Re: [PATCH 09/24] xen/arm: compile and run xenbus

On Thu, Jul 26, 2012 at 04:33:51PM +0100, Stefano Stabellini wrote:

bind_evtchn_to_irqhandler can legitimately return 0 (irq 0): it is not an error.

If Linux is running as an HVM domain and is running as Dom0, use xenstored_local_init to initialize the xenstore page and event channel.

Signed-off-by: Stefano Stabellini stefano.stabellini@eu.citrix.com

drivers/xen/xenbus/xenbus_comms.c | 2 +- drivers/xen/xenbus/xenbus_probe.c | 27 +++++++++++++++++---------- drivers/xen/xenbus/xenbus_xs.c | 1 + 3 files changed, 19 insertions(+), 11 deletions(-)

diff --git a/drivers/xen/xenbus/xenbus_comms.c b/drivers/xen/xenbus/xenbus_comms.c index 52fe7ad..c5aa55c 100644 --- a/drivers/xen/xenbus/xenbus_comms.c +++ b/drivers/xen/xenbus/xenbus_comms.c @@ -224,7 +224,7 @@ int xb_init_comms(void) int err; err = bind_evtchn_to_irqhandler(xen_store_evtchn, wake_waiting, 0, "xenbus", &xb_waitq);

• if (err <= 0) {
  

• if (err < 0) {
  printk(KERN_ERR "XENBUS request irq failed %i\n", err);
  return err;
  

  }

diff --git a/drivers/xen/xenbus/xenbus_probe.c b/drivers/xen/xenbus/xenbus_probe.c index b793723..3ae47c2 100644 --- a/drivers/xen/xenbus/xenbus_probe.c +++ b/drivers/xen/xenbus/xenbus_probe.c @@ -729,16 +729,23 @@ static int __init xenbus_init(void) xenbus_ring_ops_init(); if (xen_hvm_domain()) {

• uint64_t v = 0;
  

• err = hvm_get_parameter(HVM_PARAM_STORE_EVTCHN, &v);
  

• if (err)
  

• 	goto out_error;
  

• xen_store_evtchn = (int)v;
  

• err = hvm_get_parameter(HVM_PARAM_STORE_PFN, &v);
  

• if (err)
  

• 	goto out_error;
  

• xen_store_mfn = (unsigned long)v;
  

• xen_store_interface = ioremap(xen_store_mfn << PAGE_SHIFT, PAGE_SIZE);
  

• if (xen_initial_domain()) {
  

• 	err = xenstored_local_init();
  

• 	xen_store_interface =
  

• 		phys_to_virt(xen_store_mfn << PAGE_SHIFT);
  

• } else {
  

• 	uint64_t v = 0;
  

• 	err = hvm_get_parameter(HVM_PARAM_STORE_EVTCHN, &v);
  

• 	if (err)
  

• 		goto out_error;
  

• 	xen_store_evtchn = (int)v;
  

• 	err = hvm_get_parameter(HVM_PARAM_STORE_PFN, &v);
  

• 	if (err)
  

• 		goto out_error;
  

• 	xen_store_mfn = (unsigned long)v;
  

• 	xen_store_interface =
  

• 		ioremap(xen_store_mfn << PAGE_SHIFT, PAGE_SIZE);
  

• }
  

This, and along with the Hybrid PV dom0 (not yet posted, but it was doing similar manipulation here) is getting more and more like a rat-mess.

Any chance we can just abstract the three different XenStore access ways and just have something like this:

enum { USE_UNKNOWN USE_HVM, USE_PV, USE_LOCAL USE_ALREADY_INIT }; int usage = USE_UNKNOWN; if (xen_pv_domain()) usage = USE_PV; if (xen_hvm_domain()) usage = USE_HVM; if (xen_initial_domain()) usage = USE_LOCAL;

if (xen_start_info->store_evtchn) usage = USE_ALREADY_INIT; .. other overwrites..

switch (usage) { .. blah blah. }

xen_store_evtchn = xen_start_info->store_evtchn;
xen_store_mfn = xen_start_info->store_mfn;

diff --git a/drivers/xen/xenbus/xenbus_xs.c b/drivers/xen/xenbus/xenbus_xs.c index d1c217b..f7feb3d 100644 --- a/drivers/xen/xenbus/xenbus_xs.c +++ b/drivers/xen/xenbus/xenbus_xs.c @@ -44,6 +44,7 @@ #include <linux/rwsem.h> #include <linux/module.h> #include <linux/mutex.h> +#include <asm/xen/hypervisor.h> #include <xen/xenbus.h> #include <xen/xen.h>

#include "xenbus_comms.h"

1.7.2.5