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From b58fb6e81bd55b6bd946abc3070770f7994c9ef9 Mon Sep 17 00:00:00 2001
From: Jason Andryuk <jandryuk@gmail.com>
Date: Tue, 7 Jun 2022 13:55:39 +0200
Subject: [PATCH 02/51] x86/irq: skip unmap_domain_pirq XSM during destruction
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
xsm_unmap_domain_irq was seen denying unmap_domain_pirq when called from
complete_domain_destroy as an RCU callback. The source context was an
unexpected, random domain. Since this is a xen-internal operation,
going through the XSM hook is inapproriate.
Check d->is_dying and skip the XSM hook when set since this is a cleanup
operation for a domain being destroyed.
Suggested-by: Roger Pau Monné <roger.pau@citrix.com>
Signed-off-by: Jason Andryuk <jandryuk@gmail.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Roger Pau Monné <roger.pau@citrix.com>
master commit: 2e6f95a942d1927a53f077c301db0b799c54c05a
master date: 2022-04-08 14:51:52 +0200
---
xen/arch/x86/irq.c | 10 ++++++++--
1 file changed, 8 insertions(+), 2 deletions(-)
diff --git a/xen/arch/x86/irq.c b/xen/arch/x86/irq.c
index 67cbf6b979dc..47b86af5dce9 100644
--- a/xen/arch/x86/irq.c
+++ b/xen/arch/x86/irq.c
@@ -2342,8 +2342,14 @@ int unmap_domain_pirq(struct domain *d, int pirq)
nr = msi_desc->msi.nvec;
}
- ret = xsm_unmap_domain_irq(XSM_HOOK, d, irq,
- msi_desc ? msi_desc->dev : NULL);
+ /*
+ * When called by complete_domain_destroy via RCU, current is a random
+ * domain. Skip the XSM check since this is a Xen-initiated action.
+ */
+ if ( !d->is_dying )
+ ret = xsm_unmap_domain_irq(XSM_HOOK, d, irq,
+ msi_desc ? msi_desc->dev : NULL);
+
if ( ret )
goto done;
--
2.35.1
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