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drivers/xen: Improve the late XenStore init protocol

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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: 5b3353949e ("xen: add support for initializing xenstore later as HVM domain")
Signed-off-by: Henry Wang <xin.wang2@amd.com>
Signed-off-by: Michal Orzel <michal.orzel@amd.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
Link: https://lore.kernel.org/r/20240517011516.1451087-1-xin.wang2@amd.com
Signed-off-by: Juergen Gross <jgross@suse.com>
This commit is contained in:
Henry Wang 2024-05-17 09:15:16 +08:00 committed by Juergen Gross
parent 89af61fb8f
commit a3607581cd
1 changed files with 23 additions and 13 deletions
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36
drivers/xen/xenbus/xenbus_probe.c
View File

@ -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);
@ -751,19 +755,19 @@ 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);
/*
* Now it is safe to free the IRQ used for xenstore late
* initialization. No need to unbind: it is about to be
* bound again from xb_init_comms. Note that calling
* unbind_from_irqhandler now would result in xen_evtchn_close()
* being called and the event channel not being enabled again
* afterwards, resulting in missed event notifications.
*/
/*
* Now it is safe to free the IRQ used for xenstore late
* initialization. No need to unbind: it is about to be
* bound again from xb_init_comms. Note that calling
* unbind_from_irqhandler now would result in xen_evtchn_close()
* 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;
}