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# HG changeset patch
# User kfraser@localhost.localdomain
# Date 1186395374 -3600
# Node ID b82e6818fb31c6373ccd3e840ef2f9719d5f21a3
# Parent e1435c1f3382069ca5044808b3233bda8b09d150
hvm: Fix PV-on-HVM drivers to not execuite hypercall page while it is
being re-initialised.
Signed-off-by: Edwin Zhai <edwin.zhai@intel.com>
---
unmodified_drivers/linux-2.6/platform-pci/machine_reboot.c | 10 ++++++++++
1 files changed, 10 insertions(+)

diff -r e1435c1f3382 -r b82e6818fb31 unmodified_drivers/linux-2.6/platform-pci/machine_reboot.c
--- a/unmodified_drivers/linux-2.6/platform-pci/machine_reboot.c Mon Aug 06 11:08:57 2007 +0100
+++ b/unmodified_drivers/linux-2.6/platform-pci/machine_reboot.c Mon Aug 06 11:16:14 2007 +0100
@@ -10,6 +10,12 @@ struct ap_suspend_info {
int do_spin;
atomic_t nr_spinning;
};
+
+/*
+ * Use a rwlock to protect the hypercall page from being executed in AP context
+ * while the BSP is re-initializing it after restore.
+ */
+static DEFINE_RWLOCK(suspend_lock);

/*
* Spinning prevents, for example, APs touching grant table entries while
@@ -27,7 +33,9 @@ static void ap_suspend(void *_info)

while (info->do_spin) {
cpu_relax();
+ read_lock(&suspend_lock);
HYPERVISOR_yield();
+ read_unlock(&suspend_lock);
}

mb();
@@ -43,7 +51,9 @@ static int bp_suspend(void)
suspend_cancelled = HYPERVISOR_shutdown(SHUTDOWN_suspend);

if (!suspend_cancelled) {
+ write_lock(&suspend_lock);
platform_pci_resume();
+ write_unlock(&suspend_lock);
gnttab_resume();
irq_resume();
}

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