void *opaque)
> +{
> +    CPUState *env = opaque;
> +
> +    __handle_buffered_iopage(env);
> +    qemu_mod_timer(buffered_io_timer, BUFFER_IO_MAX_DELAY +
> +                   qemu_get_clock(rt_clock));
> +}
> +
> +static void cpu_handle_ioreq(void *opaque)
> +{
> +    CPUState *env = opaque;
> +    ioreq_t *req = cpu_get_ioreq();
> +
> +    __handle_buffered_iopage(env);
> +    if (req) {
> +        __handle_ioreq(env, req);
> +
> +        if (req->state != STATE_IOREQ_INPROCESS) {
> +            fprintf(stderr, "Badness in I/O request ... not in service?!: "
> +                    "%x, ptr: %x, port: %"PRIx64", "
> +                    "data: %"PRIx64", count: %u, size: %u\n",
> +                    req->state, req->data_is_ptr, req->addr,
> +                    req->data, req->count, req->size);
> +            destroy_hvm_domain();
> +            return;
> +        }
> +
> +        xen_wmb(); /* Update ioreq contents /then/ update state. */
> +
> +        req->state = STATE_IORESP_READY;
> +        xc_evtchn_notify(xce_handle, ioreq_local_port[send_vcpu]);
> +    }
> +}
> +
>   void xen_main_loop_prepare(void)
>   {
> +    CPUState *env = cpu_single_env;
> +
> +    int evtchn_fd = xce_handle == -1 ? -1 : xc_evtchn_fd(xce_handle);
> +
> +    buffered_io_timer = qemu_new_timer(rt_clock, handle_buffered_io,
> +                                       cpu_single_env);
> +    qemu_mod_timer(buffered_io_timer, qemu_get_clock(rt_clock));
> +
> +    if (evtchn_fd != -1)
> +        qemu_set_fd_handler(evtchn_fd, cpu_handle_ioreq, NULL, env);
> +
>       xenstore_record_dm_state("running");
>   }
> +
> +void destroy_hvm_domain(void)
> +{
> +    xc_interface *xcHandle;
> +    int sts;
> +
> +    xcHandle = xc_interface_open(NULL, NULL, 0);
> +    if (xcHandle<  0)
> +        fprintf(stderr, "Cannot acquire xenctrl handle\n");
> +    else {
> +        sts = xc_domain_shutdown(xcHandle, xen_domid, SHUTDOWN_poweroff);
> +        if (sts != 0)
> +            fprintf(stderr, "? xc_domain_shutdown failed to issue poweroff, "
> +                    "sts %d, errno %d\n", sts, errno);
> +        else
> +            fprintf(stderr, "Issued domain %d poweroff\n", xen_domid);
> +        xc_interface_close(xcHandle);
> +    }
> +}
> diff --git a/target-xen/qemu-xen.h b/target-xen/qemu-xen.h
> index 091ae07..79a4638 100644
> --- a/target-xen/qemu-xen.h
> +++ b/target-xen/qemu-xen.h
> @@ -22,12 +22,14 @@ void     qemu_invalidate_map_cache(void);
>
>   /* target-xen/exec-dm.c */
>
> +void destroy_hvm_domain(void);
>   int cpu_register_io_memory_fixed(int io_index,
>                              CPUReadMemoryFunc * const *mem_read,
>                              CPUWriteMemoryFunc * const *mem_write,
>                              void *opaque);
>
>   /* target-xen/helper.c */
> +extern int xce_handle;
>   void xen_main_loop_prepare(void);
>
>   #endif /*QEMU_XEN_H*/
>