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authorDavid Woodhouse <dwmw@amazon.co.uk>2021-01-06 15:39:56 +0000
committerJuergen Gross <jgross@suse.com>2021-01-13 16:12:06 +0100
commitb36b0fe96af13460278bf9b173beced1bd15f85d (patch)
treef0f96ae68922154c71cf08bcb200cb10eeb34e4c /arch/x86/xen
parent8f4fd86aa5d6aa122619623910065d236592e37c (diff)
downloadlinux-b36b0fe96af13460278bf9b173beced1bd15f85d.tar.gz
x86/xen: Add xen_no_vector_callback option to test PCI INTX delivery
It's useful to be able to test non-vector event channel delivery, to make
sure Linux will work properly on older Xen which doesn't have it.

It's also useful for those working on Xen and Xen-compatible hypervisors,
because there are guest kernels still in active use which use PCI INTX
even when vector delivery is available.

Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Link: https://lore.kernel.org/r/20210106153958.584169-4-dwmw2@infradead.org
Signed-off-by: Juergen Gross <jgross@suse.com>
Diffstat (limited to 'arch/x86/xen')
-rw-r--r--arch/x86/xen/enlighten_hvm.c11
1 files changed, 10 insertions, 1 deletions
diff --git a/arch/x86/xen/enlighten_hvm.c b/arch/x86/xen/enlighten_hvm.c
index 9e87ab010c82..ec50b7423a4c 100644
--- a/arch/x86/xen/enlighten_hvm.c
+++ b/arch/x86/xen/enlighten_hvm.c
@@ -188,6 +188,8 @@ static int xen_cpu_dead_hvm(unsigned int cpu)
        return 0;
 }
 
+static bool no_vector_callback __initdata;
+
 static void __init xen_hvm_guest_init(void)
 {
 	if (xen_pv_domain())
@@ -207,7 +209,7 @@ static void __init xen_hvm_guest_init(void)
 
 	xen_panic_handler_init();
 
-	if (xen_feature(XENFEAT_hvm_callback_vector))
+	if (!no_vector_callback && xen_feature(XENFEAT_hvm_callback_vector))
 		xen_have_vector_callback = 1;
 
 	xen_hvm_smp_init();
@@ -233,6 +235,13 @@ static __init int xen_parse_nopv(char *arg)
 }
 early_param("xen_nopv", xen_parse_nopv);
 
+static __init int xen_parse_no_vector_callback(char *arg)
+{
+	no_vector_callback = true;
+	return 0;
+}
+early_param("xen_no_vector_callback", xen_parse_no_vector_callback);
+
 bool __init xen_hvm_need_lapic(void)
 {
 	if (xen_pv_domain())