linux-kernel - [PATCH] xen/pvh: don't try to unplug emulated devices

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Date:   Thu, 25 Oct 2018 09:54:15 +0200
From:   Juergen Gross <jgross@...e.com>
To:     linux-kernel@...r.kernel.org, xen-devel@...ts.xenproject.org
Cc:     boris.ostrovsky@...cle.com, sstabellini@...nel.org,
        Juergen Gross <jgross@...e.com>, stable@...r.kernel.org
Subject: [PATCH] xen/pvh: don't try to unplug emulated devices

A Xen PVH guest has no associated qemu device model, so trying to
unplug any emulated devices is making no sense at all.

Bail out early from xen_unplug_emulated_devices() when running as PVH
guest. This will avoid issuing the boot message:

[    0.000000] Xen Platform PCI: unrecognised magic value

Cc: <stable@...r.kernel.org> # 4.11
Signed-off-by: Juergen Gross <jgross@...e.com>
---
 arch/x86/xen/platform-pci-unplug.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/arch/x86/xen/platform-pci-unplug.c b/arch/x86/xen/platform-pci-unplug.c
index 66ab96a4e2b3..96d7f7d39cb9 100644
--- a/arch/x86/xen/platform-pci-unplug.c
+++ b/arch/x86/xen/platform-pci-unplug.c
@@ -134,6 +134,10 @@ void xen_unplug_emulated_devices(void)
 {
 	int r;
 
+	/* PVH guests don't have emulated devices. */
+	if (xen_pvh_domain())
+		return;
+
 	/* user explicitly requested no unplug */
 	if (xen_emul_unplug & XEN_UNPLUG_NEVER)
 		return;
-- 
2.16.4