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[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(¬ify_dom0_con_ring_tasklet);
> > + }
> >
> > - if ( opt_console_to_ring )
> > + spin_unlock_irq(&console_lock);
> > + }
> > + else
> > {
> > - conring_puts(kbuf);
> > - tasklet_schedule(¬ify_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;
>
>
>
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