From mboxrd@z Thu Jan 1 00:00:00 1970 From: Keir Fraser Subject: Re: [PATCH v2] xen/console: buffer and show origin of guest PV writes Date: Mon, 09 Sep 2013 04:13:42 -0700 Message-ID: References: <1376679706-2896-1-git-send-email-dgdegra@tycho.nsa.gov> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1376679706-2896-1-git-send-email-dgdegra@tycho.nsa.gov> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: Daniel De Graaf Cc: Andrew Cooper , JBeulich@suse.com, xen-devel@lists.xen.org List-Id: xen-devel@lists.xenproject.org On 16/08/2013 20:01, "Daniel De Graaf" 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 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?? -- 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 > #include > #include > +#include > #include > #include > #include /* 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;