[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [Xen-devel] [PATCH v2] xen/console: buffer and show origin of guest PV writes



On Mon, 2013-09-09 at 04:13 -0700, Keir Fraser wrote:
> On 16/08/2013 20:01, "Daniel De Graaf" <dgdegra@xxxxxxxxxxxxx> wrote:
> 
> > Guests other than domain 0 using the console output have previously been
> > controlled by the VERBOSE define, but with no designation of which
> > guest's output was on the console. This patch converts the HVM output
> > buffering to be used by all domains, line buffering their output and
> > prefixing it with the domain ID. This is especially useful for debugging
> > stub domains.
> > 
> > Signed-off-by: Daniel De Graaf <dgdegra@xxxxxxxxxxxxx>
> 
> This seems good, but, if we process and buffer dom0's output, we lose the
> possibility of running a terminal session in dom0 over the Xen console.
> Personally I do that quite a bit -- serial access only, get Xen's debugging
> there, but also can log in to dom0. Does noone else??

I think I do too, I'm more likely to on ARM as well since there is often
only a single debug serial port and no graphics.

Oh, doesn't code like:
> +        if ( is_hardware_domain(cd) )
> > +        {
> > +            /* Use direct console output as it could be interactive */
> > +            spin_lock_irq(&console_lock);
> > +
> > +            sercon_puts(kbuf);
> > +            video_puts(kbuf);

...mean that Daniel has already done the right thing for dom0 here?

> 
>  -- Keir
> 
> > ---
> > 
> > Changes since v1 (RFC):
> >  - Use prefix of (d%d) in place of (XEN) for both PV and HVM output
> >  - Guests other than dom0 have non-printable characters stripped
> >  - Use unsigned type for pbuf_idx
> >  - Formatting fixes
> > 
> >  xen/arch/x86/hvm/hvm.c           | 27 +++++-------
> >  xen/common/domain.c              |  8 ++++
> >  xen/drivers/char/console.c       | 94
> > ++++++++++++++++++++++++++++++++--------
> >  xen/include/asm-x86/hvm/domain.h |  6 ---
> >  xen/include/xen/lib.h            |  2 +
> >  xen/include/xen/sched.h          |  6 +++
> >  6 files changed, 103 insertions(+), 40 deletions(-)
> > 
> > diff --git a/xen/arch/x86/hvm/hvm.c b/xen/arch/x86/hvm/hvm.c
> > index 1fcaed0..4ff76cc 100644
> > --- a/xen/arch/x86/hvm/hvm.c
> > +++ b/xen/arch/x86/hvm/hvm.c
> > @@ -485,8 +485,7 @@ static int hvm_set_ioreq_page(
> >  static int hvm_print_line(
> >      int dir, uint32_t port, uint32_t bytes, uint32_t *val)
> >  {
> > -    struct vcpu *curr = current;
> > -    struct hvm_domain *hd = &curr->domain->arch.hvm_domain;
> > +    struct domain *cd = current->domain;
> >      char c = *val;
> >  
> >      BUG_ON(bytes != 1);
> > @@ -495,17 +494,16 @@ static int hvm_print_line(
> >      if ( !isprint(c) && (c != '\n') && (c != '\t') )
> >          return X86EMUL_OKAY;
> >  
> > -    spin_lock(&hd->pbuf_lock);
> > -    hd->pbuf[hd->pbuf_idx++] = c;
> > -    if ( (hd->pbuf_idx == (HVM_PBUF_SIZE - 2)) || (c == '\n') )
> > +    spin_lock(&cd->pbuf_lock);
> > +    if ( c != '\n' )
> > +        cd->pbuf[cd->pbuf_idx++] = c;
> > +    if ( (cd->pbuf_idx == (DOMAIN_PBUF_SIZE - 1)) || (c == '\n') )
> >      {
> > -        if ( c != '\n' )
> > -            hd->pbuf[hd->pbuf_idx++] = '\n';
> > -        hd->pbuf[hd->pbuf_idx] = '\0';
> > -        printk(XENLOG_G_DEBUG "HVM%u: %s", curr->domain->domain_id,
> > hd->pbuf);
> > -        hd->pbuf_idx = 0;
> > +        cd->pbuf[cd->pbuf_idx] = '\0';
> > +        guest_printk(cd, XENLOG_G_DEBUG "%s\n", cd->pbuf);
> > +        cd->pbuf_idx = 0;
> >      }
> > -    spin_unlock(&hd->pbuf_lock);
> > +    spin_unlock(&cd->pbuf_lock);
> >  
> >      return X86EMUL_OKAY;
> >  }
> > @@ -521,19 +519,16 @@ int hvm_domain_initialise(struct domain *d)
> >          return -EINVAL;
> >      }
> >  
> > -    spin_lock_init(&d->arch.hvm_domain.pbuf_lock);
> >      spin_lock_init(&d->arch.hvm_domain.irq_lock);
> >      spin_lock_init(&d->arch.hvm_domain.uc_lock);
> >  
> >      INIT_LIST_HEAD(&d->arch.hvm_domain.msixtbl_list);
> >      spin_lock_init(&d->arch.hvm_domain.msixtbl_list_lock);
> >  
> > -    d->arch.hvm_domain.pbuf = xzalloc_array(char, HVM_PBUF_SIZE);
> >      d->arch.hvm_domain.params = xzalloc_array(uint64_t, HVM_NR_PARAMS);
> >      d->arch.hvm_domain.io_handler = xmalloc(struct hvm_io_handler);
> >      rc = -ENOMEM;
> > -    if ( !d->arch.hvm_domain.pbuf || !d->arch.hvm_domain.params ||
> > -         !d->arch.hvm_domain.io_handler )
> > +    if ( !d->arch.hvm_domain.params || !d->arch.hvm_domain.io_handler )
> >          goto fail0;
> >      d->arch.hvm_domain.io_handler->num_slot = 0;
> >  
> > @@ -578,7 +573,6 @@ int hvm_domain_initialise(struct domain *d)
> >   fail0:
> >      xfree(d->arch.hvm_domain.io_handler);
> >      xfree(d->arch.hvm_domain.params);
> > -    xfree(d->arch.hvm_domain.pbuf);
> >      return rc;
> >  }
> >  
> > @@ -603,7 +597,6 @@ void hvm_domain_relinquish_resources(struct domain *d)
> >  
> >      xfree(d->arch.hvm_domain.io_handler);
> >      xfree(d->arch.hvm_domain.params);
> > -    xfree(d->arch.hvm_domain.pbuf);
> >  }
> >  
> >  void hvm_domain_destroy(struct domain *d)
> > diff --git a/xen/common/domain.c b/xen/common/domain.c
> > index 6c264a5..daac2c9 100644
> > --- a/xen/common/domain.c
> > +++ b/xen/common/domain.c
> > @@ -231,6 +231,8 @@ struct domain *domain_create(
> >      spin_lock_init(&d->shutdown_lock);
> >      d->shutdown_code = -1;
> >  
> > +    spin_lock_init(&d->pbuf_lock);
> > +
> >      err = -ENOMEM;
> >      if ( !zalloc_cpumask_var(&d->domain_dirty_cpumask) )
> >          goto fail;
> > @@ -286,6 +288,10 @@ struct domain *domain_create(
> >          d->mem_event = xzalloc(struct mem_event_per_domain);
> >          if ( !d->mem_event )
> >              goto fail;
> > +
> > +        d->pbuf = xzalloc_array(char, DOMAIN_PBUF_SIZE);
> > +        if ( !d->pbuf )
> > +            goto fail;
> >      }
> >  
> >      if ( (err = arch_domain_create(d, domcr_flags)) != 0 )
> > @@ -318,6 +324,7 @@ struct domain *domain_create(
> >      d->is_dying = DOMDYING_dead;
> >      atomic_set(&d->refcnt, DOMAIN_DESTROYED);
> >      xfree(d->mem_event);
> > +    xfree(d->pbuf);
> >      if ( init_status & INIT_arch )
> >          arch_domain_destroy(d);
> >      if ( init_status & INIT_gnttab )
> > @@ -730,6 +737,7 @@ static void complete_domain_destroy(struct rcu_head 
> > *head)
> >  #endif
> >  
> >      xfree(d->mem_event);
> > +    xfree(d->pbuf);
> >  
> >      for ( i = d->max_vcpus - 1; i >= 0; i-- )
> >          if ( (v = d->vcpu[i]) != NULL )
> > diff --git a/xen/drivers/char/console.c b/xen/drivers/char/console.c
> > index 8ac32e4..b8d9a9f 100644
> > --- a/xen/drivers/char/console.c
> > +++ b/xen/drivers/char/console.c
> > @@ -24,6 +24,7 @@
> >  #include <xen/shutdown.h>
> >  #include <xen/video.h>
> >  #include <xen/kexec.h>
> > +#include <xen/ctype.h>
> >  #include <asm/debugger.h>
> >  #include <asm/div64.h>
> >  #include <xen/hypercall.h> /* for do_console_io */
> > @@ -375,6 +376,7 @@ static long
> > guest_console_write(XEN_GUEST_HANDLE_PARAM(char) buffer, int count)
> >  {
> >      char kbuf[128];
> >      int kcount;
> > +    struct domain *cd = current->domain;
> >  
> >      while ( count > 0 )
> >      {
> > @@ -388,19 +390,60 @@ static long
> > guest_console_write(XEN_GUEST_HANDLE_PARAM(char) buffer, int count)
> >              return -EFAULT;
> >          kbuf[kcount] = '\0';
> >  
> > -        spin_lock_irq(&console_lock);
> > +        if ( is_hardware_domain(cd) )
> > +        {
> > +            /* Use direct console output as it could be interactive */
> > +            spin_lock_irq(&console_lock);
> > +
> > +            sercon_puts(kbuf);
> > +            video_puts(kbuf);
> >  
> > -        sercon_puts(kbuf);
> > -        video_puts(kbuf);
> > +            if ( opt_console_to_ring )
> > +            {
> > +                conring_puts(kbuf);
> > +                tasklet_schedule(&notify_dom0_con_ring_tasklet);
> > +            }
> >  
> > -        if ( opt_console_to_ring )
> > +            spin_unlock_irq(&console_lock);
> > +        }
> > +        else
> >          {
> > -            conring_puts(kbuf);
> > -            tasklet_schedule(&notify_dom0_con_ring_tasklet);
> > +            char *kin = kbuf;
> > +            char *kout = kbuf;
> > +            char c;
> > +            /* Strip non-printable characters */
> > +            for ( ; ; )
> > +            {
> > +                c = *kin++;
> > +                if ( c == '\0' || c == '\n' )
> > +                    break;
> > +                if ( isprint(c) || c == '\t' )
> > +                    *kout++ = c;
> > +            }
> > +            *kout = '\0';
> > +            spin_lock(&cd->pbuf_lock);
> > +            if ( c == '\n' )
> > +            {
> > +                kcount = kin - kbuf;
> > +                cd->pbuf[cd->pbuf_idx] = '\0';
> > +                guest_printk(cd, XENLOG_G_DEBUG "%s%s\n", cd->pbuf, kbuf);
> > +                cd->pbuf_idx = 0;
> > +            }
> > +            else if ( cd->pbuf_idx + kcount < (DOMAIN_PBUF_SIZE - 1) )
> > +            {
> > +                /* buffer the output until a newline */
> > +                memcpy(cd->pbuf + cd->pbuf_idx, kbuf, kcount);
> > +                cd->pbuf_idx += kcount;
> > +            }
> > +            else
> > +            {
> > +                cd->pbuf[cd->pbuf_idx] = '\0';
> > +                guest_printk(cd, XENLOG_G_DEBUG "%s%s\n", cd->pbuf, kbuf);
> > +                cd->pbuf_idx = 0;
> > +            }
> > +            spin_unlock(&cd->pbuf_lock);
> >          }
> >  
> > -        spin_unlock_irq(&console_lock);
> > -
> >          guest_handle_add_offset(buffer, kcount);
> >          count -= kcount;
> >      }
> > @@ -504,12 +547,12 @@ static int printk_prefix_check(char *p, char **pp)
> >              ((loglvl < upper_thresh) && printk_ratelimit()));
> >  } 
> >  
> > -static void printk_start_of_line(void)
> > +static void printk_start_of_line(const char *prefix)
> >  {
> >      struct tm tm;
> >      char tstr[32];
> >  
> > -    __putstr("(XEN) ");
> > +    __putstr(prefix);
> >  
> >      if ( !opt_console_timestamps )
> >          return;
> > @@ -524,12 +567,11 @@ static void printk_start_of_line(void)
> >      __putstr(tstr);
> >  }
> >  
> > -void printk(const char *fmt, ...)
> > +static void vprintk_common(const char *prefix, const char *fmt, va_list 
> > args)
> >  {
> >      static char   buf[1024];
> >      static int    start_of_line = 1, do_print;
> >  
> > -    va_list       args;
> >      char         *p, *q;
> >      unsigned long flags;
> >  
> > @@ -537,9 +579,7 @@ void printk(const char *fmt, ...)
> >      local_irq_save(flags);
> >      spin_lock_recursive(&console_lock);
> >  
> > -    va_start(args, fmt);
> >      (void)vsnprintf(buf, sizeof(buf), fmt, args);
> > -    va_end(args);
> >  
> >      p = buf;
> >  
> > @@ -551,7 +591,7 @@ void printk(const char *fmt, ...)
> >          if ( do_print )
> >          {
> >              if ( start_of_line )
> > -                printk_start_of_line();
> > +                printk_start_of_line(prefix);
> >              __putstr(p);
> >              __putstr("\n");
> >          }
> > @@ -566,7 +606,7 @@ void printk(const char *fmt, ...)
> >          if ( do_print )
> >          {
> >              if ( start_of_line )
> > -                printk_start_of_line();
> > +                printk_start_of_line(prefix);
> >              __putstr(p);
> >          }
> >          start_of_line = 0;
> > @@ -576,6 +616,26 @@ void printk(const char *fmt, ...)
> >      local_irq_restore(flags);
> >  }
> >  
> > +void printk(const char *fmt, ...)
> > +{
> > +    va_list args;
> > +    va_start(args, fmt);
> > +    vprintk_common("(XEN) ", fmt, args);
> > +    va_end(args);
> > +}
> > +
> > +void guest_printk(struct domain *d, const char *fmt, ...)
> > +{
> > +    va_list args;
> > +    char prefix[16];
> > +
> > +    snprintf(prefix, sizeof(prefix), "(d%d) ", d->domain_id);
> > +
> > +    va_start(args, fmt);
> > +    vprintk_common(prefix, fmt, args);
> > +    va_end(args);
> > +}
> > +
> >  void __init console_init_preirq(void)
> >  {
> >      char *p;
> > @@ -791,7 +851,7 @@ int __printk_ratelimit(int ratelimit_ms, int
> > ratelimit_burst)
> >              snprintf(lost_str, sizeof(lost_str), "%d", lost);
> >              /* console_lock may already be acquired by printk(). */
> >              spin_lock_recursive(&console_lock);
> > -            printk_start_of_line();
> > +            printk_start_of_line("(XEN) ");
> >              __putstr("printk: ");
> >              __putstr(lost_str);
> >              __putstr(" messages suppressed.\n");
> > diff --git a/xen/include/asm-x86/hvm/domain.h
> > b/xen/include/asm-x86/hvm/domain.h
> > index 27b3de5..b1e3187 100644
> > --- a/xen/include/asm-x86/hvm/domain.h
> > +++ b/xen/include/asm-x86/hvm/domain.h
> > @@ -62,12 +62,6 @@ struct hvm_domain {
> >      /* emulated irq to pirq */
> >      struct radix_tree_root emuirq_pirq;
> >  
> > -    /* hvm_print_line() logging. */
> > -#define HVM_PBUF_SIZE 80
> > -    char                  *pbuf;
> > -    int                    pbuf_idx;
> > -    spinlock_t             pbuf_lock;
> > -
> >      uint64_t              *params;
> >  
> >      /* Memory ranges with pinned cache attributes. */
> > diff --git a/xen/include/xen/lib.h b/xen/include/xen/lib.h
> > index 74b34eb..40afe12 100644
> > --- a/xen/include/xen/lib.h
> > +++ b/xen/include/xen/lib.h
> > @@ -83,6 +83,8 @@ extern void debugtrace_printk(const char *fmt, ...);
> >  #define _p(_x) ((void *)(unsigned long)(_x))
> >  extern void printk(const char *format, ...)
> >      __attribute__ ((format (printf, 1, 2)));
> > +extern void guest_printk(struct domain *d, const char *format, ...)
> > +    __attribute__ ((format (printf, 2, 3)));
> >  extern void panic(const char *format, ...)
> >      __attribute__ ((format (printf, 1, 2)));
> >  extern long vm_assist(struct domain *, unsigned int, unsigned int);
> > diff --git a/xen/include/xen/sched.h b/xen/include/xen/sched.h
> > index ae6a3b8..0013a8d 100644
> > --- a/xen/include/xen/sched.h
> > +++ b/xen/include/xen/sched.h
> > @@ -341,6 +341,12 @@ struct domain
> >      /* Control-plane tools handle for this domain. */
> >      xen_domain_handle_t handle;
> >  
> > +    /* hvm_print_line() and guest_console_write() logging. */
> > +#define DOMAIN_PBUF_SIZE 80
> > +    char       *pbuf;
> > +    unsigned    pbuf_idx;
> > +    spinlock_t  pbuf_lock;
> > +
> >      /* OProfile support. */
> >      struct xenoprof *xenoprof;
> >      int32_t time_offset_seconds;
> 
> 
> 
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@xxxxxxxxxxxxx
> http://lists.xen.org/xen-devel



_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
http://lists.xen.org/xen-devel


 


Rackspace

Lists.xenproject.org is hosted with RackSpace, monitoring our
servers 24x7x365 and backed by RackSpace's Fanatical Support®.