Commit a3607581 authored by Henry Wang's avatar Henry Wang Committed by Juergen Gross
Browse files

drivers/xen: Improve the late XenStore init protocol 



Currently, the late XenStore init protocol is only triggered properly
for the case that HVM_PARAM_STORE_PFN is ~0ULL (invalid). For the
case that XenStore interface is allocated but not ready (the connection
status is not XENSTORE_CONNECTED), Linux should also wait until the
XenStore is set up properly.

Introduce a macro to describe the XenStore interface is ready, use
it in xenbus_probe_initcall() to select the code path of doing the
late XenStore init protocol or not. Since now we have more than one
condition for XenStore late init, rework the check in xenbus_probe()
for the free_irq().

Take the opportunity to enhance the check of the allocated XenStore
interface can be properly mapped, and return error early if the
memremap() fails.

Fixes: 5b335394 ("xen: add support for initializing xenstore later as HVM domain")
Signed-off-by: default avatarHenry Wang <xin.wang2@amd.com>
Signed-off-by: default avatarMichal Orzel <michal.orzel@amd.com>
Reviewed-by: default avatarStefano Stabellini <sstabellini@kernel.org>
Link: https://lore.kernel.org/r/20240517011516.1451087-1-xin.wang2@amd.com


Signed-off-by: default avatarJuergen Gross <jgross@suse.com>
parent 89af61fb

drivers/xen/xenbus/xenbus_probe.c

+23 −13
Original line number Diff line number Diff line
@@ -65,13 +65,17 @@ 
#include "xenbus.h"





static int xs_init_irq;

static int xs_init_irq = -1;

int xen_store_evtchn;

EXPORT_SYMBOL_GPL(xen_store_evtchn);



struct xenstore_domain_interface *xen_store_interface;

EXPORT_SYMBOL_GPL(xen_store_interface);



#define XS_INTERFACE_READY \

	((xen_store_interface != NULL) && \

	 (xen_store_interface->connection == XENSTORE_CONNECTED))



enum xenstore_init xen_store_domain_type;

EXPORT_SYMBOL_GPL(xen_store_domain_type);
@@ -751,7 +755,7 @@ static void xenbus_probe(void) 
{

	xenstored_ready = 1;



	if (!xen_store_interface) {

	if (!xen_store_interface)

		xen_store_interface = memremap(xen_store_gfn << XEN_PAGE_SHIFT,

					       XEN_PAGE_SIZE, MEMREMAP_WB);

	/*
@@ -762,8 +766,8 @@ static void xenbus_probe(void) 
	 * being called and the event channel not being enabled again

	 * afterwards, resulting in missed event notifications.

	 */

	if (xs_init_irq >= 0)

		free_irq(xs_init_irq, &xb_waitq);

	}



	/*

	 * In the HVM case, xenbus_init() deferred its call to
@@ -822,7 +826,7 @@ static int __init xenbus_probe_initcall(void) 
	if (xen_store_domain_type == XS_PV ||

	    (xen_store_domain_type == XS_HVM &&

	     !xs_hvm_defer_init_for_callback() &&

	     xen_store_interface != NULL))

	     XS_INTERFACE_READY))

		xenbus_probe();



	/*
@@ -831,7 +835,7 @@ static int __init xenbus_probe_initcall(void) 
	 * started, then probe.  It will be triggered when communication

	 * starts happening, by waiting on xb_waitq.

	 */

	if (xen_store_domain_type == XS_LOCAL || xen_store_interface == NULL) {

	if (xen_store_domain_type == XS_LOCAL || !XS_INTERFACE_READY) {

		struct task_struct *probe_task;



		probe_task = kthread_run(xenbus_probe_thread, NULL,
@@ -1014,6 +1018,12 @@ static int __init xenbus_init(void) 
			xen_store_interface =

				memremap(xen_store_gfn << XEN_PAGE_SHIFT,

					 XEN_PAGE_SIZE, MEMREMAP_WB);

			if (!xen_store_interface) {

				pr_err("%s: cannot map HVM_PARAM_STORE_PFN=%llx\n",

				       __func__, v);

				err = -EINVAL;

				goto out_error;

			}

			if (xen_store_interface->connection != XENSTORE_CONNECTED)

				wait = true;

		}